CN117469050A

CN117469050A - Heat power conversion device and operation method

Info

Publication number: CN117469050A
Application number: CN202311288262.8A
Authority: CN
Inventors: 罗宝军; 苏晓雪; 牛启明; 刘凯
Original assignee: Hunan University
Current assignee: Hunan University
Priority date: 2023-10-07
Filing date: 2023-10-07
Publication date: 2024-01-30

Abstract

The utility model provides a heat power conversion device, includes low temperature chamber, low temperature heat exchanger, high temperature heat exchanger and the high temperature chamber that links to each other in proper order, still includes with the parallel first working medium bypass flow channel of high temperature heat exchanger and/or with the parallel second working medium bypass flow channel of low temperature heat exchanger, the cold working medium in the low temperature chamber passes through the second working medium bypass flow channel flows, the heat working medium in the high temperature chamber passes through first working medium bypass flow channel flows. The operation method comprises the steps that when working media flow from a high-temperature cavity to a heat regenerator, a flow passage between the high-temperature heat exchanger and the high-temperature cavity is closed, a first working media bypass flow passage is opened, and the working media flow to the heat regenerator through the high-temperature cavity and the first working media bypass flow passage; when working medium flows from the low-temperature cavity to the heat regenerator, a flow passage between the low-temperature heat exchanger and the low-temperature cavity is closed, a second working medium bypass flow passage is opened, and working medium flows into the flow passage through the low-temperature cavity and the second working medium to flow to the heat regenerator. The invention can realize the high compression ratio and low loss operation of the heat power conversion device, thereby having high thermodynamic perfection and high energy storage density.

Description

Heat power conversion device and operation method

Technical Field

The invention relates to the fields of engines, refrigerators and heat pumps, in particular to a heat-power conversion device and an operation method.

Background

The energy storage system is one of key technologies for solving instability and intermittence of renewable energy sources, and is also one of key technologies for peak clipping and valley filling of a conventional power system and improving efficiency and safety of a regional energy system. Currently, the mainstream energy storage technology comprises pumped storage, chemical battery energy storage, valley electricity hydrogen production, compressed air energy storage and the like.

In recent years, a carnot battery energy storage system is getting attention, the device converts low-valley electric energy or surplus electric energy into high-temperature heat energy and low-temperature cold energy through reverse circulation and stores the high-temperature heat energy and the low-temperature cold energy respectively, and when the electric energy is used, the stored high-temperature heat energy is used as a high-temperature heat source, the low-temperature cold energy is used as a low-temperature cold source through forward power circulation, and the heat/cold energy is converted into electric energy to be released, so that the carnot battery energy storage system needs a heat-power conversion device. The prior thermal power conversion devices of the Carnot battery are mainly based on the Brayton cycle, the organic Rankine cycle and the like, the compression process and the expansion process are involved in the thermal power conversion devices, one compressor and one expander are needed to realize the processes, and the isentropic efficiency of the compressor and the expander is critical to the efficiency of the thermal power conversion device. However, at present, a turbo-mechanical scheme is adopted for a main flow compressor and an expansion machine in the thermal power conversion device, so that the isentropic efficiency can only reach 90%, and the difficulty of continuously improving the isentropic efficiency is very high. In summary, the thermal power conversion device of the prior carnot battery energy storage system has the problems of low compression efficiency and expansion efficiency, so that the efficiency is low, the cost is high, and compared with other energy storage modes such as pumped storage, chemical battery energy storage, valley electricity hydrogen production, compressed air energy storage and the like, no matter the efficiency and the cost have a great gap, so that commercialization of the carnot battery energy storage system cannot be realized.

In addition, the refrigerating and heating requirements are wide, and the consumed energy accounts for 40% of the total energy of the whole society, so that the improvement of the efficiency of the refrigerating and heating device is very critical to achieving the double-carbon target.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a heat-power conversion device based on a constant volume process, realizes compression and expansion processes through a reciprocating piston, has the advantage of high compression and expansion efficiency, and simultaneously utilizes a working medium bypass flow channel to avoid irreversible heat exchange between a high Wen Qianggao temperature working medium flowing to a heat transfer medium in a high temperature heat exchanger and between a low temperature working medium flowing to the high temperature heat exchanger, and between the low temperature working medium flowing to the low temperature heat exchanger and the heat transfer medium in the low temperature heat exchanger, and has the advantages of high thermodynamic perfection and high energy storage density.

The invention further provides an operation method of the regenerative device.

In order to solve the technical problems, the invention adopts the following technical scheme:

the heat work conversion device comprises a low-temperature cavity, a low-temperature heat exchanger, a high-temperature heat exchanger and a high-temperature cavity which are sequentially connected, wherein the low-temperature cavity and the high-temperature cavity are arranged in a cylinder, a piston is arranged in the cylinder, the heat work conversion device further comprises a first working medium bypass flow channel parallel to the high-temperature heat exchanger, a heat working medium in the high-temperature cavity flows out through the first working medium bypass flow channel, a cold working medium from the low-temperature cavity flows into the high-temperature cavity through the high-temperature heat exchanger, and a heat working medium from the high-temperature cavity flows into the low-temperature cavity through the low-temperature heat exchanger;

And/or the heat work conversion device further comprises a second working medium bypass flow passage parallel to the low-temperature heat exchanger, the cold working medium in the low-temperature cavity flows out through the second working medium bypass flow passage, the cold working medium from the low-temperature cavity flows into the high-temperature cavity through the high-temperature heat exchanger, and the heat working medium from the high-temperature cavity flows into the low-temperature cavity through the low-temperature heat exchanger.

As a further improvement of the above technical scheme: the low-temperature heat exchanger is provided with a heat regenerator between the high-temperature heat exchanger, one end of the first working medium bypass flow passage is connected with one end of the heat regenerator, the other end of the first working medium inflow flow passage is connected with the high-temperature cavity, one end of the second working medium bypass flow passage is connected with the other end of the heat regenerator, and the other end of the second working medium bypass flow passage is connected with the low-temperature cavity.

As a further improvement of the above technical scheme: the heat exchanger wall of the high-temperature heat exchanger is provided with a heat transfer medium runner, a heat transfer medium inlet of the heat transfer medium runner is positioned at one end close to the high-temperature cavity, a heat transfer medium outlet of the heat transfer medium runner is positioned at one end close to the low-temperature cavity, the heat exchanger wall of the low-temperature heat exchanger is also provided with a heat transfer medium runner, a heat transfer medium inlet of the heat transfer medium runner is positioned at one end close to the low-temperature cavity, and a heat transfer medium outlet of the heat transfer medium runner is positioned at one end close to the high-temperature cavity.

As a further improvement of the above technical scheme: the heat transfer medium flow passage is spiral;

and/or the length of the low-temperature heat exchanger is more than or equal to 10cm, and the length of the high-temperature heat exchanger is more than or equal to 10cm;

and/or the inlet temperature of the heat transfer medium in the high-temperature heat exchanger is less than or equal to 500 ℃;

and/or the temperature difference between the inlet and the outlet of the heat transfer medium in the high-temperature heat exchanger is more than or equal to 20 ℃, and the temperature difference between the inlet and the outlet of the heat transfer medium in the low-temperature heat exchanger is more than or equal to 20 ℃;

and/or the high-temperature heat exchanger is connected with a first heat storage unit, and the low-temperature heat exchanger is connected with a second heat storage unit.

As a further improvement of the above technical scheme: the ratio of the temperature difference between the heat transfer medium inlet and the heat transfer medium outlet in the low-temperature heat exchanger to the temperature difference between the two ends of the heat regenerator is between 0.15 and 10;

and/or the ratio of the temperature difference between the heat transfer medium inlet and the heat transfer medium outlet in the high-temperature heat exchanger and the temperature difference between the two ends of the heat regenerator is between 0.15 and 10;

and/or the ratio of the highest pressure to the lowest pressure of the working medium in the low-temperature cavity is 1.2-10;

and/or the heat-power conversion device further comprises a pressure ratio adjusting mechanism.

As a further improvement of the above technical scheme: the heat-power conversion device further comprises an elastic element, one end of the elastic element is connected with the piston, and the other end of the elastic element is fixed.

As a further improvement of the above technical scheme: the length of the high-temperature heat exchanger is longer than that of the first working medium bypass flow passage;

as a further improvement of the above technical scheme: the length of the low-temperature heat exchanger is longer than that of the second working medium bypass flow passage.

The heat power conversion device comprises a piston, a transmission mechanism, a low-temperature cavity, a low-temperature heat exchanger, a high-temperature heat exchanger and a high-temperature cavity which are sequentially connected, wherein the low-temperature cavity, the high-temperature cavity and the piston are arranged in a cylinder, the transmission mechanism is provided with a transmission shaft, the piston is connected with the transmission shaft of the transmission mechanism,

the piston comprises a first piston and a second piston; or, the thermal power conversion device further comprises an ejector;

the high-temperature heat exchanger is provided with a first parallel working medium bypass flow passage and/or the low-temperature heat exchanger is provided with a second parallel working medium bypass flow passage;

in the engine mode, the hot working medium in the high-temperature cavity flows out through the first working medium bypass flow passage, and the cold working medium in the low-temperature cavity flows out through the second working medium bypass flow passage.

