A geothermal power generation system coupling a heat pump, an organic Rankine cycle and a thermovoltaic power generation

Abstract

The present application relates to the technical field of low-grade energy, in particular to a geothermal power generation system and method coupled with heat pump, organic Rankine cycle and thermoelectric power generation, comprising a flash cycle unit and an organic Rankine cycle-thermoelectric power generation unit connected; the flash cycle 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 present application combines the organic Rankine cycle with the thermoelectric power generation technology, and the overall system can achieve a comprehensive power generation efficiency of 23.2%, realizing effective and reasonable utilization of medium and low temperature geothermal energy; in addition, the present application has the advantages of simple structure, low requirement for equipment performance, safety and stability, good system economy and the like, and provides an effective and feasible scheme for utilization of medium and low temperature geothermal resources and other low-grade waste heat.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-grade energy, in particular to a geothermal power generation system and method coupled with organic Rankine cycle and thermoelectric power generation. BACKGROUND

[0002] In order to cope with global climate change and a series of environmental problems, more and more countries begin to pay attention to the development and utilization of renewable energy, and traditional fossil energy is gradually eliminated. At present, the most rapidly developed and largest renewable energy in energy structure is solar energy and wind energy. These two kinds of energy have the characteristics of intermittency, volatility and instability, which is not conducive to the stable operation of power grid. Geothermal energy has the advantages of environmental protection, sustainable supply, no influence of climate change and uninterrupted operation, and does not need to build supporting energy storage system, which can form good complementation with wind energy and solar energy.

[0003] At present, the utilization methods of geothermal energy mainly include geothermal power generation and direct utilization. The high-temperature geothermal power generation technology is relatively mature and can achieve good benefits. The utilization of middle and low temperature geothermal energy which has more reserves and is more widely distributed is mainly direct heating, and the corresponding power generation technology develops slowly. This is mainly because the energy quality of middle and low temperature geothermal energy is low, and the power generation efficiency is low when it is directly used for power generation, so it is difficult to achieve good benefits.

[0004] Flash heat pump technology is a new type of heat pump technology, which can upgrade the middle and low temperature geothermal energy through heat pump cycle to obtain a higher temperature heat source. When the upgraded middle and low temperature geothermal energy is used for power generation, a higher efficiency can be obtained. The thermoelectric power generation technology is a new type of power generation technology, which can directly convert heat energy into electric energy, including the utilization of oilfield waste heat, geothermal energy and oilfield associated geothermal energy. Therefore, how to combine these two technologies to realize the power generation and utilization of middle and low temperature geothermal energy is the problem to be solved by the present application. SUMMARY

[0005] In view of the problems in the prior art, the present application provides a geothermal power generation system and method coupled with organic Rankine cycle and thermoelectric power generation, which can upgrade the middle and low temperature geothermal energy through flash heat pump, and then use the organic Rankine cycle-thermoelectric power generation system to generate electricity, so as to realize the efficient utilization of middle and low temperature geothermal energy.

[0006] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0007] The geothermal power generation system coupled with organic Rankine cycle and thermoelectric power generation of the present application comprises a flash cycle unit and an organic Rankine cycle-thermoelectric power generation unit connected in series.

[0008] The flash cycle 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.

[0009] The first heat exchanger cold phase outlet is connected with the heat pump regenerator cold phase inlet, the heat pump regenerator cold phase outlet is connected with the first stage compressor inlet, the first stage compressor outlet is connected with the working medium mixer superheated steam inlet, the working medium mixer outlet is connected with the second stage compressor inlet, the second stage compressor outlet is connected with the second heat exchanger hot phase inlet, the second heat exchanger hot phase outlet is connected with the gas-liquid separator inlet, the gas-liquid separator gas side outlet is connected with the working medium mixer saturated steam inlet, the gas-liquid separator liquid side outlet is connected with the heat pump regenerator hot phase inlet, and the heat pump regenerator hot phase outlet is connected with the first heat exchanger cold phase inlet.

[0010] The organic Rankine cycle-thermal voltage power generation unit comprises an expander, a thermal voltage power generation module, a thermal engine regenerator and a third heat exchanger.

[0011] The expander inlet is connected with the second heat exchanger cold phase outlet, the expander outlet is connected with the thermal voltage power generation module hot side inlet, the thermal voltage power generation module hot side outlet is connected with the thermal engine regenerator hot phase inlet, the thermal engine regenerator hot phase outlet is connected with the third heat exchanger hot phase inlet, and the third heat exchanger hot phase outlet is connected with the thermal engine regenerator cold phase inlet.

