TECHNICAL FIELD

The invention relates to a field of external thermal energy conversion, particularly, to methods and devices for converting an external thermal energy to a mechanical work, and it may be used to create power generation and pumping devices and systems.

BACKGROUND

A method for converting an external thermal energy to a mechanical work is known, the method is based on using Stirling cycle that involves using a working fluid, heating the working fluid, and a device for performing the method is known as well (Walker G. Stirling Engines. - M.: Machine industry, 1985). The known method and device utilize a gas as the working fluid. A drawback of the disclosed prior art lies in that it is necessary to use an additional device, namely a piston, as a tool for converting a gas pressure to the mechanical work, in that it is not possible to re-use the working fluid, i.e., it is consumed, in insufficient overall efficiency of the method and the device, including in view of a friction of the piston against walls of a working chamber and its reciprocal motion, in that high temperatures (at least 500°C) and a high initial internal pressure of the working fluid are required.

The prior art solution that is technically closest to the claimed invention includes a method for converting an external thermal energy to a mechanical work, the method comprises using a heat-transfer fluid and a heat absorber as working fluids, heating the heat-transfer fluid, transferring the thermal energy from the heat-transfer fluid to the heat absorber by mixing the heat-transfer fluid with the heat absorber in working chambers, converting the thermal energy of the liquid heat absorber to a potential energy of the heat absorber vapor via its evaporation, as well as a device for performing the method (patent No. RU 2166103 C2 dated 27.04.2001, IPC F01K 25/04). In the known method, after the heat-transfer fluid is mixed with the heat absorber, the working fluid of the heat absorber is further expanded, and then the obtained energy of the working fluid expansion is converted to the mechanical work. The used heat absorber is discharged to the environment, while the heat-transfer fluid is forwarded to re-heating by the thermal energy of an external medium.

The device that performs the known method comprises the heat-transfer fluid, the heat absorber, the working chambers, a heat source that transfers the external thermal energy to the heat-transfer fluid, connecting pipelines that interconnect all the elements of the device. The known device utilizes a piston to convert the vapor energy to the mechanical work.

Drawbacks of the known prior art include consumption of the heat absorber without any possibility of its re-use, thereby causing additional costs and restriction of a list of substances which could be used as the heat absorber to the ones which are environmentally friendly, mechanical costs due to the friction of the piston against the walls of the working chamber, losses of the heat-transfer fluid via sealing of the piston, i.e., the method and the device are not sufficiently efficient in general.

SUMMARY

A technical objective of the claimed invention is to provide a method and a device which could convert an external thermal energy to a mechanical work and which could avoid losses of working fluids, avoid restriction of types of the suitable working fluids, minimize mechanical costs, increase the overall efficiency of the method and the device.

The objective is achieved by a method for converting an external thermal energy to a mechanical work, the method comprises using a heat-transfer fluid and a heat absorber as working fluids, heating the heat-transfer fluid, transferring a thermal energy from the heattransfer fluid to the heat absorber by mixing the heat-transfer fluid with the heat absorber in working chambers, converting the thermal energy of the liquid heat absorber to a potential energy of a heat absorber vapor via its evaporation, and the method, according to the invention, comprises: using, as the heat absorber, an easily evaporated liquid heat absorber that is insoluble or low-soluble in the heat-transfer fluid, transferring the liquid heat absorber to a feeding device, feeding the heat absorber to a layer of the heat-transfer fluid followed by evaporating the heat absorber and accumulating the heat absorber vapor above a surface of the heat-transfer fluid, converting an energy of the heat-transfer fluid flow that is created under a pressure of the heat absorber vapor and due to a redistribution of the pressure of the heat absorber vapor between the working chambers, to the mechanical work using a hydraulic machine, cooling and condensing the discharged exhaust heat absorber vapor to a liquid state so as to make it re-usable.