An operation method of the heat-power conversion device,

when working medium flows from the high-temperature cavity to the heat regenerator, a flow passage between the high-temperature heat exchanger and the high-temperature cavity is closed, a first working medium bypass flow passage is opened, and the working medium flows to the heat regenerator through the high-temperature cavity and the first working medium bypass flow passage in sequence; when the working medium flows from the heat regenerator to the high Wen Qiangshi, the first working medium bypass flow channel is closed, the flow channel between the high-temperature cavity and the high-temperature heat exchanger is opened, and the working medium flows to the high-temperature cavity through the heat regenerator and the high-temperature heat exchanger in sequence;

When working medium flows from the heat regenerator to the low-temperature cavity, a flow passage between the low-temperature cavity and the low-temperature heat exchanger is opened, a second working medium bypass flow passage is closed, and the working medium flows to the low-temperature cavity through the heat regenerator and the low-temperature heat exchanger in sequence; when the working medium flows from the low-temperature cavity to the heat regenerator, a flow passage between the low-temperature heat exchanger and the low-temperature cavity is closed, a second working medium bypass flow passage is opened, and the working medium flows into the flow passage to flow to the heat regenerator through the low-temperature cavity and the second working medium in sequence;

the heat transfer medium flowing out of the first heat storage unit flows in from the heat transfer medium inlet of the high-temperature heat exchanger, flows out from the heat transfer medium outlet of the high-temperature heat exchanger, flows in from the heat transfer medium inlet of the low-temperature heat exchanger, and flows out from the heat transfer medium outlet of the low-temperature heat exchanger.

An operation method of the heat-power conversion device,

when the thermal power conversion device comprises a first piston and a second piston, the first piston operation phase leads the second piston operation phase by 60-150 degrees in an engine mode;

or, when the thermal power conversion device includes a piston and an ejector, the ejector operation phase leads the piston operation phase by 60 to 150 ° in the engine mode.

Compared with the prior art, the invention has the advantages that:

the invention discloses a heat-power conversion device, which comprises a piston, a low-temperature cavity, a low-temperature heat exchanger, a high-temperature heat exchanger and a high-temperature cavity which are sequentially connected, wherein the low-temperature heat exchanger is provided with a parallel second working medium bypass flow channel, the high-temperature heat exchanger is provided with a parallel first working medium bypass flow channel, so that cold working medium in the low-temperature cavity flows out through the second working medium bypass flow channel, hot working medium in the high-temperature cavity flows out through the first working medium bypass flow channel, working medium from the high-temperature cavity flows into the low-temperature cavity through the low-temperature heat exchanger, and working medium from the low-temperature cavity flows into the high-temperature cavity through the high-temperature heat exchanger, thereby realizing the operation of the heat-power conversion device with large compression ratio and low irreversible loss, and further having high thermodynamic perfection and high energy storage density.

According to the running method of the heat power conversion device, the opening and closing of the flow channels are controlled, so that cold working medium in the low-temperature cavity flows out through the second working medium bypass flow channel, hot working medium in the high-temperature cavity flows out through the first working medium bypass flow channel, cold working medium from the low-temperature cavity flows into the high-temperature cavity through the high-temperature heat exchanger, and hot working medium from the high-temperature cavity flows into the low-temperature cavity through the low-temperature heat exchanger, so that the running method is easy to realize and high efficiency can be realized.

Drawings

Fig. 1 is a schematic diagram of a thermal power conversion device according to the present invention.

Fig. 2 is a schematic diagram of the heat exchanger heat transfer medium inlet and outlet configuration of the present invention.

Fig. 3 is a schematic structural view of the thermal power conversion device with ejector of the present invention.

Fig. 4 is a schematic structural view of a thermal power conversion device having 1 piston and 2 ejectors according to the present invention.

Fig. 5 is a schematic structural view of a thermal power conversion device with an elastic element according to the present invention.

Fig. 6 is a schematic structural view of a thermal power conversion device with a solar collector according to the present invention.

Fig. 7 is a schematic view of the gear transmission structure between two transmission shafts of the present invention.

Fig. 8 is a schematic structural view of a heat exchanger with a U-shaped structure according to the present invention.

The reference numerals in the drawings denote: 1. a cylinder; 2. a low temperature chamber; 3. a low temperature heat exchanger; 4. a regenerator; 5. a high temperature heat exchanger; 502. a heat transfer medium flow passage; 503. a heat exchanger wall; 5021. a heat transfer medium inlet; 5022. a heat transfer medium outlet; 61. a first working medium bypass flow passage; 62. a second working medium bypass flow passage; 7. a high temperature chamber; 81. a first control valve; 82. a second control valve; 83. a third control valve; 84. a fourth control valve; 91. a first rectifier; 92. a second rectifier; 10. a piston; 101. a first piston; 102. a second piston; 111. a first heat storage unit; 112. a second heat storage unit; 113. a third heat storage unit; 114. a fourth heat storage unit; 12. an ejector; 13. a transmission mechanism; 14. a motor; 15. an elastic element; 16. a gear; 17. a back pressure chamber; 18. a transmission shaft; 181. a first drive shaft; 182. a second drive shaft; 191. a first gear; 192. a second gear; 193. a third gear; 201. a first separator; 202. a second separator; 22. a gear cavity; 24. a solar collector.

Detailed Description

The invention is described in further detail below with reference to the drawings and specific examples of the specification.

Example 1

At present, a thermal power conversion device based on the brayton cycle and the organic rankine cycle generally needs a high-efficiency compressor and an expander, however, the isentropic efficiency of a turbine compressor or an expander, a piston compressor with an air inlet valve or an air outlet valve or an expander is particularly difficult to continuously improve, which results in lower system efficiency, for example: the compressor and the expander with 90% isentropic efficiency have the thermodynamic perfection of less than 85%, the thermodynamic perfection refers to the ratio of actual operation efficiency to ideal Carnot cycle operation efficiency, in order to achieve 90% isentropic efficiency, the cost of the compressor and the expander is very high, meanwhile, in order to achieve the higher thermodynamic perfection of the system, a very high Wen Waijie heat source (up to more than 1000 ℃) is also needed, and when the thermal power conversion device is applied to a Carnot battery energy storage system, the very high external heat source causes very high heat storage cost, so that the application prospect of the Carnot battery energy storage system is reduced. On the other hand, the inventors of the present application found that: the heat-power conversion device based on the constant volume process has the potential of very efficient compression and expansion because the compression and expansion of the heat-power conversion device can be realized through the reciprocating piston and the air inlet and outlet valves are eliminated, so the heat-power conversion device based on the constant volume process has the potential of high-thermodynamic perfection operation. At present, a Stirling engine is used as a thermal power conversion device based on a constant volume process. Further, the inventors of the present application found that: the higher efficiency target of the Carnot battery energy storage system has higher requirement on the thermodynamic perfection of the heat-power conversion device, however, no relevant public report that the thermodynamic perfection of the actual Stirling engine is more than or equal to 80% is yet seen; moreover, the reason for the lower thermodynamic perfection of the actual Stirling engine is that the heat regenerator has large loss and the heat exchanger has large irreversible heat exchange loss, namely when the working medium absorbs heat from the high-temperature heat exchanger 5 and adiabatically expands in the high-temperature cavity 7, the temperature of the working medium gradually decreases in the high-temperature cavity 7, when the expansion process is finished, the temperature of the working medium in the high-temperature cavity 7 is lower than the temperature of the end of the high-temperature cavity 7 in the high-temperature heat exchanger 5, if the working medium flows to the heat regenerator 4 through the high-temperature heat exchanger 5, the working medium can generate irreversible heat exchange in the high-temperature heat exchanger 5, the irreversible loss is large, and likewise, when the working medium is adiabatically compressed in the low-temperature cavity 2, gradually increases in the temperature of the low-temperature cavity 2, when the compression process is finished, the temperature of the working medium in the low-temperature cavity 2 is lower than the temperature of the working medium in the low-temperature heat exchanger 3, if the working medium flows to the heat regenerator 4 through the low-temperature heat exchanger 3, the irreversible heat exchange is generated in the low-temperature heat exchanger 3, and meanwhile, the working medium has large irreversible heat exchange loss is generated in the low-temperature heat exchanger 3, and the working medium has large irreversible heat exchange loss due to the fact that the temperature difference of the working medium has large reversible heat exchange loss is increased in the heat exchanger; in addition, the energy storage density of the heat storage and cold storage medium in the Carnot battery energy storage system is related to the heat release temperature difference of the heat storage and cold storage medium, and the temperature in the heat exchanger of the Stirling engine is nearly constant in practice, so that when the Stirling engine is applied to the Carnot battery, the temperature difference between an inlet and an outlet is small when the heat storage and cold storage medium flows through the heat exchanger of the Stirling engine, and the energy storage density of the heat storage and cold storage medium in the Carnot battery energy storage system is low.

