GENERATOR

FIELD OF THE DISCLOSED SUBJECT MATTER

This subject matter of the present application relates to energy generating systems, more particularly, systems adapted for the generation of electrical energy utilizing heating/cooling and corresponding expansion/compression of a material. BACKGROUND OF THE DISCLOSED SUBJECT MATTER

Generation of electrical power is a process in which one form of energy is converted into electricity, and a great plurality of processes is known and used today for performing the same. Some of these processes involve turning one form of energy into mechanical energy allowing the movement/rotation of a mechanical element within a magnetic field for the generation of electricity.

Some of these processes are as follows:

burning coal in order to turn water into steam and allowing the steam to expand within and revolve a turbine, the turbine being the mechanical element;

- using solar energy in order to turn water into steam and implementing the same;

using the power of a waterfall for driving a turbine;

burning gas within a combustion chamber to drive a piston (for example in an internal combustion engine);

In addition, there also exist processes for the generation of electricity which rely on the compression/expansion of a medium, entailing reciprocation/movement of a mechanical element. In some of these processes, compression/expansion of the medium is performed by heating/cooling thereof. Such systems are disclosed, for example, in the following publications: GB1536437, WO2009064378A2, US2008236166A1, US2005198960A1, US2006059912A1 etc.

SUMMARY OF THE DISCLOSED SUBJECT MATTER

According to the subject matter of the present application, there is provided a generator configured for extracting heat from and medium, and utilizing said heat in a process for the generation electrical energy. In particular, said heat can be utilized for reciprocating/rotating a mechanical element for the generation of said electricity.

According to one aspect of the subject matter of the present application, there is provided a generator comprising a heat differential module configured for providing a first reservoir and a second reservoir having a temperature difference therebetween, a pressure module containing a pressure medium configured for performing an alternate heat exchange process with the reservoirs of the heat differential module so as to fluctuate its temperature, and a conversion module configured to utilize the fluctuation of the pressure module for the generation of energy.

In particular, said generator can comprise:

a heat differential module comprising at least:

o a first, high temperature reservoir configured for containing a work medium at high temperature and being in selective thermal communication with the pressure medium of said pressure module; o a second, low temperature reservoir configured for containing a work medium at low temperature and being in selective thermal communication with the pressure medium of said pressure module; and

o a heat mechanism configured for maintaining a temperature difference between the reservoirs;

a pressure module comprising a pressure medium configured for alternately performing a heat exchange process with the high/low temperature work medium so as to fluctuate its temperature between a minimal operative temperature and a maximal operative temperature corresponding to the high and low temperature of the reservoirs; the pressure medium being in mechanical communication with the conversion module so as to operate it a conversion module configured for converting temperature fluctuation of the pressure medium into output energy; and

a heat recovery arrangement configured transferring heat from the pressure module back to the heat differential module or to the pressure module.

It is appreciated that the term 'medium' is used herein to describe any of the following: solids, fluids - liquids and gasses. For example, the pressure medium can even be a solid, or, for example, even a substance which solidifies under pressure.

It is also appreciated that the terms 'high' and 'low' temperature refer to two different temperatures, TH and Tc (can also be referred to herein as T _L ), so that TH > To According to different examples, the temperatures TH and Tc can vary as follows:

both TH and Tc are above ambient temperature;

both T _H and Tc are below ambient temperature; and

- TH is above ambient temperature and Tc is below ambient temperature. The term 'ambient is used herein to define the average temperature of the external environment in which at least the heat differential module of the generator is located. In particular, while in general this environment is simply ambient air, the generator can also be configured to be immersed in any desired medium, whereby the term 'ambient will refer to the average temperature of that medium.

The heat differential module can be constituted by a work medium sub-system comprising the high temperature reservoir and the low temperature reservoir. In particular, each of the high/low temperature reservoirs can be provided with an inlet line configured for providing selective fluid communication between the reservoirs and an inlet access end of the pressure module, and an outlet line configured for providing selective fluid communication between an outlet access end of the pressure module and the reservoirs.

The respective inlet/outlet lines of the heat differential module are configured for alternately providing high/low temperature work medium to the pressure module so as to perform a heat exchange process with the pressure medium.

The work medium sub-system can comprise a heat pump having an evaporator end and a condenser end, the heat pump being configured for withdrawing an amount of heat Q from the evaporator end towards the condenser end under the provision thereto of input power W. As a result of operation of the heat pump, the condenser end is constantly provided with heat, so that the temperature of the condenser end exceeds that of the evaporator end.

The arrangement is such that at least one of the high temperature reservoir and the low temperature reservoir is thermally associated with one of said evaporator end and condenser end of the heat pump. For example, the high temperature reservoir can be thermally associated with the condenser end of the heat pump and/or the low temperature reservoir can be associated with the evaporator end of the heat pump. Thus, the heat pump can operate as a cooling unit to maintain the low temperature reservoir at a desired 'low' temperature, while heat expelled from the air heat pump during cooling is used to maintain the high temperature reservoir at a desired 'high' temperature.

Thermal association between the evaporator/condenser end of the heat pump and the high/low temperature reservoir can be achieved via direct/indirect contact between the evaporator/condenser end of the heat pump and the work medium contained within the high/low temperature reservoir, allowing for a heat exchange process between the former and the latter. According to a specific example, such contact is achieved via emersion of the evaporator/condenser end of the heat pump within the high/low work medium.

According to one specific design, the high temperature reservoir is in direct thermal communication with the condenser side of the heat pump while the low temperature reservoir is associated with the outside environment (i.e. exposed to ambient temperature). According to a specific example of this design, the low temperature reservoir, though exposed to the outside environment can also be fitted with an element providing thermal association of the low temperature reservoir with the evaporator end of the heat pump.

According to another design, the high temperature reservoir is in direct thermal communication with the condenser side of the heat pump while the low temperature reservoir is in direct thermal communication with the evaporator side of the heat pump.

The pressure module can comprise a vessel containing the pressure medium and at least one conduit (referred herein as 'conduit' or 'core') having an inlet end and an outlet end, constituting the respective inlet and outlet access ends of the pressure module. Thus, said conduit can be configured for being in selective fluid communication with said high/low temperature reservoirs, to allow passage of high/low temperature work medium therethrough. The generator is configured such that high/low temperature work medium can be alternatively passed through the conduit of the vessel (using selective fluid communication with the reservoirs) so as to perform a heat-exchange process with the pressure medium. Thus, the high temperature work medium is used to bring the pressure medium to said maximal operative temperature and said low temperature work medium is used to bring said pressure medium to said minimal operative temperature.

As a result, the pressure medium is configured to fluctuate between a maximal operative temperature and a minimum operative temperature thereof, said fluctuation causing a respective increase/decrease of the volume of said pressure medium, which can be utilized by the conversion module for the production of energy.

With respect to the pressure module, the following features can be used (individually or in combination with one another):

? the vessel can be a pressure vessel in which the pressure medium is preloaded to constitute a high-pressure medium. The advantages of pre-loading the pressure medium will become apparent when discussing the operation of the generator in further detail;

? the vessel can comprise more than one cores passing therethrough, each being configured for selective fluid communication with reservoirs of the heat differential module;

? the cores can be in selective fluid communication with one another, so as to allow them to assume at least a first, linear configuration in which the cores form a long single flow path for the work medium and a second, parallel configuration in which the cores are configured for simultaneous flow of work medium therein;

? the core/s can be made of materials having high resistance to compression/pressure forces, a low heat capacity and high heat transfer coefficient. For example, such materials can be Silicon Carbide, Tungsten Carbide, Titanium etc.;

? the length L of the pressure vessel can be considerably longer than a diameter D thereof, whereby several supports may be require within the pressure vessel to support the cores passing therethrough;

? the pressure vessel can comprise one or more cores which are co-aligned, having connection points at the supports; ? at least one of the cores can be fitted with a dissipation arrangement being in contact with the pressure medium and configured for increasing the efficiency of heat transfer into the pressure medium, consequently increasing the efficiency of the heat exchange process between the work medium and the pressure medium;

? the dissipation arrangement can be integral with the core or can be a separate arrangement fitted thereto. In the former case, the core can be formed with increased surface area in the form of ribs/spikes or the like, and in the latter case the core can be fitted with at least one dissipation member mounted thereon (e.g. ribs/wings/blades etc.);

? one or more cores can be configured for revolving about their own axis, or all the cores can be configured to revolve about a mutual axis (e.g. a central axis of the pressure vessel;

? the separate dissipation arrangement can also be configured to revolve about the cores on which it is mounted;

? the separate dissipation arrangement can be configured to be driven by a motor. The arrangement may also be such that the dissipation arrangements of several cores are simultaneously driven by a single motor;

? the motor driving the dissipation arrangement can be located outside the pressure vessel;

? a drive shaft of the motor can be configured to extend from both sides of the pressure vessel, and even be driven by two motors, one engaged with the drive shaft at each end. It is appreciated that is the drive shaft only protrudes from one end of the pressure vessel, i.e. having its second end within the pressure vessel, the pressure within the vessel can apply a great load on the drive shaft attempting to push it out of the pressure vessel. This effect may be so severe that the drive shaft is in danger of being 'shot out' of the vessel;

? each core can also be fitted with an inner arrangement configured for increasing heat transfer within the work medium, thereby increasing the efficiency of the heat exchange process between the pressure medium and the work medium; ? according to one example, the inner arrangement can be a static arrangement, i.e. simply located within the core. According to another example, the inner arrangement can be a dynamic arrangement configured for displacing/revolving within the core so as to circulate the work medium passing through the core;

? the inner arrangement can also be configured for actively displacing the work medium along the core (e.g. similar to an Archimedes' screw);

? for relatively long pressure vessels, the pressure vessel can comprise two or more cores which are co-linearly connected with one another, and also be provided with sealed supports at the junction points between two adjacent cores;

? the pressure medium within said vessel can be pre-loaded and contained under pressure in the range of 2000-8000 atm., more particularly of 3000- 7500 atm., even more particularly of 4000-7000 atm. and ever more particularly of 5000-6500 atm. It is appreciated that providing suitable materials from which the pressure vessel is made, even higher pre-loading of the pressure medium is possivle;

? the pressure medium can have a heat expansion coefficient in the range of 100-1200, more particularly of 250-1100, even more particularly of 500- 1000 and ever more particularly of 600-900; and

? the pressure medium can be selected from a group of: Ethyl Bromide, water,

N-Pentene, Diethyl ether, Methanol, Ethanol, Mercury and acids. In addition, at least one or more of the components of the generator through which a heat transfer process takes place (e.g. cylinders, tubes, surfaces etc.) can be formed with a heat transferring surface which has an increased surface area. Specifically, said surface can be formed with a plurality of elements increasing its surface area, e.g. bulges, protrusions etc. According to one particular example, the elements can be micro-structures having geometric shapes such as cubes, pyramids, cones etc. According to another example, the elements can be ridges (either parallel or spiraling).

In the latter case, such ridge elements yield that in cross-section of the pipes taken along a central axis thereof, the surface appears undulating (between peaks and troughs). In case the ridges are formed both on the internal and on the external surface of the pipe, the arrangement can be such that a peak on the inner surface faces a trough on the outer surface and vise verse, thereby maintaining a generally constant material thickness in each cross-section perpendicular to the central axis.

It is appreciated that whereas pre-forming an outer surface of a cylindrical component (as mentioned above) with said micro-structures is fairly simple, preforming an inner surface of said cylindrical component poses a more complex problem. For this purpose, the steps of a method for pre-forming an inner surface of a cylindrical component with micro-structures are presented below:

(a) providing a generally planar plate having a first face and an opposite second face;

(b) pre-forming said micro-structures on said first face;

(c) providing a mold formed with a non-through going cavity corresponding in size and shape to said plate, said cavity having a base surface and an opening at a surface of the mold;

(d) placing said plate in said cavity such that said second face is mated against said base surface and said first faces facing the opening of the cavity, such that there remains a space between said first face and said opening; (e) introducing a filler material into the cavity so as to fill said space, including spaced formed between the micro-structures;

(f) letting said filler material solidify so as to form a single plate constituted by said plate and solidified filler material, having a first face constituted by said filler material and a second face constituted by the second face of the original plate;

(g) deforming said single plate to obtain at least a partially cylindrical shape, such that the second face of said single plate constitutes and outer surface of said cylinder and the first face of said single plate constituted an inner surface of said cylinder;

(h) removing said filler material from said single plate, thereby resulting in the original plate having micro-structures formed on the inner surface thereof; and

(i) performing a final finish on the inner surface with the micro-structures.

The conversion module of the generator can comprise a dynamic arrangement being in mechanical communication with the pressure medium so as to be driven thereby. In particular, the dynamic arrangement can comprise a movable member configured to reciprocate in correspondence with the fluctuation of the pressure medium from said maximal operative temperature and said minimal operative temperature.

According to a specific example, the dynamic arrangement can be constituted by a piston assembly, comprising a housing with a piston located therein, the piston sealingly dividing the housing into a first, input chamber being in mechanical communication with the pressure medium and the second, output chamber being in mechanical communication with a motor assembly configured for generating output energy.

The piston of the conversion module can be configured for reciprocating within the housing respective to volumetric fluctuations of the pressure medium. Specifically, as the temperature of the pressure medium increases, its volume increases correspondingly, thereby displacing the piston so that the volume of the input chamber increases and the volume of the output chamber decreases. Respectively, as the temperature of the pressure medium decreases, its volume decreases correspondingly, thereby displacing the piston so that the volume of the input chamber decreases and the volume of the output chamber increases. This reciprocation can be used by the motor assembly for the production of output energy.

According to one example, the motor assembly comprises a crank shaft arrangement so that reciprocation of the piston is configured for generating revolution of the crank shaft about is axis. This revolution can be converted, by known means, for the production of output energy.

According to another example, the piston can be associated with a linear shaft which is configured to be meshed with a gear assembly, which in turn is configured for converting the linear reciprocation of the shaft into rotational movement. This rotational movement can be converted, by known means, for the production of output energy.

According to a specific design embodiment, there can be provided an intermediary device between the piston and the motor, for example, the piston can be adapted to drive a utility piston via pressure on an intermediary substance such as oil.

The generator of the present application can further comprise at least one auxiliary heat exchanger which is in thermal communication at least with one of the outlet lines of the high temperature reservoir and the low temperature reservoir. The heat exchanger can be configured for performing a heat exchange process between the work medium within said outlet lines and the outside environment and/or a medium in which the heat exchanger is immersed.

Thus, the heat exchanger can be configured to respectively cool down / heat up the work medium heated up / cooled down during the heat exchange process with the pressure medium of the pressure module, upon its exit from the pressure vessel.

Several examples of various constructional configurations of the generator, as well as methods for operation of each configuration will now be described, in some of which configurations the generator may comprise additional elements, members, modules and/or arrangements. It should be appreciated that while each configuration may be used independently, different features of the various configurations can also be combined together to produce new configurations of the generator.

Basic configuration

According to a basic configuration of the above described generator, the heat differential module comprises a high temperature reservoir which is in thermal communication with a condenser end of a heat pump, and a low temperature reservoir which is in thermal communication with the outside environment.

It is appreciated that under this configuration, the evaporator end of the heat pump is also exposed to the outside environment, so that, in operation, the evaporator end constantly withdrawn heat from the environment, and the heat pump constantly withdrawn heat from the evaporator end to the condenser end.

The pressure module comprises a single pressure vessel containing therein a pressure medium which is pre-loaded to high pressure (approx. 6000 atm.), and having at least one conduit passing therethrough. The pressure vessel is further provided with an inlet valve associated with an inlet end of the conduit and an outlet valve associated with an outlet end of the conduit. The pressure vessel can also be provided with an output line which is in fluid communication with a dynamic arrangement of the conversion module.

Each of the high/low temperature reservoirs comprises an inlet line providing selective fluid communication between the reservoir and the inlet valve and an outlet line providing selective fluid communication between the reservoir and the outlet valve.

There is thus provided a method for generating output energy using the generator of the above example, said method comprising the steps of: a) selectively opening the inlet and outlet valve to provide fluid communication between the high temperature reservoir and the pressure vessel and passing high temperature work medium from the high temperature reservoir into inlet valve, through the conduit and out of the outlet valve back into the high temperature reservoir. As a result of a heat exchange process between the high temperature work medium and the pressure medium, the former cools down while the latter heats up to a maximal operative temperature thereof. When heating up, the pressure medium increases its volume and causes displacement of the piston in one direction; and

b) selectively opening the inlet and outlet valve to provide fluid communication between the low temperature reservoir and the pressure vessel and passing low temperature work medium from the low temperature reservoir into inlet valve, through conduit and out of the outlet valve back into the low temperature reservoir. As a result of a heat exchange process between the low temperature work medium and the pressure medium, the former heats up while the latter cools down to a minimal operative temperature. When cooling down, the pressure medium decreases in volume and causes displacement of the piston in an opposite direction.

Performing the above steps repeatedly provides reciprocation of the piston back and forth, thereby allowing generation of electricity by the generator.

It is pointed out that higher the pressure of the high-pressure medium, the more efficient the thermodynamic operation of the generator (providing that mechanical integrity of the generator is maintained). More specifically, the piston has a predetermined resistance which requires a predetermined threshold pressure of the high- pressure medium to overcome this resistance and displace the piston. In the event a low- pressure medium is used, heating thereof will first result in a pressure increase of the low-pressure medium to the threshold pressure and only then displacement of the piston.

In light of the above, pre-loading the medium within the pressure vessel to a high pressure (exceeding that of the threshold pressure) ensures that upon heating of the pressure medium will directly entail displacement of the piston and will not go to waste for pressuring the medium to the threshold pressure.

The following should also be noted: - when returning to the high temperature reservoir, the cooled down high temperature work medium can be free to absorb further heat from the condenser end of the heat pump so as to bring it back to its original high temperature;

- when returning to the low temperature reservoir, the heated up low temperature work medium can emit at least some heat into the outside environment so as to cool down and bring its temperature back to its original low temperature;

- when switching from step (a) to step (b) and depending on the length of the conduit, it can be beneficial, after the selective switching of the position of inlet valve to provide fluid communication with the low temperature reservoir, to delay selective switching of the position of the outlet valve to provide fluid communication with the low temperature reservoir. In this way, upon beginning the performing of step (b), the high temperature work medium contained within the conduit can be first be pushed through its outlet line into the high temperature reservoir, and only then will the outlet valve be selectively switched to provide fluid communication with the low temperature reservoir. The same holds true when switching from step (b) to step (a);

The above method can further include an additional step (c) in which the heated up low temperature work medium is passed through the auxiliary heat exchanger in order to allow more efficient emission of heat from the work medium to the outside environment.

Direct recovery configuration

According to the above configuration, the outlet line of the low temperature reservoir is not returned directly back into the low temperature reservoir upon exiting the pressure vessel, but rather is first passed through the evaporator end of the heat pump. In this manner, instead of its heat being emitted to the environment and reabsorbed by the heat pump at the evaporator end, it is directly returned to the evaporator end of the heat pump, thereby increasing the efficiency of the operation of the generator.

Cooled reservoir configuration According to the above configuration of the generator is shown demonstrating a cooled reservoir arrangement in which the first, high temperature reservoir is in thermal communication with the condenser end of the heat pump (as in previous examples), while the low temperature reservoir is in thermal communication with the evaporator end of the heat pump.

Under the above arrangement, the low temperature work medium recovers a partial amount of heat from the pressure medium upon a heat exchange process therewith, and a remaining amount of heat from the environment to provide an overall amount of heat from the evaporator end to the condenser end of the heat pump HP.

Dual operation

The generator can comprise two pressure vessels, each of which is connected to the high and the low temperature reservoir via corresponding inlet/outlet valves. In addition, the pressure medium of each of the pressure vessels is in fluid mechanical communication with a respective piston.

Using two pressure vessels allows for at least two modes of operation of the generator:

a) simultaneous cycle - both the pressure vessels perform steps (a) and

(b) above in parallel. In other words, at any time point throughout the generator cycle, the temperature of the pressure medium in one pressure vessel is similar to that of the pressure medium in the other pressure vessel, i.e. both pressure mediums heat up simultaneously and cool down simultaneously. Under this arrangement, the generator can be provided with two motor assemblies, each being driven by its respective piston;

b) alternating cycle - the pressure vessels perform steps (a) and (b) at an offset, e.g. when one pressure vessel performs step (a) of the cycle, the other pressure vessel performs step (b) of the cycle. In other words, when the pressure medium in one pressure vessel undergoes heating, the pressure medium in the other pressure vessel undergoes cooling and vise versa. Under this arrangement, the generator can be provided with one motor assembly, which is driven by two pistons (i.e. both pistons can reciprocate in synchronization with one another).

Intermediate reservoir configuration Under the above configuration, the generator can comprise three reservoirs: a high temperature reservoir, a low temperature reservoir and an intermediate temperature reservoir. This arrangement is based on the cooled reservoir configuration, wherein an additional intermediate reservoir is added containing intermediate temperature work medium. The intermediate temperature reservoir is configured to contain an intermediate temperature work medium, the term 'intermediate' referring to a temperature between said high temperature and said low temperature. Each of the high/intermediate/low temperature reservoirs is in selective fluid communication with the pressure vessel.

Under this arrangement, two additional steps (a') and (b') are performed on top of steps (a) and (b) described with respect to the basic configuration, as follows:

(a') [performed after step (a)] passing intermediate temperature work medium from the intermediate temperature reservoir through the conduit of the pressure vessel, thereby reducing the temperature of the pressure medium (via heat exchange process therewith) from the maximal operative temperature to an intermediate operative temperature (between the maximal operative temperature and the minimal operative temperature); and

(b') [performed after step (b)] passing intermediate temperature work medium from the intermediate temperature reservoir is passed through the conduit of the pressure vessel, thereby increasing the temperature of the pressure medium (via heat exchange process therewith) from the minimal operative temperature to an intermediate operative temperature (between the maximal operative temperature and the minimal operative temperature).

Specifically, during steps (a') and (b ¹ ) above, the intermediate temperature work medium is used for cooling/heating of the pressure medium between the cooling/heating thereof by high/low temperature work medium respectively. Thus, each cooling/heating step is divided into two stages, the first being performed by intermediate work medium and the second being performed by high/low work medium.