Also, the objective is achieved by a device for converting an external thermal energy to a mechanical work, the device comprises a heat-transfer fluid, a heat absorber, a heat source that transfers the external thermal energy to the heat-transfer fluid, connecting pipelines that interconnect all the elements of the device, and the device, according to the invention, further consists of: two working chambers, two feeding devices, controlled valves and check valves, an accumulation and distribution device that is configured to accumulate the liquid heat absorber and to alternately transfer it to the feeding devices by means of the controlled valves, and the feeding devices are arranged in the working chambers and are configured to transfer the thermal energy to the liquid heat absorber in the feeding device from the heat-transfer fluid that is arranged outside in the working chamber, as well as to further partially evaporate the heat absorber and to feed, due to a vapor pressure, the remainder of the liquid heat absorber to a layer of the heat-transfer fluid that is arranged in the working chamber, and the working chambers are configured to cause the heat-transfer fluid to transfer the thermal energy to the heat absorber followed by evaporation of the heat absorber and accumulation of the heat absorber vapor above a surface of the heat-transfer fluid, a hydraulic machine that is coupled to the working chambers by means of the check valves and that is configured to convert the heat-transfer fluid flow from the working chambers to the mechanical work, a condenser that is configured to condense the heat absorber vapor that is fed from the working chambers by means of the controlled valves to a liquid state and to further feed the heat absorber in the condensed liquid state to the accumulation and distribution device by means of the controlled valves, a control unit, level sensors, temperature sensors, and the control unit is configured to control a start and a stop of operation of the device by means of the controlled valves, to control a level of filling of the working chamber with the heat-transfer fluid by means of the level sensors, to control a temperature of the heat-transfer fluid and a condensation temperature of the heat absorber by means of the temperature sensors.

The accumulation and distribution device may be configured to adjust a volume of the heat absorber that is transferred to the feeding device.

The device may further comprise a controlled valve and a circulation pump which are configured to perform a pre-start heating of the heat-transfer fluid.

A set of essential features of the invention allows to avoid losses of the working fluids, since the features of the invention avoid discharging of the heat absorber to the environment and it is condensed to the liquid state and is re-used in the next cycles, thereby also avoiding any restriction of the types of the suitable working fluids and increasing the efficiency of both the method and the device.

The set of features of the invention minimizes mechanical costs, in particular, when no third-party devices are used to transfer the working fluids, and implements the invention owing to changing the state and properties of the working fluids and to action of natural forces, thereby increasing the overall efficiency of both the method and the device.

BRIEF DESCRIPTION OF THE FIGURE

The invention will be explained hereinafter using a detailed description of its structural design referring to the appended drawings:

Fig. 1 illustrates a diagram of the device that performs the claimed method for converting the external thermal energy to the mechanical work.

Fig. 2 illustrates a diagram of the device that performs the claimed method for converting the external thermal energy to the mechanical work, the method has reduced thermal losses in the thermodynamic cycle and enables to adjust an output power upon change of the temperature of the heat-transfer fluid and/or the condensation temperature of the heat absorber.

For the sake of convenience, directions of flows of the working fluids are indicated with arrows in the Figures, and their aggregate states are indicated as well.

DETAILED DESCRIPTION OF THE EMBODIMENT

Fig. 1 illustrates the diagram of the device that depicts the method for converting the external thermal energy to the mechanical work. The device for performing the method consists of a condenser 1, a controlled valve 2, a working chamber 7, a feeding device 8, a check valve 10, a level sensor 13, a check valve 14, a hydraulic machine 15, a check valve 16, a level sensor

18, a controlled valve 19, a working chamber 24, a feeding device 25, a check valve 26, an accumulation and distribution device 34 and connecting pipelines. The accumulation and distribution device 34 consists of a controlled valve 3, an accumulating unit 4, a controlled valve 5, a controlled valve 6, a controlled valve 12, a controlled valve 17, a controlled valve 20, an accumulating unit 21, a controlled valve 22, a controlled valve 23 and connecting pipelines.

A heat-transfer fluid 9 is located in the working chamber 7, in the working chamber 24, in the hydraulic machine 15, in the check valve 10, in the check valve 14, in the check valve 16, in the check valve 26 and in the connecting pipelines which interconnect the above-mentioned elements of the device. An overall volume of the heat-transfer fluid 9 that is located in the working chamber 7 and in the working chamber 24 is smaller than an overall volume of the working chamber 7 and of the working chamber 24. The overall volume of the working chamber 7 and of the working chamber 24 that is not fdled with the heat-transfer fluid 9 is a working volume of the device. Other elements of the device are filled with the heat absorber 11 in a liquid or gaseous state. A main part of the liquid heat absorber 11 is accumulated in the accumulating unit 4 and in the accumulating unit 21. It is proposed to use water as the heat-transfer fluid 9, since water has good heat capacity and it is a cost-effective and affordable resource. Substances such as butane, isobutane, propane, difluoromethane and other halons, may act as the heat absorber 11.

