Geothermal power generation system with heat pump coupled with organic Rankine cycle and thermovoltaic power generation

Abstract

The invention relates to the technical field of low-grade energy, in particular to a geothermal power generation system and method with a heat pump coupled with organic Rankine cycle and thermovolt power generation. Comprising a flash evaporation type circulation unit and an organic Rankine cycle-thermovolt power generation unit which are connected, the flash evaporation type circulating unit comprises a first heat exchanger, a heat pump regenerator, a first-stage compressor, a working medium mixer, a second-stage compressor, a second heat exchanger and a gas-liquid separator; the organic Rankine cycle and the thermovolt power generation technology are combined, the comprehensive power generation efficiency of the whole system can reach 23.2%, and effective and reasonable utilization of medium and low temperature terrestrial heat is achieved; in addition, the system has the advantages of being simple in structure, low in requirement for equipment performance, safe, stable, good in system economy and the like, and an effective and feasible scheme is provided for utilization of medium and low temperature geothermal resources and other low-grade waste heat.

Description

Technical Field

[0001] The present invention relates to the technical field of low-grade energy, and in particular to a geothermal power generation system and method of heat pump coupled organic Rankine cycle and thermovoltaic power generation. Background Art

[0002] In order to cope with global climate change and a series of environmental problems, more and more countries have begun to pay attention to the development and utilization of renewable energy, and traditional fossil energy is gradually being eliminated. At present, the fastest growing and largest renewable energy sources in the energy structure are solar energy and wind energy. Both energy sources are intermittent, volatile, and unstable, which are not conducive to the stable operation of the power grid. Geothermal energy has the advantages of environmental protection, pollution-free, sustainable supply, unaffected by climate change, uninterrupted operation, and does not require the construction of supporting energy storage systems, which can form a good complement to wind energy and solar energy.

[0003] At present, the main ways of utilizing geothermal energy include geothermal power generation and direct utilization. Among them, high-temperature geothermal power generation technology has become relatively mature and can achieve good benefits. However, the utilization of medium and low-temperature geothermal energy, which has more abundant reserves and is more widely distributed, is still mainly based on direct heating, and the corresponding power generation technology is progressing relatively slowly. This is mainly because the energy quality of medium and low-temperature geothermal energy is relatively low. When it is used directly for power generation, the power generation efficiency is low and it is difficult to achieve good benefits.

[0004] Flash heat pump technology is a new type of heat pump technology. It can heat and upgrade medium and low temperature geothermal energy through heat pump circulation to obtain a higher temperature heat source. When the upgraded medium and low temperature geothermal energy is used for power generation, higher efficiency can be obtained. Thermovoltaic power generation technology is a new type of power generation technology that can directly convert thermal energy into electrical energy, including the utilization of waste heat from oil fields, geothermal energy, and geothermal energy associated with oil fields. Therefore, how to combine these two technologies to achieve power generation and utilization of medium and low temperature geothermal energy is the problem to be solved by the present invention. Summary of the invention

[0005] In response to the problems mentioned in the prior art, the present invention proposes a geothermal power generation system and method of a heat pump coupled with an organic Rankine cycle and thermovoltaic power generation. The medium and low temperature geothermal energy can be upgraded and heated by a flash heat pump, and then used to generate electricity by an organic Rankine cycle-thermovoltaic power generation system, thereby realizing efficient utilization of medium and low temperature geothermal energy.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: The present invention discloses a geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation, comprising a flash cycle unit and an organic Rankine cycle-thermovoltaic power generation unit connected to each other; The flash circulation unit includes a first heat exchanger, a heat pump regenerator, a first-stage compressor, a working fluid mixer, a second-stage compressor, a second heat exchanger and a gas-liquid separator; The cold phase outlet of the first heat exchanger is connected to the cold phase inlet of the heat pump regenerator, the cold phase outlet of the heat pump regenerator is connected to the inlet of the first-stage compressor, the outlet of the first-stage compressor is connected to the superheated steam inlet of the working medium mixer, the outlet of the working medium mixer is connected to the inlet of the second-stage compressor, the outlet of the second-stage compressor is connected to the hot phase inlet of the second heat exchanger, the hot phase outlet of the second heat exchanger is connected to the inlet of the gas-liquid separator, wherein the gas-side outlet of the gas-liquid separator is connected to the saturated steam inlet of the working medium mixer, the liquid-side outlet of the gas-liquid separator is connected to the hot phase inlet of the heat pump regenerator, and the hot phase outlet of the heat pump regenerator is connected to the cold phase inlet of the first heat exchanger; The organic Rankine cycle-thermovoltaic power generation unit includes an expander, a thermovoltaic power generation module, a heat engine regenerator and a third heat exchanger; The expander inlet is connected to the cold phase outlet of the second heat exchanger, the expander outlet is connected to the hot side inlet of the thermovoltaic power generation module, the hot side outlet of the thermovoltaic power generation module is connected to the hot phase inlet of the heat engine regenerator, the hot phase outlet of the heat engine regenerator is connected to the hot phase inlet of the third heat exchanger, and the hot phase outlet of the third heat exchanger is connected to the cold phase inlet of the heat engine regenerator.