Under the above arrangement, it is appreciated that the high/low temperature work medium is practically used to provide heating/cooling within a reduced temperature range (i.e. between intermediate and high and/or between intermediate and low), thereby making the operation of the generator more effective. With respect to the above arrangement, it is appreciated that the intermediate temperature reservoir can be in thermal communication with the outside environment, while the high/low temperature reservoirs are in thermal communication with the condenser/evaporator ends of the heat pump respectively.

In addition, any one of the outlet lines of the high/intermediate/low temperature reservoirs can be passed through the auxiliary heat exchanger upon exiting the pressure vessel. According to a particular example of this arrangement, the intermediate outlet line can pass through the auxiliary heat exchanger so as to respectively convey to/absorb from the atmosphere the required amount of heat gained/lost during the heat exchange process with the pressure medium before returning to its reservoir. To the contrary, the outlet lines of the high/low temperature reservoirs can return the work medium directly to its respective reservoir without necessarily passing through the heat exchanger.

Cross-over configuration

According to the above configuration, the generator comprises two pressure vessels (similar to the dual operation arrangement), and each of the outlet valve is also in selective fluid communication with the inlet valves.

Specifically, each outlet valve O is also provided with a cross-over line COL which provides fluid communication between the outlet valve of one pressure vessel and the inlet valve of the other pressure vessel. Under this arrangement, it is possible to perform additional cross-over steps as explained below:

(a") [performed after step (a')] in which the intermediate work medium WM, upon exiting the conduit of one pressure vessel PV is provided, via cross-over line COL to the inlet valve of the other pressure vessel PV in order to begin heating the pressure medium therein and only then back to the intermediate temperature reservoir via the other outlet valve; and

(b") [performed after step (b')] in which the intermediate work medium WM, upon exiting the conduit of one pressure vessel PV is provided, via cross-over line COL to the inlet valve of the other pressure vessel PV in order to begin cooling the pressure medium therein and only then back to the intermediate temperature reservoir via the other outlet valve.

The above arrangement provides for a more significant heat recovery from the pressure medium. More specifically, instead of emitting/withdrawing a certain amount of heat to/from the environment during its return to the intermediate temperature reservoir, the intermediate temperature work medium now emits/withdraws a portion of that amount of heat in a heat exchange with the pressure medium, thereby increasing the efficiency of the generator.

Heat gradient recovery configuration

Under the above configuration, the generator also comprises one pressure vessel (similar to the basic arrangement), and at least one gradient tank associated with the outlet valve.

The gradient tank can comprise an arrangement configured for preventing mixing of portions of work medium contained therein, thereby considerably reducing heat transfer between the portions and the speed with which these portions reach a thermal equilibrium. In particular, the gradient tank, when used in the present generator, can contain a first portion of work medium at a temperature Tl, a second portion of work medium at temperature T2 and so forth so that Tl≠T2≠ and so forth.

Specifically, under operation of the generator as will now be explained, the gradient tank allows for maintaining the work medium contained therein at a temperature gradient so that Tl > T2 > .... > Tn, or alternatively, Tl < T2 < .... < Tn.

Thus, the portions of the heated/cooled intermediate temperature work medium entering the gradient tank have different temperatures, and, as will be explained in detail later, it can be beneficial to maintain a temperature gradient between these portions within the gradient tanks. For this purpose, the gradient tank can further comprise a non-mix mechanism, configured for maintaining a temperature gradient within the reservoir by preventing different portions of the work medium from mixing with one another. In other words, the non-mix mechanism is configured for slowing down the work medium received within the gradient tank from reaching a uniform temperature.

The non-mix mechanism can be any mechanism formed with a flow path such that the cross-sectional area for heat transfer between consecutive portions of the work medium entering the gradient tank is small enough to considerably slow down the heat transfer. The term 'small enough' refers to a cross-sectional area defined by a nominal cross-sectional dimension D which is considerably smaller than the length L of the path.

Examples of such a non-mix mechanism can be:

a long tube of length L and cross-sectional D « L;

a spiraling tube having similar characteristics; a spiraling surface located within the reservoir so as to form a flow path of the above properties; and

a confining labyrinth formed with a plurality of flow paths, each adhering to the above properties.

In all of the above examples, the flow path can be made out of a material having isolating properties, i.e. having poor heat conduction. One example for such a material can be plastic.

In operation, several additional steps are added to the basic operation steps (a) and (b) as explained with respect to the basic configuration, as follows:

(b ^m ) [performed before step (b)] in which low temperature work medium is passed through the conduit of the pressure vessel to be heated via a heat exchange process with the pressure medium, but instead of being returned to the low temperature reservoir is introduced into the gradient tank. It is appreciated that the first portion of the low temperature work medium to exit the pressure vessel with reach the gradient at a higher temperature than the last portion (as the pressure medium gradually cools down during this heat exchange process). The design of the gradient tank allows maintaining these portions each at their own respective temperature, so that eventually, the uppermost portion in the gradient tank is the of the highest temperature while the lower-most portion in the gradient tank is the of the lowest temperature.

(b"") [performed after step (b)] in which the work medium in the gradient tank is re-circulated back through the pressure vessel in a LIFO (Last In First Out) order, thereby gradually heating up the pressure medium to an intermediate temperature, and only then commencing step (a) of the operation.

In essence, these steps of the operation of the generator describe a "stair operation in which the work medium WM in the gradient tank is held therein (stalled) until the right time, and then released into the piping of the generator to perform the required heat exchange process.

It is appreciated that each portion of the intermediate temperature work medium passing through the heated/cooled pressure vessel is emitted therefrom having a different temperature. For example, if operation of the system is observed in a quantified manner, when the intermediate temperature work medium of temperature T INTERMEDIATE begins circulating through the heated pressure vessel containing the pressure medium at the high temperature THOT > INTERMEDIATE, the first portion of the intermediate temperature work medium will be emitted from the pressure vessel at a temperature Τ _Η οτ such that T!NTERMEDIATE < HOT' < Τ _Η οτ, the second portion of the work medium will be emitted from the pressure vessel at a temperature THOT", such that TINTERMEDIATE < Τ _Η οτ" < ΤΗΟΤ' < HOT etc. A similar process occurs with the intermediate temperature work medium passing through the cooled pressure vessel, only T INTERMEDIATE > T COLD" > TCOLD' > TCOLD- The temperatures THOT, TINTERMEDIATE and TCOLD correspond to the high/intermediate/low temperature of the work medium in the respective high/intermediate/low temperature reservoirs.

The above arrangement provide for another way of performing heat recovery in the generator, thereby further increasing its efficiency. It is also appreciated that the use of the LIFO configuration allows the pressure medium to be gradually heated (starting from the lowest temperature portion first), making better use of the amount of heat of each portion of the work medium.

It is also appreciated that the gradient tank can be used both for the heated low temperature work medium and the cooled high temperature work medium. According to specific examples as will be described in detail later, the generator can comprise more than one gradient tank. For example, each pressure vessel can be provided with its own gradient tank and/or gradient tanks are provided for high/low temperature work medium.

According to a specific arrangement, the heat gradient recovery configuration can be combined with the dual operation configuration, wherein the operation of the generator can be described as follows:

At a first stage, similar to the previously described example (without gradient tanks), high temperature work medium at temperature THOT is passed through one pressure vessel to heat up the pressure medium contained therein, while, simultaneously, low temperature work medium at temperature TCOLD is passed through the other pressure vessel to cool down the pressure medium contained therein. After this stage, the pressure medium in one pressure vessel is heated up to a temperature Τ _Η οτ' < THOT and the pressure medium in the other pressure vessel is cooled down to a temperature T _C OLD' > T _C OLD-

Thereafter, a return step is performed, during which intermediate temperature work medium at temperature TINTERMEDIATE is passed through both pressure vessels in order to cool down / heat up the pressure medium therein. Specifically, the intermediate temperature work medium passing through the heated pressure vessel performs a heat transfer process with the latter and cools it down to a temperature closer to TINTERMEDIATE, while the intermediate temperature work medium passing through the cooled pressure vessel performs a heat transfer process with the latter and heats it up to a temperature closer to TINTERMEDIATE (however, not reaching TINTERMEDIATE).

However, contrary to the previous example in which the intermediate temperature work medium, after passing through the pressure vessels was returned back to the intermediate reservoir via the radiator, in the present example, the intermediate temperature work medium flows into the gradient tanks in a two-beat sequence.

During the first beat of the sequence, the first portion of the heated intermediate temperature work medium to exit the pressure vessel is at a temperature THEATED such that Tt TER EDiATE < THEATED < THOT', the second portion of the work medium will be emitted from the pressure vessel at a temperature THOT' such that TINTERMEDIATE < THEATED' < THEATED < THOT' etc. The heated work medium is passed into the gradient tank of its respective pressure vessel such that the gradient tank contains therein the different portions of the heated work medium and maintains a temperature gradient therebetween.

Simultaneously, the first portion of the cooled intermediate temperature work medium to exit the pressure vessel is at a temperature TCOOLED such that TINTERMEDIATE > TCOOLED > ΤςοοιΛ the second portion of the work medium will be emitted from the pressure vessel at a temperature TCOOLED' such that TINTERMEDIATE > TCOOLED' > TCOOLED > TCOOL' etc. The cooled work medium is passed into the gradient tank of its respective pressure vessel such that the gradient tank contains therein the different portions of the cooled work medium and maintains a temperature gradient therebetween.

In any case, it is important to note that since the heated pressure medium within the heated pressure vessel never reaches TINTERMEDIATE during this step, the intermediate temperature work medium passing therethrough also never leaves the pressure vessel at a temperature TINTERMEDIATE, but rather always slightly hotter. In other words, each portion of the heated intermediate temperature work medium is at a temperature THEATED" such that T^TERMEDIATE < THEATED" < Τ _Η οτ· At the same time, since the cooled pressure medium within the cooled pressure vessel also never reaches TINTERMEDIATE during this step, the intermediate temperature work medium passing therethrough also never leaves the pressure vessel at a temperature TINTERMEDIATE, but rather always slightly cooler. In other words, each portion of the cooled intermediate temperature work medium is at a temperature TCOOLED" such that TIN _TERMED IATE > TCOOLED" > TCOOL- Due to the non-mix mechanism in each of the gradient tanks, the work medium in each of the gradient tanks is maintained with a temperature gradient, slowing down mixing between the different portions of the heated/cooled intermediate temperature work medium.

When the first beat of the sequence is complete, the majority of each of the gradient tanks is filled with a heated/cooled intermediate temperature work medium at a varying temperature across the reservoir. At this point, the second beat of the sequence is performed, also referred to as the cross-over step:

work medium from the gradient tank of the heated pressure vessel (i.e. the gradient tank containing the heated intermediate temperature work medium used during the first beat) is passed through the opposite (cooled) pressure vessel containing the pressure medium previously cooled down by the low temperature work medium to a temperature TCOLD , and work medium from the gradient tank of the cooled pressure vessel (i.e. the gradient tank containing the cooled intermediate temperature work medium used during the first beat) is passed through the opposite pressure vessel containing the pressure medium previously heated up by the high temperature work medium to a temperature ΤΗΟΤ'·

In addition, the work medium from the gradient tanks flows to the opposite pressure vessels in a First In Last Out (FILO) order, i.e. the last portion of the heated up intermediate temperature work medium to enter the gradient tank (which is also the coolest portion of the heated intermediate temperature work medium) will be the first portion to be passed through the opposite pressure vessel. In this way, the temperature of the work medium passed through the now low/high temperature pressure vessel during the cross-over step constantly and gradually increases/decreases.

It is noted that the even the coolest portion of the heated up work medium is at a temperature THOT" > TINTERMEDIATE ^> TCOLD', and even the hottest portion of the cooled down intermediate temperature work medium is at a temperature TCOLD" < TINTERMEDIATE < Τ _Η οτ'· Therefore, it is appreciated that the temperature difference between the cooled/heated pressure medium TCOLD'/ΤΗΟΤ' and the coolest/hottest portion of the heated/cooled intermediate temperature work medium THOT"/TCOLD" is much greater than the previous temperature difference between the former and the intermediate temperature work medium at I NTERMEDIATE-

It is also noted that one of the reason for performing the cross-over step at a LIFO order is that if a First In First Out (FIFO) order were used, the hottest/coolest portion of the heated/cooled intermediate temperature work medium would perform such an intense heat transfer process with the pressure medium that the coolest/hottest portion of the heated/cooled intermediate temperature work medium would have little effect on the heat transfer process. Using LIFO order allows better utilization of each portion of the work medium.

During the above step (switch step), a heat transfer takes place between the heated up intermediate temperature work medium and the cooled pressure medium resulting in an average temperature of the cooled down pressure medium which is relatively TAV_C ⁼ (TCOLD' + THEATED")/2. Simultaneously, a heat transfer takes place between the cooled down intermediate temperature work medium and the heated pressure medium resulting in an average temperature of the cooled down pressure medium which is relatively T _A V_H ⁼ (ΤΗΟΤ' + TCOOLED")/2.

It should be noted that due to the temperature difference discussed above (i.e. TINTERMEDIATE < THEATED" < HOT' and TINTERMEDIATE > TCOOLED" > TCOLD' the temperatures TAV_C and T _A V_H are hotter/cooler than a corresponding average temperature TAV_C' and T _A V_H' that would have been achieved if only intermediate temperature work medium at TINTERMEDIATE was used to cool/heat the pressure medium.

After the pressure mediums of both pressure vessels finish the heat transfer process and reach the temperatures of TAV_C and TAV_H, the main cycle (steps (I) and (III)) repeats itself but with high temperature work medium now flowing to the previously cooled pressure vessel and the low temperature work medium now flowing to the previously heated pressure vessel.

The switch step thus provides an improvement over the previously described example of the generator allowing for a more efficient heat transfer process with the pressure medium, so that the heated/cooled pressure medium returns, after heating/cooling to a temperature much closer to TINTERMEDIATE, and can even reach a temperature which is lower/higher than TINTERMEDIATE-

In both beats of the sequence, intermediate temperature work medium (although not necessarily at temperature TINTERMEDIATE) is passed through the radiator, allowing it to perform a heat transfer process with the outside environment (usually ambient air but can be any other medium in which the radiator is immersed).

Throughout the operation of the generator, due to thermodynamic performance of the work medium and pressure medium, the generator constantly produces heat, which is, in turn, emitted to the ambient environment through the radiator. More particularly, the arrangement is such that the increase in temperature of the heated intermediate temperature work medium is slightly greater than the decrease in temperature of the cooled intermediate temperature work medium. This difference in increase/decrease is expressed by slight overheating of the intermediate temperature work medium, i.e. excess heat being generated. However, it is compensated by the eviction of the excess heat via the radiator.

It should also be noted that the entire generator, and more particularly, all the piping of the generator configured for passing high/low/intermediate temperature work medium is always under constant pressure (i.e. there is always work medium present in each section of the pipe, whether circulating or not). Thus, in an initial position of the system, the gradient tanks contain therein intermediate temperature water (i.e. water at temperature TI _NT ERMEDIATE)- During the first beat of the sequence, when heated/cooled intermediate temperature work medium enters the gradient tanks, the work medium previously contained therein is emitted and re-circulated back into the auxiliary storage reservoir containing intermediate temperature work medium at temperature

TlNTERMEDIATE-

During the switch step (second beat of the sequence), in order to pump the work medium contained in the gradient tanks into the proper pressure vessels, intermediate temperature work medium is circulated into the gradient tanks, thus pushing the heated/cooled intermediate temperature work medium out of the reservoir and into the desired pressure vessel. It is noted that during the second beat of the sequence, the reservoirs (high/low/intermediate) are shut off from the circulating fluid so that, in fact, only intermediate temperature work medium is circulated through the piping of the generator.

The generator can also comprise one or more thermostats configure for providing control over high/low/intermediate temperature work medium as well as heated/cooled pressure medium. For example, the thermostat/s can be configured for maintaining the intermediate temperature work medium at a temperature generally equal to that of the ambient environment (air, water etc.) the generator is surrounded by.

Accumulator configuration

According to the above configuration, the generator can further comprise an accumulator unit containing a storage work medium. The accumulator unit is provided with a heating arrangement which is configured to be operated by output power provided by the generator.

The accumulator unit can be in selective fluid communication with the pressure vessel via corresponding inlet and outlet lines which are connected to the inlet and outlet valve respectively.

In operation, a portion of the output power of the generator can be used to operate the heating arrangement, so that it heats up the work medium contained within the accumulator unit. Thus, at a required moment, the high temperature reservoir can be shut-off, and the accumulator unit can provide the necessary high temperature work medium. Under this arrangement, any excess output power which is not used can be provided to the accumulator unit, thereby operating, de facto, as an accumulator.

According to a specific example, the heating element can be a heating coil or any other element which is configured to be heated so as to heat the storage work medium. Alternatively, the heating arrangement can be constituted by an auxiliary heat pump (not shown), and the accumulator unit can comprise two compartments, one being in thermal communication with the evaporator side of the auxiliary heat pump and the other in thermal communication with the condenser side of the auxiliary heat pump.

In particular, each of the compartments can have a respective inlet to which corresponding inlet and outlet lines are attached respectively. The arrangement can be such that the outlet is located at a top end of the high temperature compartment, while the inlet is located at a bottom end of the high compartment. In contrast, the outlet of the low temperature compartment can be located at a bottom end of the compartment while the inlet thereof can be located at a top end of the compartment.

The above arrangement allows for withdrawing high temperature work medium from a high temperature zone of the high temperature compartment, and returning the work medium to a low temperature zone of the high temperature compartment. Correspondingly, this arrangement allows withdrawing low temperature work medium from a low temperature zone of the low temperature compartment, and returning the temperature work medium to a high temperature zone of the low temperature compartment.

In operation, once the auxiliary work medium in the compartments and reaches temperatures which are similar to those of the high/low temperature reservoirs respectively, it can be used in operation of the generator while the main heat pump temporarily ceases its operation.

It is appreciated that the accumulator can comprise both a heat pump and direct heating elements (e.g. coil), and work in combination with both. Specifically, the high temperature compartment can be provided with heaters which are configured for directly heating the storage fluid contained within the compartment. It is appreciated that during operation of the auxiliary heat pump, the storage medium within the high/low temperature compartment can reach a heating/cooling limit (i.e. reaching a maximal/minimal temperature limit). In such an event, the operation of the auxiliary heat pump can be interrupted, and the heaters are then used to further heat the storage medium in the high temperature compartment.

Under the above arrangement, once the auxiliary heat pump is interrupted, the work medium in the high temperature compartment can be used as a high temperature work medium, while the work medium in the low temperature compartment is used as the low/intermediate work medium.

In all of the above aspects of the subject matter of the present application, the A/C unit used for generating the heat/cold source for the respective high/low temperature reservoir can be in the form of a cascade arrangement, comprising several grades, each of which operates as a basic A/C compression/expansion manner.

In particular, the cascade arrangement can comprise a first end-grade configured for providing the heat for the high temperature reservoir and a second end-grade configured for providing the necessary cold for the low temperature reservoir.

Each of the grades comprises an evaporator section, a compressor, an expansion member and a condenser section, and contains a fluid (gas or liquid) configured for undergoing corresponding compression and expansion to provide a high temperature source at the condenser and a low temperature source at the evaporator as known per se. Specifically, the fluid in each of the grades is configured to have an evaporator temperature TEVAP(II) and a condenser temperature TcoND(n), where TcoND(n) > _E vAP(n), and n denotes the number of the grade.

The cascade arrangement is designed such that the condenser section of one grade is configured for performing a heat exchange process with the evaporator section of the subsequent grade. In particular, the design can be such that the temperature of compressed fluid in the condenser of the one grade is higher than the temperature of the expanded fluid in the evaporator of the subsequent grade with which the heat exchange process takes place.

Each of the grades can operate in a closed-loop, i.e. the fluid of each grade does not come in contact with the fluid of a subsequent grade. Specifically, the heat exchange process between two subsequent grades can be performed via an intermediate member, e.g. a heat conducting surface.

According to a specific example, the heat exchange process between two subsequent grades takes place in a heat exchanger comprising an inner tube of diameter Dj passing through an outer tube of diameter D ₂ < Dj. The inner tube constitutes the condenser of the one grade while the outer tube constitutes the evaporator of the subsequent grade.

Thus, in operation, compressed fluid of one grade, heated due to compression thereof to a temperature Tco _N D(n), flows through the inner tube an expanded fluid of the subsequent grade, cooled due to expansion thereof to a temperature TEVAP( _II +I ) < TcoND(n), flows through the outer tube (so as to flow around the inner tube). As a result, a heat exchange process takes place via the wall of the inner tube - the heated fluid coming in contact with an inner surface of the inner tube and the cooled fluid coming in contact with an outer surface of the inner tube. In this heat exchange process, heat is emitted from the fluid flowing within the inner tube to the fluid flowing in the outer tube.

It should be noted that the design of the heat exchanger can be such that the volume defined by the inner tube is smaller than the volume defined between the external surface of the inner tube and the internal surface of the outer tube. In particular, while the inner surface of the outer tube is essentially round in cross-section taken perpendicular to a longitudinal axis of the tube, while the inner and/or outer surfaces of the inner tube can be of a more convoluted shape in the same cross-section. The flow direction within the condensing portion and evaporator portion can either be parallel, i.e. both the compressed fluid and the expanded fluid flow in the same direction (as in a parallel heat exchanger). Alternatively, the flow direction can be opposite, i.e. i.e. the compressed fluid and the expanded fluid flow in opposite directions (as in a counterflow heat exchanger).

Each of the grades can contain a different fluid, and is configured for operation at a different temperature range. In particular, within the same grade the difference between the high temperature T of the fluid in the condenser and the low temperature T of the fluid in the evaporator can be generally similar between all the grades. For example, the temperature difference can be about 30°C.

According to a specific example, the cascade arrangement can comprise seven grades, each operating at a temperature range Δ of about 30°C, with the temperature of the fluid at the evaporator of the first grade T is as low as 0°C, and the temperature of the fluid at the condenser of the seventh grade T is as high as 245°C.