The device is equipped with a control unit that may control the temperature of the heattransfer fluid 9 and the condensation temperature of the heat absorber 11 by means of temperature sensors. The level sensor 13 supplies a signal to the control unit when the working chamber 7 is filled with the heat-transfer fluid 9 up to a maximum level. The level sensor 18 supplies a signal to the control unit when the working chamber 24 is filled with the heat-transfer fluid 9 up to a maximum level. The control unit controls a start, a process and a stop of the operation of the device by opening or closing the controlled valve 2, the controlled valve 3, the controlled valve 5, the controlled valve 6, the controlled valve 12, the controlled valve 17, the controlled valve

19, the controlled valve 20, the controlled valve 22 and the controlled valve 23.

The external thermal energy may be transferred to the heat-transfer fluid 9 directly through a housing of the working chamber 7 and/or through a housing of the working chamber 24, e.g., by means of solar concentrators. In the same way, the external thermal energy may be transferred to the heat-transfer fluid 9 by means of a heat source that is arranged in the working chamber 7 and/or by means of a heat source that is arranged in the working chamber 24. An air heat exchanger or a liquid heat exchanger may be used as the condenser 1.

The accumulating unit 4 and the accumulating unit 21 are made from materials having a minimum thermal conductivity. This is required to minimize a heat exchange between the heat absorber 11 and the accumulating unit 4, as well as between the heat absorber 11 and the accumulating unit 21. The feeding device 8 and the feeding device 25 are made from materials having a high thermal conductivity.

An upper part of the working chamber 7 is coupled to an inlet of the condenser 1 via the controlled valve 2. When the controlled valve 2 is open, the heat absorber 1 1 vapor will be able to transfer from the working chamber 7 to the condenser 1. The feeding device 8 is arranged in the working chamber 7. The feeding device 8, via the housing of the working chamber 7, is connected to an upper part of the accumulating unit 4 via the controlled valve 5 and to a lower part of the accumulating unit 4 via the controlled valve 6. The accumulating unit 4 is arranged above the feeding device 8. When both the controlled valve 5 and the controlled valve 6 are open, the liquid heat absorber 11 will be able to transfer from the accumulating unit 4 to the feeding device 8 under gravity through the controlled valve 6, while the heat absorber 11 vapor transfers from the feeding device 8 to the accumulating unit 4 via the controlled valve 5. A lower part of the feeding device 8 is provided with an opening that couples an internal volume of the feeding device 8 to an internal volume of the working chamber 7. The lower part of the working chamber 7 is coupled to an inlet of the hydraulic machine 15 via the check valve 14 and to an outlet of the hydraulic machine 15 via the check valve 10.

An upper part of the working chamber 24 is coupled to an inlet of the condenser 1 via the controlled valve 19. When the controlled valve 19 is open, the heat absorber 11 vapor will be able to transfer from the working chamber 24 to the condenser 1. The feeding device 25 is arranged in the working chamber 24. The feeding device 25, via the housing of the working chamber 24, is connected to an upper part of the accumulating unit 21 via the controlled valve 22 and to a lower part of the accumulating unit 21 via the controlled valve 23. The accumulating unit 21 is arranged above the feeding device 25. When both the controlled valve 22 and the controlled valve 23 are open, the liquid heat absorber 11 will be able to transfer from the accumulating unit 21 to the feeding device 25 under gravity through the controlled valve 23, while the heat absorber 11 vapor transfers from the feeding device 25 to the accumulating unit 21 via the controlled valve 22. A lower part of the feeding device 25 is provided with an opening that couples an internal volume of the feeding device 25 to an internal volume of the working chamber 24. The lower part of the working chamber 24 is coupled to the inlet of the hydraulic machine 15 via the check valve 16 and to the outlet of the hydraulic machine 15 via the check valve 26.

The condenser 1 is arranged above the accumulation and distribution device 34.