Therefore, the invention provides a working medium bypass flow passage parallel to the heat exchanger, namely, the working medium flows out of the high temperature cavity 7 or the low temperature cavity 2 through the working medium bypass flow passage, the working medium flows into the high temperature cavity 7 or the low temperature cavity 2 through the heat exchanger, and external media enters the heat exchanger from the high temperature cavity 7 or the low temperature cavity 2 end of the heat exchanger and flows out of the heat exchanger from the heat regenerator 4 end of the heat exchanger. The inventors of the present application found that: the heat-power conversion device can realize smaller irreversible loss in the heat exchanger; compared with the difference between the temperature of the working medium flowing into the high-temperature cavity 7 and the temperature of the working medium flowing into the low-temperature cavity 2, the bypass flow passage of the working medium parallel to the heat exchanger can reduce the temperature difference at two ends of the heat regenerator 4, so that smaller heat regeneration loss can be realized; in addition, because the irreversible loss in the heat exchanger is small, the heat-power conversion device can adopt high working medium pressure ratio, thereby improving the working capacity of the working medium with unit mass in one cycle, and therefore, the ratio of the loss of the heat regenerator 4, the flow resistance loss, the mechanical friction loss and the like to the working capacity of the working medium with unit mass in the cycle is reduced; finally, due to the small irreversible heat exchange loss in the heat exchanger, the temperature difference between the inlet and the outlet can be large when the heat storage medium flows through the heat exchanger of the Stirling engine. Therefore, the heat-power conversion device has the potential of high thermodynamic perfection, has the potential of adopting a low-temperature heat storage medium, has higher energy storage density, and is particularly suitable for the field of energy storage.

Specifically, fig. 1a shows an embodiment of the thermal power conversion device of the present invention, which includes: the low-temperature heat exchanger comprises a cylinder 1, a low-temperature cavity 2, a low-temperature heat exchanger 3, a heat regenerator 4, a high-temperature heat exchanger 5, a first working medium bypass flow channel 61, a second working medium bypass flow channel 62, a high-temperature cavity 7, a piston 10 and an ejector 12, wherein the piston 10 comprises a first piston 101 and a second piston 102, the low-temperature cavity 2, the high-temperature cavity 7, the first piston 101 and the second piston 102 are positioned in the cylinder 1, wherein the highest temperature in the high-temperature heat exchanger 5 is higher than the highest temperature in the low-temperature heat exchanger 3, or the average temperature in the high-temperature heat exchanger 5 is higher than the average temperature in the low-temperature heat exchanger 3. One end of the low-temperature heat exchanger 3 is connected with the low-temperature cavity 2, the other end of the low-temperature heat exchanger 3 is connected with one end of the high-temperature heat exchanger 5 through the heat regenerator 4, the other end of the high-temperature heat exchanger 5 is connected with the high-temperature cavity 7, the first working medium bypass flow passage 61 is parallel to the high-temperature heat exchanger 5, and the second working medium bypass flow passage 62 is parallel to the low-temperature heat exchanger 3. The piston 10 is used to generate oscillating pressure waves. The heat regenerator 4 is provided with a rectifier at any one end or a first rectifier 91 and a second rectifier 92 are respectively arranged at two ends, one end of the first rectifier 91 is connected with the heat regenerator 4, the other end of the first rectifier 91 is connected with the high-temperature heat exchanger 5 and/or the first working medium bypass flow passage 61, one end of the second rectifier 92 is connected with the heat regenerator 4, and the other end of the second rectifier 92 is connected with the low-temperature heat exchanger 3 and/or the second working medium bypass flow passage 62 for flow equalization. Further, a rectifier may be provided between the low temperature chamber 2 and the low temperature heat exchanger 3 and the second working medium bypass flow passage 62, and a rectifier may be provided between the high temperature chamber 7 and the high temperature heat exchanger 5 and the first working medium bypass flow passage 61. The working medium can be helium, hydrogen, nitrogen, air and the like. It should be noted that the regenerator 4 may be omitted in some special applications, such as the case where the difference between the highest temperature in the low temperature heat exchanger 3 and the lowest temperature in the high temperature heat exchanger 5 is small. If the regenerative device does not comprise the heat regenerator 4, one end of the low-temperature heat exchanger 3 is connected with the low-temperature cavity 2, the other end of the low-temperature heat exchanger 3 is connected with one end of the high-temperature heat exchanger 5, and the other end of the high-temperature heat exchanger 5 is connected with the high-temperature cavity 7. As shown in fig. 1b, the heat-power conversion device does not include the regenerator 4, and the high-temperature chamber 7 and the low-temperature chamber 2 are connected through a heat exchanger, in which case the high-temperature heat exchanger 5 should be regarded as a working medium bypass flow path of the low-temperature heat exchanger 3, and the low-temperature heat exchanger 3 should be regarded as a working medium bypass flow path of the high-temperature heat exchanger 5, that is, when the working medium in the high-temperature chamber 7 flows out from the high-temperature chamber 7, the working medium flows to the low-temperature chamber 2 through the flow path of the low-temperature heat exchanger 3; when the working medium in the low-temperature cavity 2 flows out from the low-temperature cavity 2, the working medium flows to the high-temperature cavity 7 through the flow channel of the high-temperature heat exchanger 5.

Further, a first control valve 81 is arranged on the flow passage of the high-temperature heat exchanger 5, a second control valve 82 is arranged on the first working medium bypass flow passage 61, a third control valve 83 is arranged on the second working medium bypass flow passage 62, a fourth control valve 84 is arranged on the flow passage of the low-temperature heat exchanger 3, preferably, the first control valve 81 is arranged on the flow passage between the high-temperature heat exchanger 5 and the high-temperature chamber 7, and the fourth control valve 84 is arranged on the flow passage between the low-temperature chamber 2 and the low-temperature heat exchanger 3. Specifically, during the inflow of the working medium into the low temperature chamber 2, the third control valve 83 remains closed, the fourth control valve 84 remains open, during the inflow of the working medium into the high temperature chamber 7, the first control valve 81 remains open, and the second control valve 82 remains closed; the fourth control valve 84 starts to close and the third control valve 83 starts to open just before the process of working medium flowing into the low temperature chamber 2 or just before the working medium flowing out of the low temperature chamber 2, the second control valve 82 starts to open and the first control valve 81 starts to close just before the process of working medium flowing into the high temperature chamber 7 or just before the working medium flowing out of the high temperature chamber 7; the third control valve 83 is closed and the fourth control valve 84 is opened just before the working medium flows out of the low temperature chamber 2 or just before the working medium flows into the low temperature chamber 2, and the first control valve 81 is opened and the second control valve 82 is closed just before the working medium flows out of the high temperature chamber 7 or just before the working medium flows into the high temperature chamber 7. Note that, in the closing and opening processes of the first control valve 81, the second control valve 82, the third control valve 83, and the fourth control valve 84, since it takes a certain period of time to close and open or oscillations generated by opening or closing are reduced, there is a possibility that they are simultaneously opened for a short period of time. The first control valve 81, the second control valve 82, the third control valve 83, and the fourth control valve 84 may be, for example, check valves, solenoid valves, three-way valves, or the like. When the check valve is adopted, the check valve on the working medium bypass flow passage extends from the heat regenerator 4 to the low-temperature cavity 2 or the high-temperature cavity 7 The reverse direction is closed and the opposite direction is opened; the check valve on the heat exchanger runner is closed from the low temperature cavity 2 and the high temperature cavity 7 to the low temperature heat exchanger 3 and the high temperature heat exchanger 5, and the check valve is opened in the opposite direction. When a three-way valve is used, the first control valve 81 and the second control valve 82 share an actuator; the third control valve 83 and the fourth control valve 84 share an actuator, and thus, when the three-way valve is used, the second control valve 82 is closed at the same time as the first control valve 81 is controlled to be opened, and vice versa. Preferably, the time required for each control valve to be fully closed to fully opened is 0.01 to 1 time t _cycle ，t _cycle The next cycle operation time is the rated frequency of the heat power conversion device. Further, control valves may be simultaneously arranged at both ends of the low-temperature heat exchanger 3, the high-temperature heat exchanger 5, and both ends of the working medium bypass flow passage, so that the working medium flows as far as possible according to a set path. It should be noted that, the flow passage of the high temperature heat exchanger 5 is provided with the first control valve 81, the first working medium bypass flow passage 61 is provided with the second control valve 82, the second working medium bypass flow passage 62 is provided with the third control valve 83, and the flow passage of the low temperature heat exchanger 3 is provided with the fourth control valve 84, which is mainly used for controlling the flow direction of fluid, so that the function of the device is obviously different from that of the air inlet and outlet valves in the piston compressor, the flow resistance loss of gas passing through the valve assembly is far smaller than that of the air inlet and outlet valves in the piston compressor, and the thermal power conversion device of the invention has the potential of higher thermodynamic perfection than that of an inverse brayton system based on a piston compression or expansion machine when the thermal power conversion device is applied to a carnot battery energy storage system.