[0012] As a further improvement of the present application, a cooling tower is further included, the third heat exchanger cold phase outlet is connected with the thermal voltage power generation module cold side inlet through the cooling tower, the thermal voltage power generation module cold side outlet is connected with the third heat exchanger cold phase inlet through the cooling tower, and the cooling tower inlet temperature and outlet temperature are 35 ℃ and 25 ℃ respectively.

[0013] As a further improvement of the present application, a geothermal system is further included, the first heat exchanger hot phase inlet is connected with the first heat exchanger hot phase outlet through the geothermal system, and the geothermal system input temperature and output temperature are 85 ℃ and 75 ℃ respectively.

[0014] As a further improvement of the present application, a first expansion valve is arranged between the heat pump regenerator hot phase outlet and the first heat exchanger cold phase inlet, a second expansion valve is arranged between the second heat exchanger hot phase outlet and the gas-liquid separator inlet, and a booster pump is arranged between the third heat exchanger hot phase outlet and the thermal engine regenerator cold phase inlet.

[0015] As a further improvement of the present application, the first heat exchanger, the heat pump regenerator, the second heat exchanger, the thermal engine regenerator and the third heat exchanger are all fixed tube sheet heat exchangers.

[0016] As a further improvement of the present application, the first stage compressor and the second stage compressor are both scroll compressors, and the compression ratio is 2.

[0017] As a further improvement of the present invention, the thermoelectric power generation module is a thermoelectric conversion system, wherein the thermoelectric material is Bi2Te3.

[0018] As a further improvement of the present invention, the expander is a turbine expander with a rated inlet temperature of 140 ℃, a rated inlet pressure of 1.37 MPa, and an expansion ratio of 12.5.

[0019] As a further improvement of the present invention, the working fluid of both the flash heat pump cycle unit and the organic Rankine cycle-thermal photovoltaic power generation unit is R123.

[0020] A method for a geothermal power generation system coupling a heat pump with an organic Rankine cycle and photovoltaic power generation, wherein when the flash cycle unit is running, the working fluid is heated and evaporated in the first heat exchanger, then enters the heat pump regenerator to absorb heat to a superheated state, then enters the first-stage compressor for compression, temperature increase, and pressure increase, then enters the working fluid mixer to mix with the saturated gaseous working fluid in the gas-liquid separator, then enters the second-stage compressor for compression to a high temperature and high pressure state, then enters the second heat exchanger to release heat to a saturated liquid state, then expands and depressurizes through the second expansion valve and enters the gas-liquid separator, at which point the saturated gaseous working fluid enters the working fluid mixer; when the saturated liquid working fluid enters the heat pump regenerator to release heat, then expands and depressurizes through the first expansion valve to a gas-liquid mixed state, then returns to the first heat exchanger, completing the heat pump cycle;

[0021] When the organic Rankine cycle-thermal photovoltaic power generation unit is running, the working fluid absorbs heat in the second heat exchanger to a superheated gaseous state, then enters the expander to expand, enters the thermal photovoltaic power generation module to release heat and 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 be pressurized to a subcooled 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.

[0022] Compared with the prior art, the present invention achieves the following technical effects:

[0023] The flash circulation unit designed in this invention can improve the quality and temperature of medium and low temperature geothermal resources, which not only enhances the quality of geothermal energy but also lays the foundation for its subsequent use in power generation, effectively improving power generation efficiency. In addition, the use of a flash heat pump is beneficial to expanding the temperature operating range of the working fluid, achieving a higher temperature rise, and reducing the requirements for equipment design parameters. In particular, it can reduce the pressure ratio of the compressor in the heat pump, extend the service life of the equipment, and further reduce the operating cost of the system.

[0024] The heat pump regenerator and heat engine regenerator set in the system of this invention help reduce irreversible losses during system operation, thereby improving the overall operating efficiency of the system. By recovering and utilizing the waste heat generated in the system, energy recycling is realized, further improving the energy utilization rate of the system. This invention combines the organic Rankine cycle with thermovoltaic power generation technology to realize the cascade utilization of heat source heat and improve the operating efficiency of the system. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0026] Reference numerals in the attached figures: 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. Expander; 12. Thermovoltaic power generation module; 13. Heat engine regenerator; 14. Third heat exchanger; 15. Booster pump; 16. Cooling tower. Detailed Implementation

[0027] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0033] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0034] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0035] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0036] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0037] like Figure 1 As shown, the present invention discloses a geothermal power generation system coupled with an organic Rankine cycle and a photovoltaic power generation system, comprising a flash cycle unit and an organic Rankine cycle-photovoltaic power generation unit connected together; 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 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. 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. The hot phase outlet of the heat pump regenerator 2 is connected to the cold phase inlet of the first heat exchanger 1.