It is noted that in all the grades, the temperature of the expanded fluid in the evaporator of one grade is always lower than the condensation temperature of compressed fluid in the condenser of the subsequent grade. In other words, T _II) <

TcOND(n+l)-

The generator can also comprise a controller configured for regulating the operation of the compressor and/or the expansion valve of each grade so as to maintain a desired difference between the compression temperature of a fluid in one grade and the expansion temperature of fluid in a subsequent grade.

As previously described, each grade can comprise a compressor configured for compressing the fluid circulating in the grade during its progression between the evaporator to the condenser. In order to maintain a generally similar temperature range between the condenser and the evaporator in each grade, the compressors of the grades can have different power consumptions so that each grade is configured for operating at a different COP.

The reasoning for this is that the COP for heating/cooling is calculated as the temperature difference divided by the high/low temperature. Therefore, a grade having a 30°C condenser/evaporator difference between 27°C and 57°C yields a COP which is different than that of a grade having a 30°C condenser/evaporator difference between 90°C and 120°C.

Alternatively, each grade can be fitted with the same compressor (i.e. providing the same power). However, under this arrangement, the temperature difference between the condenser/evaporator in each grade (from low to high) will gradually be reduced. For example, the Δ for the first grade can be 30°C for the first grade, 24°C for the second grade, 20°C for the third grade and so forth.

It is appreciated that by using a cascade arrangement having several grades, each contributing to the overall temperature difference between THOT of the high temperature reservoir and TCOLD of the low temperature reservoir. As in the above example, each of the seven grades can contribute about 30°C, thereby yielding a temperature difference of 240°C.

It should be understood that a single compression/expansion cycle having a temperature difference of 240°C has a COP which is much lower than that of seven compressors, each contributing to its own compression/expansion cycle. As a result, the energy going to waste in the single compression/expansion cycle is greater than that of the cascade arrangement, making the latter more efficient for the presently described generator.

As previously described, the generator can comprise a radiator configured for allowing the work medium to perform a heat exchange process with the environment after heating/cooling the pressure fluid within the pressure vessels.

According to a particular design, the high work medium, after heating the pressure fluid (and subsequently cooling down) is provided directly back into the high temperature reservoir, while the low temperature work medium, after cooling the pressure fluid (and subsequently heating up) passes through the radiator in order to be cooled down by the environment.

The radiator unit can be configured for being controlled according to the temperature of the environment and the resulting temperature of the low temperature work medium, so that the low temperature work medium leaves the radiator unit at a generally constant and predetermined temperature.

More particularly, the radiator unit can comprise a control element configured for determining the cooling rate provided by the radiator, and a sensing unit configured, on the one hand, for measuring the temperature of the low temperature work medium leaving the radiator unit, and, on the other hand, providing the data to the control unit.

For example, if it is desired that the low temperature work medium leaves the radiator unit and enters the low temperature reservoir at a predetermined temperature T, the sensing unit measures the temperature T' of the low temperature work medium leaving the radiator unit and:

(a) if T' > T, the sensing unit provides this reading to the control unit, which, in turn, increases the cooling rate of the radiator unit (for example by increasing the revolution speed of a cooling fan), to reduce the temperature T; and

(b) if T' < T, the sensing unit provides this reading to the control unit, which, in turn, decreases the cooling rate of the radiator unit (for example by decreasing the revolution speed of a cooling fan), to increase the temperature TV

With reference to the above, when using the cascade arrangement, the configuration is such that the heat exchange process within the radiator takes place with the low temperature work medium entering the first grade of the cascade arrangement associated with the low temperature reservoir. In particular, this heat exchange process brings the low temperature work medium (which is now heated after passing through the pressure vessel) to a temperature T ~ TENV, while TCOND > E V > TEVAP, where TCOND is the high temperature of the compressed fluid at the condenser of the first grade and TEVAP is the low temperature of the expanded fluid at the evaporator of the first grade.

It should be noted that each grade (depending on its compressor) is designed for a predetermined temperature range, i.e. it is configured to remove a predetermined amount of heat from the cold end (evaporator). If the evaporator is located at an environment providing it with more heat than the compressor can withdraw in the compression/expansion cycle of the grade, the grade becomes less efficient (i.e. the compressor can't cope with removing heat from the evaporator).

Thus, the cascade arrangement can further be configured for adjusting its operation, and its overall temperature range, in accordance with the temperature of the environment. More particularly, if the temperature of the environment increases such that TENV > TCO D > TEVAP, and the first grade of the cascade arrangement becomes less efficient (as described above), the cascade arrangement can be configured for bypassing the first grade and connecting the low temperature reservoir to the second grade.

Under the above arrangement, instead of operating between a low temperature of TEVAP( I ) and a high temperature of TCOND(7), the cascade arrangement now operates between as low temperature of TEVAP(2) and a high temperature of TCOND(7)- Thus, the overall temperature difference between the high and low temperature reservoir decreases, but the efficiency of the cascade arrangement remains generally the same.

In order to perform the above adjustment, the cascade arrangement can have a bypass module comprising an evaporator associated to the second grade and located within the low temperature reservoir. The bypass module can further comprise valves allowing shutting off the first grade completely, and directing the compressed fluid of the second grade to expand within the evaporator of the bypass module instead of in the original evaporator of the second grade.

According to a specific design of the generator, it can include the following features:

- Multiple pressure vessels - each side (left/right) of the generator comprises four pressure vessels, each being of similar structure to the pressure vessels described with respect to previous examples;

- Linear core connection - each vessels comprises six cores, but contrary to previous examples, the cores are connected linearly to one another so as to form a long work medium flow path (six times as long in comparison to a parallel connection as previously disclosed);

- Linear vessel connection (work medium) - the cores of the four pressure vessels of each side are linearly connected to one another so as to form an even longer work medium flow path;

- Linear vessel connection (pressure medium) - the compartments of the four pressure vessels on each side containing the high pressure medium are also in fluid communication with one another via high-pressure connections, thereby forming a long pressure medium flow path;

- External low temperature reservoir - the low temperature reservoir constituted by the evaporator of the A/C unit is exposed to the environment and is not used for circulation of work medium therethrough. In operation, a full cycle of one side of the generator can include the following steps (taking into account that the opposite side undergoes the same steps only at a shift):

a) High temperature work medium is passed from the condenser end of the AJC unit along the length of twenty four cores (six cores in each of the four pressure vessels), thereby increasing the temperature of the pressure medium to its maximal operating temperature, and simultaneously being cooled down to a lower temperature;

b) From the last core of the fourth pressure vessel, the cooled down high temperature work medium is returned to the condenser end of the AJC unit after passing through a radiator for expelling therefrom at least an additional part of the heat remained therein;

c) Intermediate temperature work medium at an ambient temperature from the intermediate reservoir is passed through all twenty four cores of the four pressure vessels, thereby lowering the temperature of the pressure medium below the maximal operating temperature, and simultaneously being heated to a higher temperature;

d) From the last core, the intermediate work medium flows into the gradient tanks to be stored there, so that the first portion of intermediate temperature work medium to enter the gradient tank is at the highest temperature and the last portion to enter the gradient tank is at the lowest temperature; e) Intermediate temperature work medium at an ambient temperature from the intermediate reservoir is passed through all twenty four cores of the four pressure vessels, thereby further lowering the temperature of the pressure medium to the minimal operative temperature, and simultaneously being heated to a higher temperature;

f) From the last core, the intermediate work medium flows back into the intermediate work reservoir, passing through the radiator to expel any additional heat to the environment;

g) Heated intermediate temperature work medium from the gradient tank is passed through the cores of the four pressure vessels, thereby gradually heating the pressure medium to a temperature above the minimal operative temperature yet still below the maximal operative temperature. Gradual heating is achieved by using a LIFO arrangement where the last portion to enter the gradient tank (which is also of the lowest temperature) is first to flow through the cores;

h) From the last core, the intermediate temperature work medium flows into the intermediate reservoir while passing through the radiator unit to expel any additional heat to the environment;

i) Repeating from step (a).

In particular, steps (a) and (b), and (e) and (f) can last for a first period of time and steps (c) and (d), and (g) and (h) can last for a second period of time which is greater than the first period of time. Specifically, the second period of time can be twice as long as the first period of time. Under a particular example, the first period of time can be about 5 seconds and the second period of time can be about 10 seconds.

The generator can be utilized in a variety of power-requiring systems, e.g. households, vehicles (for example cars, boats, plains, submarines etc.), industrial systems etc. In particular, in the example of systems configured for operation when at least partially submerged in a medium other than ambient air, the generator can be configured to use this particular medium as the work medium. For example, in case the generator is used on a boat for sailing at sea, the work medium can be sea water.

With respect to the pressure medium, the following should be noted:

- When pre-loading the pressure medium, the heat transfer coefficient thereof increases;

When pre-loading the pressure medium, the volumetric expansion coefficient of the pressure medium decreases;

When pre-loading the pressure medium, the density of the pressure medium increases;

The higher the density of the pressure medium, the lower is its susceptibility to volumetric changes under pressure;

When pre-loading the pressure medium, the density of the pressure medium increases;

- When pre-loading the pressure medium, the heat capacity decreases; and

When pre-loading the pressure medium, the viscosity of the pressure medium increases. In addition to the above, the generator of the present application can incorporate the following features:

During operation of the generator, when switching from one step of operation to the subsequent step, it can be beneficial to delay the selective opening of the outlet valves with respect to the selective opening of the inlet valves. For example, during step (a), high temperature work medium is passed through the cores so that both the inlet and the outlet valve are in fluid communication with the high temperature reservoir, and during step (b), low temperature work medium is passed through the cores so that both the inlet and the outlet valve are in fluid communication with the low temperature reservoir. When switching from (a) to (b), it can be beneficial to delay selective switching of the outlet valve so that it remains in fluid communication with the high temperature reservoir until all the high temperature work medium contained within the core is first fully returned to the high temperature reservoir, and only then switching the outlet valve to be in fluid communication with the low temperature reservoir;

The static spiral within the core can be made of a material having very low heat transfer coefficient, so as not to absorb heat from the work medium. Example of such a material can be fiberglass, having a heat transfer coefficient of about 0.1 ;

The generator can comprise several gradient tanks, some being designated for use solely with high temperature work medium while others are designated for use solely with low temperature work medium;

The core can be formed with strengthening ribs, providing the core with increased resistance to pressure. Increased resistance can allow for reducing the thickness of the core wall, thereby increasing heat transfer between the work medium and the pressure medium;

The accumulator can also be pre-loaded, so as to raise the boiling point of the work medium contained therein, thereby allowing it to absorb more heat; The accumulator can itself be used as a backup for the work medium subsystem;

The generator can comprise a controller configured for performing optimization of the operation of the generator, including control of the compressor and thereby control of the COP of the air conditioning unit, operation of the valves etc.;

The accumulator can comprise two compartments, one for containing high temperature storage medium and the other for containing low temperature storage medium;

The compartment of the accumulator can have a vertical orientation, so as to allow a heat gradient therein, similar to the gradient tanks;

A generator for producing about 1MW can have a weight of about 30 ton. And occupy an area of about 100 square meters;

- The accumulator can be used as a direct source of hot/cold water supply for houses/offices/factories etc.;

The use of an accumulator unit can reduce the overall power capacity of the generator by as much as 66% (when the accumulator operates using a heat pump), thereby allowing to reduce the dimensions of the generator system by as much as a 2/3.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it can be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

Figs. A to H are schematic diagrams of examples of different variations of the generator according to the subject matter of the present application;

Figs. 1A to ID are respective schematic isometric, front, side and cross-section views of the generator of the disclosed subject matter;

Fig. 2 A is a schematic isometric view of the generator shown in Fig. 1A, without the mechanical power units and the energy generation unit;

Fig. 2B is a schematic enlarged view of detail A shown in Fig. 2A;

Fig. 3A is a schematic isometric view of the pressure vessels and energy generation units of the generator of Fig. 1A;

Fig. 3B is a schematic cross-section of the pressure vessels shown in Fig. 3 A; Fig. 3C is a schematic enlarged view of detail B shown in Fig. 3B;

Fig. 3D is a schematic enlarged view of detail C shown in Fig. 3B;

Fig. 3E is a schematic front view of the cross-section shown in Fig. 3B; Fig. 4A is a schematic isometric view of a pressure vessel of the generator shown in Fig. 1 A;

Fig. 4B is a schematic enlarged view of detail D shown in Fig. 4A;

Fig. 4C is a schematic isometric view of detail D shown in Fig. 4A, with the shell of the pressure vessel being stripped away;

Fig. 4D is a schematic isometric view of the pressure vessel shown in Fig. 4A with the shell being stripped away;

Fig. 4E is a schematic enlarged view of detail E with several other components being stripped away;

Fig. 4F is a schematic enlarged view of detail F. shown in Fig. 4 A;

Fig. 5A is a schematic isometric cross-section view of the pressure vessel;

Fig. 5B is a schematic isometric view of a segment of the core of the pressure vessel;

Fig. 5C is an additional isometric cross-sectional view of the pressure vessel; Figs. 6A to 6C are respective schematic isometric view of the power generation unit of the generator shown in Fig. 1A;

Figs. 7A to 7C are respective schematic front views of heat dissipation units used in the pressure vessel;

Figs. 8A to 8F are respective schematic diagrams of analysis of operation of the generator;

Fig. 9 is a schematic isometric view of the generator of Fig. 1 A when used in conjunction with an accumulator arrangement;

Fig. 10 is an additional schematic diagram of analysis of operation of the generator;

Fig. 11 A is a front schematic isometric view of another example of the generator shown in Figs. 1 A to ID;

Fig. 1 IB is a schematic rear isometric view of the generator shown in Fig. 1 1 A; Fig. 12A is a schematic isometric view of a gradient system used in the generator shown in Figs. 11 A and 1 IB;

Fig. 12B is a schematic enlarged view of the gradient system shown in Fig. 12A;

Fig. 12C is a schematic isometric view of the gradient system shown in Fig. 12A, with several components thereof being removed;

Fig. 12D is a schematic side view of the generator as shown in Fig. 12C; Fig. 13A is a schematic isometric view of a radiator section used in the generator shown in Figs. 11 A and 1 IB;

Fig. 13B is a schematic isometric view of a work medium reservoir used in the generator shown in Figs. 11 A and 1 IB, with the casing thereof being transparent;

Fig. 14A is a schematic isometric view of a mixing mechanism used in the generator shown in Figs. 1 1 A and 1 IB;

Fig. 14B is a schematic isometric view of the mixing mechanism shown in Fig. 14A, with the several components of the generator being removed;

Fig. 14C is a schematic enlarged view of detail G shown in Fig. 14B;

Fig. 14D is a schematic cross-sectional view of a pressure vessel used in the generator shown in Figs. 11 A and 1 IB, taken along a plane perpendicular to the central axis of the pressure vessel;

Figs. 14E and 14F are respective schematic isometric and isometric cross- sectional views of a drive screw used in the generator shown in Figs. 1 1 A and 1 IB;

Fig. 15A is a schematic isometric view of a flow regulator used in the generator shown in Figs. 1 1 A and 1 IB;

Fig. 15B is a schematic enlarged view of the regulator shown in Fig. 15 A, with the cover thereof being transparent;

Fig. 15C is a schematic view of the flow regulator shown in Fig. 15B;

Fig. 16A is a schematic isometric view of an accumulator arrangement used in the generator shown in Figs. 1 1 A and 1 IB;

Fig. 16B is a schematic rear isometric view of an accumulator arrangement shown in Fig. 16 A;

Figs. 17A to 17D are respective schematic isometric views of piping junctions of the generator shown in Figs. 1 1 A and 1 IB;

Fig. 17E and 17E' are a schematic charts of the temperature of the work medium of the generator shown in Figs. 11 A and 1 IB;

Fig. 18A is a schematic isometric view of a vehicle comprising the generator shown in Figs. 1 1 A and 1 IB;

Fig. 18B is a schematic isometric view of the vehicle shown in Fig. 18A, with several components thereof being removed;

Fig. 18C is a schematic isometric view of the vehicle shown in Fig. 18B, with further components thereof being removed; Figs. 18D and 18E are respective schematic top and bottom views of the vehicle shown in Fig. 18C;

Figs. 18F and 18G are respective schematic enlarged views of details H and I shown in Fig. 18C respectively;

Fig. 19A is a schematic isometric view of a marine vessel comprising the generator shown in Figs. 11 A and 1 IB;

Fig. 19B is a schematic isometric view of the marine vessel shown in Fig. 19A, with several components thereof being removed;

Fig. 19C is a schematic isometric view of the marine vessel shown in Fig. 19B, with further components thereof being removed;

Figs. 19D to 19F are respective schematic enlarged views of details J, K and L shown in Fig. 19C respectively;

Figs. 20A and 20B are respective schematic cross-sectional views of a cylindrical component of the generator shown in Figs. 1 1 A and 1 IB;

Fig. 20C is a schematic isometric partial cross-sectional view of the cylindrical component shown in Fig. 20A, with a spiral element located therein;

Fig. 20D is a schematic isometric view of another example for a cylindrical component to be used in the generator of the present application;

Fig. 20E is a schematic cross-sectional view of the cylindrical component shown in Fig. 20D taken along a central axis thereof;

Figs. 21A to 21G are respective schematic isometric views of various stages of producing the cylindrical component shown in Figs. 20A and 20B;

Figs. 22A and 22B are respective schematic front and rear isometric views of a generator according to another example of the present application;

Fig. 22C is a schematic enlarged view of detail M shown in Fig. 22A;

Fig. 22D is a schematic enlarged view of detail N shown in Fig. 22B;

Fig. 23A is a schematic isometric view of a work medium sub-system used in the generator shown in Fig. 22A;

Fig. 23B is a schematic isometric view of the work medium sub-system shown in Fig. 23 A, with the housing thereof being removed for clearer view;

Fig. 23C is a schematic right-side view of the work medium sub-system shown in Fig. 23B; Fig. 23D is a schematic cross-sectional view of the work medium sub-system shown in Fig. 23 A, taken along a plane I-I shown in Fig. 23B;

Fig. 23E is a schematic enlarged view of detail O shown in Fig. 23D;

Fig. 23F is a schematic cross-sectional view of the work medium sub-system 5 shown in Fig. 23A, taken along a plane II-II shown in Fig. 23B;

Figs. 24A and 24B are respective schematic front and rear isometric views of another example of a work medium sub-system used in the generator of the subject matter of the present application;

Figs. 24C and 24D are respective schematic enlarged views of details P and Q 10 taken from Figs. 24 A and 24B respectively;

Fig. 25A is a schematic isometric view of another example of a work medium sub-system used in the generator of the subject matter of the present application;

Fig. 25B is a schematic enlarged view of detail R taken from Fig. 25A;

Figs. 26A and 26B are respective schematic tables showing the properties of two 15 materials which can be used in construction of the generator shown in the above figures;

Fig. 27A is a schematic isometric view of a generator according to another example of the subject matter of the present application;

Fig. 27B is a schematic isometric view of the generator shown in Fig. 27A, with the supporting structure being removed for a clearer view;

20 Figs. 27C to 27E are respective schematic front, rear and side views of the generator shown in Fig. 27B;

Fig. 28A is a schematic isometric view of the piping junctions of the front of the generator shown in Figs. 27A to 27E;

Fig. 28B is a schematic enlarged view of the piping junctions shown in Fig.

