Low-temperature heat and power cogeneration system and method for coupled solar and geothermal energy

Abstract

The present application relates to the technical field of comprehensive utilization of clean energy, and provides a low-temperature heat and power cogeneration system and method for coupled solar and geothermal energy. The system comprises a first working medium supply pipe, a solar energy heat collector, a geothermal heat exchange pipe, a first working medium outlet pipe, a turbine, a generator, a bypass pipe, and a first compressor. An inlet end of the first working medium supply pipe is in communication with a working medium supply source. An inlet end of the solar energy heat collector and an inlet end of the geothermal heat exchange pipe are both in communication with an outlet end of the first working medium supply pipe. An outlet end of the solar energy heat collector and an outlet end of the geothermal heat exchange pipe are both in communication with the inlet end of the first working medium outlet pipe. A working medium inlet side of the turbine is connected to an outlet end of the first working medium outlet pipe. The turbine is connected to the generator. The bypass pipe is connected to the outlet end of the solar energy heat collector and the outlet end of the geothermal heat exchange pipe. The present application couples solar energy and geothermal energy, so that the advantages of the two renewable energy sources complement one another, can provide a continuous and stable driving heat source for a power generation cycle, and meets and maintains user heat load requirements.

Description

Low-temperature cogeneration system and method of solar-energy coupled geothermal energy Technical Field

[0001] The present application relates to the technical field of comprehensive utilization of clean energy, and in particular to a low-temperature cogeneration system and method of solar energy coupled with geothermal energy. Background Art

[0002] Solar energy is widely used due to its abundant reserves, convenient access, optimal cleanliness, and renewable nature. However, due to technical limitations, its current utilization is primarily through photovoltaic power generation, solar thermal power generation, and solar thermal heating. Taking solar thermal power generation as an example, the relevant technologies for solar thermal power generation are similar to the steam-water cycle of conventional thermal power generation, except that the steam generation heat source is replaced by a solar thermal focusing tower. This steam-water cycle has high requirements for the initial steam parameters, requiring solar energy to be able to reach a temperature above 370°C. It also has high requirements for site requirements, light resource conditions, equipment investment, and operation and maintenance costs. Furthermore, due to the volatility of solar energy and the large difference between day and night, this technology is also subject to significant limitations, making it unsuitable for use in many scenarios and small power stations. Summary of the Invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of one aspect of the present invention proposes a low-temperature cogeneration system of solar energy coupled with geothermal energy. The low-temperature cogeneration system of solar energy coupled with geothermal energy couples solar energy and geothermal energy, so that the advantages of the two renewable energy sources complement each other, thereby eliminating the impact of solar energy volatility and intermittency, and at the same time solving the problem of frozen soil caused by single heating of geothermal energy. The combination of the two can provide a continuous and stable driving heat source for the power generation cycle, meet and maintain the user's heat load requirements, and improve the system operation flexibility.

[0005] Another embodiment of the present invention provides a low-temperature cogeneration method of solar energy coupled with geothermal energy.

[0006] According to an embodiment of the present invention, a low-temperature cogeneration system of solar energy coupled with geothermal energy includes a first working fluid supply pipe, a solar collector, a geothermal heat exchange pipe, a first working fluid outlet pipe, a turbine, a generator, a bypass pipe and a first compressor.

[0007] The inlet end of the first working fluid supply pipe is connected to the working fluid supply source, the inlet end of the solar thermal collector and the inlet end of the geothermal heat exchange pipe are both connected to the outlet end of the first working fluid supply pipe, and the outlet end of the solar thermal collector and the outlet end of the geothermal heat exchange pipe are both connected to the inlet end of the first working fluid outlet pipe;

[0008] The working medium inlet side of the turbine is connected to the outlet end of the first working medium outlet pipe, and the turbine is connected to the generator and is used to drive the generator to rotate and generate electricity;

[0009] Among them, the bypass pipe connects the outlet end of the solar collector and the outlet end of the geothermal heat exchange pipe, and the first compressor is installed on the bypass pipe. The first compressor is used to pump the first working fluid from the outlet end of the solar collector to the geothermal heat exchange pipe for heat storage.