[0007] As a further improvement of the present invention, it also includes a cooling tower, the cold phase outlet of the third heat exchanger is connected to the cold side inlet of the thermovoltaic power generation module through the cooling tower, and the cold side outlet of the thermovoltaic power generation module is connected to the cold phase inlet of the third heat exchanger through the cooling tower; the inlet temperature and outlet temperature of the cooling tower are 35°C and 25°C respectively.

[0008] As a further improvement of the present invention, it also includes a geothermal system, wherein the hot phase inlet of the first heat exchanger is connected to the hot phase outlet of the first heat exchanger through the geothermal system; the input temperature and output temperature of the geothermal system are 85°C and 75°C respectively.

[0009] As a further improvement of the present invention, a first expansion valve is provided between the hot phase outlet of the heat pump regenerator and the cold phase inlet of the first heat exchanger; a second expansion valve is provided between the hot phase outlet of the second heat exchanger and the inlet of the gas-liquid separator; and a booster pump is provided between the hot phase outlet of the third heat exchanger and the cold phase inlet of the heat engine regenerator.

[0010] As a further improvement of the present invention, the first heat exchanger, the heat pump regenerator, the second heat exchanger, the heat engine regenerator and the third heat exchanger are all fixed tube sheet heat exchangers. As a further improvement of the present invention, both the first-stage compressor and the second-stage compressor are scroll compressors, and the compression ratio is 2. As a further improvement of the present invention, the thermovoltaic power generation module is a thermoelectric conversion system, wherein the thermoelectric material is Bi2Te3.

[0011] As a further improvement of the present invention, the expander is a turbine expander with a rated inlet temperature of 140° C., a rated inlet pressure of 1.37 MPa, and an expansion ratio of 12.5.

[0012] As a further improvement of the present invention, the circulating working fluids of the flash heat pump circulation unit and the organic Rankine cycle-thermovoltaic power generation unit are both R123.

[0013] A method for a geothermal power generation system of a heat pump coupled with an organic Rankine cycle and thermovoltaic power generation, wherein when a flash cycle unit is in operation, the working fluid is heated and evaporated in a first heat exchanger, enters a heat pump regenerator to absorb heat to a superheated state, enters a first-stage compressor for compression and temperature increase, enters a working fluid mixer to mix with a saturated gaseous working fluid in a gas-liquid separator, enters a second-stage compressor for compression to a high-temperature and high-pressure state, enters a second heat exchanger to release heat to a saturated liquid state, enters a gas-liquid separator after expansion and decompression by a second expansion valve, and at this time, the saturated gaseous working fluid enters the working fluid mixer; when the saturated liquid working fluid enters the heat pump regenerator to release heat, it is expanded and decompressed by a first expansion valve to a gas-liquid mixed state, and then returns to the first heat exchanger to complete the heat pump cycle; When the organic Rankine cycle-thermovoltaic power generation unit is in operation, the working fluid absorbs heat to a superheated gas state in the second heat exchanger, enters the expander to perform work and expand, enters the thermovoltaic power generation module to release heat to generate electricity again, enters the heat engine regenerator to release heat, enters the third heat exchanger to release heat again to a saturated liquid state, enters the booster pump to boost the pressure to a supercooled state, enters the heat engine regenerator to absorb heat to a saturated liquid state, and then returns to the second heat exchanger to complete the organic Rankine cycle.