25 28A;

Fig. 29A is a schematic isometric view of the pressure system used in the generator shown in Figs. 27A to 27E;

Figs. 29B and 29C are respective schematic isometric and front views of a front portion of a single cylinder of the pressure system shown in Fig. 29A;

30 Figs. 30A to 30C are respective schematic top-isometric, bottom-isometric and side views of a mid portion of the pressure system shown in Fig. 29 A; Figs. 31A and 31B are respective schematic rear-isometric and side views of the pressure system shown in Fig. 29 A, with some of the cylinders removed for a clearer view;

Figs. 32A and 32B are two schematic isometric views of gradient tanks used in the generator shown in Figs. 27A to 27E;

Fig. 33A is a schematic isometric view of an accumulator arrangement used in the generator shown in Figs. 27A to 27E when connected to reservoirs of the generator;

Fig. 33B is a schematic isometric view of the accumulator arrangement shown in Fig. 33B;

Fig. 33C is a schematic isometric view of the accumulator arrangement shown in Fig. 33B;

Fig. 34 is a schematic isometric view of a heat pump used in the generator shown in Figs. 27A to 27E;

Fig. 35A is a schematic isometric view of a gear assembly used in the generator shown in Figs. 27 A to 27E;

Fig. 35B is a schematic isometric view of the gear assembly shown in Fig. 35 A, with a casing thereof being removed;

Figs. 35C to 35E are respective schematic enlarged isometric, side and top views of a mechanism of the gear assembly shown in Figs. 35A and 35B;

Figs. 36A and 36B are respective schematic isometric and side views of a generator according to still another example of the subject matter of the present application;

Fig. 36C is a schematic enlarged isometric view of the generator shown in Figs. 36A and 36B;

Fig. 36D is a schematic isometric view of the generator shown in Figs. 36 A and

36B, with the pressure vessels thereof being removed for clearer view;

Fig. 37A is a schematic enlarged isometric view of the piping junction shown in Fig. 36D;

Fig. 37B is a schematic further enlarged isometric view of a front right side of the piping junction shown in Fig. 37A

Fig. 37C is a schematic further enlarged isometric view of a front left side of the piping junction shown in Fig. 37 A; Fig. 37D is a schematic isometric view of a rear-end of the generator shown in Figs. 36A and 36B;

Fig. 37E is a schematic enlarged isometric view of the piping junction shown in Fig. 37C;

Fig. 38 is a schematic isometric view of the pressure system used in the generator shown in Figs. 36A and 36B;

Fig. 39 is a schematic isometric view of a heat pump used in the generator shown in Figs. 36A and 36B;

Fig. 40A is a schematic isometric view of an accumulator arrangement used in the generator shown in Figs. 36A to 36D;

Fig. 40B is an enlarged view of a piping system of the accumulator arrangement shown in Fig. 40A;

Figs. 40C and 40D are schematic enlarged isometric views of compartments of the accumulator arrangement shown in Fig. 40A;

Fig. 41 A is a schematic isometric view of a single cylinder used in the generator shown in Figs. 36A and 36B;

Fig. 41B is a schematic isometric enlarged view of a front end of the cylinder shown in Fig. 41 A;

Fig. 41C is a schematic isometric view of the single cylinder shown in Fig. 41 A, with a housing thereof being removed;

Fig. 41D is a schematic isometric enlarged view of a front end of the cylinder shown in Fig. 41C;

Fig. 41E is a schematic isometric enlarged view of a mid-portion of the cylinder shown in Fig. 41 C;

Fig. 42A is a schematic isometric view of a portion of a core used in a pressure vessel of the generator shown in Figs. 36A and 36B according to another example of the subject matter of the present application;

Fig. 42B is a schematic enlarged isometric view of a front portion of the core shown in Fig. 42A;

Fig. 42C is a schematic enlarged isometric view of a rear portion of the core shown in Fig. 42A;

Fig. 42D is a schematic rear view of the core shown in Fig. 42A; Fig. 42E is a schematic enlarged isometric view of a rear portion of the core shown in Fig. 42C;

Fig. 43 is a schematic isometric view of a portion of a core used in a pressure vessel of the generator shown in Figs. 36A and 36B according to yet another example of the subject matter of the present application;

Fig. 44A is a schematic isometric view of a portion of a core used in a pressure vessel of the generator shown in Figs. 36A and 36B according to still another example of the subject matter of the present application;

Fig. 44B is a schematic enlarged isometric view of a front portion of the core shown in Fig. 44 A;

Fig. 44C is a schematic enlarged isometric view of a rear portion of the core shown in Fig. 44A;

Fig. 45A is a schematic isometric view of a portion of a core used in a pressure vessel of the generator shown in Figs. 36A and 36B according to still another example of the subject matter of the present application;

Fig. 45B is a schematic enlarged isometric view of a rear portion of the core shown in Fig. 44A;

Fig. 45C is a schematic enlarged isometric view of a front portion of the core shown in Fig. 44A;

Fig. 46A is a schematic isometric exploded view of a pressure vessel used in the generator shown in Figs. 36A and 36B;

Figs. 46B to 46D are schematic enlarged isometric views of portions of the pressure vessel shown in Fig. 46A;

Fig. 47 is a schematic isometric view of a mechanism of a gear arrangement used in the generator shown in Figs. 36A and 36B, according to another example of the subject matter of the present application;

Fig. 48A is a schematic isometric view of a work medium sub-system used in the generator of the subject matter of the present application;

Figs. 48B and 48C are schematic respective isometric lateral and longitudinal cross-sectional views of the sub-system shown in Fig. 49 A, taken along planes A-A and B-B respectively;

Fig. 49A is a schematic isometric view of a pressure vessel used in the generator shown in Figs. 36 A to 36D; Figs. 49B to 49E are schematic enlarged views of details shown in Fig. 49A; Fig. 49F is a schematic isometric view of a bracing arrangement used in the pressure vessel shown in Fig. 49A and holding a single core thereof;

Fig. 49G is a schematic isometric view of the bracing arrangement shown in Fig. 49F; and

Fig. 49H is a schematic isometric enlarged view of a detail shown in Fig. 49G.

DETAILED DESCRIPTION OF EMBODIMENTS

With reference to Fig. A, a schematic diagram is shown demonstrating a basic arrangement of the generator of the present invention comprising a heat differential module, a pressure module and a conversion module.

The heat differential module comprises a first, high temperature reservoir and a second, low temperature reservoir, each containing therein a work medium WM (not shown) at a respective high/low temperature. The first, high temperature reservoir is thermally associated with a condenser end CE of a heat pump HP, so that operation of the heat pump HP (under provision of power Wi) provides heat Q to the condenser end so as to maintain the work medium WM in the first reservoir at high temperature. The second, low temperature reservoir is thermally associated with the environment.

Each of the reservoirs is provided with an inlet line IL which is in selective fluid communication with an inlet of the pressure vessel PV of the pressure module via an inlet valve I and an outlet line OL which is in selective fluid communication with an outlet of the pressure vessel PV via an outlet valve O.

The pressure vessel PV contains therein a pressure medium PM and is formed with a central conduit C passing therethrough which is in fluid communication with the inlet valve I and with an outlet valve O, allowing the passage therethrough of the work medium WM from the reservoirs.

The pressure vessel PV is provided with a pressure line PL being in fluid communication with the pressure medium PM, which is in fluid communication with the conversion module. The conversion module, in turn, comprises a piston P which is in fluid communication with the pressure line PL, and with a generator. The piston in configured for reciprocation which is utilized by the generator for the generation of output power W ₂ . In operation, high/low temperature work medium WM is selectively provided into the pressure vessel, entailing expansion and shrinkage of the pressure medium PM, consequently entailing reciprocation of the piston P. Specifically, the following steps are performed:

a) passing high temperature work medium WM from the high temperature reservoir into inlet valve I, through conduit C and out of outlet valve O back into the high temperature reservoir. As a result of a heat exchange process between the high temperature work medium WM and the pressure medium PM, the former cools down while the latter heats up to a maximal operative temperature. When heating up, the pressure medium PM increases its volume and causes displacement of the piston P to the right; and b) passing low temperature work medium WM from the low temperature reservoir into inlet valve I, through conduit C and out of outlet valve O back into the low temperature reservoir. As a result of a heat exchange process between the low temperature work medium WM and the pressure medium PM, the former heats up while the latter cools down to a minimal operative temperature. When cooling down, the pressure medium PM decreases in volume and causes displacement of the piston P to the left.

Performing the above steps repeatedly will provide reciprocation of the piston P back and forth, thereby allowing generation of electricity by the generator.

The following should be noted:

- when returning to the high temperature reservoir, the cooled down high temperature work medium WM is free to absorb further heat from the condenser end of the heat pump so as to bring it back to its original high temperature;

when returning to the low temperature reservoir, the heated up low temperature work medium WM emits at least some heat into the outside environment so as to cool down and bring its temperature back to its original low temperature;

- depending on the length of the conduit C, it can be beneficial, after the selective switching of the position of inlet valve I to provide fluid communication with the low temperature reservoir, to delay selective switching of the position of the outlet valve O to provide fluid communication with the low temperature reservoir. In this way, upon beginning the performing of step (b), the high temperature work medium WM contained within the conduit C will first be pushed through its outlet line OL into the high temperature reservoir, and only then will the outlet valve O be selectively switched to provide fluid communication with the low temperature reservoir. The same holds true when switching from step (b) to step (a);

In terms of the thermodynamic operation, the heat pump HP withdraws an amount of heat Q' (heat absorbed from the environment with which the evaporator is in thermal communication) from the evaporator end thereof into the condenser end by applying an amount of work Wi. Thus, the amount of heat Q contained within the high temperature work medium WM of the high temperature reservoir Q = Q' + Wj.

In operation, the amount of heat Q is provided to the pressure medium PM via the heat exchange process, so that a portion Qi of the amount Q of heat is used for displacing the piston P, and at least a portion amount Q ₂ of heat is absorbed by the low temperature work medium WM via heat exchange with the pressure medium PM.

An amount of heat Q ₂ is released back to the outside environment during passage of the heated low temperature work medium WM via outlet line OL, and from the environment, is free to be re-drawn into the evaporator end of the heat pump HP. Such an arrangement provides for a certain amount of heat Q ₂ to be recovered by the generator (i.e. a recovery arrangement).

It is appreciated that the amount of heat Q ₂ is less than the amount of heat Q' participating in the thermodynamic process of the heat pump HP, and thus the heat pump constantly withdraws additional heat from the environment (on top of Q ₂ ) to allow provision of a full amount Q' to the condenser end.

The amount of output work W ₂ provided by the generator of the conversion unit depends on the amount Qi of heat which is converted into energy thereby. The arrangement is such that the amount Qi of heat is greater than the amount Q' + Wi, so that the output energy W ₂ produced is greater than W^

Specifically, since a heat pump HP is used in order to circulate heat within the generator, it is appreciated that an amount of input work Wi is sufficient for displacing an amount of heat Q' > Wj, depending on the COP (Coefficient of performance) of the heat pump. For example, under COP = 3, the heat pump will withdrawn Q' = 2KW of heat from the evaporator to the condenser under the application of Wi = 1KW. Thus, the amount of heat Qj can be greater than W _l5 thereby producing an output energy W ₂ > Wi.

Turning now to Fig. B, an alternative arrangement is shown, demonstrating direct heat recovery arrangement. Under this arrangement, the outlet line LO of the low temperature reservoir is not returned directly back into the low temperature reservoir upon exiting the pressure vessel, but rather is first passed through the evaporator end of the heat pump HP. In this manner, instead of the heat Q ₂ being emitted to the environment and re-absorbed by the heat pump from the evaporator end, it is directly returned to the evaporator end of the heat pump HP, thereby increasing the efficiency of the operation of the generator.

Turning now to Fig. C, yet another alternative arrangement of the generator is shown demonstrating a cooled reservoir arrangement in which the first, high temperature reservoir is in thermal communication with the condenser end of the heat pump HP (as in previous examples), while the low temperature reservoir is in thermal communication with the evaporator end of the heat pump HP.

Under the above arrangement, the low temperature work medium WM recovers a partial amount of heat Q ₂ from the pressure medium PM upon a heat exchange process therewith, and a remaining amount of heat q from the environment to provide an amount of heat Q' form the evaporator end to the condenser end of the heat pump HP.

Turning now to Fig. D, another arrangement of the generator is shown, demonstrating dual operation of pressure vessels. In particular, it is observed that the pressure module comprises two pressure vessels, each being in selective fluid communication with the high/low temperature reservoirs on the one hand, and on the other hand being in fluid communication with its own piston arrangement. The arrangement is further such that each of the pistons is in mechanical connection with the generator, so that reciprocation of both pistons is used by the generator for the generation of output power.

Under the above arrangement, when one pressure vessel is in fluid communication with the high temperature reservoir, the other pressure vessel is in fluid communication with the low temperature reservoir and vise versa. Thus, when the pressure medium PM in one pressure vessel is heated, the pressure medium PM in the other pressure vessel is cooled down and vise verse. Under the above arrangement, reciprocation of the pistons is coordinated so that when both pistons displace generally in the same direction generally at the same time. In other words, when the pressure medium PM of the bottom pressure vessel increases its volume and pushes its piston to the right, the pressure medium PM of the top pressure vessel decreases it volume, displacing the piston to the left and vise versa. It is noted that the terms 'top' and 'bottom' are used solely for descriptive purposes - as it will be shown in later arrangements, the pistons can also be positioned side-by-side. It is also appreciated that the above arrangement provides for the use of a plurality of pressure vessels (not only two) which are interconnected with each other.

Attention is now drawn to Fig. E, in which yet another example of the generator is shown demonstrating an intermediate reservoir arrangement in which the generator comprises three reservoirs: a high/intermediate/low temperature reservoir. This arrangement is a combination of the cooled reservoir arrangement shown in Fig. C, wherein an additional intermediate reservoir has been added containing intermediate temperature work medium. Each of the high/intermediate/low temperature reservoirs is in selective fluid communication with the pressure vessel.

Under this arrangement, two additional steps (a') and (b') are performed on top of steps (a) and (b) described with respect to Fig. A as follows:

(a') [performed after step (a)] during which intermediate temperature work medium WM from the intermediate temperature reservoir is passed through the conduit of the pressure vessel, thereby reducing the temperature of the pressure medium PM (via heat exchange process therewith) from the maximal operative temperature to an intermediate operative temperature (between the maximal operative temperature and the minimal operative temperature); and

(b') [performed after step (b)] during which intermediate temperature work medium WM from the intermediate temperature reservoir is passed through the conduit of the pressure vessel, thereby increasing the temperature of the pressure medium PM (via heat exchange process therewith) from the minimal operative temperature to an intermediate operative temperature (between the maximal operative temperature and the minimal operative temperature).

With respect to the above arrangement, it is appreciated that the intermediate temperature reservoir can be in thermal communication with the outside environment, while the high/low temperature reservoirs are in thermal communication with the condenser/evaporator ends of the heat pump HP respectively.

Turning now to Fig. F, still another example of the generator is shown demonstrating a cross-over arrangement in which the generator comprises two pressure vessels (similar to the dual operation arrangement), and each of the outlet valve is also in selective fluid communication with the inlet valves.

Specifically, each outlet valve O is also provided with a cross-over line COL which provides fluid communication between the outlet valve of one pressure vessel and the inlet valve of the other pressure vessel. Under this arrangement, it is possible to perform additional cross-over steps as explained below:

(a") [performed after step (a')] in which the intermediate work medium WM, upon exiting the conduit of one pressure vessel PV is provided, via cross-over line COL to the inlet valve of the other pressure vessel PV in order to begin heating the pressure medium therein and only then back to the intermediate temperature reservoir via the other outlet valve; and

(b") [performed after step (b')] in which the intermediate work medium WM, upon exiting the conduit of one pressure vessel PV is provided, via cross-over line COL to the inlet valve of the other pressure vessel PV in order to begin cooling the pressure medium therein and only then back to the intermediate temperature reservoir via the other outlet valve.

The above arrangement provides for a more significant heat recovery from the pressure medium PM. More specifically, instead of emitting/withdrawing a certain amount of heat to/from the environment during it return to the intermediate temperature reservoir, the intermediate temperature work medium WM now emits/withdraws a portion of that amount in a heat exchange with the pressure medium PM, thereby increasing the efficiency of the generator.

Turning now to Fig. G, still a further example of the generator is shown demonstrating a heat gradient arrangement in which the generator comprises one pressure vessel (similar to the basic arrangement), and a gradient tank associated with the outlet valve O.

The gradient tank comprises an arrangement configured for preventing mixing of portions of work medium contained therein, thereby considerably reducing heat transfer between the portions and the speed with which these portions reach a thermal equilibrium. In particular, the gradient tank, when used in the present generator, can contain a first portion of work medium at a temperature Tl, a second portion of work medium at temperature T2 and so forth so that Tl≠T2≠ and so forth.

Specifically, under operation of the generator as will now be explained, the gradient tank allows for maintaining the work medium contained therein at a temperature gradient so that Tl > T2 > .... > Tn, or alternatively, Tl < T2 < .... < Tn.

In operation, several additional steps are added to the basic operation steps (a) and (b) as explained with respect to Fig. A, as follows:

(b ^m ) [performed before step (b)] in which low temperature work medium WM is passed through the conduit of the pressure vessel PV to be heated via a heat exchange process with the pressure medium, but instead of being returned to the low temperature reservoir is introduced into the gradient tank. It is appreciated that the first portion of the low temperature work medium to exit the pressure vessel with reach the gradient at a higher temperature than the last portion (as the pressure medium PM gradually cools down during this heat exchange process). The design of the gradient tank allows maintaining these portions each at their own respective temperature, so that eventually, the upper-most portion in the gradient tank is the of the highest temperature while the lower-most portion in the gradient tank is the of the lowest temperature.

(b"") [performed after step (b)] in which the work medium in the gradient tank is re-circulated back through the pressure vessel in a LIFO (Last In First Out) order, thereby gradually heating up the pressure medium to an intermediate temperature, and only then commencing step (a) of the operation.

In essence, these steps of the operation of the generator describe a "stal operation in which the work medium WM in the gradient tank is held therein (stalled) until the right time, and then released into the piping of the generator to perform the required heat exchange process.

The above arrangement provide for another way of performing heat recovery in the generator, thereby further increasing its efficiency. It is also appreciated that the use of the LIFO configuration allows the pressure medium to be gradually heated (starting from the lowest temperature portion first), making better use of the amount of heat of each portion of the work medium.

It is also appreciated that the gradient tank can be used both for the heated low temperature work medium WM and the cooled high temperature work medium WM. According to specific examples as will be described in detail later, the generator can comprise more than one gradient tank. For example, each pressure vessel can be provided with its own gradient tank and/or gradient tanks are provided for high/low temperature work medium.

Turning now to Fig. H, still a further example of the generator is shown demonstrating an accumulator (green battery) arrangement in which the generator further comprises an accumulator unit containing a storage work medium. The accumulator unit is provided with a heating arrangement which is configured to be operated by output power W ₂ provided by the generator.

The accumulator unit is in selective fluid communication with the pressure vessel PV via corresponding inlet and outlet lines which are connected to the inlet and outlet valve respectively.

In operation, a portion of the output power of the generator is used to operate the heating arrangement, so that it heats up the work medium contained within the accumulator unit. Thus, at a required moment, the high temperature reservoir can be shut-off, and the accumulator unit can provide the necessary high temperature work medium.

Under the above arrangement, any excess output power which is not used can be provided to the accumulator unit, thereby operating, de facto, as an accumulator.

According to a specific example, the heating element can be a heating coil or any other element which is configured to be heated so as to heat the storage work medium. Alternatively, the heating arrangement can be constituted by an auxiliary heat pump (not shown), and the accumulator unit can comprise two compartments, one being in thermal communication with the evaporator side of the auxiliary heat pump and the other in thermal communication with the condenser side of the auxiliary heat pump.

With reference to Fig. 1A, there is shown a generator generally designated 1, comprising an air conditioning unit 10 connected to a work medium sub-system 100, two pressure vessels 200, a mechanical power assembly 300, a radiator unit 400, a power generator unit 500, an accumulator unit 50 and output.

In general, each of the vessels 200 contains a pressurized fluid, and the generator operates on the principle of periodic increase/decrease of the volume of the pressurized liquid to be used for mechanical back and forth displacement of a piston for generating electricity. With further reference to Fig. 3C, the pressure vessel 200 has a hollow cylinder body 210, and a hollow central core 240 passing therethrough, such that there is formed a cavity between the outer surface 242 of the central core 240 and the inner surface 214 of the cylinder body 210, which is adapted to contain the pressurized fluid. The inner space 243 of the hollow central core 240 is adapted to received therethrough a high/intermediate/low temperature work medium from the work medium sub-system 100, in order to manipulate the temperature of the pressurize fluid.

With reference to Figs. 1 A to ID, the work medium sub-system 100 comprises a high temperature reservoir 110, a low temperature reservoir 120 and a reservoir 130 of intermediate temperature water at room temperature. The terms 'high', 'low' and 'intermediate' refer in this specific example to the corresponding temperatures: about 40°C, about 10°C and about 25°C. The work medium sub-system is in fluid communication on one side with an air conditioning unit 10, and on the other side with the pressure vessels 200.

Each of the reservoirs 110, 120 and 130 is connected to both of the pressure vessels 200 via distribution valves 140. Since the generator 1 comprises two pressure vessels 200, and is generally symmetric about a central plane passing therethrough, left (L) and right (R) designations are used where applicable. The manner of connection between the work medium sub-system 100 and the right pressure vessels 200R will now be explained in detail (it should be noted that the manner of connection to the second pressure vessel 200 is essentially similar):

The high temperature reservoir 110 is connected to the distribution valve 140R via inlet 111R and to the outlet of the pressure vessel 200R via line 112R. Correspondingly, low temperature reservoir 120 is connected to the distribution valve 140R via inlet 121R and to the outlet of the pressure vessel 200R via line 122R. The reservoir 130 is connected to the distribution valve 140R via inlet 131R and to the outlet of the pressure vessel 200R via line 132R. The line 132R is then connected to a cooling element 410R of the radiator unit 400, and the outlet of the cooling element 410 is connected back to the reservoir 130 via line 133R.

The reservoirs 110 and 120 as well as the piping connecting them to the pressure vessels 200L, 200R, and the radiator unit 400 can be applied with thermal insulation in order to prevent heat losses to the piping itself. Similarly, the distribution valves 140L, 140R can also be made of low conductivity materials (e.g. Titanium or plastic) or covered with thermal insulation.

To the contrary, the piping connecting the reservoir 130 to the pressure vessels 200L, 200R, and the radiator unit 400 can be made of materials having high heat transfer coefficients (for example copper) and be exposed to the environment, allowing the temperature of the 'intermediate' water to be as equalized as possible with that of the surrounding environment.

In general, the piping described above can be constructed such that it has an inbuilt water pressure (and no air), that is maintained throughout the operation of the generator 1. Furthermore, the intermediate temperature water reservoir 130 can be connected to the household water pressure (consumer pressure) via faucet 135 (Fig. 1C), such that in case of a drop of pressure in the system, additional water can be provided to the system to re-build the pressure.

The general operation of the generator 1 will now be described (it should be noted that operation is described herein with respect to the vessel 200R, however, a similar operation takes place simultaneously in the vessel 200L).

At an initial position, the vessels 200 are filled with the pressure medium, which is pressurized to about 5000 Atm. The cores 240 as well as all of the above connecting lines are filled with the work medium at a standard household pressure (consumer pressure). In this position, the temperature of the pressure medium is equal to the room temperature (e.g. about 25°C), and correspondingly, the piston of the motor is at an intermediary position.

At a first stage of operation, the distribution valve 140R opens the port for line 111R, and high temperature water from the high temperature reservoir begins circulating through the core 240 of the vessel 200R. While passing through the core 240, a heat exchange process takes place between the high temperature water (at about 40°C) and the pressure medium (at about 25°C), causing the pressure medium to be heated up. As a result of heating, the pressure medium increases its volume (expands), consequently displacing the piston towards a first end point thereof.

The high temperature water, now of slightly reduced temperature, now exits the pressure vessel 200R via line 112R, and is returned to the high temperature reservoir. This process takes place until the pressure medium is heated (and expanded) to a desired/sufficient amount, i.e. until the piston is displaced to its desired first end position. Typically, the pressure medium is not heated to be the same temperature as the high temperature water, but rather several degrees below, e.g. 32-35°C.

Thereafter, the distribution valve 140R closes the port for the high temperature water inlet, and opens the port for line 131R of the intermediate temperature water reservoir. Intermediate temperature water (i.e. at 25°C) then flow through the pressure vessel 200R, causing a reverse heat transfer process to take place, in which the heated pressure medium (at about 32-35°C) gives away its heat to the intermediate temperature water. As a result, the pressure medium is cooled and the intermediate temperature water is heated.

The cooling down of the pressure medium causes its volume to consequently be reduced, entailing mechanical displacement of the piston towards its initial position. This process continues until the pressure medium is cooled to a desired/sufficient amount, i.e. until the piston is displaced back to its initial (intermediary) position.