A lower part of the accumulating unit 4 is coupled to the outlet of the condenser 1 via the controlled valve 12. An upper part of the accumulating unit 4 is coupled to the inlet of the condenser 1 via the controlled valve 3. When both the controlled valve 3 and the controlled valve 12 are open, the liquid heat absorber 11 will be able to accumulate in the accumulating unit 4 after being condensed in the condenser 1. A lower part of the accumulating unit 21 is coupled to the outlet of the condenser 1 via the controlled valve 17. An upper part of the accumulating unit 21 is coupled to the inlet of the condenser 1 via the controlled valve 20. When both the controlled valve 20 and the controlled valve 17 are open, the liquid heat absorber 11 will be able to accumulate in the accumulating unit 4 after being condensed in the condenser 1.

The external thermal energy is converted to the mechanical work in the following way. The external thermal energy is transferred to the heat-transfer fluid 9. When there is a sufficient difference between the temperature of the heat-transfer fluid 9 and the condensation temperature of the heat absorber 11, all of the controlled valve 2, the controlled valve 3, the controlled valve 12, the controlled valve 22 and the controlled valve 23 will be opened. The controlled valve 5, the controlled valve 6, the controlled valve 17, the controlled valve 19 and the controlled valve 20 remain closed. The liquid heat absorber 11 flows from the accumulating unit 21 to the feeding device 25. The liquid heat absorber 11 is heated by the heat-transfer fluid 9 via the housing of the feeding device 25. A part of the liquid heat absorber 11 is evaporated. A pressure of the heat absorber 11 vapor in a circuit that is formed by the feeding device 25, the open controlled valve 23, the open controlled valve 22 and the accumulating unit 21, becomes higher than a pressure of the heat absorber 11 vapor in the working chamber 24. Owing to the pressure difference, the liquid heat absorber 11 is fed through a lower opening of the feeding device 25 to a layer of the heat-transfer fluid 9, evaporated and transferred to the upper part of the working chamber 24 in a form of bubbles. The pressure of the heat absorber 11 vapor in a circuit that is formed by the feeding device 25, the open controlled valve 23, the open controlled valve 22 and the accumulating unit 21, and in the working chamber 24 will strive towards equilibrium. At the same time, an overall pressure of the heat absorber 11 vapor in a circuit that is formed by the feeding device 25, the open controlled valve 23, the open controlled valve 22 and the accumulating unit 21, and in the working chamber 24 will exceed the pressure of the heat absorber 11 vapor in the working chamber 7, in the condenser 1 and in the accumulating unit 4. Thus, the heat-transfer fluid 9 is pushed out of the working chamber 24 through the check valve 16, the hydraulic machine 15 and the check valve 10 to the working chamber 7. The feeding of the liquid heat absorber 11 through the lower opening of the feeding device 25 followed by its evaporation will occur uniformly as the the heat-transfer fluid 9 is pushed out of the working chamber 24. In the hydraulic machine 15, the flow of the heat-transfer fluid 9 is converted to the mechanical work. The heat-transfer fluid 9 that comes to the working chamber 7 pushes out the heat absorber 11 vapor through the open controlled valve 2 to the condenser 1. The heat absorber 11 vapor is cooled and condensed in the condenser 1. The liquid heat absorber 11 flows from the condenser 1 through the open controlled valve 12 to the accumulating unit 4. When the heattransfer fluid 9 achieves its maximum level in the working chamber 7, all of the controlled valve 2, the controlled valve 3, the controlled valve 12, the controlled valve 22, the controlled valve 23 will be closed, while all of the controlled valve 5, the controlled valve 6, the controlled valve 17, the controlled valve 19, the controlled valve 20 will be opened.