[0014] Compared with the prior art, the present invention has achieved the following technical effects: The flash circulation unit provided in the present invention can improve the quality and temperature of medium and low temperature geothermal resources, which not only improves the quality of geothermal energy, but also lays a foundation for its subsequent use in power generation, effectively improving the power generation efficiency; in addition, the use of a flash heat pump is conducive to expanding the temperature operating range of the working fluid, achieving a higher temperature rise, and reducing the requirements for equipment design parameters, especially reducing the pressure ratio of the compressor in the heat pump, extending the service life of the equipment, and further reducing the operating cost of the system.

[0015] The heat pump regenerator and heat engine regenerator provided in the system of the present invention help to reduce the irreversible losses of the system during operation, thereby improving the overall operating efficiency of the system. By recovering and utilizing the waste heat generated in the system, energy recycling is achieved, further improving the energy utilization rate of the system. The present invention combines the organic Rankine cycle with thermovoltaic power generation technology to achieve cascade utilization of heat from the heat source and improve the operating efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0017] Figure numerals: 1. first heat exchanger; 2. heat pump regenerator; 3. first-stage compressor; 4. working fluid mixer; 5. second-stage compressor; 6. second heat exchanger; 7. second expansion valve; 8. gas-liquid separator; 9. first expansion valve; 10. geothermal system; 11. expansion machine; 12. thermovoltaic power generation module; 13. heat engine regenerator; 14. third heat exchanger; 15. booster pump; 16. cooling tower. DETAILED DESCRIPTION

[0018] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0023] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0024] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0025] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0026] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0027] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] like Figure 1As shown, the present invention is a geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation, including a flash cycle unit and an organic Rankine cycle-thermovoltaic power generation unit connected; the flash cycle unit includes a first heat exchanger 1, a heat pump regenerator 2, a first-stage compressor 3, a working fluid mixer 4, a second-stage compressor 5, a second heat exchanger 6 and a gas-liquid separator 8; the cold phase outlet of the first heat exchanger 1 is connected to the cold phase inlet of the heat pump regenerator 2, and the cold phase outlet of the heat pump regenerator 2 is connected to the inlet of the first-stage compressor 3 , the outlet of the first-stage compressor 3 is connected to the superheated steam inlet of the working medium mixer 4, the outlet of the working medium mixer 4 is connected to the inlet of the second-stage compressor 5, the outlet of the second-stage compressor 5 is connected to the hot phase inlet of the second heat exchanger 6, the hot phase outlet of the second heat exchanger 6 is connected to the inlet of the gas-liquid separator 8, wherein the gas-side outlet of the gas-liquid separator 8 is connected to the saturated steam inlet of the working medium mixer 4, the liquid-side outlet of the gas-liquid separator 8 is connected to the hot phase inlet of the heat pump regenerator 2, and the hot phase outlet of the heat pump regenerator 2 is connected to the cold phase inlet of the first heat exchanger 1; The organic Rankine cycle-thermovoltaic power generation unit includes an expander 11, a thermovoltaic power generation module 12, a heat engine regenerator 13 and a third heat exchanger 14; The inlet of the expander 11 is connected to the cold phase outlet of the second heat exchanger 6, the outlet of the expander 11 is connected to the hot side inlet of the thermovoltaic power generation module 12, the hot side outlet of the thermovoltaic power generation module 12 is connected to the hot phase inlet of the heat engine regenerator 13, the hot phase outlet of the heat engine regenerator 13 is connected to the hot phase inlet of the third heat exchanger 14, and the hot phase outlet of the third heat exchanger 14 is connected to the cold phase inlet of the heat engine regenerator 13.

