that uses the heat of the phase transition of the substance into a solid

This invention relates to the heat exchanger channel that changes its shape during the process of the phase transition of the substance into a solid, preferably to be used as the bottom source of a heat pump, which allows to remove ice from the heat exchanger surface during the heat pump operation, without supplying additional energy for thawing of accumulated ice and provides uninterrupted stream of heat, independent from the thawing process,

Heat pumps as the particularly energy efficient solution for heating and cooling of the domestic and industrial rooms are more and more commonly used. They use renewable sources of geothermal energy, air, natural and artificial water reservoirs and rivers. They often use waste energy the in cases, where the medium carrying that energy has too low temperature, to be used directly for heating. In practice, the following most popular solutions of the bottom heat sources are used for heat pumps, starting from the most efficient from the performance point of view, in the„\vater - water" form, which however is limited by hydrological conditions and parameters of water, that flows through the heat pump evaporator. The most common performance problems include contamination of the heat exchanger or silting of the discharge well due to the fact that significant volumes of water need to be pumped. Good efficiency is obtained by other geothermal solutions in the form of the„brine— water" system that has the form of horizontal heat exchangers arranged on the bottom of water tanks or below the frost penetration area in a garden, or vertical straight wells, in which polyethylene pipe is placed, in the loop arrangement, with antifreeze agent flowing through such as brine or glycol. In this case, we are facing a number of problems, that must be taken into consideration at the phase of designing the bottom source. Very important parameter is the ability of the ground to regenerate, as this dominates the costs to produce the system and at the time of operation it can lead to freezing of the heat exchanger which ends in a breakdown and makes further operation of such a bottom source impossible, by the time it was properly regenerated. In some areas, uncontrolled change in hydrological parameters can occur, e.g., in the case of mining activities, drawdown of ground water level as a result of the investments, etc., which can significantly restrict the output of the bottom source. The vital limitation also relates to the relatively large area of a real property that has to be allotted for horizontal heat exchangers or boreholes, which excludes their application in highly urbanized areas. Due to a number of problems and risks connected with the geothermal installations, significantly increased the popularity of the least efficient solutions of„air- water" type, which in turn are facing the problems with freezing of a heat exchanger, and this enforces the use defrosting systems, which impair the system efficiency. Additional electric sources of heat are often used and these are turned on at the extreme weather conditions. Varying working parameters of the air heat exchanger, due to significant variations of air temperature, force to use expensive solutions within the heat pump construction, in order to optimize its working parameters in the changing conditions. Another troublesome parameter is the noise generated by fans and freezing condensate - after defrosting of the heat exchanger.

There is a number of bottom source solutions that utilize the energy of the phase transition of water into ice, but these are the solutions, which most often have the energy resources limited by constructional reasons - frozen water reservoirs, alternatively complemented by a solar system to thaw them, external radiators -„icicle", which cover with hoarfrost absorbing heat from the humidity contained in air. These are solutions available commercially, and the contribute to the offer of the bottom sources for heat pumps, however each of them is restricted by a number of specific features which make it impossible to obtain the maximum efficiency in the case of each installation and heating season. In addition, we always have to take into account, that the built-up ice constitutes the insulation that reduces the flow of heat, which in turn causes the decrease of heat stream from such a source and reduces efficiency of the system.

To sum up - heat pump is the most efficient source of heat, the efficiency of which is reduced by the limitations, operational problems and risks connected with the bottom source. Elimination of these problems will make it possible to build the most efficient heat source, both performance-wise and investment-wise, because low costs of the bottom source and stability of its parameters, will allow to build less expensive heat pumps, free from the systems and solutions that optimize their work in the variable heating parameters of the bottom source. Combination of these solutions with the photovoltaics seems to be very attractive for investors, due to economic reasons, burdening of the environment -renewable energy sources installation, durability and payback period of the investment.

There is the solution known from the Polish patent application WO2015099547, which presents the device that draws energy from the phase transition of water into ice, equipped with collectors with deformable surface due to flexible frame, containing evaporator of the heat pump, immersed in the tank with water to the depth allowing for free outflow of ice. It contains the tank with antifreeze fluid with the double-acting pump, which increases pressure in the collector in order to deform and defrost it. It is equipped with the ice removing system in the form of the grinding pump and the systems that aerate and improve thermal exchange on the collector surface and the systems that assist loosening of ice from the heat exchanger. Large number of systems consuming the energy in the above- mentioned device decreases its energy efficiency and the required quantity of water, necessary for the system to operate, has large weight which restricts possibility to make the installation inside the building, only to the rooms with adequately high floor-loading capacity.