[0038] The organic Rankine cycle-thermal photovoltaic power generation unit includes an expander 11, a thermal photovoltaic power generation module 12, a heat engine regenerator 13, and a third heat exchanger 14.

[0039] 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 thermal photovoltaic power generation module 12, the hot side outlet of the thermal photovoltaic 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.

[0040] The system also includes a cooling tower 16. The cold phase outlet of the third heat exchanger 14 is connected to the cold side inlet of the photovoltaic power generation module 12 via the cooling tower 16, and the cold side outlet of the photovoltaic power generation module 12 is connected to the cold phase inlet of the third heat exchanger 14 via the cooling tower 16. The inlet temperature and outlet temperature of the cooling tower 16 are 35 ℃ and 25 ℃, respectively. In this embodiment, the cooling tower 16 provides a cold source, which is chilled water, for the photovoltaic power generation module 12 and the third heat exchanger 14. By limiting the inlet and outlet temperatures of the cooling tower 16, the operating temperature range of the Ken cycle is expanded, resulting in higher system efficiency.

[0041] It also includes a geothermal system 10, through which the hot phase inlet and hot phase outlet of the first heat exchanger 1 are connected; the input temperature and output temperature of the geothermal system 10 are 85 ℃ and 75 ℃, respectively. In this embodiment, the geothermal energy provides heat to the first heat exchanger 1, and the combination with the cooling tower 16 can reduce costs; limiting the inlet and outlet temperatures of the geothermal system 10 expands the operating temperature range of the Ken cycle, enabling the system to achieve higher efficiency.

[0042] 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; and 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.

[0043] 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. In this embodiment, the first heat exchanger 1 is used for heat exchange between the working fluid and geothermal energy, the second heat exchanger 6 is used for heat exchange between working fluids, and the third heat exchanger 14 is used for heat exchange between cold water and the working fluid. Fixed tube sheet heat exchangers are preferred in this embodiment. Fixed tube sheet heat exchangers have advantages such as simple design, low manufacturing cost, large heat transfer area, easy cleaning, compact and lightweight structure, low cost, and high heat transfer efficiency. This helps reduce system costs while ensuring high efficiency in the heat exchange process and facilitating equipment maintenance.

[0044] Both the first-stage compressor 3 and the second-stage compressor 5 are scroll compressors with a compression ratio of 2. In this embodiment, a compression ratio of 2 is preferred. A smaller compression ratio is beneficial for extending the life of the equipment. At the same time, scroll compressors have advantages such as compact structure, stable operation, low leakage, good economy, and high reliability, which are conducive to reducing investment costs and ensuring stable system operation.

[0045] The thermoelectric power generation module 12 is a thermoelectric conversion system, in which the thermoelectric material is Bi2Te3. The thermoelectric material used has advantages such as excellent thermoelectric performance, good stability, broad application prospects, customizability, unique layered structure, high normalized power density, and environmental friendliness, enabling the system to achieve better performance during operation.

[0046] The expander 11 is a turbine expander 11 with a rated inlet temperature of 140 ℃, a rated inlet pressure of 1.37 MPa, and an expansion ratio of 12.5. In this embodiment, the turbine expander 11 has advantages such as high efficiency, frictionless parts, compact structure, wide applicability, high speed, long service life, and advanced design, which is conducive to the system obtaining better operating conditions.

[0047] Both the flash heat pump cycle unit and the organic Rankine cycle-thermal photovoltaic power generation unit use R123 as the working fluid. In this embodiment, R123 is preferred as the working fluid because it has a high critical temperature, good overall performance, and a relatively short atmospheric lifetime, which is beneficial to the efficient and stable operation of the system.

[0048] When the flash circulation unit is running, the working fluid evaporates in the first heat exchanger 1, then enters the heat pump regenerator 2 to absorb heat until it reaches a superheated state. It then enters the first-stage compressor 3 for compression, temperature increase, and pressure boosting. After mixing with the saturated gaseous working fluid in the gas-liquid separator 8, it enters the second-stage compressor 5 for compression to a high temperature and high pressure state. It then enters the second heat exchanger 6 to release heat until it reaches a saturated liquid state. After expanding and depressurizing through the second expansion valve 7, it enters the gas-liquid separator 8, at which point the saturated gaseous working fluid enters the working fluid mixer 4. When the saturated liquid working fluid enters the heat pump regenerator 2 and releases heat, it expands and depressurizes through the first expansion valve 9 until it reaches a gas-liquid mixed state, then returns to the first heat exchanger 1, completing the heat pump cycle.