The heated intermediate temperature water leaves the pressure vessel 200R via line 132R, and enters the cooling element 410R of the radiator unit 400. In the cooling element 410R, the heated intermediate temperature water undergoes another heat exchange process in which it emits to the surrounding atmosphere the heat absorbed from the heated pressure medium. Thus, the intermediate temperature water returns to the intermediate temperature water reservoir 130 via line 133R at a temperature close to its initial temperature within the reservoir (at about 25°C).

The above concludes the first part of the generator cycle.

Following the first part of the cycle, the second part takes place, in which a similar operation is performed using the low temperature water as follows: the distribution valve 140R shuts off the water from the intermediate temperature water reservoir 130, and opens for fluid communication with line 121R incoming from the low temperature reservoir. Low temperature water is then passed through the core 240 of the vessel 200R. While passing through the core 240, a heat exchange process takes place between the low temperature water (at about 10°C) and the pressure medium (which is now, after the first part of the cycle, back to about 25°C), causing the pressure medium to be cooled down. As a result of cooling, the pressure medium decreases its volume (compresses), consequently displacing the piston towards a second end point thereof. The low temperature water, now of slightly elevated temperature, exits the pressure vessel 200R via line 122R, and is returned to the low temperature reservoir. This process takes place until the pressure medium is cooled (and compressed) to a desired/sufficient amount, i.e. until the piston is displaced to its desired second end position. Typically, the pressure medium is not cooled down to be the same temperature as the low temperature water, but rather several degrees below, e.g. 15-18°C.

Thereafter, the distribution valve 140R closes the port for the low temperature water inlet, and re-opens the port for line 131R of the intermediate temperature water reservoir. Intermediate temperature water (i.e. at 25°C) then flows through the pressure vessel 200R, causing a reverse heat transfer process to take place, in which the cooled pressure medium (at about 15-18°C) absorbs heat from the intermediate temperature water. As a result, the pressure medium is heated up and the intermediate temperature water is cooled down.

The heating of the pressure medium causes its volume to consequently be increased, entailing mechanical displacement of the piston towards its initial position. This process continues until the pressure medium is heated to a desired/sufficient amount, i.e. until the piston is displaced back to its initial (intermediary) position.

The cooled intermediate temperature water leaves the pressure vessel 200R via line 132R, and enters the cooling element 410R of the radiator unit 400. In the cooling element 410R, the cooled intermediate temperature water undergoes another heat exchange process in which it absorbs from the surrounding atmosphere the heat lost to the heated pressure medium. Thus, the intermediate temperature water returns to the intermediate temperature water reservoir 130 via line 133R at a temperature close to its initial temperature within the reservoir (at about 25°C).

This concludes the second part of the generator cycle.

In summary, during the full generator cycle can be described as follows:

I) the pressure medium is first heated up (by high temperature water from the high temperature reservoir 110) from about 25°C to about 32- 35°C, displacing the piston from its initial position to a first end position;

II) the pressure medium is cooled back down (by intermediate temperature water from the intermediate temperature water reservoir 130) from 32-35°C to about 25°C, displacing the piston back to its initial position;

III) the pressure medium is cooled down (by low temperature water from the low temperature reservoir 120) from about 25°C to about 15-18°C, displacing the piston from its initial position to a second end position;

IV) the pressure medium is heated back up (by intermediate temperature water from the intermediate temperature water reservoir 130) from 15- 18°C to about 25°C, displacing the piston back to its initial position;

It should be noted that while the low/high temperature water, after passing through the pressure vessel 200R, is returned directly to their respective reservoirs 120, 110, the intermediate temperature water, after passing through the pressure vessel 200R, is passed through the cooling element 410 of the radiator unit 400, in order to respectively convey to/absorb from the atmosphere the required amount of heat gained/lost during the heat exchange process with the pressure medium.

In construction, the high temperature reservoir 110 and the low temperature reservoir 120 constitute part of the air conditioning unit 10, as is observed from Fig. ID. Each of the reservoirs 110, 120 has fully immersed therein a tube array adapted to receive an operating fluid of the air conditioning unit 10, e.g. Freon gas.

In particular, the air conditioning unit 10 has a compressor (not shown) adapted to compress the Freon gas into the tubes of the high temperature reservoir 110 through line 12, such that the heated Freon gas conveys the heat to the water of the high temperature reservoir. The cooled Freon gas then leaves the high temperature reservoir 110 via line 14 back to the air conditioning unit 10. The cooled Freon gas is then provided to the low temperature reservoir 120 via inlet 22, in the tubes of which it is allowed to expand, thereby cooling the water of the low temperature reservoir 120, and leaving it via line 24 back into the air conditioning unit 10. This process takes place repeatedly in order to provide a high temperature water reservoir in the high temperature reservoir 110, and a low temperature water reservoir in the low temperature reservoir 120.

It is appreciated that the above operation was described with respect only to the right pressure vessel 200R, however, a similar operation can be simultaneously performed on the left pressure vessel 200L. Thus, two main operational cycles can be performed as follows: a) simultaneous cycle - both the left and the right pressure vessel 200L, 200R perform steps (I) to (IV) above in parallel. In other words, at any time point throughout the generator cycle, the temperature of the pressure medium in the right pressure vessel 200R is similar to that of the pressure medium in the left pressure vessel 200L, i.e. both pressure mediums heat up simultaneously and cool simultaneously; b) alternating cycle - the pressure vessels 200L, 200R perform steps (I) to (IV) at an offset, e.g. when the right pressure vessel 200R performs step (I) of the cycle, the left pressure vessel 200L performs step (III) of the cycle. In other words, when the pressure medium in the right pressure vessel 200R undergoes heating, the pressure medium in the left pressure vessel 200L undergoes cooling and vise versa.

In general, the pressurized fluid within the pressure vessels 200L, 200R should be chosen such that it has good heat expansion properties (expands considerably under heating), as well as sufficient heat transfer capabilities. Examples of materials used for the pressurized fluid can be (yet not limited to): water, N-Pentene, Diethyl ether, Ethyl Bromide, Methanol, Ethanol, Mercury, acids and others. It should also be understood that the pressurized fluid is not limited to a liquid medium and can be constituted also by a gas material.

The work medium passing through the core 240 should be chosen such that it has sufficient heat transfer properties and a density allowing easy propulsion thereof through the generator 1. Examples of materials used for the pressurized fluid can be (yet not limited to): water, Mercury, Freon and others. It should also be understood that the work medium is not limited to a liquid medium and can be constituted also by a gas material (e.g. Freon in gas form).

Turning now to Figs. 2A to 4A to 4F, unique construction of the pressure vessels 200 and the cores 240 will be described in detail.

Each of the pressure vessel 200L, 200R comprises an external shell 210 made of a material which is both strong enough and thick enough to sufficiently withstand the pressure of the pressurized fluid, i.e. about 5000 atm. An example of such a material can be steel.

Within the pressure vessel 200L, 200R, there passes a core 240 through which the work medium is adapted to pass. The core 240 can be made, on the one hand of a material which is also able to withstand the high pressure within the pressure vessel 200L, 200R, and on the other hand has sufficient heat capacity and heat transfer properties in order to provide an effective heat transfer process between the work medium and the pressurized fluid. Examples of such a material can be Copper- 5 Beryllium, 4340 steel etc.

Particular reference is drawn to Fig. 4B, in which a segment of the core 240 is shown. It is observed that the inner and outer surfaces of the core are formed with surface elements 247 in the form of pyramids. The purpose of the surface elements 247 is to increase the contact area with the work medium and the pressurized fluid, thereby

10 increasing the effectiveness of the heat transfer between the core 240 and the work medium / pressurized fluid. Forming of the elements 247 can be performed by gradual sand spraying on the outside, and on the inside using a designated finishing head (not shown). In this manner, the surface area of the core 240 can be increased by almost 20 times (compared to a smooth inner/outer surface).

15 With particular reference to Fig. 4F, on the core there is mounted a mixing unit

220 adapted for mixing the pressurized fluid during operation of the generator in order to increase its effectiveness. The mixing unit 220 has a central axis X extending in the direction of the core 240 and comprises a plurality of fan blades 224 spread about the central axis X, connected to one another using rings 225. The mixing unit 220 is

20 delimited on each side by a limit ring 223. The fan blades 224 can be made of a material having sufficient insulation properties so as to reduce heat losses to the blades 224 themselves, having low heat capacity to reduce heat absorption and lightweight to minimize the required drive power. Such a material can be, for example, Titanium.

The limit ring 223 is fitted with a spur-gear 229 adapted to mesh with a gear

25 228a mounted on a driving rod 226. The driving rod 226 is driven by an external motor

205L, 250R, the connection being between a gear 228b mounted on the driving rod 226 and a corresponding gear 254 of the driving motor 250R.

It should be noted that according to a particular design, the motor can be located within the pressure vessel, not necessarily outside the vessel - saves on energy required

30 for overcoming dynamic resistance of the shaft and the forces acting in conjunction with the seal. Another option is revolving the shaft using a magnetic mechanism - eliminating the need for complex dynamic seals. As an alternative to the mixing unit 220 described above, attention is drawn to Figs. 7A to 7C, where three variations of passive heat dissipation units 280, 290 and 290' are shown. The heat dissipation unit 280 is in the form of a sleeve 282 from which a plurality of heat dissipating elements 284 extend radially, adapted for increasing the heat transfer between the core 240 and the pressurized fluid. The heat dissipation unit 290 has a central sleeve 292 with radial heat dissipation elements 294 extending therefrom. The heat dissipation unit 290' is generally similar with the difference being in that each of the heat dissipation elements 294' is formed with additional extension 296' for increased heat transfer.

The heat dissipation units 280, 290 and 290' are firmly attached to the core 240 so as to have a maximal surface contact therewith, allowing for better conduction heat transfer.

With particular reference being drawn to Fig. 5A, the pressure vessel 200L, 200R further comprises an inner shell 230 having a diameter smaller than that of the inner surface 214 of the shell 210, and greater than that of the mixing unit 220. Thus, the shell 230 divides the inner space of the pressure vessel 200L, 200R into an inner chamber 232 between the shell 230 and the mixing unit 220, and an outer chamber 234 between the shell 230 and the inner surface 214 of the pressure vessel 200L, 200R. The shell 230 can be made of a material having sufficient insulation properties so as to reduce heat losses to the shell 230 itself, for example, Titanium.

It should be noted that the inner chamber 232 and the outer chamber 234 are in fluid communication with one another since the shell 230 is open at both ends. In operation of the generator 1, separation to an inner chamber 232 and an outer chamber 234 facilitates insulation of the pressurized fluid of the inner chamber 232 by the pressurized fluid in the outer chamber 234 (despite the face they are in fluid communication with one another). Insulation of the pressurized fluid increases the efficiency of the generator 1 by reducing the heat losses to the external steel shell 210. It should also be noted that the circulation created by the mixing unit 240 hardly effects that pressurized fluid contained between the shell 230 and the inner surface of shell 210.

Reverting to Fig. 4F, the core 240 is fitted therein with a drive-screw 248 adapted to revolve about itself in order to propel the work medium through the core 240 (working on a principle similar to the Archemedes screw). The drive-screw 248 is driven by an external motor 260L, 260R, and is connected thereto via meshing of the gear 246 with the gear 264 of the motor 260L, 260R. The drive-screw 248 can be made of a material having sufficient insulation properties so as to reduce heat losses to the drive-screw 248 itself. Examples of such a material can be Titanium or high-strength plastic. It is noted that over variations of the drive screw 248 can be used, as will be evident from Figs. 14F and 14G to be later discussed.

With reference to Figs. 3C and 4E, each of the pressure vessels 200R, 200L is fitted at both ends thereof with a sealing assembly 270, comprising a head seal 272 fastened by bolts, a main seal body 273 onto which three sealing members 274 are mounted, an auxiliary seal assembly 276 and a soft sealing member 278. In addition, there are provided two seals 276', 278' of similar design (shown Fig. 3C), used for sealing the space between the main seal body 273 and the core 240.

Turning now to Figs. 3 A to 3E, the mechanical power assembly 300 and the power generator unit 500 will now be described in detail. Each of the pressure vessels 200L, 200R is fitted at one end thereof with a mechanical power assembly 300L, 300R. Since both mechanical power assemblies 300L, 300R are essentially similar, only one of them will now be described in detail, understanding that the description holds true for the other assembly as well.

The mechanical power assembly 300R is in maintained in fluid communication with the pressure vessel 200R via an outlet port 216R. The mechanical power assembly 300R comprises a piston unit 320R, and a pressure regulator 340R.

The piston unit 320R has a hollow housing 322 and a neck portion 324 articulated to the port 216 of the pressure vessel 200R. The neck portion 324 is formed with an inlet orifice 326 providing fluid communication between the pressure vessel 200R and the neck portion 324.

Within the housing 322 there is contained a displaceable piston 330 having a head portion 332 snugly and sealingly received within the housing 322 by o-rings 333, and a neck portion 334 snugly received within the neck portion 324. Thus, the housing 322 is divided into an inlet chamber 323i being in fluid communication with the pressure vessel 200R to receive therein the pressure medium, and an outlet chamber 323o, the chambers being isolated from one another by the heat portion 332.

The design of the piston unit 320 is such that the inlet chamber 323i is adapted to contain therein some of the pressure medium and the outlet chamber 323o is adapted to contain therein an auxiliary work medium, adapted for operating the generator unit 500. Such a fluid can be, for example, machine oil or the like. The housing 322 is further formed with an outlet port 325 through which the auxiliary fluid can leave the piston unit towards the generator unit 500.

In operation, during stage (I) of the generator cycle, the pressure medium heat 5 up and its volume increases, thereby flowing into the inlet chamber 323i, pushing the head portion 332 of the piston 330 towards the bottom 328 of the housing 322. As a result, the auxiliary work medium contained within the outlet chamber 323<j is pressured out through the outlet port 325 and into line 302.

During stages (II) and (HI) of the cycle, the pressure medium cools down and its 10 volume decreases, thereby flowing from the inlet chamber 323i back into the pressure vessel 200R, pulling the head portion 332 of the piston 330 towards the neck portion 324 of the housing 322. As a result, the auxiliary work medium is sucked back into the outlet chamber 323o-

The piston 330 is designed such that the cross-sectional area of the head portion 15 322 is 20 times greater than that of the cross-sectional area of the neck portion 324, thereby reducing the pressure in the outlet chamber 323o from 5000 atm. to about 250 atm. The back and forth movement of the auxiliary fluid is used for operating a piston of the motor 520 (Figs. 6A and 6B), which is in turn used for the generation of electricity.

20 In addition, the auxiliary work medium is also in fluid communication with the pressure regulator 340 situated between the piston unit 320 and the generator unit 500. The pressure regulator 340 is formed with a housing 342 holding therein a piston 350 biased by a compression spring 360. According to alternative examples the piston 350 can be biased by a compresses gas, e.g. Nitrogen. The pressure regulator 340 is formed

25 with a T-junction member 343 having an inlet port 345 adapted to receive line 302, a housing inlet 346 and an outlet port 347 connected to line 304.

In operation, most of the auxiliary fluid leaving the outlet chamber 323o of the piston unit 320 via line 302 flows directly, through the T-junction 343 into line 304 via outlet 345, while the remainder of the auxiliary fluid flows into the pressure regulator

30 340. Thus, upon an undesired increase of pressure, the piston 350 of the pressure regulator 340 is pushed against the biasing force of the spring 360, whereby the pressure of the auxiliary fluid within line 304 leading to the generator unit 500 is maintained at a desire pressure. The pressure regulator also functions as a synchronizer of the piston movement in the following manner: if the expansion of the pressure medium in one pressure vessel is too great, and the piston of the other pressure vessel has no room to "retreat", the gas piston will absorb the additional pressure, and will return it upon reciprocation of the mechanism. More particularly, any additional pressure provided to the piston which should not be expressed in movement of the opposite piton is absorbed by the gas piston 340, and alternatively, upon a shortage of pressure, the gas piston 340 compensates for the above shortage.

Turning now to Figs. 6A and 6C, the generator unit 500 will now be described in detail. The generator unit 500 comprises a motion converter 520 and a power unit 540. The motion converter 520 comprises a base housing 510, and two piston housings 522R, 522L, each connected at one end to the main conversion unit and at the other end to line 304.

The base housing is formed of a top member 512 and a bottom member 514 (of similar design), each member being formed with a channel 516 such that when the two members are attached, there is formed a space 518 (not shown) in which a center plate 513 is adapted to reciprocate.

The center plate 513 is fitted with a cam follower 517 via stud 515. The cam follower 517 is adapted to revolve about a second stud 519 under reciprocation of the center plate 513. The cam follower 517 is fixedly attached to plate 511, such that revolution of the cam follower 517 about the stud 519 entails revolution of the plate 511 about its central axis X. A fly wheel (not shown) can also be provided between the gear and the generator in order to overcome top/bottom "dead points".

The housing 522R (only one will be described since they are both of similar design), comprises a piston 530R adapted to reciprocate therein, forming in the housing 522R an inlet chamber 524R. The housing 522R is formed with an inlet 526R providing fluid communication between the inlet chamber 524R and the auxiliary work medium incoming from line 304. The pistons 530R and 530L are formed at one end with a head portion 532R, 532L, located closer to the inlets 526R, 526L respectively, and at the other, opposite end, are integrally formed with the center plate 513.

In operation, for example under an alternating cycle as described above, during stage I of the cycle, the pressurized fluid in the right chamber 200R heats up and increases in volume, the pressurized fluid in the left chamber 200L cools down and decreases in volume. As a result, the auxiliary work medium in the right piston unit 320R is urged towards the piston 530R pushing on it, while the auxiliary work medium in the left piston unit 320R is sucked in, pulling on the piston 530L. During this stage, the movement of the pistons 530R, 530L displaced the center plate 513 in one direction.

Thereafter, during stages II and III of the cycle, a reverse operation takes place, i.e. the pressurized fluid in the left chamber 200L heats up and increases in volume, the pressurized fluid in the right chamber 200R cools down and decreases in volume. As a result, the auxiliary work medium in the left piston unit 320R is urged towards the piston 530L, pushing on it. The movement of the pistons 530R, 530L displaced the center plate 513 in the other direction, as seen in Figs. 6B and 6C.

Reciprocation of the center plate 513 entails revolution of the cam follower 517 resulting in revolution of the plate 511 about its central axis. This rotational movement is converted into electrical energy by the power unit 540.

Reverting to Fig. IB, a part of the electrical power generated by the power unit 540 is provided to the output, a part for the air conditioning unit 10, and the remainder is provided to a battery 50. The battery 50 can be used for jump starting the system.

It is appreciated, that the above described system 1 can produce at least up to 4 times the amount of electricity used for its operation, i.e. if the generator 1 requires lkwh (kilowatts per hour) for its operation, it can produce at least up to 4kwh of electricity. It should also be understood that this profit in electricity is gained by performing a heat exchange process with the environment, i.e. using the surrounding medium (air, water) to absorb/convey heat to the water running through the radiator 400.

In particular, the use of an air conditioning unit 10 allows for the significant gain in electricity production. As opposed to intermediate air conditioning systems in which, the heat produced during cooling of a space (e.g. a room) is expelled to the outside environment (heat emitted to the outside of the room by the air conditioning system), in the present generator, this heat does not go to waste and is used for heating the water in the high temperature reservoir.

Experimental analysis of the generator 1 are disclosed in Figs. 8A to 8F, showing diagrams of the temperature fluctuation of the work medium and of the pressurized fluid under different cycle times. Turning to Fig. 9 The generator 1 can also comprise an accumulator arrangement 590 filled with a storage medium, e.g. water, where, in the event that an excess amount of electricity is produced by the generator 1, this excess amount will be diverted to a heating body used for heating the water within the accumulator 5 arrangement 590. In this manner, the accumulator arrangement 590 can function as a battery.

For example, when the water in the accumulator arrangement 590 is heated to a desired degree, e.g. to a temperature similar to the temperature of the high temperature reservoir 110, the high temperature water for the operation of the generator 1 can be

10 provided by the accumulator arrangement 590 instead of by the high temperature reservoir 110. As a result, the operation of the air conditioning unit 10 can be reduced (or even be completely interrupted), allowing it to consume less electricity.

Once the amount of electricity produced by the generator 1 is commensurate to the desired consumption, the air conditioning unit 10 returns to normal operation and

15 the water in the accumulator arrangement 590 will gradually be cooled down. In addition, increased pressure within the accumulator arrangement can allow heating it above the boiling point of the work medium, in order to accumulate more heat. For example: water at 5atm (standard household pressure) can boil at 150°C.

Furthermore, the accumulator arrangement 590 can comprise a heating element

20 configured for directly heating up the water in the accumulator arrangement in order to maintain therein a desired temperature.

The generator 1 can also comprise a controller (not shown) adapted to monitor the temperature of the pressurized fluid, the work medium, the temperature of the water in the accumulator arrangement 590, the displacement of the pistons 330R, 330L,

25 530R, 530L, the pressure within the pressure regulator 340, the displacement of the center plate 513 etc. The controller can be used to control the operation of the distribution valves 140, the operation of the motors 250, 260, the displacement of the pistons etc.

Turning now to Figs. 11 A and 1 IB, another example of the generator is shown, 30 generally designated as 1', and comprising an air conditioning unit 10 connected to a work medium sub-system 100', two pressure vessels 200', a mechanical power assembly 300, a radiator unit 400, a power generator unit 500, a gradient assembly 600, an accumulator unit 50 and output. In principle, the generator 1' is similar in design to the generator 1 previously described, with the difference being in the design and number of the cores passing through the pressure vessels 200', a different design of the radiator unit 400', the additional gradient assembly 600, and corresponding valves and piping associating various components of the generator to one another.

Firstly, the gradient assembly 600 and its utilization in the generator 1' will be described in detail with respect to Figs. 12A to 12D:

At an initial position of the generator (when the generator is at rest), the piping of the generator are filled with work medium at a predetermined pressure, the work medium being at an intermediate temperature. Consequently, the pressure medium is also at the intermediate temperature.