From description in the American patent US6681593 Bl, there is a known solution of elastic tilted heat receivers placed horizontally downwards at the tank bottom, connected by adhesion with the heat exchanger, on the surface of which the exchange of heat takes place and ice received in result is removed by way of tilting it to vertical and deflecting it, which causes ice to flow out onto the tank surface. Under operating conditions of the a.m. system, we have mechanical loosening of ice, which needs significant expenditure of energy, complicated mechanical system, the heat exchanger is only used in less than 50% of the surface which significantly decreases the energy efficiency of the system.

From description in the American patent US20151 14019 (Al ), there is a known solution of a heat pump combined with the exchanger of the latent heat, equipped with a scraper for removal of ice accumulating on its surface, which takes heat away from the liquid in the tank, which can be supplied from different sources, and ice accumulated on the top area of the tank is removed out of the system and can be utilized for known puiposes. The heat pump system described above uses the mechanical ice scraper from the heat exchanger, which creates a number of operational problems connected with the drive transmission, preferably in the systems with higher power, and consequently the larger exchange areas. Accelerated wear and tear of the heat exchanger surface and the scraper itself can also occur.

From description in the American patent US20110079025 (Al), there is a known solution for storage of cold in the form of ice production in the periods of decreased demand for cold in the form of a tank with the number heat exchangers, from which one group covers with frost in a controlled way in the periods of decreased demand for cold (e.g., at night), while the other supports the refrigerating system at the time of increased demand for cold. The solution is favorable in air-conditioning systems, however accretion of ice on heat exchangers limits the dynamics of the process due to ice insulating properties, which should be considered as the unfavorable effect. The system also has limited energy capacity due to the tank volume.

From description in the American patent US6053006, there is a known solution of a system for storage of cold in the form of a tubular heat exchanger through which refrigerating medium flows, that causes creation of ice on the exchangers and its accretion, and the other heat exchanger, that enables further distribution of cold to the air conditioning installation. This solution has many operational advantages connected with the lack of need to control the degree of the heat exchanger icing and its freezing and defrosting can be executed at any moment. This is a practical arrangement of the accumulator of cold for the air conditioning installation, however it is burdened with similar drop of efficiency and the increase of ice thickness, which the author of the solution counteracts by concentration of the heat exchangers.

From description in the Japanese patent US2005163681 (Al ), there is a known solution that produces ice slurry, that consists of a number of heat exchangers with the flow control systems, defrosting system in case of choking of the heat exchanger. Ice slurry is produced from the mixture of water and chemical compounds responsible for creation of fine ice crystals. As in a number of solutions, the system has designed capacity and consequently, limited energetic parameters and it utilizes the water solution of chemical agents which enforces strict separation from the environment. The solution is dedicated for storage of cold in air-conditioning systems.

The solution according to the invention enables easy use of energy of the phase transition of the substance - water into a solid, the quantity of which corresponds to the energy obtained from chilling of the same unit of water from temp. 80°C to 0°C. The heat exchanger built utilizing the solution according to the invention enables to execute the bottom source of heat of the modular construction, which from the supplied water with any physical and chemical parameters (this can be sewage, rainwater, ground waters, soil waters, water from water line or the domestic well, etc., filtered from solid particles) takes heat away and produces ice, which is immediately removed away from the system (e.g., respectively to the sewage system, to rainwater tank, to designated area, from which thawed water can freely flow down to the rainwater tank, or onto the lawn from which it will return to ecosystem, to rainwater system in the urbanized areas), which allows to draw heat in uninterrupted way in quantities resulting from the device rated parameters. The defrosting process itself does not discontinue the stream of acquired heat. The solution according to the invention can be used for all commonly used heat pumps as the efficient alternative for the bottom source or can be applied as the reserve bottom source of heat in the already executed installations, also including the installations that collect energy from the air. The solution according to the invention allows to build a heat exchanger with direct evaporation of the refrigerating medium, which enables the execution of very efficient systems of high power heat pumps with compact overall dimensions of the bottom source.

The heat exchanger channel according to the invention constitutes the base for designing of heat exchangers or the heat exchanger plates with the assumed thermal and flow parameters, the construction of which is executed according to the best knowledge on the phenomena occurring in the typical channels of heat exchangers within the range of flow and heat exchange. Plates arranged in groups constitute the complete heat exchanger and allow to build the whole series of types of devices in order to thermally and flow-wise match with the heat pumps or other needs. The distinctive element that differs the heat exchanger produced this way is the fact, that freezing it is the desired, normal condition of operation and it is not its failure, which in most cases leads to complete destruction of the classic heat exchanger.