Further, the thermal power conversion device further includes a heat storage unit. The heat-power conversion device in the existing Carnot battery energy storage system has the advantages that the direct working medium exchanges heat with the solid heat storage medium, namely the solid heat storage medium contacts with the working medium, and indirect heat exchange is also realized, namely the heat storage medium does not contact with the working medium. The inventors of the present application found that: for the heat-power conversion device, the dead volume is very large due to direct contact, the ratio of power to weight is very low, and the unit power cost of the heat-power conversion device is increased. Therefore, the heat storage medium in the heat storage unit is not in direct contact with the working medium in the thermal power conversion device of the invention. As shown in fig. 1, the working substance absorbs heat from the first heat storage unit 111 through the heat transfer medium and releases heat to the second heat storage unit 112 through the heat transfer medium. Further, the heat storage unit further includes a third heat storage unit 113 and a fourth heat storage unit 114, and the heat transfer medium flowing out of the first heat storage unit 111 and the second heat storage unit 112 flows into the third heat storage unit 113 and the fourth heat storage unit 114 after exchanging heat in the heat exchanger, respectively. Further, the heat transfer medium in the first heat storage unit 111 and the second heat storage unit 112 may be different. Further, the inventors of the present application found that: the heat-power conversion device has potential high-efficiency expansion and compression efficiency and small irreversible heat exchange loss, so that the highest temperature in the high-temperature heat exchanger 5 can be greatly reduced, and higher thermodynamic perfection is realized at a lower highest temperature. Specifically, the maximum temperature in the high-temperature heat exchanger 5 is equal to or less than 500 ℃, which is favorable for reducing the cost of the first heat storage unit 111, and preferably, the maximum temperature is 40-400 ℃.

Further, the high-temperature heat exchanger 5 and the low-temperature heat exchanger 3 are provided with heat transfer medium flow channels 502, wherein the heat transfer medium can be aqueous solution, molten salt, oil and the like, a heat transfer medium outlet 5022 of the heat transfer medium flow channels 502 in the high-temperature heat exchanger 5 and the low-temperature heat exchanger 3 is arranged at the end of a regenerator 4, a heat transfer medium inlet 5021 is arranged at the end of a low-temperature cavity 2 or a high-temperature cavity 7, and heat transfer medium exchanges heat with working media in the high-temperature heat exchanger 5 and the low-temperature heat exchanger 3. When the regenerator 4 is not arranged, the heat transfer medium outlet 5022 of the heat transfer medium flow passage 502 in the high-temperature heat exchanger 5 is arranged at the end of the low-temperature cavity 2, the heat transfer medium inlet 5021 is arranged at the end of the high-temperature cavity 7, the heat transfer medium outlet 5022 of the heat transfer medium flow passage 502 in the low-temperature heat exchanger 3 is arranged at the end of the high-temperature cavity 7, and the heat transfer medium inlet 5021 is arranged at the end of the low-temperature cavity 2. It should be noted that the heat transfer medium inlet 5021 and the heat transfer medium outlet 5022 of the heat exchanger, i.e. the substantial heat transfer medium inlet and outlet, can be judged by the fluid flowing direction, when the fluid flows from the high temperature chamber 7 end to the regenerator 4 end in the high temperature heat exchanger 5, the heat transfer medium inlet is the high temperature chamber 7 end, the heat transfer medium outlet is the regenerator 4 end, similarly, when the fluid flows from the low temperature chamber 2 end to the regenerator 4 end in the low temperature heat exchanger 3, the heat transfer medium inlet is the low temperature chamber 7 end, and the heat transfer medium outlet is the regenerator 4 end. As shown in fig. 2, fig. 2a shows from the appearance that the heat transfer medium inlet 5021 is at the inlet end of the heat exchanger interior heat transfer medium flow direction and the heat transfer medium outlet 5022 is at the outlet end of the heat exchanger interior heat transfer medium flow direction; although the heat transfer medium inlet 5021 is shown in the external view as being at the outlet end of the heat exchanger internal heat transfer medium flow direction and the heat transfer medium outlet 5022 is shown at the inlet end of the heat exchanger internal heat transfer medium flow direction in fig. 2b, the substantial heat transfer medium inlet 5021 is still at the inlet end of the heat exchanger internal heat transfer medium flow direction and the substantial heat transfer medium outlet 5022 is still at the outlet end of the heat exchanger internal heat transfer medium flow direction.

Further, the inventors of the present application found that: in the heat-power conversion device, if the temperature difference between the heat transfer medium inlet and the heat transfer medium outlet in the heat exchanger is too small, the parallel scheme of the working medium bypass flow channel and the heat exchanger can reduce irreversible loss in the heat exchanger, reduce the influence of other losses such as flow resistance and mechanical friction, reduce the loss of the heat regenerator, improve the energy storage density and the like, so that the heat transfer medium inlet and the heat transfer medium outlet in the heat exchanger can have larger temperature difference in order to exert the advantages of the technical scheme. Specifically, the temperature difference between the inlet and the outlet of the heat transfer medium in the high-temperature heat exchanger 5 is more than or equal to 20 ℃, the temperature difference between the inlet and the outlet of the heat transfer medium in the low-temperature heat exchanger 3 is more than or equal to 20 ℃, and the temperature difference between the inlet and the outlet of the heat transfer medium in the heat exchanger is preferably 50-200 ℃. Further, the temperature difference between the inlet and the outlet of the heat transfer medium is based on rated working conditions. In addition, the high temperature heat exchanger 5 or the low temperature heat exchanger 3 may be connected in series by a plurality of heat exchangers, and when the plurality of heat exchangers are connected in series, the temperature difference in each heat exchanger may be very small, approximately isothermal, but there is a temperature difference between the heat exchangers connected in series, so when the high temperature heat exchanger 5 is connected in series by a plurality of high temperature heat exchangers, the plurality of high temperature heat exchangers should be regarded as an integral high temperature heat exchanger, and similarly when the low temperature heat exchanger 3 is connected in series by a plurality of low temperature heat exchangers, the plurality of low temperature heat exchangers should be regarded as an integral low temperature heat exchanger.

Further, the inventors of the present application found that: in the heat-power conversion device, if the ratio of the temperature difference between the heat transfer medium inlet and the heat transfer medium outlet in the heat exchanger to the temperature difference between the two ends of the heat regenerator 4 is too small, the effect of reducing the loss of the heat regenerator 4 by adopting the parallel scheme of the working medium bypass flow passage and the heat exchanger is poor, so that the ratio of the temperature difference between the heat transfer medium inlet and the heat transfer medium outlet in the low-temperature heat exchanger 3 to the temperature difference between the two ends of the heat regenerator 4 is between 0.15 and 10 in order to exert the advantages of the technical scheme; and/or the ratio of the temperature difference between the inlet and the outlet of the heat transfer medium in the high-temperature heat exchanger 5 to the temperature difference between the two ends of the heat regenerator 4 is between 0.15 and 10, namely, when the temperature difference between the two ends of the heat regenerator 4 is 200 ℃, the temperature difference between the inlet and the outlet of the heat transfer medium in the heat exchanger is 30 ℃. Preferably, the ratio of the temperature difference between the inlet and the outlet of the heat transfer medium in the low-temperature heat exchanger 3 to the temperature difference between the two ends of the regenerator 4 is between 0.25 and 5, and the ratio of the temperature difference between the inlet and the outlet of the heat transfer medium in the high-temperature heat exchanger 5 to the temperature difference between the two ends of the regenerator 4 is between 0.25 and 5. Further, the ratio of the temperature difference between the heat transfer medium inlet and the heat transfer medium outlet in the heat exchanger and the temperature difference between the two ends of the heat regenerator is based on the rated working condition.

Further, the heat transfer medium flow channel 502 may be a straight pipe flow channel or a spiral flow channel, preferably, the heat transfer medium flow channel 502 is spiral, so that a heat exchange path is increased, which is beneficial to improving heat exchange between the heat transfer medium and the working medium. It should be noted that the spiral flow channel is a spiral pipe which is a relatively obvious bend in the flow direction during the flow of the heat transfer medium, compared with a straight pipe flow channel, for example, the flow is in a zigzag shape or a serpentine shape, or the flow channel with the flow path length of the heat transfer medium in the flow process being more than or equal to 110% of the shortest straight line length between the outlet and the inlet is in a spiral shape.

Further, the inventors of the present application found that: in order to exert the advantages of the technical proposal, the temperature difference between the inlet and the outlet of the heat transfer medium in the heat exchanger is larger, thus, in order to reduce the temperature difference between the two ends of the heat exchanger in the process of larger heat conductionThe length of the heat exchanger must be sufficiently long for losses. Further, the length of the low-temperature heat exchanger 3 is more than or equal to 10cm, and the length of the high-temperature heat exchanger 5 is more than or equal to 10cm. Preferably, the length of the low-temperature heat exchanger 3 is 20-200 cm, and the length of the high-temperature heat exchanger 5 is 20-200 cm. Further, the heat exchanger material is copper, stainless steel, aluminum alloy, or the like, preferably, the heat exchanger material is stainless steel. Further, the methodThe inventors of the present application found that: for the heat-power conversion device for energy storage, the efficiency is the key of competition due to competition with other energy storage modes, and in order to realize higher efficiency, the heat exchange temperature difference between the working medium in the high-temperature heat exchanger 5 and the heat transfer medium is less than or equal to 15 ℃ under the rated working condition, the heat exchange temperature difference between the working medium in the low-temperature heat exchanger 3 and the heat transfer medium is less than or equal to 15 ℃, and the heat exchange temperature difference between the working medium in the heat exchanger and the heat transfer medium is preferably 2-10 ℃.

Further, the inventors of the present application found that: the heat-power conversion device is characterized in that the working medium in the heat exchanger and the wall surface are close to one-way heat exchange, and the heat exchange device is different from the two-way heat exchange in the traditional oscillatory flow device, so that the length of the heat exchanger is longer, meanwhile, the efficiency of the heat-power conversion device is critical to the energy storage economy due to competition with other energy storage modes for the heat-power conversion device with energy storage purpose, and the smaller running frequency is beneficial to lower heat exchange temperature difference and lower flow resistance loss although not beneficial to the output power of unit volume, so that the economy is ensured. Thus, the piston movement frequency is less than or equal to 25Hz under rated conditions, preferably, the piston 10 movement frequency is less than or equal to 10Hz, and it is pointed out that the piston 10 is a working piston.