[0010] According to the low-temperature cogeneration system of solar energy coupled with geothermal energy in an embodiment of the present invention, the first working medium supply pipe can supply the circulating working medium to the solar collector and the geothermal heat exchange tube respectively, so as to absorb solar energy and geothermal energy and evaporate into superheated steam. The superheated steam enters the turbine through the first working medium outlet pipe, drives the turbine to drive the generator to rotate and generate electricity, thereby meeting the power supply needs of users. This makes up for the problem of insufficient energy supply caused by the volatility of solar energy and the large difference between day and night in the related technology, and it is difficult to provide a continuous heat source to ensure power supply stability. At this time, the system under this structure has three working modes, namely, the solar collector and the geothermal heat exchange tube work in time-sharing or simultaneously. In addition, the bypass pipe connected between the outlet end of the solar collector and the outlet end of the geothermal heat exchange tube can allow the superheated steam evaporated in the solar collector to be re-injected into the geothermal heat exchange tube to store heat in the underground soil, solving the problem of geothermal energy being unable to be extracted due to the permafrost layer caused by the imbalance of the soil temperature field, and allowing the system to enter the solar heat storage mode. Therefore, the system can couple solar energy and geothermal energy to provide a continuous and stable driving heat source for the power generation cycle, maintain the user's electricity demand, and the system operation mode is highly flexible.

[0011] In some embodiments, stop valves are provided at the inlet and outlet ends of the solar collector, the inlet and outlet ends of the geothermal heat exchange pipe, and both ends of the bypass pipe, and the stop valves are used to control the on and off of the solar collector, the geothermal heat exchange pipe, and the bypass pipe.

[0012] In some embodiments, a check valve is further installed on the bypass pipe, and the check valve is located between the outlet end of the solar thermal collector and the first compressor.

[0013] In some embodiments, the solar-geothermal-coupled low-temperature heat and power cogeneration system further includes a booster pump, a buffer tank, a first working fluid return pipe, and a condenser.

[0014] The working medium inlet side of the booster pump is connected to the buffer tank, and the working medium outlet side of the booster pump is connected to the inlet end of the first working medium supply pipe;

[0015] Wherein, both ends of the first working medium return pipe are respectively connected to the working medium outlet side of the turbine and the buffer tank, and the condenser is installed on the first working medium return pipe.

[0016] In some embodiments, the booster pump is coaxially connected to the turbine and is driven by the turbine to operate.

[0017] In some embodiments, the solar-geothermal-coupled low-temperature heat and power cogeneration system further includes a heat network pipe, an evaporator, a second compressor, a condenser, an expansion valve, a circulating water pipe, and a circulating pump.

[0018] The evaporator, the second compressor, the condenser and the expansion valve are sequentially connected in series through a second working fluid circulation pipe to form a closed loop. The condenser is installed in the heat network pipe. The second working fluid circulation pipe in the condenser can heat the heat network water in the heat network pipe so that the heat network pipe can provide heating for users.

[0019] In which, at least a portion of the circulating water pipe is coiled in the condenser, the circulating water in the circulating water pipe can be heated by the first working fluid return pipe in the condenser, the circulating pump and the evaporator are connected in series on the circulating water pipe in sequence, the circulating pump is used to pump the heated circulating water to the evaporator to provide a low-temperature heat source, and the second working fluid in the second working fluid circulation pipe in the evaporator can be heated by the low-temperature heat source.

[0020] In some embodiments, the second compressor is electrically connected to the generator.

[0021] According to a low-temperature cogeneration method of solar-geothermal energy coupled with geothermal energy according to an embodiment of the present invention, the operating mode of the low-temperature cogeneration system of solar-geothermal energy coupled with geothermal energy is determined according to actual illumination conditions, wherein:

[0022] When the light intensity is high, the first working fluid enters the solar thermal collector through the first working fluid supply pipe and absorbs solar heat to evaporate into superheated steam. The superheated steam is divided into two paths at the outlet end of the solar thermal collector. One path enters the bypass pipe and is pressurized by the first compressor. It condenses and releases heat in the geothermal heat exchange pipe, stores the heat in the underground soil, and then returns to the solar thermal collector. The other path enters the turbine through the first working fluid outlet pipe to expand and generate power to drive the generator to generate electricity.

[0023] When the light intensity is low, the first working medium is divided into two paths at the outlet end of the first working medium supply pipe and enters the solar collector and the geothermal heat exchange pipe respectively. The first working medium absorbs the solar heat and geothermal heat and evaporates into superheated steam. The superheated steam enters the turbine through the first working medium outlet pipe to expand and generate power to drive the generator to generate electricity.