Process of removal of ice from the exchange surface of the heat exchanger channel, according to the invention, is based on the change in shape of the thermal exchange mantle, consisting of at least one layer of the inextensible material hereinafter referred to as the mantle. The mantle can adopt two forms: rigid, the free deflection of which adopts the form of a smooth arc - hereinafter referred to as the rigid mantle or the flexible form, the free deflection of which adopts the random form of a broken line - hereinafter referred to as the flexible mantle. The mantle constitutes the area of heat exchange - hereinafter referred to as the exchange area, in the part limited by the exchange area border - hereinafter referred to as the border, which is determined by a curve that connects points of contact of the mantle with the other structural elements of the channel or the spacing elements, that ensure to obtain the designed channel flow cross sections in the stable phases of work. As the stable phase of work the position should be deemed, in which the exchange mantle is at the moment of the ice accretion process and the other extreme position, conventionally named the defrosting position - is the moment, in which in normal conditions ice should be completely separated from the exchange area - the maximum designed expansion of the exchange area. Due to constant flow of the medium through the channel, the process of heat draw is not interrupted regardless the position of the exchange mantle, and we can imagine a situation, that complete loosening of ice will take place only at the time of transition of the channel to the icing position. The border is typical of each phase of the channel work and can change its position together with the change in the mantle position. The mantle apart from the border most distant from the lengthwise axis of the exchange area, in its fixed part, is permanently fixed to the structural elements of the channel - inner or outer, which are capable of transmitting stresses resulting from the forces of reaction of the pressure inside the channel and their component parts. The mantle in each layer of material contains at least one area that compensate changes of the shape and related dimensions, which are reduced by compression or extension of the exchange area, changing it to bending, which allows for the change of linear dimensions in relation to the fastening of the exchange mantle in order to change the shape, without exceeding the fatigue strength of the material (with the safety margin) to guarantee the operational durability of the channel according to the invention. With the rigid mantle the areas of compensation must also occur in all places, where compressive or tensile stresses appear due to the movement of the mantle, e.g., at the channel ends, bends, etc. In result of the shape change and related dimensions of the mantle, on the ice layer which is on the exchange area, in each movement phase, forces act that are tangent to the exchange plane with opposing vectors for both halves of the exchange area divided by the lengthwise axis, which causes that ice is compressed or extended (according to the phase of movement) and additionally bent in the perpendicular plane, in connection with the change of shape of the exchange area. Such concentration of forces in various planes makes it easier to overcome the forces of adhesion and to loosen the ice. Characteristic for the rigid mantle is also simultaneous loosening on the whole area of ice adhesion with the exchange area. An example of the compensation area can be the embossing in the axis of the exchange area, completed by the compensating elements at the channel ends and in places of possible change of the channel direction, also in the form of embossed sides parallel to the mantle fixing line. In case of the flexible mantle, the compensation area is located between the borders of the exchange area, characteristic to the stable phases of movements, which placed within the area of the decreasing stream of heat - the icing border, can be filled, together with the increase of pressure, to the extent allowing to compensate the shape and related dimensions at the time of the working phase changes. Areas of compensation for the flexible mantle can freely set under the influence of pressure of the heat carrying medium, thus compensating the dynamic process of ice loosening from the exchange area and the accompanying changes in shape and related dimensions. In the case of flexible mantle we are facing the loosening that proceeds from the border of the exchange area towards its center, while the points, where loosening occurs - breaking of adhesive connection form at least one closed line with the length decreasing to zero at the moment of the complete ice loosening, which differs from the case of the rigid mantle, in the case of which the process relates to the entire area of the adhesion contact of ice with the area of exchange. Change in the channel surface shape, consists in the alternate adoption of the working position below and in the plane or in the plane and above or below and above of the border in the determined working position and is triggered by the working medium continuously flowing through the heat exchanger, with constant flow parameters and transported stream of heat, which is the heat carrier for the heat pump evaporator, pressure of which changes according to the needs, in individual channels or groups of them in result of the flow being choked. The channel according to the invention has two work phases: ice accretion and defrosting, while the ice accretion time is decidedly longer than the time of defrosting and each phase occurs sequentially. The deicing phase should be determined as the period of the pressure increase in the channel, up to its complete filling and stabilization and the period of the pressure drop, up to obtaining the icing phase shape of the channel. During the icing and deicing process, the flow is maintained, which ensures maintaining of the rated flow through the heat pump evaporator. This allows to obtain constant and unchanging parameters of the heat stream flow by means of appropriate tuning of sequence of the operation phases of individual channels or their groups. In each case, where we have effective exchange of heat in the heat exchanger, its construction should ensure, at the assumed flow rate, the turbulence of the medium in the heat exchanger channel, in order to achieve the highest overall heat transfer coefficient through the exchange area. This target can be achieved through minimization of thickness of the heating medium stream, using the appropriate spacing elements and such shape of at least a part of the channel surface, which makes it impossible to create a laminar stream. Methods to produce such surface, its shape and geometrical parameters are known and used in the classical heat exchangers. Stream of heat flowing locally through the exchange area depends on its thickness or insulation by contact with the structural and/or spacing elements, proper distribution of which on the surface of the exchange area causes segmentation of ice in a way that facilitates to remove it outside the heat exchanger. The channel mantle according to the invention can be produced as the element consisting of more than one layer of material, forming a space between these layers, through which the heat-carrying medium flows. Such construction, basing on the rigid mantle allows to make the heat exchanger with direct evaporation, because it is capable of transferring significant loads characteristic to the process of evaporation of the heating medium and work of the internal circulation of the heat pump. The feature of the space formed between the layers is that it maintains a constant volume and the ability to change the shape which is executed using the spacing elements between the layers, and the areas to compensate the shapes and related dimensions in each layer. In the case of the multi- layered mantle, change of shape of the plane of exchange is induced in result of interaction of external forces, e.g., through the incompressible steering medium (favorably with low viscosity in negative temperatures) forced in and sucked out from the area created between the two two-layered exchange mantles forming the tank with movable walls or in combination with the internal or external structural elements or changes of position induced mechanically, e.g., using the bimetal controlled by electric heating element, actuator, mechanical lever with any drive, etc. Essential element is to maintain the turbulent flow of medium which is the carrier of heat in the channel according to the invention, which can be obtained by appropriate shaping of the whole or a part of the channel interior and ensuring correct flow rates of the medium, in accordance with the common knowledge in this field. The surface of heat transfer on which a layer of ice forms should be made in a way that facilitates the loosening of ice, particularly important is here its smoothness and low adhesion.