The liquid heat absorber 11 flows from the accumulating unit 4 to the feeding device 8. The liquid heat absorber 11 is heated by the heat-transfer fluid 9 via the housing of the feeding device 8. A part of the liquid heat absorber 11 is evaporated. The pressure of the heat absorber 11 vapor in the circuit that is formed by the feeding device 8, the open controlled valve 5, the open controlled valve 6 and the accumulating unit 4, becomes higher than the pressure of the heat absorber 11 vapor in the working chamber 7. Owing to the pressure difference, the liquid heat absorber 11 is fed through a lower opening of the feeding device 8 to the layer of the heattransfer fluid 9, evaporated and transferred to the upper part of the working chamber 7 in the form of bubbles. The pressure of the heat absorber 11 vapor in the circuit that is formed by the feeding device 8, the open controlled valve 5, the open controlled valve 6 and the accumulating unit 4, and in the working chamber 7 will strive towards equilibrium. At the same time, the overall pressure of the heat absorber 11 vapor in the circuit that is formed by the feeding device 8, the open controlled valve 5, the open controlled valve 6 and the accumulating unit 4, and in the working chamber 7 will exceed the pressure of the heat absorber 11 vapor in the working chamber 24, in the condenser 1 and in the accumulating unit 21. Thus, the heat-transfer fluid 9 is pushed out of the working chamber 7 through the check valve 14, the hydraulic machine 15 and the check valve 26 to the working chamber 24. The feeding of the liquid heat absorber 11 through the lower opening of the feeding device 8 followed by its evaporation will occur uniformly as the the heat-transfer fluid 9 is pushed out of the working chamber 7. In the hydraulic machine 15, the flow of the heat-transfer fluid 9 is converted to the mechanical work. The heat-transfer fluid 9 that comes to the working chamber 24 pushes out the heat absorber 11 vapor through the open controlled valve 19 to the condenser 1. The heat absorber 11 vapor is cooled and condensed in the condenser 1. The liquid heat absorber 11 flows from the condenser 1 through the open controlled valve 17 to the accumulating unit 21. When the heat-transfer fluid 9 achieves its maximum level in the working chamber 24, all of the controlled valve 2, the controlled valve 3, the controlled valve 12, the controlled valve 22, the controlled valve 23 will be opened, while all of the controlled valve 5, the controlled valve 6, the controlled valve 17, the controlled valve 19, the controlled valve 20 will be closed. The operation of the device will be continued according to the order as described above.

Therefore, owing to the set of features of the invention, the conversion of the external thermal energy does not require use of any additional devices as in the prior art solutions, e.g., a piston, that otherwise could lead to significant mechanical losses at least due to a friction of the piston against walls of the device. Moreover, the ability of the invention to condense and to reuse the working fluid helps to avoid losses of the working fluid as in the prior art. All these circumstances increase the overall efficiency of both the method and the device.

EXAMPLES

Example 1

Fig. 2 illustrates the diagram of the device that utilizes the inventive method for converting the external thermal energy to the mechanical work. It differs from the device having the diagram depicted in Fig. 1 in that the accumulation and distribution device 34 is configured to adjust the volume of the heat absorber that is transferred to the feeding device as well as in that it further comprises a controlled valve 32 and a circulation pump 33 which are configured to perform a pre-start heating of the heat-transfer fluid.

According to this embodiment of the invention, owing to reduction of a time period for transferring of the heat absorber to the feeding device, losses of the heat absorber vapor in the thermodynamic cycle will be reduced, while the energy of the vapor must be used to create the flow of the heat-transfer fluid, thereby increasing the overall efficiency of the invention. The accumulation and distribution device 34 consists of the accumulating unit 4, the controlled valve 5, the controlled valve 6, the controlled valve 22, the controlled valve 23, a dosing unit 27, a level sensor 28, a controlled valve 29, a controlled valve 30. The device further comprises a heater 31, the controlled valve 32 and the circulation pump 33.

The level sensor 28 transmits a signal about the level of the liquid heat absorber 11 in the dosing unit 27 to the control unit. The dosing unit 27 is made from materials having a minimum thermal conductivity. This is required to minimize the heat exchange between the heat absorber 11 and the dosing unit 27.