[0024] At night when there is no light, the first working fluid enters the geothermal heat exchange pipe through the first working fluid supply pipe and absorbs the geothermal energy to evaporate into superheated steam. The superheated steam enters the turbine through the first working fluid outlet pipe to expand and perform work to drive the generator to generate electricity.

[0025] The technical advantages of the low-temperature cogeneration method of solar-geothermal energy coupled with geothermal energy according to the embodiment of the present invention are the same as the technical advantages of the above-mentioned low-temperature cogeneration system of solar-geothermal energy coupled with geothermal energy, and will not be repeated here.

[0026] In some embodiments, the solar-geothermal-energy-coupled low-temperature cogeneration method further includes determining an operating mode of the solar-geothermal-energy-coupled low-temperature cogeneration system according to user needs, wherein:

[0027] When the user side needs electricity and heating, the power generated by the generator is used to power the user and the second compressor at the same time. The circulating water in the circulating water pipe is heated by the first working medium return pipe in the condenser. The circulating pump pumps the heated circulating water to the evaporator as a low-temperature heat source for the evaporator. The second working medium in the second working medium circulation pipe is heated by the low-temperature heat source and is pressurized and heated again by the second compressor before entering the condenser. The heated and pressurized second working medium heats the hot water in the hot network pipe in the condenser, and the hot network pipe provides heating for the user.

[0028] When there is no electricity or heating on the user side, the first working fluid enters the solar collector through the first working fluid supply pipe and absorbs solar heat to evaporate into superheated steam. After the superheated steam is pressurized by the first compressor, it condenses and releases heat in the geothermal heat exchange pipe, storing the heat in the underground soil.

[0029] In some embodiments, when there are fluctuations in user heating, the input power of the second compressor is adjusted to change the heating power of the compression heat pump composed of the evaporator, the second compressor, the condenser and the expansion valve to ensure the user's heating needs.

[0030] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic structural diagram of a low-temperature cogeneration system of solar energy coupled with geothermal energy according to an embodiment of the present invention.

[0032] Figure numerals: 10, first working fluid supply pipe, 11, solar collector, 12, geothermal heat exchange pipe, 13, first working fluid outlet pipe, 14, turbine, 15, generator, 16, bypass pipe, 161, check valve, 17, first compressor, 180, booster pump, 181, buffer tank, 182, first working fluid return pipe, 183, condenser, 190, heat network pipe, 191, evaporator, 192, second compressor, 193, condenser, 194, expansion valve, 195, circulating water pipe, 196, circulating pump, 197, second working fluid circulation pipe. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0034] As shown in Figure 1, a low-temperature cogeneration system of solar energy coupled with geothermal energy according to an embodiment of the present invention includes a first working fluid supply pipe 10, a solar collector 11, a geothermal heat exchange pipe 12, a first working fluid outlet pipe 13, a turbine 14, a generator 15, a bypass pipe 16 and a first compressor 17.

[0035] Among them, the inlet end of the first working fluid supply pipe 10 is connected to the working fluid supply source, the inlet end of the solar collector 11 and the inlet end of the geothermal heat exchange pipe 12 are both connected to the outlet end of the first working fluid supply pipe 10, and the outlet end of the solar collector 11 and the outlet end of the geothermal heat exchange pipe 12 are both connected to the inlet end of the first working fluid outlet pipe 13.

[0036] The working medium inlet side of the turbine 14 is connected to the outlet end of the first working medium outlet pipe 13 , and the turbine 14 is connected to the generator 15 and is used to drive the generator 15 to rotate and generate electricity.

[0037] Among them, the bypass pipe 16 connects the outlet end of the solar collector 11 and the outlet end of the geothermal heat exchange pipe 12. The first compressor 17 is installed on the bypass pipe 16. The first compressor 17 is used to pump the first working fluid at the outlet end of the solar collector 11 to the geothermal heat exchange pipe 12 for heat storage.