Construction of bottom sources of heat pumps and efficient storages of cold for the installation of air conditioning based on the solution according to the invention will allow to limit the investment risk and to reduce the cost, through high concentration of energy in the unit of volume, uniqueness of parameters of physical process and easiness to modify the installation. Stability of work parameters of the bottom source in time will enable to use more simple constructions, and consequently cheaper heat pumps - which will undoubtedly contribute to popularization of such heat source on the commercial market. Efficiency of operation of the heating installation using the solution according to the invention, allows to achieve the lowest levels of operation costs, definitely more profitable than the most efficient solutions currently available on the market in the field of heat pumps. Finally, the possibility to construct compact the high-power heat pumps in combination with the bottom source built on the basis of the solution according to the invention, will create conditions to operate heat pumps in the very strict centers of towns and cities, in large multi-family buildings, etc. The solution according to the invention allows to change the operational concept of the heat distribution network with high parameters of steam or water, to the distribution of the so- called low-temperature heat, which is the renewable source of energy and substitution of heat exchangers by heat pumps. Unquestionably, this will allow to limit the level of losses and air pollution, preferably in the small local boiler houses. Also important is the dynamic development of the photovoltaics, which can be the excellent source of renewable energy to supply the heat pump in both winter and summer seasons, and the collected ice in the heating period can be the costless source of cold in the summer season. The device is fully scalable and with the provision of water supply and ice reception it can generate heat with no interruptions in quantities resulting from the rated parameters.