The feeding device 8, via the housing of the working chamber 7, is connected to an upper part of the dosing unit 27 via the controlled valve 5 and to a lower part of the dosing unit 27 via the controlled valve 6. The feeding device 25, via the housing of the working chamber 24, is connected to an upper part of the dosing unit 27 via the controlled valve 22 and to a lower part of the dosing unit 27 via the controlled valve 23. The dosing unit 27 is arranged above both the feeding device 8 and the feeding device 25. When both the controlled valve 5 and the controlled valve 6 are open, the liquid heat absorber 11 will be able to transfer from the dosing unit 27 to the feeding device 8 under gravity through the controlled valve 6, and the heat absorber 11 vapor transfers from the feeding device 8 to the dosing unit 27 via the controlled valve 5. When both the controlled valve 22 and the controlled valve 23 are open, the liquid heat absorber 11 will be able to transfer from the dosing unit 27 to the feeding device 25 under gravity through the controlled valve 23, and the heat absorber 11 vapor transfers from the feeding device 25 to the dosing unit 27 via the controlled valve 22. The outlet of the condenser 1 is coupled to the upper part of the accumulating unit 4. The lower part of the accumulating unit 4 is coupled to lower part of the dosing unit 27 via the valve 30. The upper part of the dosing unit 27 is coupled to the inlet of the condenser 1 via the controlled valve 29. When both the controlled valve 29 and the controlled valve 30 are open, the liquid heat absorber 11 will be able to transfer to the dosing unit 27 from the accumulating unit 4.

The lower part of the working chamber 7 is coupled to the inlet of the heater 31 via the check valve 14 and to the outlet of the hydraulic machine 15 via the check valve 10. The lower part of the working chamber 24 is coupled to the inlet of the heater 31 via the check valve 16 and to the outlet of the hydraulic machine 15 via the check valve 26. The outlet of the heater 31 is coupled to the hydraulic machine 15. The outlet of the heater 31 is coupled to the controlled valve 32. The controlled valve 32 is coupled to the circulation pump 33. The circulation pump 33 is coupled to the lower part of the working chamber 7 and to the lower part of the working chamber 24.

The external thermal energy of the heat-transfer fluid 9 is transferred in two ways. The first way is used as a preparation of the device for operation. The control unit puts the controlled valve 32 to the open position and turns on the circulation pump 33. The heat-transfer fluid 9 is pumped along two closed circuits. The first closed circuit is formed by the working chamber 7, the check valve 14, the heater 31, the controlled valve 32, the circulation pump 33. The second closed circuit is formed by the working chamber 24, the check valve 16, the heater 31, the controlled valve 32, the circulation pump 33. The second way for transferring the external thermal energy of the heat-transfer fluid 9 is performed during operation of the device and implies that the heat-transfer fluid 9 is transferred in the device in two paths. The first path is from the working chamber 7 via the check valve 14, the heater 31, the hydraulic machine 15, the check valve 26 to the working chamber 24. The second path is from the working chamber 24 via the check valve 16, the heater 31, the hydraulic machine 15, the check valve 10 to the working chamber 7. The heat-transfer fluid 9 receives the thermal energy in the heater 31 during each transfer.

The power of the device may be maintained at fluctuations of the temperature of the heattransfer fluid 9 and/or of the condensation temperature of the heat absorber 11 in the following way. The control unit controls the temperature of the heat-transfer fluid 9 and the condensation temperature of the heat absorber 11. Based on this information, the volume of the liquid heat absorber 11 to be transferred from the dosing unit 27 to the working chamber 7 or to the working chamber 24 is determined. In order to transfer the heat absorber 11 from the dosing unit 27 to the working chamber 7, the controlled valve 5 and the controlled valve 6 are open. The heat absorber 11 is transferred to the feeding device 8. Data about a change of the level of the heat absorber 11 in the dosing unit 27 as provided by the level sensor 28 enables the control unit to determine a momentum when the required volume of the heat absorber 11 has transferred to the feeding device 8 and to close the controlled valve 5 and the controlled valve 6. Therefore, the heat absorber 11 vapor that arises in the process of receiving the thermal energy from the working fluid 9 through the walls of the feeding device 8 will not be able to transfer from the feeding device 8 to the dosing unit 27. A takeaway of the thermal energy by the heat absorber 11 vapor to the dosing unit 27 will be reduced during the thermodynamic cycle. In the same way, the heat absorber 11 is transferred from the dosing unit 27 to the working chamber 24 by means of the controlled valve 22 and the controlled valve 23. Therefore, the claimed invention enables to avoid losses of the working fluids, to avoid restriction of the types of the working fluids which are suitable for use, to minimize mechanical costs, to increase the overall efficiency of both the method and the device.

The claimed device is simple in manufacturing as well as convenient and efficient for being used in the claimed method.

The claimed invention may be widely used in industry for mass and individual manufacture of the device, in particular, to create power generation and pumping devices and systems.