During a first stage of operation of the generator, the air conditioning unit AC begins its operation, heating up the work medium in the high reservoir 110' and cooling down the work medium in the low temperature reservoir 120'. The intermediate reservoir 130' has working medium remaining at intermediate temperature. Once the work medium in the high/low temperature reservoirs 110', 120' respectively has reached its desired temperature, the driving mechanisms 250', 260' begin their operation as follows:

(a) (i) high temperature work medium from the high reservoir 110' is passed through the right pressure vessel 200R so as to heat up the pressure medium, and is re-circulated through lines P _H R back into the high temperature reservoir 110' (lines Li, L ₂ );

(ii) simultaneously, low temperature work medium from the high temperature reservoir 120' is passed through the left pressure vessel 200L so as to cool down the pressure medium, and is re-circulated through lines PcR back into the low temperature reservoir 120' (lines Li, L3);

(iii) step (a) continues until the pressure medium in each pressure vessel 200R', 200L' reaches a desired high temperature THOT/TCOLD respectively;

(b) (i) work medium at intermediate temperature from the intermediate reservoir

130' is passed through pressure vessel 200R' so as to be heated up by the hot pressure medium, thereby removing heat therefrom;

(ii) simultaneously, work medium at intermediate temperature from the intermediate reservoir 130' is passed through pressure vessel 200L' so as to be cooled down by the cold pressure medium, thereby providing heat thereto;

(c) (i) the heated intermediate temperature work medium is passed into the gradient tank 600R (lines L _L5 L4), having a temperature gradient therein, so that the top portion of the gradient tank 600R contains a hotter heated intermediate temperature work medium than the bottom portion of the gradient tank 600R;

(ii) simultaneously, the cooled intermediate temperature work medium is passed into the gradient tank 600L (lines Li, L4), having a temperature gradient therein, so that the top portion of the gradient tank 600R contains a cooler cooled intermediate temperature work medium than the bottom portion of the gradient tank 600L;

(iii) this stage continues until the intermediate temperature work medium reaches a desired temperature in each of the gradient tanks 600R, 600L; (d) (i) heated intermediate temperature work medium is passed from the gradient tank 600R to the front of the generator, where it re-enters the left pressure vessel 200L' (see lines L^H, L ₇ C in Fig. 17A), thereby further providing heat to the cold pressure medium and heating it up back to a temperature close to INTERMEDIATE;

(ii) Simultaneously, cooled intermediate temperature work medium is passed from the gradient tank 600L to the front of the generator, where it re-enters the right pressure vessel 200R' (lines ec, Lra in Fig. 17A) thereby further removing heat from the hot pressure medium and cooling it down back to a temperature close to INTERMEDIATE;

(iii) this step continues until the pressure medium in both pressure vessels

200R' and 200L' is at a temperature of INTER EDIATE;

Steps (a) to (d) then repeat themselves but in an opposite manner, i.e. high temperature work medium is now passed through the left pressure vessel 200L' and low temperature work medium is passed through the right pressure vessel 200R', and so on.

It is appreciated that the first portion of the heated intermediate temperature work medium entering the gradient tank 600R is the hotter than the next portion of intermediate temperature work medium passing into the gradient tank 600R, and respectively, the first portion of the cooled intermediate temperature work medium entering the gradient tank 600L is the cooler than the next portion of intermediate temperature work medium passing into the gradient tank 600L.

This cross-over step provides for many advantages, one of which is a better heat transfer process with the pressure medium. In particular, it is noted that in each vessel, the pressure medium first performs a heat transfer process with intermediate temperature work medium at temperature THMTER EDIATE (steps (b)(i) and (b)(ii)), and thereafter an additional heat transfer process with a heated/cooled intermediate temperature work medium (steps (c)(i) and (c)(ii)).

It is noted that during steps (b)(i) and (b)(ii), the intermediate temperature work medium contained in the gradient tanks 600R, 600L, flows through lines LSR, LSL and _L5 into the radiator, where any accumulated heat of the generator can be removed via a heat transfer process with the outside environment.

With particular reference being drawn to Fig. 12C, the gradient tanks 600R, 600L are formed with a spiral structure 620R, 620L, configured for preventing the different portions of the heated/cooled intermediate work medium from performing a heat exchange process therebetween, and thus maintaining a temperature gradient within the reservoirs 600R, 600L.

Turning now to Fig. 13 A, further piping arrangements of the generator are shown, in particular:

L3 - leading low temperature water which has passed through the pressure vessel back to the low temperature reservoir 120';

L5', L _5L ' - leading intermediate temperature water after passing through the radiator back into the intermediate reservoir 130';

Ls - leading intermediate temperature work medium back to the intermediate reservoir 130; and

L9 - leading intermediate temperature water back to the rear of the generator towards the gradient tanks 600R, 600L.

With reference to Fig. 13B, it is observed that the low temperature reservoir 120' comprises a heat transfer element 124' configured for cooling the work medium in the reservoir 120' by constituting a condenser of the air conditioning unit AC. The reservoir 120' further comprises a fan 128' driven by an external motor 126', configured for maintaining a uniform temperature within the reservoir 120'. Turning now to Figs. 14A to 14D, the driving mechanism of the work medium and the cores of the pressure vessels 200R', 200L' will be described:

It is observed that, whereas the previously described generator 1 only has one core 240 per vessel, the presently described generator 1' has six cores 240' per vessel, 5 each having a design similar to that of the previously described core 240.

In order to circulate the work medium through all cores 240 simultaneously, a motor 250' is provided, configured for driving a gear 254' meshing with a gear 256', which in turn drives a mutual gear 259', meshing with the respective gears 242' of each of the cores 240. The gears 242' are responsible for the rotation of the drive screw (not 10 shown) which propels the work medium through the entire generator piping system.

In addition, there is provided a secondary drive motor 260', configured for revolving the cores 240' the fan arrangement 220' of each of the cores 240' about the axis of the cores (it is noted that in some application, even the cores themselves can revolve about their axis). The drive motor 260' is configured to be meshed with the 15 mutual drive wheel 269', which, in turn, meshes with the gears 222' of the fan arrangement 220'.

It is noted that the generator further comprises an additional array of driving motors 250', 260' located at a rear side of the generator, i.e. at the other end of the pressure vessels 200R', 200L'. In this manner, the driving load is distributed between 20 the front array and the rear array of motors.

With particular reference being drawn to Figs. 14E and 14F, the drive screw used in the presently described generator can be of a different design, the difference lying in the pitch angle of the screw (70 deg.), which further contributes to circulation of the work medium through the core 240' and to pushing the work medium towards the 25 inner surface of the core 240'.

Turning now to Figs. 15A to 15C, a controller of the generator 1' is shown, generally designated as 700. The controller 700 is positioned so as to interject between line Lo exiting the pressure vessel 200' and line Li leading to the valve 140'. The purpose of the controller 700 is to regulate the flow rate Q from the pressure vessel 30 200', by controlling the cross-sectional area through which the work medium is passed.

With particular reference to Fig. 15C, the controller 700 comprises a casing. 720 formed with an inlet hole 722 in fluid communication with line Lo, and an outlet hole 724 in fluid communication with line Li. The controller 700 further comprises a plunger 740 formed with a top portion 742, a neck portion 744 and a main block 746. The main block 746 is formed with a passageway 748, and a spring is mounted onto the neck portion 744, pressing against the casing, so as to bias the plunger 740 downwards.

Thus, when the passageway 748 is aligned with the inlet/outlet holes 722, 744, a maximal cross-sectional flow area is provided. When the plunger is shifted, and the passageway 748 is misaligned, the cross-sectional flow area reduces. By controlling the load of the spring, e.g. by any conventional means such as screws (not shown), it can be possible to regulate the flow rate through the generator 1'.

Turning now to Figs. 16A and 16B, the accumulator arrangement 590 is shown when used in the generator 1' described above. The reservoir 590 has two lines Lio leading thereto, one from each pressure vessel 200'. In addition, the accumulator arrangement 590 further has lines Ln leading thereto from the rear side of the generator 1'. The storage reservoirs also have an outlet line 592 leading to a user port (not shown). The accumulator arrangement 590 may, as previously described, comprise a heating element therein, configured for heating up the work medium contained therein.

In general, the accumulator arrangement 590 can be used to accumulate excess energy produced by the generator 1'. More specifically, any additional energy generated by the generator 1' (i.e. energy not consumed by a user) can be diverted to heating up the work medium contained in the accumulator arrangement 590. The heated work medium of the accumulator arrangement 590 can later be used instead of the high temperature work medium produced in the high temperature reservoir 110' by the air conditioning unit AC, thereby saving on the power of the AC.

Alternatively, the pressure of the work medium in the accumulator arrangement 590 can be increased (greater than that required to the end user of line 592) so that the boiling point of the work medium increases, thereby allowing the work medium in the accumulator arrangement to absorb more energy.

Turning now to Figs. 17A to 17D, the valves and piping system of the generator 1' are displayed:

Vi - main front valve, having inlets/outlets to the following lines:

LH - outlet pipe from the high temperature reservoir 110';

Lc - outlet pipe from the low temperature reservoir 120';

Lio - outlet pipe leading to the accumulator arrangement 590;

L - main core line leading work medium into the pressure vessels 200'; and L6C, LeH - cross-over lines, leading work medium from a gradient tank 600 to an opposite pressure vessel 200'.

V2 - auxiliary front valve, having inlets/outlets to the following lines:

LSL', LSR' (splitting from L5') - lines leading intermediate temperature work medium at intermediate temperature from the gradient tanks 600;

Lg - leading intermediate temperature work medium back to the intermediate reservoir 130'; and

L9 - leading intermediate temperature work medium to the rear of the generator 1' to provide pressure.

V3 - main rear valve, having inlets/outlets to the following lines:

Li - leading work medium from the core of the pressure vessels 200';

L ₂ - leading high temperature work medium back to the high temperature reservoir 110';

L3 - leading low temperature work medium back to the low temperature reservoir 120';

L4 - leading intermediate temperature work medium to the gradient tank 600; and

L9 - leading intermediate temperature work medium to the rear of the generator 1' to provide pressure.

V4 - auxiliary rear valve, having inlets/outlets to the following lines:

L4 - leading intermediate temperature work medium to the gradient tank 600; L5 - leading intermediate temperature work medium to the gradient tank 600; and

L<6C _? L6H - cross-over lines, leading work medium from a gradient tank 600 to an opposite pressure vessel 200'.

Turning now to Fig. 17E, a schematic chart of the temperature of the work medium passing through the core is shown, one for each of the pressure vessels 200R', 200L'. The chart can be divided into the following sections:

Si - equivalent to step (a)(i) of a first half-cycle described above - high temperature work medium at temperature THOT of 15°C is passed through the core from t ~ lOsec to t = 15sec; 52 - equivalent to step (b)(i) of a first half-cycle described above - intermediate temperature work medium at temperature I NTERMEDIATE are passed through the core from t = 15sec to t ~ 20sec;

53 - equivalent to step (d)(i) of a first half-cycle described above - cooled intermediate temperature work medium at a gradient temperature from the gradient tank

600 of the opposite pressure vessel 200' is passed through the core from t ~ 20sec to t ~ 25sec;

54 - equivalent to step (a)(i) of a second half-cycle described above, where the pressure vessels trade place - low temperature work medium at TCOLD is passed through the core from t ~ 25sec to t ~ 30sec;

55 - equivalent to step (b)(i) of a second half-cycle described above - intermediate temperature work medium at TINTERMEDI _A TE is passed through the pressure vessels 200' from t ~ 30sec to t ~ 35sec; and

Se - equivalent to step (d)(i) of a second half-cycle described above - heated intermediate temperature work medium at a gradient temperature from the gradient tank 600 of the opposite pressure vessel 200' is passed through the core from t ~ 35sec to t ~ 40sec;

This concludes a full cycle of the generator 1'. It is appreciated that the lower chart depicts the temperature of the work medium passing through the core of the opposite pressure vessel. Thus, the above stages are applicable to the lower chart, with the changing of the index from (i) to (ii), e.g. step (b)(ii) instead of step (b)(i).

Turning now to Figs. 18A to 18G, a vehicle is shown, generally designated as 800, in which a modified version of generator 1' is employed, generally designated as 1". It is observed that the containers of the work medium are disposed at the front F of the vehicle 800 while all the movement generating mechanisms are located at the rear R of the vehicle 800. The pressure vessels 200' are disposed horizontally along the chassis 820 of the vehicle, connecting between the front F and the rear R.

Unlike the generator 1' described above, in the present generator, the gradient tanks 600 are located on the same side f the pressure vessels 200' as the work medium reservoirs 110', 120' and 130'.

It is also appreciated that the disposition of the pressure vessels 200' provides the vehicle 800 with extra stability due to the weight of the pressure vessels 200'. It is also appreciated that since the vehicle 800 is usually in movement when the generator 1' is active, the efficiency of the operation of the radiator 400 can be considerably improved due to the increase in the heat transfer coefficient between the moving vehicle 800 and the ambient air.

Turning now to Figs. 19A to 19F. a marine vessel generally designated 900 is shown comprising a modified version of the previously described generator 1', generally designated as 1"'.

It is noted that in the generator 1"', the intermediate reservoir 130' is missing. The reason for this is that the generator 1"' uses the water it is submerged in as its main work medium, and therefore, the reservoir holding the water in which it is submerged (lake, ocean, pool) replaces the reservoir 130'. In order to utilize the medium, two lines I are provided, allowing the generator to withdraw water from the above medium into the generator 1"'.

Turning now to Figs. 20A and 20B, there is shown a cross-section of a core of the pressure vessel 200' when without pressure and when pressure is applied thereto respectively. It is observed that the inner surface of the core is lined with an inner layer 1000 having an increased surface area due to micro-structures 1100 formed thereon. Increasing the surface area is desired in order to increase the heat transfer coefficient between the inner layer and the work medium flowing through the core.

Fig. 20C shows the core of the vessel 200' with the spiral 240' passing therein, configured for causing progression of the work medium through the pressure vessel 200' and the entire generator system 1.

Turning now to Figs. 21 A to 21G, a method for producing the inner layer is shown, including the following steps:

(a) providing a generally planar plate 1000' having a first face Fi and an opposite second face F ₂ ;

(b) pre-forming the micro-structures 1100 on the first face Fi using two pressing wheels Wi, W ₂ one of which is formed with a corresponding surface MS for forming the micro-structures 1100;

(c) providing a mold M formed with a non-through going cavity C corresponding in size and shape to the plate 1000', the cavity C having a base surface and an opening at a surface of the mold M;

(d) placing the plate 1000' in the cavity such that the second face F ₂ is mated against the base surface and the first face Fi is facing the opening of the cavity C, such that there remains a space between the first face Fi and the opening;

(e) introducing a filler material F into the cavity C so as to fill the space, including spaces formed between the micro-structures MS;

(f) letting the filler material F solidify so as to form a single plate constituted by the plate 1000' and solidified filler material F, having a first face constituted by the filler material and a second face F ₂ constituted by the second face of the original plate 1000';

(g) deforming the single plate by a pressure block PB and a deformation mold D, to obtain at least a partially cylindrical shape of diameter Dm, such that the second face F ₂ of the single plate 1000' constitutes and outer surface of the cylinder and the first face of the single plate constituted an inner surface of the cylinder;

(h) removing the filler material F from the single plate 1000', thereby resulting in the original plate 1000 having micro-structures MS formed on the inner surface thereof; and

(i) performing a final finish on the inner surface with the micro-structures.

With reference to Figs. 2GD and 20E, another example of a core is shown generally designated as 240", which formed, both on its inner surface and on its outer surface, with ridges 246" and 247" respectively. This core 240" can be made of tungsten or other materials (see Figs. 26A, 26B), and its design provides for a more robust core 240".

It is noted that the ridges 246" and 247" are designed such that the peak of one is opposite the trough of another and vise versa, so that the thickness in each point along the central axis X is generally the same (N).

The ridges 246", 247" can be parallel as in the present example, or, alternatively, be in the form of one spiraling ridge (as in a thread). One advantage of the latter example is the simplicity of production - the external ridges 247" can be made by turning and the internal ridges 246" can be formed by a tap.

Turning now to Figs. 22A and 22B, still another example of the generator is shown, generally designated as 2000 which is generally similar in construction to the generator 1 previously described, but differs from it mainly by the design of the work medium sub-system 2100 (as opposed to the work medium sub-system 100). The work medium subs-system 2100 is in the form of a cascade arrangement 2150 which comprises a high temperature reservoir 2110 and a low temperature reservoir 2120, without an intermediate work medium reservoir as in the previous examples.

5 Each of the pressure vessels 2200R, 2200L is provided at its inlet end with a respective inlet line 2136R, 2136L, regulated by respective valves 2140B and 2140A, and at its outlet end with a respective inlet line 2146R, 2146L, regulated by respective valves 2140D and 2140C.

An outlet end of the high temperature reservoir 2110 is connected to the valves 10 2140B and 2140A via respective lines 2134R, 2134L, and an inlet end of the high temperature reservoir 2110 is connected to the valves 2140D and 2140C via respective lines 2144R, 2144L.

An outlet end of the low temperature reservoir 2120 is connected to the valves 2140B and 2140A via respective lines 2132R, 2132L, and an inlet end of the low 15 temperature reservoir 2120 is connected to the valves 2140D and 2140C via respective lines 2142R, 2142L.

In the present generator (as in previously described examples), in the initial position, the pressure fluid within the pressure vessel is at the temperature TENV which is roughly the temperature of the environment. The initial steps of the operation cycle of 20 the presently described generator can be described as follows:

(a) passing high temperature water from the high temperature reservoir 2110, at a temperature T _H through the pressure vessel so as to heat up the pressure fluid contained therein. This results in heating the pressure fluid to a temperature of T ₀ t > TENV (however T ₀ t < T _H ) and simultaneously in

25 cooling of the high temperature work medium to a temperature T _H -cooied <

T _H ;

(b) passing low temperature work medium from the low temperature reservoir 2120, at a temperature Tc < TENV through the pressure vessel so as to cool down the heated pressure fluid contained therein. This results in cooling the

30 pressure fluid from a temperature of T _h0 t to a temperature T _CO i _d > Tc, and simultaneously in heating the low temperature water to a temperature Tc-

Heated > Tc. Thereafter, steps (a) and (b) repeat themselves, with the difference being that the pressure fluid now constantly fluctuates between the temperatures T _h0 t and T _co i _d .

Simultaneously with the performance of step (a), the heated low temperature work medium, which is now at a temperature of Tc-Heated > Tc, is cooled down by performing a heat exchange process with the environment which is at a temperature TENV < c-Heated- This process is regulated by a radiator unit 2400 (shown Figs. 22A, 22B). In addition, simultaneously with the performance of step (b), the cooled high temperature work medium, which is now at a temperature of T _H -cooied < TH, is heated up by the A/C system, bringing it back to the temperature TH.

It is appreciated that while step (a) takes place in one pressure vessel (for example vessel 2200R), the second pressure vessel 2200L undergoes step (b). Thus, the pressure vessels keep alternating - while the pressure fluid in one heats up, the pressure fluid in the other is cooled down and vise versa.

Turning now to Figs. 23A to 23F, the main difference in the design of the work medium sub-system 2100 is that the A/C previously used to provide the high/low temperature reservoirs at the respective condenser/evaporator sections of the A/C is now replaced by a cascade arrangement 2150, having several grades Gi to G ₇ , each operating as a basic A/C compression/expansion mechanism as will now be explained. The arrangement is such that the cascade 2150 has a first end-grade Gi which provides the 'low' for the low temperature reservoir 2120 and a second end-grade G ₇ which provides the heat for the high temperature reservoir 2110.

Each of the grades G _(n) comprises a compressor C _(n) , a condenser section 2152 _(n) , an expansion valve 2154(„ ₎ , an evaporator section 2156(„ ₎ and a return pipe 2158 _(n) to the compressor C(„ ₎ , where (n) denotes the number of the grade G.

Each of the grades Gi to G ₇ comprises a compressible fluid (gas or liquid), and is designed to operate between a high fluid temperature ΤΗ _(Π) at the respective condenser section 2152(„) and a low temperature Tc( _n) at the respective evaporator section 2156(„).

The arrangement is such that the condenser section 2152 _(n) of one grade G ₍ „ ₎ and the evaporator section 2156 _(n) of a subsequent grade G _(n+ i ₎ are thermally coupled to provide a heat exchange process. Specifically, the arrangement is of concentric tubes where the condenser section 2152(„ ₎ is constituted by the inner tube and the evaporator section 2156(„ ₎ is constituted by the outer tube. Under this arrangement, compressed fluid from one grade G _(n) flows within the inner tube and performs a heat exchange process with the expanded fluid from the subsequent grade G( _n+ i> which flows between the inner surface of the outer tube and the outer surface of the inner tube (see Fig. 23E).

The cascade arrangement 2150 is designed such that the temperature Tc( _n) of the fluid in the evaporator section 2156 _(n) of one grade G _(n > is lower than the condensation temperature of the fluid flowing in the subsequent grade G _(n+ i>, and necessarily lower than the temperature ΤΉ( _η+ ΐ ₎ of the fluid in the condenser section 2152( _n+ i ₎ of that grade G ₍ n ₊ i ₎ . As a result, a heat exchange process takes place where the expanded fluid of one grade G _(n) takes up the heat from the compressed fluid of the subsequent grade G _(n+ i ₎ .

However, it is appreciated that the temperature Tc _(n+ i ₎ of the cooled-down fluid of the subsequent grade G _(n+ i ₎

An example of the temperatures Tc(n), Η _Π ) and TCOND are shown below:

In practice, the evaporator section 2156i of the first grade Gi is submerged within the low temperature reservoir 2120 bringing the low temperature water to a temperature of about 3°C, and the condenser section 2152 ₇ of the seventh grade is submerged within the high temperature reservoir 2110 bringing the high temperature water to a temperature of about 242°C. It is appreciated that the high/low temperatures of the high/low temperature reservoirs 2110, 2120 never reach the temperature of the respective condenser/evaporator sections 2152 ₇ , 2156i, and are always slightly lower/higher respectively.

It is observed from Figs. 22A and 22B, that the generator 2000 is fitted with a front and a rear driving motor 2250F and 2250R respectively configured for driving the cores of the pressure vessels 2200, and with a front and a rear driving motor 2260F and 2260R configured for driving the spiral for circulating the work medium within the generator 2000.