[0038] According to the low-temperature cogeneration system of solar energy coupled with geothermal energy in an embodiment of the present invention, the first working medium supply pipe 10 can supply the circulating working medium to the solar collector 11 and the geothermal heat exchange pipe 12 respectively, so as to absorb solar energy and geothermal energy and evaporate into superheated steam. The superheated steam enters the turbine 14 through the first working medium outlet pipe 13, drives the turbine 14 to drive the generator 15 to rotate and generate electricity, thereby meeting the user's power supply needs, making up for the problem of insufficient energy supply caused by the volatility of solar energy and the large difference between day and night in the related technology, and it is difficult to provide a continuous heat source to ensure power supply stability. At this time, the system under this structure has three working modes, namely, the solar collector 11 and the geothermal heat exchange pipe 12 work in time-sharing or simultaneously. In addition, the bypass pipe 16 connected between the outlet end of the solar collector 11 and the outlet end of the geothermal heat exchange pipe 12 can allow the superheated steam evaporated in the solar collector 11 to be re-injected into the geothermal heat exchange pipe 12 to store heat in the underground soil, solving the problem of geothermal energy being unable to be extracted due to the frozen layer caused by the imbalance of the soil temperature field, so that the system enters the solar heat storage mode. Therefore, the system connects the solar collector 11 and the geothermal heat exchange pipe 12 in parallel to form a ground-light complementary heat source loop, and sets a heat storage bypass pipe 16, which can provide a continuous and stable driving heat source for the power generation cycle, maintain the user's electricity demand, and the system operation mode is highly flexible.

[0039] Specifically, the first working fluid in the working fluid supply source can be an organic working fluid. This low-boiling-point organic working fluid replaces water vapor as the circulating working fluid in the system. After absorbing low-temperature solar and geothermal energy, the organic working fluid is evaporated into superheated steam, driving turbine 14 to produce work. This reduces the required heating temperature for the working fluid during power generation, improves the utilization of renewable energy, and reduces power generation costs and pollutant emissions. Turbine 14 is coaxially connected to generator 15. First compressor 17 is a booster compressor.

[0040] It should be noted that due to the volatility and large difference between day and night, solar energy is difficult to provide a continuous and stable heat source during the process of solar thermal power generation. When the soil temperature field is unbalanced, geothermal energy will produce a permafrost layer, making it impossible to extract heat. Therefore, the system in this application uses solar energy to store heat in the underground soil to avoid the permafrost problem. At the same time, because geothermal energy is relatively continuous and stable, it can be supplemented by geothermal energy when solar energy is not enough to provide a heat source. The two are complementary and coupled to provide a continuous and stable heat source for the system power generation.

[0041] In addition, the first compressor 17 is installed on the bypass pipe 16 because the pressure of the working fluid passing through the solar thermal collector 11 is reduced, and the working fluid used for heat storage needs to be transferred from the outlet of the solar thermal collector 11 to the geothermal heat exchange pipe 12 for heat exchange, and then flow back to the inlet of the solar thermal collector 11. The pressure of this process is increased, so in order to ensure that the working fluid flows smoothly between the geothermal heat exchange pipe 12 and the solar thermal collector 11, the booster compressor is required to provide a lift to overcome the pressure difference between the solar inlet and outlet.

[0042] As shown in Figure 1, in some embodiments, stop valves are provided at the inlet and outlet ends of the solar collector 11, the inlet and outlet ends of the geothermal heat exchange pipe 12, and both ends of the bypass pipe 16. The stop valves are used to control the on and off of the solar collector 11, the geothermal heat exchange pipe 12 and the bypass pipe 16.

[0043] With the cooperation of various stop valves, the system can switch freely between single geothermal power generation mode, solar-geothermal energy coordinated power generation mode, solar power generation-heat storage mode and solar heat storage mode to match actual working conditions and improve system operation efficiency.

[0044] Specifically, shut-off valves may also be installed on the first working medium supply pipe 10 and the first working medium outlet pipe 13 to switch on and off the supply of the first working medium or the supply of superheated steam, cooperating with the system to ensure the normal operation of the corresponding working mode.

[0045] It can be understood that when the single geothermal energy power generation mode is operated, the stop valves at the inlet and outlet ends of the geothermal heat exchange pipe 12 are opened, the shut-off valve is opened, and the other stop valves are closed; when the solar-geothermal energy coordinated power generation mode is operated, the stop valves at the inlet and outlet ends of the solar collector and the inlet and outlet ends of the geothermal heat exchange pipe 12 are opened, the shut-off valve is opened, and the other stop valves are closed; when the solar power generation-heat storage mode is operated, the stop valve at the outlet end of the geothermal heat exchange pipe 12 is closed, the shut-off valve is opened, and the other stop valves are opened; when the solar heat storage mode is operated, the stop valve at the outlet end of the geothermal heat exchange pipe 12 is closed, the shut-off valve is closed, and the other stop valves are opened.