[0049] When the organic Rankine cycle-thermal photovoltaic power generation unit is running, the working fluid absorbs heat in the second heat exchanger 6 to a superheated and high-pressure hot gaseous state, then enters the expander 11 to do work and expand. After the temperature and pressure drop, it enters the thermal photovoltaic power generation module 12 to release heat and generate electricity again. Then, it enters the heat engine regenerator 13 to release heat again, and then enters the third heat exchanger 14 to release heat again to a saturated liquid state. After entering the booster pump 15 to be pressurized to a low-temperature and high-pressure subcooled state, it 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.

[0050] When the system operates as described above, with the inlet flow rate of the first-stage compressor 3 in the flash heat pump cycle unit being 10 kg / s, the inlet flow rate of the second-stage compressor 5 being 11.1 kg / s, the working fluid flow rate of the organic Rankine cycle being 9.7 kg / s, the geothermal water flow rate required by the geothermal system 10 being 32.8 kg / s, and the cooling water flow rate required by the cooling tower 16 being 41.8 kg / s, the coefficient of performance (COP) of the flash heat pump cycle unit is 5.7, the power generation efficiency of the organic Rankine cycle-thermal photovoltaic power generation unit is 23.2%, and the net output power of the entire system is 94 kW. This achieves a precise match between the heat pump's heat supply and the organic Rankine cycle-thermal photovoltaic power generation's heat consumption, resulting in a greater output power.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0052] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A geothermal power generation system coupling a heat pump with an organic Rankine cycle and thermal photovoltaic power generation, characterized in that, It includes connected flash cycle units and organic Rankine cycle-thermal power generation units; The flash circulation 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), 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-thermal power generation unit includes an expander (11), a thermal 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 thermal power generation module (12), the hot side outlet of the thermal 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). It also includes a cooling tower (16), the cold phase outlet of the third heat exchanger (14) is connected to the cold side inlet of the photovoltaic power generation module (12) through the cooling tower (16), and the cold side outlet of the photovoltaic 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 ℃ and 25 ℃, respectively; It also includes a geothermal system (10), wherein the hot phase inlet of the first heat exchanger (1) and the hot phase outlet of the first heat exchanger (1) are connected through the geothermal system (10); the input temperature and output temperature of the geothermal system (10) are 85 ℃ and 75 ℃, respectively; 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).

2. The geothermal power generation system according to claim 1, 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.

3. The geothermal power generation system according to claim 1, characterized in that, Both the first-stage compressor (3) and the second-stage compressor (5) are scroll compressors with a compression ratio of 2.

4. The geothermal power generation system according to claim 1, characterized in that, The thermoelectric power generation module (12) is a thermoelectric conversion system, wherein the thermoelectric material is Bi2Te3.

5. The geothermal power generation system according to claim 1, characterized in that, The expander (11) is a turbine expander with a rated inlet temperature of 140 ℃, a rated inlet pressure of 1.37MPa, and an expansion ratio of 12.

5.

6. The geothermal power generation system according to claim 1, characterized in that, Both the flash heat pump cycle unit and the organic Rankine cycle-thermal power generation unit use R123 as their working fluid.

7. The method for a geothermal power generation system coupling a heat pump with an organic Rankine cycle and thermal photovoltaic power generation according to claim 1, characterized in that, When the flash evaporation cycle unit is running, the working fluid is heated and evaporated in the first heat exchanger (1), then enters the heat pump regenerator (2) to absorb heat to a superheated state, then enters the first stage compressor (3) to compress and increase temperature and pressure, then enters the working fluid mixer (4) to mix with the saturated gaseous working fluid in the gas-liquid separator (8), then enters the second stage compressor (5) to be compressed to a high temperature and high pressure state, then enters the second heat exchanger (6) to release heat to a saturated liquid state, then enters the gas-liquid separator (8) after expanding and depressurizing through the second expansion valve (7), at which 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, then expands and depressurizes through the first expansion valve (9) to a gas-liquid mixed state, then returns to the first heat exchanger (1) to complete the heat pump cycle; When the organic Rankine cycle-thermal photovoltaic power generation unit is running, the working fluid absorbs heat to a superheated gaseous state in the second heat exchanger (6), then enters the expander (11) to expand and do work. After expanding, it enters the thermal photovoltaic power generation module (12) to release heat and generate electricity again. After releasing heat, it enters the heat engine regenerator (13) to release heat again. After releasing heat again, it enters the third heat exchanger (14) to release heat to a saturated liquid state. Then, it enters the booster pump (15) to be pressurized to a subcooled state. After entering the heat engine regenerator (13) to absorb heat to a saturated liquid state, it returns to the second heat exchanger (6) to complete the organic Rankine cycle.

Images