The use of front and rear motors for driving the same element facilitates lower loads exerted on the revolved element (core or spiral) which are positioned within a high pressure environment. Should only one motor be used, the core and/or spiral will tend to bend within the pressure vessel, which can lead to damage of the mechanical integrity of the system.

Reverting now to Fig. 22D, the radiator unit 2400 is shown positioned along the lines 2146R, 2146L leading from the pressure vessels 2200R, 2200L to the low temperature reservoir 2120. The purpose of the radiator unit 2400 is to provide for a heat exchange process between the heated low temperature water flowing in these lines (at a temperature of Tc-Heated) and the ambient air of the environment.

The radiator unit is fitted with a fan (not shown) and control unit (not shown) configured for regulating the operation of the fan, so that the low temperature water leaving the radiator remain essentially at a constant temperature. For example, if Tc- Heated is about 50°C, it is required to lower this temperature down to about 20°C to allow the first grade Gi to perform efficiently. Thus, the control unit is used to maintain the low temperature water leaving the radiator at a temperature of about 20°C.

The control unit can comprise a sensor associated with line 2149 of the low temperature water emitted from the radiator and configured for measuring its temperature. Should this temperature exceed the predetermined temperature (in this particular example 20°C), the control unit will cause the fan to revolve faster in order to increase the heat-exchange rate within the radiator unit 2400. Alternatively, should this temperature be lower than the predetermined temperature (in this particular example 20°C), the control unit will cause the fan to revolve slower in order to decrease the heat- exchange rate within the radiator unit 2400.

Turning now to Figs. 24A to 24D, another example of a cascade arrangement is shown generally designated as 2150', and configured for adjusting its operation mode to the ambient temperature of the outside environment.

The difference between the currently described cascade arrangement 2150' and the cascade arrangement 2150 previously described with respect to Figs. 23A to 23F lies in the design of the first and second grade Gi, G ₂ , and in particular, in the bypass arrangement 2170 associated therewith. In general, it can be that at different times, the ambient temperature of the environment increases to an extent when it exceeds the temperature of the compressed fluid in the condensation section 2152 ₂ of the second grade G ₂ . In such case, the low temperature water emitted from the radiator unit after performing a heat exchange process therewith will also be at a temperature exceeding that of the compressed fluid in the condensation section 2152 ₂ of the second grade G ₂ .

As a result, the evaporator section 2156i of the first grade Gi will be submerged in a very hot environment. Since each grade is fitted with a compressor of predetermined power and is design for a predetermined temperature difference Δ, the compressor Cj simply will not be able to remove so much heat from the evaporator section 2156i rendering the operation of the first grade Gi inefficient.

In order to overcome this, a bypass arrangement 2170 is used, configured to bypass the first grade Gi and connect the low temperature reservoir 2120 with the evaporator of the second grade G ₂ .

Specifically, the bypass arrangement 2170 comprises two valves 2172 _A , 2172B associated with the evaporator section of the second grade G ₂ and the compressor C ₂ of the second grade respectively. The bypass arrangement 2170 has an expansion valve 2174 leading to an evaporator section 2176 which is in the form of a tube leading into the low temperature reservoir 2120, and an outlet lien 2178 leading out of the low temperature reservoir 2120.

Under a normal operation mode, when the temperature of the environment is lower than the temperature of the compressed fluid in the second grade G ₂ , ports Ai and Bi are open and ports A ₂ and B ₂ are closed, and the cascade arrangement 2150 operates in a manner identical to that of the cascade arrangement 2150.

Once the temperature of the ambient air of the outside environment rises beyond the temperature of the compressed fluid in the second grade G ₂ , ports Ai and Bi are closed and ports A ₂ and B ₂ are open to allow the following:

Compressed fluid from the condenser section 2152 ₂ of the second grade G ₂ passes to the expansion valve 2174 allowing the fluid to expand and cool down. After passing through the expansion valve 2174, the expanded fluid progresses along the line 2176 to pass into the low temperature reservoir 2120 where it cools down the water and is emitted (slightly heated) through line 2178 leading to the compressor C ₂ . It is appreciated that whereas in the normal operation mode the temperature difference between the low temperature reservoir 2120 and the high temperature reservoir 2110 was about 240°C (between 3°C provided by the 0°C of the first grade evaporator 2156i and 242°C provided by the 242°C of the seventh grade condenser 2152 ₇ ), the temperature difference now is about 210°C between 30°C provided by the 27°C of the second grade evaporator 2156 ₂ and 242°C provided by the 242°C of the seventh grade condenser 2152 .

In other words, while reducing the overall temperature difference of the cascade arrangement 2150', the efficiency remains generally the same, on account of eliminating from the process the operation of the first grade Gi of the cascade arrangement 2150Ά

Turning now to Figs. 25A and 25B, another example of a cascade arrangement is shown generally designated as 2150", which is similar to the previously described cascade arrangement 2150, with the difference being in that the flow of the fluids in the heat exchanger of each grade is now in opposite directions (as opposed to parallel flow in the previously described example).

Specifically, compressed fluid of the first grade Gi flows through its respective condenser section 2152i" in one direction, while expanded fluid of the second grade G ₂ flows through its respective evaporator section 2156 ₂ " in the opposite direction. As well known, counterflow heat exchangers provide for higher efficiency of the heat exchanger and consequently for a more efficient operation of the cascade arrangement 2150".

It is also noted that while the present example of the cascade arrangement 2150" is shown without a bypass arrangement 2170 (see Figs. 24A to 24D) as in the previous example of cascade arrangement 2150', such a bypass arrangement 2170 can be fitted to the presently described cascade arrangement 2150".

Turning now to Figs. 27A to 27E, yet another example of a generator is shown, generally designated as 3000. In general, the structure of the generator 3000 is generally similar to that of the previously described generators, however, with the following differences:

- Multiple pressure vessels - each side (left/right) of the generator comprises four pressure vessels, each being of similar structure to the pressure vessels described with respect to previous examples;

- Linear core connection - each vessels comprises six cores, but contrary to previous examples, the cores are connected linearly to ohe another so as to form a long work medium flow path (six times as long in comparison to a parallel connection as previously disclosed);

Linear vessel connection (work medium) - the cores of the four pressure vessels of each side are linearly connected to one another so as to form an even longer work medium flow path;

Linear vessel connection (pressure medium) - the compartments of the four pressure vessels on each side containing the high pressure medium are also in fluid communication with one another via high-pressure connections, thereby forming a long pressure medium flow path;

- External low temperature reservoir - the low temperature reservoir constituted by the evaporator of the A/C unit is exposed to the environment and is not used for circulation of work medium therethrough.

In operation, a full cycle of one side of the generator can include the following steps (taking into account that the opposite side undergoes the same steps only at a shift):

a) High temperature work medium is passed from the condenser end of the A/C unit along the length of twenty four cores (six cores in each of the four pressure vessels), thereby increasing the temperature of the pressure medium to its maximal operating temperature, and simultaneously being cooled down to a lower temperature;

b) From the last core of the fourth pressure vessel, the cooled down high temperature work medium is returned to the condenser end of the A/C unit after passing through a radiator for expelling therefrom at least an additional part of the heat remained therein;

c) Intermediate temperature work medium at an ambient temperature from the intermediate reservoir is passed through all twenty four cores of the four pressure vessels, thereby lowering the temperature of the pressure medium below the maximal operating temperature, and simultaneously being heated to a higher temperature;

d) From the last core, the intermediate work medium flows into the gradient tanks to be stored there, so that the first portion of intermediate temperature work medium to enter the gradient tank is at the highest temperature and the last portion to enter the gradient tank is at the lowest temperature; e) Intermediate temperature work medium at an ambient temperature from the intermediate reservoir is passed through all twenty four cores of the four pressure vessels, thereby further lowering the temperature of the pressure medium to the minimal operative temperature, and simultaneously being heated to a higher temperature;

f) From the last core, the intermediate work medium flows back into the intermediate work reservoir, passing through the radiator to expel any additional heat to the environment;

g) Heated intermediate temperature work medium from the gradient tank is passed through the cores of the four pressure vessels, thereby gradually heating the pressure medium to a temperature above the minimal operative temperature yet still below the maximal operative temperature. Gradual heating is achieved by using a LIFO arrangement where the last portion to enter the gradient tank (which is also of the lowest temperature) is first to flow through the cores;

h) From the last core, the intermediate temperature work medium flows into the intermediate reservoir while passing through the radiator unit to expel any additional heat to the environment;

i) Repeating from step (a).

In particular, steps (a) and (b), and (e) and (f) can last for a first period of time and steps (c) and (d), and (g) and (h) can last for a second period of time which is greater than the first period of time. Specifically, the second period of time can be twice as long as the first period of time. Under a particular example, the first period of time can be about 5 seconds and the second period of time can be about 10 secnods.

With particular reference being made to Figs. 28A and 28B, the steps are carried out as follows:

Steps (a) and (b): High temperature work medium flows from the high temperature reservoir into valve E: enter via E2, exit via E and line LE => line LB2 into valve B: enter via B2, exit via B and line LRj => exit cores via line LRo and into valve D: enter via D, exit via D3 and line LD3 => line Lp into valve F: enter via F, exit via Fl and line LFI back to the high temperature water reservoir.

Steps (c) and (d) Intermediate temperature work medium flows from the intermediate temperature reservoir via line LM into valve B: enter via B3, exit via B and line LRi => exit cores via line LRo and into valve D: enter via D, exit via Dl and line LDI => line LH into valve H: enter via HI, exit via H into the gradient tank. Water previously stored in the gradient tank will be pushed through line Lp (shown Fig. 27A) and the radiator 3400 and back into the intermediate reservoir.

Steps (e) and (f): Intermediate temperature work medium flows from the intermediate temperature reservoir via line L into valve B: enter via B3, exit via B and line LRi => exit cores via line LRo and into valve D: enter via D, exit via D2 and line LD2 ^=> line LN into the radiator unit 3400 and back to the intermediate reservoir.

Steps (g and fti): Intermediate temperature work medium flows from the gradient tank into valve H: enter via H, exit via H2 and line LBI into valve B: enter via Bl, exit via B and line LRi => exit cores via line LRo and into valve D: enter via D, exit via D2 and line L02 ^=> line LN into the radiator unit 3400 and back to the intermediate reservoir.

It is appreciated that valve A is equivalent to valve B, valve C is equivalent to D, and valve G is equivalent to H. Valves E and F are not equivalent, and are each responsible for a different reservoir - valve E for the high temperature work medium reservoir and valve F for the intermediate temperature work medium reservoir.

With reference being drawn to Figs. 29A to 29C, it is observed that the generator 3000 comprises four pressure vessels 3200, each comprising six cores Ci through C6- It is also noted that the cores are inter-connected so as to form a single flow path. In particular, the cores are connected as follows:

- At the front end of the pressure vessel 3200, the cores Q and C ₂ are in fluid communication via connector CCi-2, cores C3 and C4 are in fluid communication via connector CC3-4 and cores C5 and C _¾ are in fluid communication via connector CC5-6;

At the rear end of the pressure vessel 3200, the cores are oppositely connected: cores C ₂ and C3 are in fluid communication via connector CC2-3, cores C4 and C5 are in fluid communication via connector CCj-s and cores C6 and Ci are in fluid communication via connector CC^i (shown Fig. 30A); Turning now to Figs. 30A to 30C, the generator 3000 is shown to have a middle- point feed, i.e. the work medium enters the pressure vessels at the area between two consecutive pressure vessels 3200 rather than at the front of the first pressure vessels 3200 as in the previously described examples. It is also observed that all four cores 3200i to 3200 _! v are inter-connected via pipes Wi _-2 , W _2- 3 and W^.

In particular, the line LRI is connected to the first core Ci of the first pressure vessels 3200j. As a result, the flow path of the work medium is as follows:

- entering the first core Ci of the first pressure vessel 3200[, passing through all the cores Ci through C6 thereof and exiting the sixth core C6 into connector pipe Wi _-2 ;

entering the first core Ci of the second pressure vessel 3200π, passing through all the cores Ci through C$ thereof and exiting the sixth core C into connector pipe W _2- 3;

entering the first core Ci of the third pressure vessel 3200m, passing through all the cores Ci through thereof and exiting the sixth core C6 into connector pipe W^t; and

entering the first core Q of the fourth pressure vessel 3200iv, passing through all the cores Ci through C thereof and exiting the sixth core Ce into line L _R0 .

Under the above arrangement, all twenty four cores of the pressure vessels 3200i to 3200iv are in fluid communication with each other, forming a long flow path.

Turning now to Figs. 31 A and 3 IB, it is observed that the pressure vessels 3200! to 3200JV are also in fluid communication with one another, i.e. the pressure fluid within each one of these vessels is in fluid communication with the pressure fluid in the other vessels. Fluid communication is provided by high-pressure connectors Pi _-2 , P _2- 3 and P-j-i. One of the four pressure vessels is fitted with an outlet high-pressure connector PEND, through which the high pressure medium is provided to the piston units 3270R, 3270L.

Turning now to Figs. 32A and 32B, the generator 3000 is shown to comprise two gradient tanks 3600L, 3600R, each being in fluid communication with pressure vessels 3200 via appropriate piping. In particular, each of the gradient tanks 3600R, 3600L is fitted with a corresponding valve H, G respectively, configured for providing the gradient tanks 3600R, 3600L with heated/cooled work medium as previously described with respect to steps (c) and (d) above.

Each of the gradient tanks 3600L, 3600R is of generally similar construction to the gradient tanks 600, 1600 and 2600 previously described. In particular, it is formed with a flow labyrinth 3610 configured for maintaining a temperature difference between consecutive portions of work medium entering the gradient tank.

In addition, it is observed that each of the gradient tanks 3600R, 3600L is connected at the top to a pipeline LQO, configured for allowing a medium contained within the gradient tank to be pushed out when work medium enters the gradient tanks via valves H and G.

With reference being made to Figs. 33A and 33B, an accumulator arrangement is disclosed generally designated as 3900, configured for storing some of the energy produced by the above generator. The accumulator arrangement 3900 comprises a casing 3910 which contains a storing medium (not shown) configured for being heated by heating elements 3920 located within the casing 3910. Specifically, the heating elements 3920 are operated using some of the electrical power generated by the generator 3000, so as to heat the storing medium.

As a result, throughout a given amount of time, the storing medium within the casing 3910 is gradually heated to a temperature similar to that of the high temperature work medium within the high temperature reservoir 3110. Upon reaching such a temperature, the valves A to G of the generator 3000 are selectively switched so that high temperature storing medium from the casing 3910 is circulated through the generator 3000 instead of high temperature work medium from the high temperature reservoir 3110, defining an auxiliary operation mode.

In particular, the arrangement is such that in the auxiliary mode, steps (a) and (b) are performed thereby as follows:

Steps (a) and (b): high temperature storing medium flows from outlet GBOUT of the casing 3910 of the accumulator arrangement 3900 into valve E: enter via El, exit via E and line L => line L _B2 into valve B: enter via B2, exit via B and line LRi => exit cores via line LRo and into valve D: enter via D, exit via D3 and line LD3 => line LF into valve F: enter via F, exit via Fl and line Lpi back to the casing 3910 through GBny.

It is appreciated that while the generator 3000 operates in the^ auxiliary mode, the high temperature reservoir 3110 is circumvented by the piping as described above, and therefore does not take part in the operation of the generator 3000. This allows temporarily shutting down the A/C unit and thereby reducing overall power consumption of the generator 3000. Turning now to Fig. 34, the A/C unit is in the form of a work medium subsystem 3100 having a condenser end 3112, an evaporator end 3122, a compressor arrangement CP and an expansion valve arrangement EV. The evaporator end 3122 is exposed to the environment so as to be in thermal communication therewith and absorb heat therefrom. The condenser end 3112 is located within a housing constituting the high temperature reservoir 3110 containing the high temperature work medium (not shown).

The compressor arrangement CP and the expansion valve arrangement EV are in fluid communication with both the condenser end 3112 and the evaporator end 3122, and operate to generate a standard cooling cycle in which a carrier medium (not shown) is compressed by the compressor arrangement CP, passes through the condenser end 3112 and expands via the expansion valve arrangement EV into the evaporator end 3122.

It is observed that the compressor arrangement CP comprises four compressors (CPi to CP ₄ ), and the expansion valve arrangement EV comprises corresponding four expansion valves (EVi to EV ₄ ), to form four working couplets CP ₁ -EV ₁ , CP ₂ -EV ₂ , CP ₃ -EV ₃ and CP ₄ -EV ₄ . Each of the compressors CPi to CP ₄ has a different power consumption and provides a different compression ratio, and each of the expansion valves EVi to EV ₄ are respectively configured for providing a different expansion degree.

The arrangement is such that the work medium sub-system 3100 is operated by at least one couplet at a time, the couplet being chosen according to the required temperature difference between the high temperature reservoir and the cold temperature reservoir, and according to the temperature of the outside environment.

The CP-EV couplets can be configured for operation during specific times of day/year. More specifically, one couplet can be configured for operation during summer days, another for summer nights, a third for winder days and a fourth for winter nights, providing for a more efficient operation of the generator 3000.

In addition, the above arrangement provides at least three backup compressors when one of the four compressors malfunctions. For example, if the summer night compressor malfunctions, the winter day compressor can be used while the summer night compressor is being repaired. Turning now to Figs. 35 A to 35E, a linear gear mechanism generally designated as 3300 is shown, replacing the previously described power assembly 300. The linear gear 3300 comprises a housing 3310 within which a rack 3320 is configured for engagement with pinion arrangements 3340R, 3340L of the gear mechanism 3300.

Each of the ends 3310R, 3310L is formed with a corresponding opening 3312R,

3312L respectively, being in fluid communication with an auxiliary work medium pumped into and out of the housing 3310 during operation of the generator 300 owing to pressure changes in the pressure medium contained in the pressure vessels 3200R, 3200L. As a result, the rack 3320 is caused to reciprocate under alternating pressure between a first end 3310R and a second end 3310L of the housing 3310.

Due to the engagement of the threaded portion 3324 of the rack 3320 with the pinions 3348R, 3348L of the pinion arrangements 3340R, 3340L, reciprocation of the rack 3320 within the housing 3310 entails revolution of the pinions 3348R, 3348L about their axis, thereby converting linear movement into rotational movement, which is eventually transferred to a drive shaft 3332.

It is observed that each of the shafts 3342L, 3342R carrying the pinions 3348R, 3348L is also fitted with bearings 3345L, 3345R at both ends thereof, so that rotation of the pinions 3348R, 3348L is uni-directional only. Specifically, and with particular reference to Fig. 35C, when the rack 3320 displaces to the left, the shaft 3342R on which the pinion 3348R is mounted, revolves about its axis, entailing revolution of the pinion 3348R. However, at the same time, while shaft 3342L on which the pinion 3348L is mounted also revolves about its axis, the pinion 3348L itself remains stationary due to the bearing 3345L. Similarly, during displacement of the rack 3320 in the opposite direction, the pinion 3348L revolves while the pinion 3348R remains stationary.

In order to stabilize the shafts 3342L, 3342R, yet still allow them to freely rotate during displacement of the rack 3320, additional bearings 3344L, 3344R are fitted to each of the shafts 3342L, 3342R.

Thus, since both pinions 3348R, 3348L are engaged with a gear 3338 of the generator shaft, any displacement of the rack 3320, in any of the two directions, will entail revolution of the gear 3338 and consequently of the shaft 3332. Revolution of the shaft 3332 can be converted to electricity in any known manner. In addition, in order to stabilize the rack 3320 in its reciprocating movement within the housing, the gear mechanism 3300 is provided with two delimiting rollers 3350R, 3350L, each being positioned in front of a respective pinion arrangement 3340L, 3340R respectively. The rollers 3350R, 3350L, are configured for engaging the rack so as to delimit its movement only to the axial direction.

Each of the delimiting rollers 3350R, 3350L comprises a shaft 3352R, 3352L respectively, on which a roller member 3356R, 3356L is mounted. In addition, each end of the shaft 3352R, 3352L is fitted with bearings 3354R, 3354L respectively, which are similar to the bearings 3344L, 3344R of the pinion arrangements 3340R, 3340L. In assembly, the roller members 3356R, 3356L are engaged with a non- threaded portion 3322 of the rack 3320, so as to allow only axial movement thereof.

It is also noted that the drive shaft 3332 itself, is also provided with a bearing 3335, allowing it to freely rotate by inertia, even if the rack 3320 has already stopped reciprocating.

It is appreciated that the rack and pinion arrangement of the linear gear assembly

3300 provides for several significant advantages:

any displacement of the rack 3320 entails revolution of the drive shaft 3332, even if a stroke in one direction is not similar in length to the stroke in the opposite direction;

- Due to the bearing 3335 of the drive shaft 3332, upon a single stroke of the rack 3320 in one direction, and after the rack as finished its movement in that direction, the drive shaft continues to further revolve, thus allowing to generate additional power even within movement of the rack;

The linear gear arrangement 3300 is more accurate than the previously described power assembly due to its simple constructions and use of a single rack 3320;

It provides a much higher transmission ratio than the previously described power assembly; and

Turning now to Figs. 36A to 36D, yet another example of a generator is shown generally designated as 4000. In essence, the generator 4000 is similar to the previously described generator 3000, however with several differences, some of which are as follows: Comprises only two pressure vessels 4200R, 4200L (not eight), each being longer that the pressure vessels 3200;

Operates on front feed and rear egress, i.e. work medium enters the pressure vessels 4200R, 4200L from a front end thereof and exits at a rear end thereof;

Propulsion of the work medium through the generator is performed by pumps;

Provided with a combined valve 4140R, 4140L configured for having two operational modes;

- Comprises an accumulator arrangement 4900 divided into two compartments and having a heat pump operating therebetween; and

The gear mechanism 4300 thereof comprises roller-gears instead of regular gears.

With reference to Fig. 36A, it is observed that the generator 4000 comprises a work medium sub-system 4100, pressure vessels 4200, a generator assembly 4300, a radiator 4400, gradient tanks 4600L, 4600R and an accumulator arrangement 4900.