[0046] As shown in FIG. 1 , in some embodiments, a check valve 161 is further installed on the bypass pipe 16 . The check valve 161 is located between the outlet end of the solar thermal collector 11 and the first compressor 17 .

[0047] The check valve 161 allows the superheated steam to enter the first compressor 17 along the bypass pipe 16 for pressure increase, and prevents the superheated steam in the bypass pipe 16 from flowing in reverse, thereby ensuring reliable operation of the system.

[0048] As shown in FIG. 1 , in some embodiments, the low-temperature cogeneration system of solar energy coupled with geothermal energy further includes a booster pump 180 , a buffer tank 181 , a first working fluid return pipe 182 , and a condenser 183 .

[0049] The working medium inlet side of the booster pump 180 is communicated with the buffer tank 181 , and the working medium outlet side of the booster pump 180 is communicated with the inlet end of the first working medium supply pipe 10 .

[0050] The two ends of the first working medium return pipe 182 are respectively connected to the working medium outlet side of the turbine 14 and the buffer tank 181 , and the condenser 183 is installed on the first working medium return pipe 182 .

[0051] A Rankine cycle power generation system is formed by a booster pump 180, a buffer tank 181, a first working fluid return pipe 182 and a condenser 183, in conjunction with the first working fluid supply pipe 10, a solar collector 11, a geothermal heat exchange pipe 12, a turbine 14 and a generator 15. The booster pump 180 can compress and boost the first working fluid in the buffer tank 181 (to the working pressure) and then pump it to the first working fluid supply pipe 10 for subsequent heat absorption and power generation. The exhaust steam on the working fluid outlet side of the turbine 14 enters the condenser 183 to condense and release heat. The condensed first working fluid then flows back to the buffer tank 181 to balance the energy fluctuations caused by the fluctuations in the cycle power generation power.

[0052] Specifically, the boost pump 180 may be a turbo boost pump. An organic working fluid solution may be provided in the buffer tank 181 to perform Rankine cycle power generation using the organic working fluid, thereby reducing the temperature requirements of the working fluid for power generation (ie, the first working fluid).

[0053] It should be noted that when user-side power consumption suddenly and significantly changes, the pressure at turbine 14 also fluctuates significantly. This can cause a temporary mismatch between the condensation and evaporation rates of the organic working fluid, requiring some time to reach dynamic equilibrium. Buffer tank 181 is used to mitigate this mismatch before dynamic equilibrium is reached, preventing damage to the equipment. Furthermore, after superheated steam enters turbine 14 and expands, converting its thermal energy into mechanical work, the steam, having released its thermal energy, is discharged from the working fluid outlet of turbine 14 as exhaust steam.

[0054] As shown in FIG. 1 , in some embodiments, the booster pump 180 is coaxially connected to the turbine 14 and the booster pump 180 is driven by the turbine 14 to operate.

[0055] The turbine 14 is used to drive the booster pump 180 to provide initial pressure and circulation power for the circulation of the organic working fluid (ie, the first working fluid), thereby improving the energy transfer efficiency and further improving the overall energy conversion efficiency of the system.

[0056] Specifically, the turbine 14 may be coaxially connected to the booster pump 180 via a coupling.

[0057] It should be noted that, compared with the conventional booster pump 180, which is electrically driven and requires the turbine 14 to drive the generator 15 to generate electricity and then use electricity to drive the booster pump 180, the conversion of mechanical energy-electrical energy-mechanical energy in the middle will cause multiple energy conversion losses. In this application, the turbine 14 is directly used to drive the booster pump 180, and only the mechanical efficiency affects the energy loss. Therefore, the energy transfer efficiency is higher.

[0058] As shown in FIG1 , in some embodiments, the low-temperature cogeneration system of solar-geothermal energy further includes a heat network pipe 190 , an evaporator 191 , a second compressor 192 , a condenser 193 , an expansion valve 194 , a circulating water pipe 195 and a circulating pump 196 .