[0029] The cooling tower 16 is also included. The cold phase outlet of the third heat exchanger 14 is connected to the cold side inlet of the thermovoltaic power generation module 12 through the cooling tower 16. The cold side outlet of the thermovoltaic power generation module 12 is connected to the cold phase inlet of the third heat exchanger 14 through the cooling tower 16. The inlet temperature and outlet temperature of the cooling tower 16 are 35°C and 25°C respectively. In the embodiment, the cooling tower 16 is to provide a cold source for the thermovoltaic power generation module 12 and the third heat exchanger 14, and the cold source is cold water. The inlet and outlet temperatures of the cooling tower 16 are limited, which expands the operating temperature range of the Ken cycle, so that the system can obtain higher efficiency.

[0030] It also includes a geothermal system 10, wherein the hot phase inlet of the first heat exchanger 1 is connected to the hot phase outlet of the first heat exchanger 1 through the geothermal system 10; the input temperature and output temperature of the geothermal system 10 are 85°C and 75°C respectively. In the embodiment, the geothermal heat provides heat for the first heat exchanger 1, and the cost can be reduced by combining with the cooling tower 16; the inlet and outlet temperatures of the geothermal system 10 are limited, and the operating temperature range of the Ken cycle is expanded, so that the system can obtain higher efficiency.

[0031] A first expansion valve 9 is provided between the hot phase outlet of the heat pump regenerator 2 and the cold phase inlet of the first heat exchanger 1; a second expansion valve 7 is provided between the hot phase outlet of the second heat exchanger 6 and the inlet of the gas-liquid separator 8; a booster pump 15 is provided between the hot phase outlet of the third heat exchanger 14 and the cold phase inlet of the heat engine regenerator 13.

[0032] The first heat exchanger 1, the heat pump regenerator 2, the second heat exchanger 6, the heat engine regenerator 13 and the third heat exchanger 14 are all fixed tube plate heat exchangers. In the embodiment, the first heat exchanger 1 is for heat exchange between working medium and geothermal heat, the second heat exchanger 6 is for heat exchange between working medium and working medium, and the third heat exchanger 14 is for heat exchange between cold water and working medium; in the embodiment, the fixed tube plate heat exchanger is preferred, which has the advantages of simple design, low manufacturing cost, large heat transfer area, convenient cleaning, compact and light structure, low cost and high heat transfer efficiency, which is conducive to reducing system cost, and at the same time can ensure the high efficiency of the heat exchange process and facilitate equipment maintenance. The first stage compressor 3 and the second stage compressor 5 are both scroll compressors, and the compression ratio is 2. In the embodiment, the compression ratio is preferably 2, and a smaller compression ratio is beneficial to prolonging the life of the equipment. At the same time, the scroll compressor has the advantages of compact structure, stable operation, less leakage, good economy, high reliability, etc., which is beneficial to reducing investment costs and facilitating the stable operation of the system. The thermovoltaic power generation module 12 is a thermoelectric conversion system, in which the thermoelectric material is Bi2Te3. The thermoelectric material used has the advantages of excellent thermoelectric performance, good stability, broad application prospects, customizability, unique layered structure, high normalized power density and environmental friendliness, so that the system can achieve better results when running.

[0033] The expander 11 is a turbo expander 11, with a rated inlet temperature of 140°C, a rated inlet pressure of 1.37MPa, and an expansion ratio of 12.5. In the embodiment, the turbo expander 11 has the advantages of high efficiency, no friction parts, compact structure, wide applicability, high speed, long life and advanced design, which is conducive to the system to obtain better operating conditions.

[0034] The circulating working fluid of the flash heat pump circulation unit and the organic Rankine cycle-thermovoltaic power generation unit is R123. In the embodiment, the working fluid R123 is preferably used, which has a high critical temperature, good comprehensive performance and a relatively short atmospheric life, which is conducive to the efficient and stable operation of the system.