Further, the inventors of the present application found that: the working medium pressure ratio in the heat-power conversion device is an important factor for determining the ratio of the temperature difference between the inlet and the outlet of the heat transfer medium in the heat exchanger and the temperature difference between the two ends of the heat regenerator 4, and in order to exert the advantages of the technical scheme, a higher working medium pressure ratio is needed. Specifically, the ratio of the highest pressure to the lowest pressure of the working medium in the high-temperature cavity 7 or the low-temperature cavity 2 is between 1.2 and 10, and preferably, the ratio of the highest pressure to the lowest pressure of the working medium in the high-temperature cavity 7 or the low-temperature cavity 2 is between 2 and 5. Further, for the thermal power conversion device shown in fig. 1, the working fluid pressure ratio is primarily dependent on the ratio of the scavenge volume of the compression chamber piston to the expansion chamber piston, which is the product of the area of the piston 10 or ejector 12 and the stroke. In particular, the ratio of the scavenge volume of the compression chamber piston to the scavenge volume of the expansion chamber piston is between 1 and 5, preferably the ratio of the scavenge volume of the compression chamber piston to the scavenge volume of the expansion chamber piston is between 1.5 and 4. Further, for the thermal power conversion device shown in fig. 3, the working medium pressure ratio is mainly dependent on the ratio of the scavenge volume of the compression chamber piston to the ejector, specifically, the ratio of the scavenge volume of the compression chamber piston to the ejector is between 1 and 5, preferably, the ratio of the scavenge volume of the compression chamber piston to the ejector is between 1.5 and 4. The inventors of the present application found that: the heat-power conversion device has excellent performance when being applied to energy storage in order to better match heat exchange between working media and external heat sources in different scenes, and further comprises a pressure ratio adjusting mechanism. Further, the pressure ratio adjusting mechanism may be a piston stroke adjusting mechanism that adjusts the pressure ratio by changing the scavenging volume of the piston by adjusting the stroke of the piston, a compression piston unloading mechanism that adjusts the pressure ratio by changing the scavenging volume of the piston by adjusting the number of operating pistons, that is, changing the area of the piston, and a dead volume adjusting mechanism that adjusts the pressure ratio by changing the dead volume inside the thermal power conversion device, specifically, the dead volume adjusting mechanism is composed of an elastic member 15 and a hydraulic mechanism that adjusts the length of the elastic member 15 by the hydraulic mechanism, and the volume inside or outside the elastic member 15 can be changed, thereby adjusting the dead volume inside the thermal power conversion device. Further, the thermal power conversion device further includes an ejector 12, and in the thermal power conversion device shown in fig. 3, the ejector 12 replaces one of the pistons 10, as compared to fig. 1.

Further, the thermal power conversion device further comprises a transmission mechanism 13 and a motor 14, the ejector 12 and the piston 10 are connected to the transmission mechanism 13, and the transmission mechanism 13 is connected to the motor 14. Further, the motor may be a generator, or may be a driving and power generation integrated machine, that is, may have a driving motor function. Fig. 3 shows various output mechanisms, fig. 3a piston directly driving a linear motor, fig. 3b and 3c a piston driving transmission mechanism 13, fig. 3b a crank link, fig. 3c a diamond transmission, a pair of gears 16 for timing in diamond transmission, and other transmission mechanisms such as scotch yokes and the like. The piston 10 and the ejector 12 are connected with one set of transmission mechanisms through a connecting rod, or the piston 10 is connected with one set of transmission mechanisms 13, and the ejector 13 is connected with the other set of transmission mechanisms 13. Fig. 3 also shows several configurations of the ejector 12 and the piston 10, wherein the ejector 12 is coaxial with the piston 10 in fig. 3a, 3b, 3c, and the ejector 12 is not coaxial with the piston 10 in fig. 3 d.

Further, the inventors of the present application found that: in order to complete heat exchange under a lower heat exchange temperature difference, the heat-power conversion device needs a larger heat exchanger area, so that the dead volume of the heat exchanger is larger, the power and the weight of the heat-power conversion device are lower, and in order to realize better economy, the heat-power conversion device needs to be provided with a combination scheme of a plurality of pistons 10 or a plurality of ejectors 12. Thus, it is preferable that the thermal power conversion device has 3 or more pistons, or that the thermal power conversion device has 2 or more ejectors. Furthermore, the heat power conversion device can share the same set of transmission mechanism for more than or equal to 3 pistons, so that the motor sharing is realized, the pistons can share the same set of transmission mechanism, and the ejectors share another set of transmission mechanism. In addition, the multiple pistons and the ejector are beneficial to heat-power conversion and kinematics. Fig. 4 shows a thermal power conversion device with 1 piston and 2 ejectors, i.e. 2 ejectors share one piston.

Further, the inventors of the present application found that: for the heat-power conversion device for energy storage, because the heat-power conversion device competes with other energy storage modes, the elastic element 15 is adopted to seal the piston 10 and the back pressure cavity 17, so that higher compression and isentropic efficiency can be realized, higher thermodynamic perfection of the system can be realized at lower external high-temperature heat source temperature, such as less than or equal to 500 ℃, the related cost of high-temperature heat storage can be reduced, the efficiency of the heat-power conversion device can be improved, and the economy can be further improved. Therefore, an elastic element 15 is also included, one end of the elastic element 15 being connected 10 to the piston, the other end being fixed. One surface of the elastic element 15 is contacted with the working medium of the heat-power conversion device, and the other surface is contacted with the rest fluid. Preferably, the fluid with which the other side of the elastic element 15 is in contact is a liquid, preferably a lubricating oil. The elastic element 15 may be a bellows or a membrane, and the material may be rubber or stainless steel, etc. As shown in fig. 5, the first piston 101 is connected with one end of the elastic element 15, the other end of the elastic element 15 is connected with the cylinder, and the working chamber of the working medium of the heat-power conversion device can be completely separated from the fluid in the back pressure chamber 17 by the elastic element 15, so that the leakage of the working medium in the compression process of the working medium is eliminated. In addition, friction between the piston 101 and the sealing gap of the cylinder 1 can be eliminated through the elastic element 15, and long-life operation of the power device can be realized. Further, the second piston 102 or the ejector 12 may also be sealed with the elastic element 15. Further, as for the elastic member 15 of a metal material, the connection between the other end of the elastic member 15 and the cylinder may be welded or may be detachable such as screw connection. Preferably, the elastic element 15 of rubber or stainless steel or the like is detachably connected.

Further, the applicant found that: in the conventional Stirling, the heat exchanger is usually annular in shape, the heat exchanger is coaxial with the piston or the ejector, and the inner diameter of the heat exchanger is larger than that of the piston or the ejector, however, for the invention, the annular heat exchanger coaxial with the piston 10 or the ejector 12 has the problems of large dead volume and pressure drop of a working medium bypass flow passage, large volume and weight of the device, small temperature slippage range and uneven flow in the regenerator. Therefore, the heat exchanger is in a curved shape, and the length of the high-temperature heat exchanger 5 is longer than that of the first working medium bypass flow passage 61; the length of the low-temperature heat exchanger 3 is greater than that of the second working medium bypass flow passage 62, for example, a tube bundle or a flat tube with a plurality of flow passages inside can be used as the heat exchanger, one end of the low-temperature heat exchanger is connected with the high-temperature cavity or the low-temperature cavity, the other end of the low-temperature heat exchanger is connected with the heat regenerator, the tube bundle or the flat tube is bent into a U shape, an omega shape or a W shape and the like, the distance between the inlet end and the outlet end of the heat exchanger is reduced, and the working medium bypass flow passage can be a straight tube, so that the length of the working medium bypass flow passage can be shortened, and related adverse effects caused by the length of the working medium bypass flow passage can be reduced. Preferably, the flat tube is an aluminum microchannel flat tube. Fig. 8 shows a schematic view of a high temperature heat exchanger 5 in a U-shaped configuration.

Furthermore, the inventors of the present application found that: the heat-power conversion device has the potential of high efficiency when being used for solar power generation or acting, because the efficiency of the solar heat collector 24 is closely related to the heat collecting temperature, the higher the heat collecting temperature is, the lower the efficiency of the solar heat collector 24 is, and when the heat source is from solar energy, the irreversible heat exchange loss in the high-temperature heat exchanger 5 is reduced through the working medium bypass flow passage, therefore, a heat collecting plate with very long flow passage distance can be adopted, the temperature difference between the inlet and outlet of the internal fluid is more than or equal to 20 ℃, or the ratio of the temperature difference between the inlet and the outlet of the internal fluid and the temperature difference between the two ends of the heat regenerator 4 is between 0.15 and 10, and the heat collecting plates can be connected in series, so that the average heat collecting temperature is effectively reduced under the condition of the same highest heat collecting temperature, and the heat collecting efficiency of the heat-power conversion device and the heat collecting system of the solar heat collector can be finally improved. As shown in fig. 6, the thermal power conversion device further includes a solar collector 24.