[0059] Among them, the evaporator 191, the second compressor 192, the condenser 193 and the expansion valve 194 are connected in series in sequence through the second working fluid circulation pipe 197 to form a closed loop. The condenser 193 is installed in the heat network pipe 190. The second working fluid circulation pipe 197 in the condenser 193 can heat the hot network water in the heat network pipe 190 so that the heat network pipe 190 can provide heating for users.

[0060] Among them, at least part of the circulating water pipe 195 is coiled in the condenser 183, and the circulating water in the circulating water pipe 195 can be heated by the first working fluid return pipe 182 in the condenser 183. The circulating pump 196 and the evaporator 191 are connected in series on the circulating water pipe 195 in sequence. The circulating pump 196 is used to pump the heated circulating water to the evaporator 191 to provide a low-temperature heat source. The second working fluid in the second working fluid circulation pipe 197 in the evaporator 191 can be heated by the low-temperature heat source.

[0061] The evaporator 191, the second compressor 192, the condenser 193 and the expansion valve 194 together constitute a compression heat pump structure. This structural design, in conjunction with the above-mentioned Rankine cycle power generation system, can not only recover the waste heat at the cold end of the Rankine cycle power generation system, but also provide heating for users, thereby improving the cycle thermal efficiency, further enhancing the energy utilization rate of the entire system, and reducing heating costs and pollutant emissions.

[0062] Specifically, heat network pipe 190 includes a heat network return pipe and a heat network supply pipe. The outlet of the heat network return pipe is connected to the heat network water inlet of condenser 193. The heat network water entering condenser 193 can be heated by the second working fluid circulation pipe 197. The inlet of the heat network supply pipe is connected to the heat network water outlet of condenser 193. Second compressor 192 can further compress the second working fluid heated by evaporator 191, increasing its pressure and temperature, so that it condenses in condenser 193 and heats the heat network water in heat network pipe 190, providing heat load heating for users. Expansion valve 194 is used to reduce the pressure and expand the condensed second working fluid, allowing the second working fluid to return to evaporator 191 for continued circulation.

[0063] As shown in FIG. 1 , in some embodiments, the second compressor 192 is electrically connected to the generator 15 .

[0064] The generator 15 supplies power to the second compressor 192, which can obtain a large amount of heat by consuming part of the system's power generation, thereby improving the flexibility of system operation regulation.

[0065] That is to say, when the user's thermal load (i.e., heating) fluctuates, the heating power of the compression heat pump part can be adjusted by adjusting the amount of electricity input by the generator 15 to the second compressor 192 (i.e., adjusting the system thermal-electric ratio) to meet the real-time thermal load demand on the user side.

[0066] As shown in FIG1 , a method for low-temperature cogeneration of heat and power by coupling solar energy with geothermal energy according to an embodiment of the present invention determines the working mode of the low-temperature cogeneration system of heat and power by coupling solar energy with geothermal energy according to actual illumination conditions, wherein:

[0067] When the light intensity is high, the first working fluid enters the solar collector 11 through the first working fluid supply pipe 10 and absorbs solar heat to evaporate into superheated steam. The superheated steam is divided into two paths at the outlet of the solar collector 11. One path enters the bypass pipe 16 and is pressurized by the first compressor 17. It condenses in the geothermal heat exchange pipe 12 and releases heat, storing the heat in the underground soil before returning to the solar collector 11. The other path enters the turbine 14 through the first working fluid outlet pipe 13, expands, and generates work to drive the generator 15 to generate electricity.

[0068] When the light intensity is low, the first working medium is divided into two paths at the outlet end of the first working medium supply pipe 10 and enters the solar collector 11 and the geothermal heat exchange pipe 12 respectively. The first working medium absorbs solar heat and geothermal heat and evaporates into superheated steam. The superheated steam enters the turbine 14 through the first working medium outlet pipe 13, expands, and generates power to drive the generator 15 to generate electricity.

[0069] At night when there is no light, the first working medium enters the geothermal heat exchange pipe 12 through the first working medium supply pipe 10 and absorbs geothermal energy to evaporate into superheated steam. The superheated steam enters the turbine 14 through the first working medium outlet pipe 13 to expand and do work to drive the generator 15 to generate electricity.

[0070] The technical advantages of the low-temperature cogeneration method of solar-geothermal energy coupled with geothermal energy according to the embodiment of the present invention are the same as the technical advantages of the above-mentioned low-temperature cogeneration system of solar-geothermal energy coupled with geothermal energy, and will not be repeated here.