[0035] When the present invention is used, when the flash circulation unit is running, the working medium is heated and evaporated in the first heat exchanger 1, enters the heat pump regenerator 2 to absorb heat to a superheated state, enters the first-stage compressor 3 to compress, increase temperature and pressure, enters the working medium mixer 4 to mix with the saturated gaseous working medium in the gas-liquid separator 8, enters the second-stage compressor 5 to be compressed to a high-temperature and high-pressure state, enters the second heat exchanger 6 to release heat to a saturated liquid state, and enters the gas-liquid separator 8 after expansion and decompression by the second expansion valve 7. At this time, the saturated gaseous working medium enters the working medium mixer 4; when the saturated liquid working medium enters the heat pump regenerator 2 to release heat, it is expanded and decompressed to a gas-liquid mixed state by the first expansion valve 9, and then returns to the first heat exchanger 1 to complete the heat pump cycle; When the organic Rankine cycle-thermovoltaic power generation unit is running, the working fluid absorbs heat to a super-high temperature and high pressure hot gas state in the second heat exchanger 6, enters the expander 11 to perform work and expand, and the temperature and pressure both drop. Then, it enters the thermovoltaic power generation module 12 to release heat and generate electricity again. Then, it enters the heat engine regenerator 13 to release heat, and then enters the third heat exchanger 14 to release heat again to a saturated liquid state. Then, it enters the booster pump 15 to boost the pressure to a super-cooled state of low temperature and high pressure, and then enters the heat engine regenerator 13 to absorb heat to a saturated liquid state, and then returns to the second heat exchanger 6 to complete the organic Rankine cycle.

[0036] When the system is operated as described above, when the inlet flow rate of the first-stage compressor 3 in the flash heat pump circulation unit is 10 kg / s, the inlet flow rate of the second-stage compressor 5 is 11.1 kg / s, the working fluid flow rate of the organic Rankine cycle is 9.7 kg / s, the geothermal water flow rate required by the geothermal system 10 is 32.8 kg / s, and the cooling water flow rate required by the cooling tower 16 is 41.8 kg / s; at this time, the heating coefficient of the flash heat pump circulation unit is 5.7, the power generation efficiency of the organic Rankine cycle-thermovoltaic power generation unit is 23.2%, and the net output power of the entire system is 94 kW, achieving a precise match between the heat supply of the heat pump and the heat consumption of the organic Rankine cycle-thermovoltaic power generation, and obtaining a greater output power.

[0037] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0038] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation, characterized in that: It includes a connected flash cycle unit and an organic Rankine cycle-thermovoltaic power generation unit; The flash circulation unit comprises a first heat exchanger (1), a heat pump regenerator (2), a first-stage compressor (3), a working fluid mixer (4), a second-stage compressor (5), a second heat exchanger (6) and a gas-liquid separator (8); The cold phase outlet of the first heat exchanger (1) is connected to the cold phase inlet of the heat pump regenerator (2), the cold phase outlet of the heat pump regenerator (2) is connected to the inlet of the first-stage compressor (3), the outlet of the first-stage compressor (3) is connected to the superheated steam inlet of the working fluid mixer (4), the outlet of the working fluid mixer (4) is connected to the inlet of the second-stage compressor (5), the outlet of the second-stage compressor (5) is connected to the hot phase inlet of the second heat exchanger (6), the hot phase outlet of the second heat exchanger (6) is connected to the inlet of the gas-liquid separator (8), wherein the gas-side outlet of the gas-liquid separator (8) is connected to the saturated steam inlet of the working fluid mixer (4), the liquid-side outlet of the gas-liquid separator (8) is connected to the hot phase inlet of the heat pump regenerator (2), and the hot phase outlet of the heat pump regenerator (2) is connected to the cold phase inlet of the first heat exchanger (1); The organic Rankine cycle-thermovoltaic power generation unit comprises an expander (11), a thermovoltaic power generation module (12), a heat engine regenerator (13) and a third heat exchanger (14); The inlet of the expander (11) is connected to the cold phase outlet of the second heat exchanger (6), the outlet of the expander (11) is connected to the hot side inlet of the thermovoltaic power generation module (12), the hot side outlet of the thermovoltaic power generation module (12) is connected to the hot phase inlet of the heat engine regenerator (13), the hot phase outlet of the heat engine regenerator (13) is connected to the hot phase inlet of the third heat exchanger (14), and the hot phase outlet of the third heat exchanger (14) is connected to the cold phase inlet of the heat engine regenerator (13).