Furthermore, the inventors of the present application found that: the solar heat collector 24 or other waste heat can also be used in the heat-power conversion device of the invention to exchange heat with the high-temperature heat exchanger 5 or the low-temperature heat exchanger 3, so that the heat-power conversion device has higher efficiency when being applied to energy storage.

Example two

An operation method of a heat-power conversion device comprises the following steps: when working medium flows into the high-temperature cavity 7 from the heat regenerator 4, a first control valve 81 on a flow passage of the high-temperature heat exchanger 5 is controlled to be kept in an open state, and a second control valve 82 on the first working medium bypass flow passage 61 is controlled to be kept in a closed state; when the flow of the working medium from the heat regenerator 4 into the high temperature cavity 7 is about to end or the flow of the working medium from the high temperature cavity 7 to the heat regenerator 4 is just started, a first control valve 81 on a flow passage of the high temperature heat exchanger 5 is controlled to start to be closed, and a second control valve 82 on a first working medium bypass flow passage 61 is controlled to start to be opened; when the flow of the working medium from the high temperature cavity 7 to the heat regenerator 4 is about to end or the flow of the working medium from the heat regenerator 4 to the high temperature cavity 7 is just started, the first control valve 81 on the flow channel of the high temperature heat exchanger 5 is controlled to start to be opened, and the second control valve 82 on the flow channel 61 of the first working medium is controlled to start to be closed. When working medium flows into the low-temperature cavity 2 from the heat regenerator 4, the fourth control valve 84 on the flow passage of the low-temperature heat exchanger 3 is controlled to be kept in an open state, and the third control valve 83 on the second working medium bypass flow passage 62 is controlled to be kept in a closed state; when the flow of the working medium from the heat regenerator 4 into the low-temperature cavity 2 is about to end or the flow of the working medium from the low-temperature cavity 2 to the heat regenerator 4 is just started, the fourth control valve 84 on the flow passage of the low-temperature heat exchanger 3 is controlled to start to be closed, and the third control valve 83 on the second working medium bypass flow passage 62 is controlled to start to be opened; when the flow of the working medium from the low-temperature cavity 2 to the heat regenerator 4 is about to end or the flow of the working medium from the heat regenerator 4 to the low-temperature cavity 2 is just started, the fourth control valve 84 on the flow passage of the low-temperature heat exchanger 3 is controlled to start to open, and the third control valve 83 on the second working medium bypass flow passage 62 is controlled to start to close.

Therefore, in the operation method of the present invention, it is required that not less than 50% of the total working fluid flowing out of the low temperature chamber 2 or the high temperature chamber 7 is flowing out through the first working fluid bypass flow passage 61 or the second working fluid bypass flow passage 62. Preferably, the proportion of the working medium flowing out of the low-temperature cavity 2 and the high-temperature cavity 7 respectively through the first working medium bypass flow channel 61 or the second working medium bypass flow channel 62 is between 0.8 and 1.

Further, the opening or closing of each control valve for inflow/outflow of the working medium is completed within plus or minus 60 degrees before or after the moment when the working medium flows from the inflow cavity to the outflow cavity or from the outflow cavity to the inflection point of the inflow cavity, and one cycle is 0-360 degrees. It is to be noted that during the closing and opening of the first control valve 81, the second control valve 82, the third control valve 83 and the fourth control valve 84, there is a short-time simultaneous open state due to the time required for complete closing and opening or in order to reduce hunting, and further, the simultaneous open state duration is continued < 60 °.

Further, the heat transfer medium flowing out of the first heat storage unit 111 flows in from the heat transfer medium inlet 5021 of the high temperature heat exchanger 5, flows out of the heat transfer medium outlet 5022 of the high temperature heat exchanger 5, flows in from the heat transfer medium inlet 5021 of the low temperature heat exchanger 3, and flows out of the heat transfer medium outlet 5022 of the low temperature heat exchanger 3.

Example III

As shown in fig. 1, a thermal power conversion apparatus includes: the low-temperature heat exchanger comprises a cylinder 1, a low-temperature cavity 2, a low-temperature heat exchanger 3, a heat regenerator 4, a high-temperature heat exchanger 5, a first working medium bypass flow channel 61, a second working medium bypass flow channel 62, a high-temperature cavity 7, a first piston 101 and a second piston 102, wherein the first piston 101 is positioned in the high-temperature cavity 7, the second piston 102 is positioned in the low-temperature cavity 2, one side of the first piston 101 is a working cavity, the other side is a back pressure cavity 17, and one side of the second piston 102 is a working cavity, and the other side is a back pressure cavity 17. As shown in fig. 3, the heat-power conversion device may further include: the device comprises a cylinder 1, a low-temperature cavity 2, a low-temperature heat exchanger 3, a heat regenerator 4, a high-temperature heat exchanger 5, a first working medium bypass flow passage 61, a second working medium bypass flow passage 62, a high-temperature cavity 7, a piston 10 and an ejector 12. Wherein the first working medium bypass flow passage 61 is parallel to the high temperature heat exchanger 5, and the second working medium bypass flow passage 62 is parallel to the low temperature heat exchanger 3. The heat-power conversion device has an engine mode: the working medium in the high temperature chamber 7 flows out of the high temperature chamber 7 through the first working medium bypass flow channel 61, and the working medium in the low temperature chamber 2 flows out of the low temperature chamber 2 through the second working medium bypass flow channel 62. In order to realize the orderly flow of the working medium, a first control valve 81 is arranged on the flow passage of the high-temperature heat exchanger 5, a fourth control valve 84 is arranged on the flow passage of the low-temperature heat exchanger 3, preferably, a second control valve 82 is arranged on the first working medium bypass flow passage 61, and a third control valve 83 is arranged on the second working medium bypass flow passage 62.

Further, the thermal power conversion device further comprises a transmission mechanism 13, the piston 10 is connected to the transmission mechanism 13, the transmission mechanism 13 is provided with a transmission shaft 18, the thermal power conversion device is provided with more than or equal to 1 first piston 101, and the thermal power conversion device is provided with more than or equal to 1 second piston 102. The inventors of the present application found that: for the heat power conversion device for energy storage, the first piston 101 and the second piston 102 are connected to the transmission shaft 18 of the transmission mechanism 13, and heat loss generated by heat conduction between the connecting rod or the cylinder body exists between the first piston 101 and the second piston 102, so that the system efficiency is reduced, therefore, the transmission mechanism 13 is provided with more than or equal to 2 transmission shafts 18, wherein: the first piston 101 is connected to a first drive shaft 181 and the second piston 102 is connected to a second drive shaft 182. Further, the first transmission shaft 181 is geared with the second transmission shaft 182. Preferably, the cylinder with the first transmission shaft 181 and the first piston 101 and the cylinder with the second transmission shaft 182 and the second piston 102 are two cylinders, so that heat transfer between the cylinders 1 can be reduced. It is noted that there may be a part of a common cylinder between two cylinders 1, for example: gear engagement portions. As shown in fig. 7, the first piston 101 is connected to the first transmission shaft 181, the second piston 102 is connected to the second transmission shaft 182, the first transmission shaft 181 and the second transmission shaft 182 are coupled through gears, the first transmission shaft 181 has a first gear 191, the second transmission shaft 182 has a second gear 192, the first gear 191 and the second gear 192 are connected to the motor 14 through a third gear 193, and the motor 14 may be a generator or a motor. Further, the piston back pressure chamber 17 is separated from the gear chamber 22 by the first partition 201 and the second partition 202, and heat transfer between the first piston 101 and the second piston 102 is further reduced.

Further, the heat-power conversion device can be used for energy storage, refrigeration and heating, for example, when the refrigeration and heating requirements are low in spring and autumn, the heat-power conversion device is used for energy storage; when the refrigerating demand in summer is large, the heat-power conversion device is used for refrigerating; when the heating requirement in winter is large, the heat-power conversion device is used for heating, and in addition, when the cooling and heating requirements are not met, the heat-power conversion device is used for storing energy. Further, the inventors of the present application found that: because of the characteristic reasons of the refrigeration and heating temperature requirements, in order to avoid the problem of lower efficiency caused by larger temperature slippage of working media, the heat power conversion device is also provided with a pressure ratio adjusting mechanism 25, and the temperature slippage amplitude can be adjusted through the pressure ratio adjusting mechanism 25 to accurately match the refrigeration and heating requirements.

Further, the inventors of the present application found that: at present, the carnot battery based on the brayton cycle and the organic rankine cycle is characterized in that the systems belong to stable unidirectional flow of working media, and the mass flow of the working media in the systems is the same everywhere, so that the same set of equipment can ensure that the sliding temperature of the working media in a heat exchanger is consistent in the process of energy storage and energy release, however, when the thermal power conversion device is used for energy release and energy storage integration, the problem that the sliding temperature of the working media in the heat exchanger is inconsistent in the process of energy release and energy storage can exist in the thermal power conversion device, for example, the thermal power conversion device shown in fig. 3 comprises a piston 10 and an ejector 12, if the phases of the piston 10 and the ejector 12 are fixed, the thermal power conversion device operates in an engine mode when the high temperature chamber 7 is an expansion chamber, the heat absorption capacity of the working media in the high temperature heat exchanger 5 is Q0, the mass flow is m0, the capacity is Cp, and the temperature difference of the working media in the high temperature heat exchanger 5 is dt0=q0/(m 0×cp); when the heat power conversion device operates in a refrigerator mode during energy storage, the high temperature cavity 7 still serves as an expansion cavity, and then the working medium is required to release Q0 heat release quantity in the low temperature heat exchanger 3, and the specific heat capacity Cp is not changed, so that the temperature difference of the working medium in the low temperature heat exchanger 3 is dT1=Q0/(m 1×Cp) because the working medium is not a stable unidirectional flow system, the mass flow is m1, and therefore, the heat power conversion device shown in fig. 3 is inconsistent in sliding temperature between the energy release process and the energy storage process in the heat exchanger due to the change of the mass flow, and irreversible loss is caused due to the inconsistency of the sliding temperature, so that the energy release-energy storage overall efficiency is reduced.