The object of the invention in the examples of arrangements is shown in the drawing, in which Fig.l shows the right section in the phase of icing. Exchange mantle (1) fastened on the area (0) to the structural element constituting at the same time the bottom of the channel, advantageously shaped (6) for the turbulent flow of a heat carrying medium, having the spacing element (7) supporting the mantle for shaping the designed flow surfaces (5). Exchange mantle (1) is limited by borders (2) thus forming the exchange area (4) that contains the area of compensation (3). Fig.2 presents the right section of the channel in the phase of deicing, where, respectively, the exchange mantle (1) is repositioned above the border of exchange area (4), which lost its contact with the spacing element and increased, also due to expansion of the area of compensation (3). During this process the border of the exchange area (2) created at the contact area with the spacing element (7), disappeared. Despite the change of the cross section (5) and weakening of the influence of the favorably shaped channel bottom (6) on the working medium flow process, it is unimportant for the heat exchange process, because the channel filling cycle (increase of pressure) in order to achieve stable deicing position and re-transition to the position of icing is measurably short in relation to the icing period and additionally the exchange area increases significantly. Fig.3 shows the icing of the exchange area (8) while Fig.4 presents the forces and their component parts acting in the rigid exchange mantle, where P is the thrust derived from the increase of pressure, which acts with identical force on the exchange areas due to the favorable symmetry of the channel construction. After bringing the thrust P down to the concentrated force F interlocked in the middle of the exchange area, we can observe the FS1 and FS2 component parts with the relatively higher values, acting in the plane of the exchange area, and therefore directly influencing the entire surface of adhesion with the formed ice. The effect of the action of these forces is relocation of the exchange plane in the direction of the compensation area located in the channel axis of symmetry, which causes the ice located on the two sides of the compensation area to press against each other. Having overpassed the level, the system of forces reverses which is followed by stretching of the compensation area. During the entire period of movement of the exchange area, also the bending forces are acting on ice, tending to loosen the ice layer, as the reaction to the change in the mantle shape. Fig.5 presents changes in shape and related dimensions of the exchange area in relation to the border in the phase under the border level (9), in the transition phase through the border level (10), in the phase of the maximum elevation over the border level in the deicing process (11). Movement of the channel can take place in changing of a position in any combination dependent on the particular constructional solution. In each case of the change of the position we are facing the change in width of the area of compensation or the movement tangential to the exchange plane in relation to the rigid ice sheet that covers it - respectively B-B is the width of the area of compensation in the position below the border A-A in the border plane, and C-C above the border. Fig. 6 presents the detail of P-P favorable shaping of the channel bottom surface in order to maintain the turbulent flow of the heat carrying medium. There is a number of methods commonly known and used in the classic heat exchangers for shaping the surfaces most characteristic for individual manufacturers. Fig. 7 shows the multi-layer mantle - the first layer (14) and the second layer (15), fastened (13) outside the border of the exchange area to the structural element (12) with the compensation area (16) in each layer. Between the first and the second layers, in the space created due to the spacers in the form of spherical embossing (18), which are arranged alternately, beneficially interact with the turbulent flow of the heat carrying medium. The space (17) formed between the multi -layer mantles of the exchange, forms the tank which is filled with the steering medium and allows to change position of walls - the multi-layer mantles in a way described above, in order to remove ice (19) shown in Fig.8, up to obtaining of the position of the maximal deformation above the border line, Fig.9 shows the multi-layer mantle of exchange (20), maximally deformed compensation area (22) and maximum portion of the steering medium. Volumetric control allows to obtain high steering forces with their simultaneous limitation at the maximum deformation of the channel. Fig. 10 presents 16-channel plate of the heat exchanger built using the channels according to the invention and having the inlet (23) and outlet (24) manifold, visible compensation areas along the axis of the exchange area in the form of embossing (25) and the semi-circular ending of the channel (26) compensated by the spherical embossing (27) at the end of embossing of the compensation area. Fig. 11 presents cross-section through the heat exchanger channel with a flexible exchange mantle (30) fixed (33) to the bottom of the channel that constitute the structural element (28) with favorable geometry (31) for the turbulent flow of the medium and the border (29) of the exchange area that has the compensation area (32) located between the borders of the exchange area (29) and Fig.12 in point (34) of the exchange mantle (35) in the maximum position above the border. Fig.13 shows the icing (36) of the channel with the flexible mantle of exchange tightened on the base of the channel under the influence of pressure of the flowing heat carrying medium. Process of deicing is presented in Fig.14 where due to the increase of pressure the formed ice (38) loosens, and the changes in the dimensions of the mantle due to relocation of the exchange area in relation to its border are compensated in the compensation area (37) and the points of loosening of the exchange area from the ice (39) form a closed line, the length of which decreases to zero at the moment of complete loosening of the ice.

Construction of the channel according to the invention provides much freedom in the application of this solution to create the heat exchangers, the construction of which is cheap, constructional materials readily available, technology of production can have the mass nature and the product can be recycled in 100%. Production of cheap and stable bottom sources along with development of the technology of heat pumps and the photovoltaics can constitute significant impetus to replace the dominating heat sources powered by fossil fuels by the wide use of the renewable energy sources, which are cheaper exploitation-wise and now can become significantly cheaper both in the investment and exploitation spheres. Construction of the integrated simple heat pump with the stable low power bottom source of heat can constitute the excellent alternative for heating of flats in place of solid fuel ovens which are the substantial sources of air pollution.