Turning now to Figs. 37A to 37D, the generator 4000 comprises four core distribution arrangements 4140L, 4140R (two of each), each pressure vessel 4200 being fitted with a core distribution arrangement 4140L, 4140R at each end thereof. It is noted that each of the pressure vessels 4200L, 4200R comprises five cores 4220, and each of the valves 4140L, 4140R is connected to the cores 4220 via five distribution lines (e.g. LA6 to LAIO for the front end of the left pressure vessel 4200L as shown in Fig. 37B), and five corresponding regulator valves (e.g. to Am).

It is also noted that the cores 4220 of each pressure vessel 4200L, 4200R are inter-connected to form a single flow path via connectors (e.g. L _A c7-s and L _A c9-io for the front end of the left pressure vessel 4200L as shown in Fig. 37B and LDCS-9 and LDCIO-6 for the rear end of the left pressure vessel 4200L).

The distribution arrangements 4140L, 4140R and the regulator valves are design to allow selective parallel/linear flow through the cores 4220. In other words, the cores 4200 can operate in parallel, i.e. unidirectional flow of work medium through all cores 4220 from one end of the pressure vessel 4200 to the other, or alternatively, form a single (and considerably long) flow path through which the work medium progresses. As will become apparent with respect to operation of the generator 4000, it can be beneficial, at certain stages of operation thereof to use a parallel flow configuration, while during other stage is can be beneficial to use a linear flow configuration.

The different stages of operation of the generator will now be described with reference to Figs. 37A to 37D. The steps are provided below starting from an initial position of the pressure vessels 4200L, 4200R in which the pressure medium within the right pressure vessel 4200R has reached its maximal temperature (e.g. 42.5°C), while the pressure medium within the left pressure vessel 4200L has reached its minimal temperature (e.g. 7.5°C). The stages will be described below with respect to the right pressure vessel 4200R, understanding that the same applies to the left pressure vessel 4200L at a phase shift:

High temperature energy absorption and storage: Intermediate temperature work medium (e.g. 25°C) flows from the intermediate temperature reservoir via line Ln into valve B: enter via B2, exit via B into pump 4150R and through there to the distribution arrangement 4140R into line LB6 ^=> pass through all cores (linear flow configuration) => exit cores via line Loo and into valve C: enter via C, exit via CI and line Lei ^=> into valve G: enter via G2 into the gradient tank. Water previously stored in the gradient tank will be pushed through line LHGL (shown Fig. 37D) and back into the intermediate reservoir 4130 through the radiator 4400. At this point, the hottest portion of the intermediate work medium in the gradient tank 4600R (top of the tank) can be about 40°C and the coldest portion of the intermediate work medium in the gradient tank 4600R (bottom of the tank) can be about 27.5°C. The temperature of the pressure medium at this point can be about 30°C.

High temperature energy recovery: Intermediate temperature work medium flows from the gradient tank 4600R into valve G: enter via G, exit via Gl and line LGI (LAI) into valve A: enter via Al, exit via A and into pump 4150L and through there to the distribution arrangement 4140L into line LA6 ^=> pass through all cores (linear flow configuration) => exit cores via line LDIO and into valve D: enter via D, exit via D2 and line Lp2 ^=> into the radiator unit and back to the gradient tank 4600L. During this step, the work medium in the right gradient tank 4600R gradually heats the pressure medium in the left pressure vessel 4200L while the intermediate work medium in the left gradient tank 4600L (ranging between about 22.5°C to 10°C) gradually cools the pressure medium in the right pressure vessel 4200R to about 15°C. Substantial cooling: low temperature work medium (e.g. 0°C) flows from the low temperature reservoir via line Lei into valve B: enter via B4, exit via B into pump 4150R and through there to the distribution arrangement 4140R into line LB6 ^=> pass through all cores simultaneously (parallel flow configuration) => exit cores via all line 5 Lc6-io and into valve C: enter via C, exit via C3 and line Lc ₃ => back into the low temperature reservoir 4120, optionally through the radiator 4400 (even partly). This can reduce the temperature of the pressure medium in the right pressure vessel 4200R to about 7.5°C.

low temperature energy absorption and storage: Intermediate temperature work

10 medium (e.g. 25°C) flows from the intermediate temperature reservoir via line Ln into valve B: enter via B2, exit via B into pump 4150R and through there to the distribution arrangement 4140R into line LB6 ^=> pass through all cores (linear flow configuration) => exit cores via line Loo and into valve C: enter via C, exit via CI and line Lei => into valve G: enter via G2 into the gradient tank. Water previously stored in the

15 gradient tank will be pushed through line LHGL (shown Fig. 37C) and back into the intermediate reservoir 4130 through the radiator 4400. At this point, the coldest portion of the intermediate work medium in the gradient tank 4600R (top of the tank) can be about 10°C and the hottest portion of the intermediate work medium in the gradient tank 4600R (bottom of the tank) can be about 22.5°C. The temperature of the pressure

20 medium at this point can be about 20°C.

low temperature energy recovery: Intermediate temperature work medium flows from the gradient tank 4600R into valve G: enter via G, exit via Gl and line LGI (LAI) into valve A: enter via Al, exit via A and into pump 4150L and through there to the distribution arrangement 4140L into line LA6 ^=> pass through all cores (linear flow

25 configuration) => exit cores via line LD6-IO and into valve D: enter via D, exit via D2 and line LD2 ^=> line Lio into the radiator unit and back to the gradient tank 4600L. During this step, the work medium in the left gradient tank 4600L gradually heats the pressure medium in the right pressure vessel 4200R to about 35°C while the intermediate work medium in the right gradient tank 4600R (ranging between about

30 22.5°C to 10°C) gradually cools the pressure medium in the left pressure vessel 4200L to about 15°C.

Substantial heating: high temperature work medium (e.g. 50°C) flows from the high temperature reservoir 4110 via line LHI into valve B: enter via B3, exit via B into pump 4150R and through there to the distribution arrangement 4140R into line LB6 ^=> pass through all cores simultaneously (parallel flow configuration) => exit cores via line Loo and into valve C: enter via C, exit via C4 and line Lc ₄ => back into the high temperature reservoir 4110 optionally through the radiator 4400 (even partly). This can 5 increase the temperature of the pressure medium in the right pressure vessel 4200R to about 42.5°C.

Each of the above described six steps can last for a predetermined amount of time, e.g. five seconds. However, under other arrangements, it can be beneficial that each steps lasts for a different period of time.

10 In order to control the operation of the generator, a controller can be provided which is configured to monitor any one of the following:

- Flow rate through the piping of the generator 4000;

The operational mode of the valve (which are open/closed, parallel/linear configuration etc.); and

15 - The duration of each step.

With reference being drawn to Fig. 38, the generator 4000 comprises a pressure system which is similar to that previously described with respect to the generator 3000. Each pressure vessel 4200L, 4200R is fitted with a work piston 4270L, 4270R and a compensation piston 4280L, 4280R respectively. Each of the work pistons 4270L, 20 4270R is attached via lines 4274L, 4274R to the housing of the gear mechanism 4300, so as to eventually cause reciprocation of the rack 4320 (shown Fig.47) therein.

Turning to Fig. 39, a work medium sub-system 4100 is shown being in the form of a heat pump which is generally similar to the sub-system 3100 previously described, with the difference being that it does not make use of four different compressors but 25 rather a single screw compressor which can operate under varying compression ratios and power consumption, and being thus able to adjust its operation to the conditions of the environment.

Turning now to Figs. 40A to 40D, the generator 4200 further comprises an accumulator arrangement 4900, which is similar in purpose to the accumulator 30 arrangement 3900 previously described. However, it is observed that the accumulator arrangement 4900 comprises a high temperature compartment 4910H and a low temperature compartment 4910c, and is connected to an auxiliary heat pump 4930 of which the condenser end 4932 is located in the first compartment 4910H and the evaporator end 4934 is located in the first compartment 4910c.

In particular, each of the compartments 4910H, 4910C, has a respective inlet GHI, GCI and outlet GHO, GCO, to which corresponding inlet and outlet lines LGHI, LGCI, LGHO, LGCO are attached respectively. It is observed that the outlet GHO is located at a top end of the compartment 4910H, while the inlet GHI is located at a bottom end of the compartment 4910H- In contrast, the outlet GCO is located at a bottom end of the compartment 4910c, while the inlet GCI is located at a top end of the compartment 4910c.

The above arrangement allows for withdrawing high temperature work medium from a high temperature zone of the high temperature compartment 4910H, and returning the work medium to a low temperature zone of the high temperature compartment 4910H- Correspondingly, this arrangement allows withdrawing low temperature work medium from a low temperature zone of the low temperature compartment 4910c, and returning the temperature work medium to a high temperature zone of the low temperature compartment 4910c.

Thus, some of the energy provided by the generator can selectively be provided to the auxiliary heat pump 4930 instead of simple heaters (as in the previously described example), thereby providing not only an auxiliary high temperature reservoir at 4910H, but also yielding a low temperature reservoir at 4910c.

In operation, once the auxiliary work medium in the compartments 4910 _H and 4910c reaches temperatures which are similar to those of the high/low temperature reservoirs respectively, it can be used in operation of the generator while the main heat pump temporarily ceases its operation.

In addition, the high temperature compartment 4910H is provided with heaters which are configured for directly heating the storage fluid contained within the compartment 4910H- It is appreciated that during operation of the auxiliary heat pump 4930, the storage medium within the high/low temperature compartment can reach a heating/cooling limit (i.e. reaching a maximal/minimal temperature limit). In such an event, the operation of the auxiliary heat pump 4930 can be interrupted, and heater are then used to further heat the storage medium in the high temperature compartment Under the above arrangement, once the auxiliary heat pump 4930 is interrupted, the work medium in the high temperature compartment 4910H can be used as a high temperature work medium, while the work medium in the low temperature compartment 4910c is used as the low/intermediate work medium.

Turning now to Figs. 41 A to 4 IE, the structure of the pressure vessel 4200 and the cores therein will be described. The pressure vessel 4200 comprises and external housing 4222 accommodating therein the five cores 4220. The pressure vessel 4200 is also provided with a sealing arrangement comprising seals 4242, 4244 and 4246, configured for preventing leaks from the pressure vessel 4200, and maintaining a high pressure of the pressure medium.

Each core 4220 is fitted, within the pressure vessel 4200 with a stirring assembly 4230, configured for revolving about the core 4220 for providing better mixing of the pressure medium and thereby a more efficient heat transfer between the pressure medium and the work medium flowing within the cores 4220 during operation of the generator 4200.

The stirring assemblies 4230 are generally similar to those previously described, and comprise a drive gear 4234 engaged with a center gear 4232 mounted on a central shaft 4235 and driven by an external motor.

It is also observed that since the pressure vessel 4200 is considerably long (its length is much greater than its nominal diameter), support arrangements 4290 are provided along the pressure vessel 4200 configured for supporting the cores 4220. In essence, these support arrangements 4290 comprise support discs 4293 formed with holes for receiving therethrough the cores 4220. Each such support arrangement 4290 is also fitted with sealing members 4295, 4297 for preventing any undesired leakage.

Reference is now made to Figs. 42A to 45C, in which various examples of core structures are shown. It is noted that these examples show the structure of the front end of the core.

With particular reference being made to Figs. 42A to 42E, a core 4220' is shown comprising a core body 4221' and a central core cavity 4222' accommodating a static flow axle.

It is observed that closer to the front end, the first portion 4223' of the flow axle is smooth and does not occupy the entire cross-section of the cavity 4222'. In addition, it is observed that the core body 422Γ at the front portion is formed with a roughened surface 4226' only on an inner side thereof. To the contrary, the second portion 4224' of the flow axle is formed as a spiral occupying the entire cross-section of the cavity 4222'. In addition, it is observed that the core body 4221' at the second portion is formed with a roughened surface 4226' both on an inner and on an outer side thereof. It is also observed that the flow axle is hollow and is formed with inner channels 4223<

It is noted that the ridges formed with the roughened surface 4226' both on an inner and on an outer side thereof are aligned with one another, so that a peak of a ridge on the outer surface is aligned against a trough on the inner surface. This provides the core with a uniform thickness at any given cross-section taken perpendicular to an axis of the core.

One reason for the above design lies in the location of the first portion within the pressure vessel. As can be observed from Figs. 41 A to 4 IE, the first portion of the core is located at the area of the seals 4242, 4244, 4246, thereby not taking place in the heat exchange process with the pressure medium. As such, it is not required to have the same structure as the second portion, and costs can be reduced by maintaining it in a simplified design as shown.

With particular reference being drawn to Fig. 42D, it is observed that the roughened surface 4226' is in the form of teeth which do not extend completely radially from the center of the core. Rather, the teeth extend at a slight angle, so that the work medium flowing through the core 4220 is swirled by the direction of the teeth and penetrates in between the teeth, allowing for a better heat exchange process.

Attention is now drawn to Fig. 43, in which a core 4220" is shown having a similar design to that shown in Figs. 42A to 42E, with the difference being that the first portion of the core 4220" is isolated using an isolating sleeve 4227", so that work medium passing through the first portion doesn't waste its energy on heating/cooling that portion of the core which does not participate in the heat exchange process.

Turning now to Figs. 44A to 45C, two additional cores 4220"' and 4220 ^IV are shown, being of similar design to that of the previously described cores 4220' and 4220" (similar elements have been designated with similar reference numerals with the addition of corresponding primes). The main difference between the cores 4220" and 4220 ^IV and the previously describe cores lies in the design of the roughened surface, which is in the form of rings rather than in the form of conical/pyramidal protrusions. Such a design is slightly easier and less costly to manufacture. Turning now to Figs. 46A to 46D, an assembly of the pressure vessel 4200 is shown. It can be observed that the cores 4220 and all the mechanical elements relating thereto (fan arrangements, gears, drive-shaft etc., herein 'core assembly) are all enclosed by sleeve members 4200s. The sleeve members 4200s are formed of a rigid material and have a sufficient thickness to provide mechanical support to the entire core assembly. For example, the sleeve member 4200s can be made of steel and have a thickness of several millimeters.

Under the above arrangement, it is possible to first fully assembly the entire core assembly and enclose it with the sleeve members 4200s and only then slide the enclosed assembly into the pressure vessel casing 4200. In addition, for servicing and maintenance purposes, it is possible to remove the enclosed core assembly from the pressure vessel 4200 (for example by sliding it out), remove the appropriate sleeve member 4200s and perform the required maintenance.

It is also observed that the sleeve members 4200s have a semi-circular cross section (i.e. have a half-pipe shape), and when two such members enclose a section of the core assembly, there remains a gap G therebetween (see Figs. 46C, 46D). The gap G provides fluid communication of the pressure medium between an inner zone defined between the sleeve members 4200S and the core assembly, and an outer zone between the sleeve members 4200S and casing 4222 of the pressure vessel 4200.

It is also noted that the seal arrangement comprises seals 4244 which are essentially made of three separate pieces, and once inserted into the sleeve 4220s and mounted onto the cores 4220, these are pressed closer to one another to provide the necessary seal for the pressure vessel 4200.

Turning now to Fig. 47, an improvement of the gear mechanism 4300 is shown, in which the gear mechanism 4300 comprises roller-pin pinions 4348R, 4348L which are engaged with the rack 4320, and gears 3349R, 3349L which are engaged with the drive shaft 4332. Roller-pin pinions 3348R, 3348L provide a much higher efficiency over regular gear engagement due to an increased contact surface and simplified teeth shape. In all other aspects, the gear mechanism 4300 operates much the same way.

However, the roller-pin pinions 4348R, 4348L provide the gear with the advantage of reduced friction, since the roller-pin pinions 4348R, 4348L are free to revolve about their own axis. Turning to Figs. 48A to 48C, another example of a work medium sub-system 4100' is shown in which each of the high/low temperature reservoirs 4110, 4120 respectively, has been divided into several compartments. The compartments are in fluid communication with one another, yet they still delay mixing between the work medium exiting the sub-system 4100 towards the pressure vessels 4200L, 4200R, and work medium entering the sub-system 4100 after performing its heat exchange process. Such an arrangement can provide a more efficient configuration of the generator.

Turning now to Figs. 49A to 49H, a pressure vessel 4200' is shown having a length L which is much greater than the diameter D thereof. The pressure vessel 4200' also comprises support assemblies 4920' as described previously with respect to Figs. 41 A to 41 D, however, contrary thereto, in the present example each core 4220' is not a single core, but rather is formed of core segments. Each two consecutive segments are adjoined with one another at the support assembly 4290' located therebetween.

In order to adjoin two core segments, an insert is introduced between the segments and is respectively received within the cores so as to provide fluid communication therebetween. It is also observed from Fig. 49B that the core segments are fully contained within the pressure vessel and that at the ends of the pressure vessel, only the inserts are protruding. The insert 4299' itself can be made of a material not requiring high heat transfer coefficients, e.g. plastic.

When adjoined at the support assembly 4290' by the insert, two consecutive core segments have a certain degree of freedom for movement with respect to one another. In order to reduce the displacement of the cores with respect to one another, the support assembly 4290' comprises bearings 4293' which allow the fan arrangements of the cores to freely revolve about themselves.

With particular reference being drawn to Fig. 49D, the bearings 4293' are of a self-aligning type, in which the housing 4294' of the bearing balls 4295' is of a curved shape, providing the cores, and the fan arrangements mounted thereon, with a certain, yet controllable, degree of freedom.

With reference being made to Figs. 49F and 49G, the support assembly 4290' is more clearly shown having the shape of a disc formed with several openings, corresponding in number to the number of the cores and the drive shaft DS.

Attention is now drawn to Fig. 49H, in which the sleeve member 4200s' is shown attached to the core assembly by bolts 4285 via an opening 4287. It is observed that the opening 4287 is not circular, but rather slightly prolonged. It should be understood that the enclosed core assembly is first introduced into the pressure vessel 4200', and only then is the pressure vessel pre-loaded with the high pressure (e.g. 6000 atm.). Under such pressure, the pressure vessel may elongate slightly, and therefore the openings holding the bolts should provide for a certain degree of freedom. This arrangement holds true not only for bolts of the sleeve member 4200s' hut for other bolted elements within the pressure vessel.

In addition, at least for a majority of bolt attachments within the pressure vessel (i.e. attachments having a bolt or screw threaded into a threaded hole), it can be beneficial to form a hole within the thread which provides fluid communication between the portion of the threaded hole not occupied by the bolt, so as to equalize the load on both sides of the bolt (its head and it end), in order to reduce sheer forces.

With respect to all of the above examples, configurations and arrangements of the generator of the present application, the following calculations can apply:

Basic data:

in general, the generator 4000 can be configured to provide approx. 2.24 times the input power, i.e. WOUTPUT = 2.24WI PUT- Naturally, if some of the output power is provided back to the operation of the generator, the net output power is about 1 .24W _1NPU T (2.24WINPUT - WI _NPU T);

- the average efficiency of standard heat pumps can be in the range of 50-

70%, i.e. for a COP 10 which should theoretically provide WOUTPUT ⁼ I OWINPUT, the actual output is in the range of 5-7WI _NP UT- For purpose of this calculation, an efficiency of 55% will be assumed;

the COP chosen for the present calculation is 8 and the temperature difference between the high temperature work medium and the low temperature work medium is about 40°C; the generator can convert approx. 30% of the heat provided to the pressure medium into output energy via the motor assembly, i.e. for an amount of heat Q provided to the pressure medium, approx. 0.3Q is converted to actual output (based on the properties of Ethyl Bromide under a pre-loading of about 6000 atm.); - the energy recovery arrangement provides for a recovery of approx. 50-66% of the remainder of the amount of heat within the pressure medium; Under the above parameters, the generator can operate as follows:

Providing 1.00 kWh of electrical energy in the heat pump of the generator (to generate the 40°C difference between the high and the low temperature reservoir) will provide for 4.40 kWh of heat energy, which is the amount of heat provided to the pressure medium. Theoretically a 40°C temperature range at appropriate temperatures and a COP 8 should yield more power, however, due to the 55% efficiency of the heat pump the output is lkWh x 8 x 55% = 4.40 kWh.

Since only 30% of the heat provided to the pressure medium is eventually converted to output energy, the above calculation yields approx. 1.32 kWh of electrical energy. This yields that the remainder of the heat within the pressure medium is about 4.40 - 1.40 = 3.00 kWh (1.4 is used instead of 1.32 to take into account various heat losses within the system).

Recovering 60% of the remainder of the amount of heat within the pressure medium yields a recovery of 1.80 kWh (3.00x0.6 = 1.80 kWh). Therefore, is out of 4.40 kWh provided to the pressure medium 1.80 is recovered, this yields that the additional heat that should be provided to the pressure medium with each operation cycle of the generator is 4.40 - 1.80 = 2.60.

In other words, in each cycle, an amount of heat of approx. 2.60 kWh is provided by the heat differential module and an amount of heat of approx. 1.80 is provided by the recovery arrangement, yielding the amount of heat of 4.40 kWh which is required for operation of the generator at a production of 1.32 kWh.

Under the above arrangement, in order to provide the required 2.60 kWh of heat, the heat pump of the heat differential module now requires only 0.59 kWh (rather than 1 kWh), under the COP = 8 as suggested above. This yields that at startup of the operation of the generator, i.e. at the first cycles of operation thereof, 1 kWh is provided as input power, but is quickly reduced to 0.59 kWh during continuous operation of the generator once the recovery arrangement takes effect.

In summary, in continuous operation of the generator (after startup), in order to provide a 1.32 kWh output energy, the generator requires a constant feed of 0.59 kWh, thereby yielding the input/output ratio of 1.32/0.59 = 2.24: 1. It should be noted that it is possible to operate the generator under a lower temperature range, for example 30°C rather than 40°C, thereby possibly increasing the net output for each operation cycle of the generator (1.67 kWh instead of 1.32 kWh). However, this may also yield a lower number of cycles per hour, thereby reducing the overall energy production of the generator.

The above calculations are provided with respect to specific parameters which depend on materials, COP, temperature range etc., and taking into account various losses, heat leaks, compensation factors etc.. These parameters can be varied to achieve different end results by the operation of the generator which may exceed (and also possible be lower than) the results presented above.

Those skilled in the art to which subject matter of the present application pertains will readily appreciate that numerous changes, variations, and modification can be made without departing from the scope of the subject matter of the present application, mutatis mutandis.