2. According to claim 1, a geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation, characterized in that: It also includes a cooling tower (16), wherein the cold phase outlet of the third heat exchanger (14) is connected to the cold side inlet of the thermovoltaic power generation module (12) through the cooling tower (16), and the cold side outlet of the thermovoltaic power generation module (12) is connected to the cold phase inlet of the third heat exchanger (14) through the cooling tower (16); The inlet temperature and outlet temperature of the cooling tower (16) are 35°C and 25°C respectively.

3. According to claim 1, a geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation, characterized in that: It also includes a geothermal system (10), wherein the hot phase inlet of the first heat exchanger (1) is connected to the hot phase outlet of the first heat exchanger (1) through the geothermal system (10); The input temperature and output temperature of the geothermal system (10) are 85°C and 75°C respectively.

4. According to claim 1, a geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation, characterized in that: A first expansion valve (9) is provided between the hot phase outlet of the heat pump regenerator (2) and the cold phase inlet of the first heat exchanger (1); A second expansion valve (7) is provided between the hot phase outlet of the second heat exchanger (6) and the inlet of the gas-liquid separator (8); A booster pump (15) is provided between the hot phase outlet of the third heat exchanger (14) and the cold phase inlet of the heat engine regenerator (13).

5. According to claim 1, a geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation, characterized in that: The first heat exchanger (1), the heat pump regenerator (2), the second heat exchanger (6), the heat engine regenerator (13) and the third heat exchanger (14) are all fixed tube sheet heat exchangers.

6. A geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation according to claim 1, characterized in that: The first-stage compressor (3) and the second-stage compressor (5) are both scroll compressors, and both have a compression ratio of 2.

7. A geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation according to claim 1, characterized in that: The thermovoltaic power generation module (12) is a thermoelectric conversion system, wherein the thermoelectric material is Bi2Te3.

8. The geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation according to claim 1, characterized in that: The expander (11) is a turbine expander with a rated inlet temperature of 140°C, a rated inlet pressure of 1.37 MPa, and an expansion ratio of 12.

5.

9. The geothermal power generation system of heat pump coupled organic Rankine cycle and thermovoltaic power generation according to claim 1, characterized in that: The circulating working fluid of the flash heat pump circulation unit and the organic Rankine cycle-thermovoltaic power generation unit is R123.

10. A method for a geothermal power generation system of a heat pump coupled with an organic Rankine cycle and thermovoltaic power generation, characterized in that: When the flash circulation unit is in operation, the working fluid is heated and evaporated in the first heat exchanger (1), enters the heat pump regenerator (2) to absorb heat to a superheated state, enters the first stage compressor (3) to be compressed to increase temperature and pressure, enters the working fluid mixer (4) to mix with the saturated gaseous working fluid in the gas-liquid separator (8), enters the second stage compressor (5) to be compressed to a high temperature and high pressure state, enters the second heat exchanger (6) to release heat to a saturated liquid state, and enters the gas-liquid separator (8) after expansion and decompression through the second expansion valve (7). At this time, the saturated gaseous working fluid enters the working fluid mixer (4); when the saturated liquid working fluid enters the heat pump regenerator (2) to release heat, it expands and decompresses through the first expansion valve (9) to a gas-liquid mixed state, and then returns to the first heat exchanger (1), completing the heat pump cycle; When the organic Rankine cycle-thermovoltaic power generation unit is in operation, the working fluid absorbs heat in the second heat exchanger (6) to a superheated gas state, enters the expander (11) to perform work and expand, enters the thermovoltaic power generation module (12) to release heat to generate electricity again, enters the heat engine regenerator (13) to release heat, enters the third heat exchanger (14) to release heat again to a saturated liquid state, enters the booster pump (15) to increase the pressure to a supercooled state, enters the heat engine regenerator (13) to absorb heat to a saturated liquid state, and then returns to the second heat exchanger (6), completing the organic Rankine cycle.

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