Further, the inventors of the present application found that: the difference of mass flow is mainly caused by different volume changes in adjacent cavities of the heat exchanger when the heat-power conversion device is used for energy release and energy storage, for example, in the heat-power conversion device shown in fig. 3, the net working medium flow m0 in the high-temperature heat exchanger 5 in one cycle is approximately equal to the working medium change amount in the high-temperature cavity 7 in the engine mode, and the net working medium flow m1 in the low-temperature heat exchanger 3 in one cycle is approximately equal to the working medium change amount in the low-temperature cavity 2 in the refrigerator mode, and the volume change amount of the high-temperature cavity 7 is inevitably smaller than the volume change amount of the low-temperature cavity 2, so that the working medium flow m0 and m1 are difficult to realize, and the sliding temperature of the working medium in the heat exchanger is inconsistent.

Further, the inventors of the present application found that: as for the thermal power conversion device shown in fig. 1, since two pistons 10 are adopted and one surfaces of the two pistons 10 are communicated with the working chamber and the other surfaces of the two pistons are communicated with the back pressure chamber 17, two methods for realizing that m0 and m1 in energy storage and release are basically equal are provided: (1) The phase between the two pistons is adjustable, namely the first piston and the second piston are adjustable between the compression piston and the expansion piston, when energy is released, the first piston 101 is the expansion piston, the second piston 102 is the compression piston, and when energy is stored, the first piston 102 is the expansion piston, and the second piston 101 is the compression piston, so that the positions of the expansion cavities can be changed; (2) The two piston scavenge volumes are identical, and thus m0 and m1 may be substantially identical, since the two piston scavenge volumes are identical.

Further, the inventors of the present application found that: for the thermal power conversion device shown in fig. 3, since it adopts a piston and an ejector, a method is implemented in which m0 and m1 in the stored energy and the released energy are substantially equal: the phase between the piston and the ejector is adjustable, for example, when the energy is released, the ejector 12 phase leads the piston 10 phase by 90 degrees, the high temperature chamber is the expansion chamber, when the energy is stored, the ejector 12 phase lags the piston 10 phase by 90 degrees, and the low temperature chamber is the expansion chamber.

Example IV

Further, an operation method of the heat-power conversion device is as follows:

when the heat-power conversion device operates in an energy release mode, namely an engine mode, and working medium flows from the high-temperature cavity 7 to the heat regenerator 4, a flow passage between the high-temperature heat exchanger 5 and the high-temperature cavity 7 is closed, a first working medium bypass flow passage 61 is opened, and the working medium flows to the heat regenerator 4 through the high-temperature cavity 7 and the first working medium bypass flow passage 61 in sequence; when working medium flows from the heat regenerator 4 to the high-temperature cavity 7, the first working medium bypass flow channel 61 is closed, a flow channel between the high-temperature cavity 7 and the high-temperature heat exchanger 5 is opened, and the working medium flows to the high-temperature cavity 7 through the heat regenerator 4 and the high-temperature heat exchanger 5 in sequence; when the working medium flows from the heat regenerator 4 to the low-temperature cavity 2, a flow passage between the low-temperature cavity 2 and the low-temperature heat exchanger 3 is opened, the second working medium bypass flow passage 62 is closed, and the working medium flows to the low-temperature cavity 2 through the heat regenerator 4 and the low-temperature heat exchanger 3 in sequence; when the working medium flows from the low-temperature cavity 2 to the heat regenerator 4, the flow passage between the low-temperature heat exchanger 3 and the low-temperature cavity 2 is closed, the second working medium bypass flow passage 62 is opened, and the working medium flows into the heat regenerator 4 through the low-temperature cavity 2 and the second working medium inflow flow passage 62 in sequence.

When the heat-power conversion device operates in an energy storage mode, namely a refrigerator mode, and working media flow from the high-temperature cavity 7 to the heat regenerator 4, a flow passage between the high-temperature heat exchanger 5 and the high-temperature cavity 7 is opened, a first working media bypass flow passage 61 is closed, and the working media sequentially flow to the heat regenerator 4 through the high-temperature cavity 7 and the high-temperature heat exchanger 5; when working medium flows from the heat regenerator 4 to the high-temperature cavity 7, the first working medium bypass flow channel 61 is opened, the flow channel between the high-temperature cavity 7 and the high-temperature heat exchanger 5 is closed, and the working medium flows to the high-temperature cavity 7 through the heat regenerator 4 and the first working medium bypass flow channel 61 in sequence; when the working medium flows from the heat regenerator 4 to the low-temperature cavity 2, a flow passage between the low-temperature cavity 2 and the low-temperature heat exchanger 3 is closed, a second working medium bypass flow passage 62 is opened, and the working medium flows to the low-temperature cavity 2 through the heat regenerator 4 and the second working medium bypass flow passage 62 in sequence; when the working medium flows from the low-temperature cavity 2 to the heat regenerator 4, a flow passage between the low-temperature heat exchanger 3 and the low-temperature cavity 2 is opened, the second working medium bypass flow passage 62 is closed, and the working medium flows to the heat regenerator 4 through the low-temperature cavity 2 and the low-temperature heat exchanger 3 in sequence.

Further, when the heat work conversion device operates in the energy release mode, i.e. the engine mode, the heat transfer medium flowing out of the first heat storage unit flows in from the heat transfer medium inlet 5021 of the high temperature heat exchanger 5, flows out from the heat transfer medium outlet 5022 of the high temperature heat exchanger 5, the heat transfer medium inlet 5021 of the high temperature heat exchanger 5 is close to the high temperature cavity 7 end, the heat transfer medium outlet 5022 is close to the regenerator end, the heat transfer medium flowing out of the second heat storage unit flows in from the heat transfer medium inlet 5021 of the low temperature heat exchanger 3, flows out from the heat transfer medium outlet 5022 of the low temperature heat exchanger 3, and the heat transfer medium inlet 5021 of the low temperature heat exchanger 3 is close to the low temperature cavity 2 end, and the heat transfer medium outlet 5022 is close to the regenerator end; when the heat-power conversion device is operated in the energy storage mode, that is, the refrigerator mode, the heat medium flowing out of the second heat storage unit flows in from the heat medium outlet 5022 of the high-temperature heat exchanger 5, flows out of the heat medium inlet 5021 of the high-temperature heat exchanger 5, flows in from the heat medium outlet 5022 of the low-temperature heat exchanger 3, and flows out of the heat medium inlet 5021 of the low-temperature heat exchanger 3.

Example five

Further, an operation method of the heat-power conversion device is as follows:

when the heat-power conversion device comprises the first piston 101 and the second piston 102, as shown in fig. 1, in the engine mode, the operation phase of the first piston 101 leads the operation phase of the second piston 102 by 60-150 degrees, and in the refrigerator mode, the operation phase of the first piston 101 lags the operation phase of the second piston 102 by 60-150 degrees. Preferably, in the engine mode, the first piston 101 is operated at a phase 90 ° ahead of the second piston 102, and in the refrigerator mode, the first piston 101 is operated at a phase 90 ° behind the second piston 102.

When the thermal power conversion device is composed of the piston 10 and the ejector 12, the operation phase of the ejector 12 leads the operation phase of the piston 10 by 60-150 DEG in the engine mode, and the operation phase of the ejector 12 lags the operation phase of the piston 10 by 60-150 DEG in the refrigerator mode. In the engine mode, the operation phase of the ejector 12 is 60-150 degrees ahead of the operation phase of the piston 10, and corresponds to the high-temperature chamber 7 shown in fig. 3 as an expansion chamber, and the high-temperature heat exchanger 5 absorbs heat from the outside.

It should be noted that the above process phase lead and lag is achieved by adjusting the rotation axis: (1) When the first piston 101 and the second piston 102 are commonly connected to the same transmission shaft 18 of the transmission mechanism 13, the phase between the first piston 101 and the second piston 102 is fixed, when the transmission shaft 18 is forward, the operation phase of the first piston 101 leads the operation phase of the second piston 102 by n degrees, n can be 60-150 degrees, when the transmission shaft 18 is backward, the operation phase of the first piston 101 lags the operation phase of the second piston 102 by n degrees, and likewise, when the piston 10 and the ejector 12 are commonly connected to the same transmission shaft 18 of the transmission mechanism 13, the phase between the piston 10 and the ejector 12 is fixed, when the transmission shaft 18 is forward, the operation phase of the piston 10 leads the operation phase of the ejector 12 by n degrees, n can be 60-150 degrees, and when the transmission shaft 18 is backward, the operation phase of the piston 10 lags the operation phase of the ejector 12 by n degrees; (2) When the first piston 101 and the second piston 102 are connected to different transmission shafts 18 of the transmission mechanism 13, the phases between the first piston 101 and the second piston 102 are not fixed, so that the operation phase of the first piston 101 is ahead of the operation phase of the second piston 102 by n degrees in the engine mode and the operation phase of the first piston 101 is behind the operation phase of the second piston 102 by n degrees in the refrigerator mode can be realized by timing the different transmission shafts 18, and likewise, when the piston 10 and the ejector 12 are connected to different transmission shafts 18 of the transmission mechanism 13, the operation phase of the piston 10 and the ejector 12 are not fixed, and the operation phase of the piston 10 is ahead of the operation phase of the ejector 12 by n degrees in the engine mode and the operation phase of the piston 10 is behind the operation phase of the ejector 12 in the refrigerator mode can be realized by timing the different transmission shafts 18. In addition, by timing different transmission shafts 18, the operation phase of the first piston 101 in the engine mode is ahead of the operation phase of the second piston 102 by n degrees, the operation phase of the first piston 101 in the refrigerator mode is behind the operation phase of the second piston 102, and in the same manner, the operation phase of the piston 10 in the engine mode is ahead of the operation phase of the ejector 12 by n degrees, and the operation phase of the piston 10 in the refrigerator mode is behind the operation phase of the ejector 12 by m degrees, which may be the same or different.

While the invention has been described with reference to preferred embodiments, it is not intended to be limiting. Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art, or equivalent embodiments with equivalent variations can be made, without departing from the scope of the invention. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. The utility model provides a heat power conversion device, includes low temperature chamber (2), low temperature heat exchanger (3), high temperature heat exchanger (5) and high temperature chamber (7) that link to each other in proper order, low temperature chamber (2) with in high temperature chamber (7) locate cylinder (1), be equipped with piston (10), its characterized in that in cylinder (1):

the heat work conversion device further comprises a first working medium bypass flow channel (61) which is parallel to the high-temperature heat exchanger (5), hot working medium in the high-temperature cavity (7) flows out through the first working medium bypass flow channel (61), cold working medium from the low-temperature cavity (2) flows into the high-temperature cavity (7) through the high-temperature heat exchanger (5), and hot working medium from the high-temperature cavity (7) flows into the low-temperature cavity (2) through the low-temperature heat exchanger (3);

And/or the heat work conversion device further comprises a second working medium bypass flow channel (62) which is parallel to the low-temperature heat exchanger (3), the cold working medium in the low-temperature cavity (2) flows out through the second working medium bypass flow channel (62), the cold working medium from the low-temperature cavity (2) flows into the high-temperature cavity (7) through the high-temperature heat exchanger (5), and the heat working medium from the high-temperature cavity (7) flows into the low-temperature cavity (2) through the low-temperature heat exchanger (3).

2. The heat-to-power conversion device according to claim 1, wherein: the low-temperature heat exchanger (3) and the high-temperature heat exchanger (5) are provided with a heat regenerator (4), one end of a first working medium bypass flow passage (61) is connected with one end of the heat regenerator (4), the other end of the first working medium inflow flow passage (61) is connected with the high-temperature cavity (7), one end of a second working medium bypass flow passage (62) is connected with the other end of the heat regenerator (4), and the other end of the second working medium bypass flow passage (62) is connected with the low-temperature cavity (2).

3. The heat-to-power conversion device according to claim 2, wherein: the heat exchanger is characterized in that a heat transfer medium runner (502) is arranged on a heat exchanger wall (503) of the high-temperature heat exchanger (5), a heat transfer medium inlet (5021) of the heat transfer medium runner (502) is positioned near one end of the high-temperature cavity (7) and a heat transfer medium outlet (5022) is positioned near one end of the low-temperature cavity (2), the heat exchanger wall (503) of the low-temperature heat exchanger (3) is also provided with the heat transfer medium runner (502) and the heat transfer medium inlet (5021) of the heat transfer medium runner (502) is positioned near one end of the low-temperature cavity (2), and the heat transfer medium outlet (5022) is positioned near one end of the high-temperature cavity (7).

4. A heat-power conversion device according to claim 3, wherein:

the heat transfer medium flow passage (502) is spiral;

and/or the length of the low-temperature heat exchanger (3) is more than or equal to 10cm, and the length of the high-temperature heat exchanger (5) is more than or equal to 10cm;

and/or the inlet temperature of the heat transfer medium in the high-temperature heat exchanger (5) is less than or equal to 500 ℃;

and/or the temperature difference between the inlet and the outlet of the heat transfer medium in the high-temperature heat exchanger (5) is more than or equal to 20 ℃, and the temperature difference between the inlet and the outlet of the heat transfer medium in the low-temperature heat exchanger (3) is more than or equal to 20 ℃;

and/or the high-temperature heat exchanger (5) is connected with a first heat storage unit (111), and the low-temperature heat exchanger (3) is connected with a second heat storage unit (112).

5. A heat-power conversion device according to claim 3, wherein:

the ratio of the temperature difference between the heat transfer medium inlet (5021) and the heat transfer medium outlet (5022) in the low-temperature heat exchanger (3) and the temperature difference between the two ends of the heat regenerator (4) is between 0.15 and 10;

and/or the ratio of the temperature difference between the heat transfer medium inlet (5021) and the heat transfer medium outlet (5022) in the high-temperature heat exchanger (5) and the temperature difference between the two ends of the heat regenerator (4) is between 0.15 and 10;

and/or the ratio of the highest pressure to the lowest pressure of the working medium in the low-temperature cavity (2) is 1.2-10;

6. The heat-power conversion device according to any one of claims 1 to 5, characterized in that: the piston also comprises an elastic element (15), one end of the elastic element (15) is connected with the piston (10), and the other end of the elastic element is fixed.

7. The heat-power conversion device according to any one of claims 1 to 5, characterized in that:

the length of the high-temperature heat exchanger (5) is longer than that of the first working medium bypass flow passage (61);

the length of the low-temperature heat exchanger (3) is longer than that of the second working medium bypass flow passage (62).

8. The utility model provides a heat power conversion device, includes piston (10), drive mechanism (13), and low temperature chamber (2), low temperature heat exchanger (3), high temperature heat exchanger (5) and high temperature chamber (7) that link to each other in proper order, low temperature chamber (2 high temperature chamber (7) with in cylinder (1) are located to piston (10), drive mechanism (13) have transmission shaft (18), piston (10) connect in transmission shaft (18) of drive mechanism (13), its characterized in that:

the piston (10) comprises a first piston (101) and a second piston (102); or, the thermal power conversion device further comprises an ejector (12);

the high-temperature heat exchanger (5) is provided with a first parallel working medium bypass flow passage (61) and/or the low-temperature heat exchanger (3) is provided with a second parallel working medium bypass flow passage (62);

In the engine mode, the hot working medium of the high-temperature cavity (7) flows out through the first working medium bypass flow channel (61), and the cold working medium of the low-temperature cavity (2) flows out through the second working medium bypass flow channel (62).

9. A method of operating a thermal power conversion device according to any one of claims 1 to 7, characterized in that:

when working medium flows from the high-temperature cavity (7) to the heat regenerator (4), a flow passage between the high-temperature heat exchanger (5) and the high-temperature cavity (7) is closed, a first working medium bypass flow passage (61) is opened, and the working medium flows to the heat regenerator (4) through the high-temperature cavity (7) and the first working medium bypass flow passage (61) in sequence; when working medium flows from the heat regenerator (4) to the high-temperature cavity (7), the first working medium bypass flow channel (61) is closed, the flow channel between the high-temperature cavity (7) and the high-temperature heat exchanger (5) is opened, and the working medium flows to the high-temperature cavity (7) through the heat regenerator (4) and the high-temperature heat exchanger (5) in sequence;

when working medium flows from the heat regenerator (4) to the low-temperature cavity (2), a flow passage between the low-temperature cavity (2) and the low-temperature heat exchanger (3) is opened, a second working medium bypass flow passage (62) is closed, and the working medium flows to the low-temperature cavity (2) through the heat regenerator (4) and the low-temperature heat exchanger (3) in sequence; when working medium flows from the low-temperature cavity (2) to the heat regenerator (4), a flow passage between the low-temperature heat exchanger (3) and the low-temperature cavity (2) is closed, a second working medium bypass flow passage (62) is opened, and the working medium flows to the heat regenerator (4) through the low-temperature cavity (2) and the second working medium inflow flow passage (62) in sequence;

The heat transfer medium flowing out of the first heat storage unit (111) flows in from the heat transfer medium inlet (5021) of the high-temperature heat exchanger (5), flows out of the heat transfer medium outlet (5022) of the high-temperature heat exchanger (5), flows in from the heat transfer medium inlet (5021) of the low-temperature heat exchanger (3) and flows out of the heat transfer medium outlet (5022) of the low-temperature heat exchanger (3).

10. A method of operating a thermal power conversion apparatus as claimed in claim 8, wherein:

when the thermal power conversion device comprises a first piston (101) and a second piston (102), and in an engine mode, the operation phase of the first piston (101) leads the operation phase of the second piston (102) by 60-150 degrees;

or, when the thermal power conversion device includes a piston (10) and an ejector (12), the ejector (12) operates in a phase 60 to 150 ° ahead of the piston (10) in an engine mode.