[0071] As shown in FIG1 , in some embodiments, the method for low-temperature cogeneration of heat and power by coupling solar energy with geothermal energy further includes determining an operating mode of the low-temperature cogeneration system of heat and power by coupling solar energy with geothermal energy according to user needs, wherein:

[0072] When the user side needs electricity and heating, the power generated by the generator 15 is used to power the user and the second compressor 192 at the same time. The circulating water in the circulating water pipe 195 is heated by the first working medium return pipe 182 in the condenser 183. The circulating pump 196 pumps the heated circulating water to the evaporator 191 as a low-temperature heat source for the evaporator 191. The second working medium in the second working medium circulation pipe 197 is heated by the low-temperature heat source and is pressurized and heated again in the second compressor 192 before entering the condenser 193. The heated and pressurized second working medium heats the hot water in the heat network pipe 190 in the condenser 193, and the heat network pipe 190 provides heating for the user.

[0073] When there is no electricity or heating on the user side, the first working fluid enters the solar collector 11 through the first working fluid supply pipe 10 and absorbs solar heat to evaporate into superheated steam. The superheated steam is pressurized by the first compressor 17 and condensed in the geothermal heat exchange pipe 12 to release heat, storing the heat in the underground soil.

[0074] As shown in FIG1 , in some embodiments, when there are fluctuations in user heating, the input power of the second compressor 192 is adjusted to change the heating power of the compression heat pump composed of the evaporator 191 , the second compressor 192 , the condenser 193 and the expansion valve 194 to ensure the user's heating needs.

[0075] 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 to 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, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0076] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0077] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0078] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0079] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0080] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A low-temperature cogeneration system integrating solar energy and geothermal energy, characterized in that, Comprising: A first working medium supply pipe, a solar collector, a geothermal heat exchange pipe, and a first working medium outlet pipe. The inlet end of the first working medium supply pipe is communicated with a working medium supply source. The inlet ends of the solar collector and the geothermal heat exchange pipe are both communicated with the outlet end of the first working medium supply pipe. The outlet end of the solar collector and the outlet end of the geothermal heat exchange pipe are both communicated with the inlet end of the first working medium outlet pipe; A turbine and a generator. The working medium inlet side of the turbine is communicated with the outlet end of the first working medium outlet pipe. The turbine is connected to the generator and is used to drive the generator to rotate and generate electricity; And A bypass pipe and a first compressor. The bypass pipe communicates the outlet end of the solar collector with the outlet end of the geothermal heat exchange pipe. The first compressor is installed on the bypass pipe. The first compressor is used to pump the first working medium at the outlet end of the solar collector to the geothermal heat exchange pipe for heat storage.

2. The low-temperature cogeneration system coupling solar energy and geothermal energy according to claim 1, wherein Cut-off valves are provided at the inlet end and the outlet end of the solar collector, the inlet end and the outlet end of the geothermal heat exchange pipe, and both ends of the bypass pipe. The cut-off valves are used to control the on-off of the solar collector, the geothermal heat exchange pipe, and the bypass pipe.

3. The low-temperature cogeneration system for solar energy coupled with geothermal energy according to claim 1 or 2, characterized in that, A check valve is also installed on the bypass pipe. The check valve is located between the outlet end of the solar collector and the first compressor.

4. The low-temperature cogeneration system of solar energy coupled with geothermal energy according to claim 1, characterized in that The low-temperature cogeneration system coupling solar energy and geothermal energy further comprises: A booster pump and a buffer tank. The working medium inlet side of the booster pump is communicated with the buffer tank. The working medium outlet side of the booster pump is communicated with the inlet end of the first working medium supply pipe; and A first working medium return pipe and a condenser. Both ends of the first working medium return pipe are respectively communicated with the working medium outlet side of the turbine and the buffer tank. The condenser is installed on the first working medium return pipe.

5. The low-temperature cogeneration system of solar energy coupled with geothermal energy according to claim 4, characterized in that, The booster pump is coaxially connected to the turbine and the turbine drives the booster pump to work.

6. The low-temperature cogeneration system of solar energy coupled with geothermal energy according to claim 4 or 5, characterized in that, The low-temperature cogeneration system coupling solar energy and geothermal energy further comprises: A heat network pipe; An evaporator, a second compressor, a condenser, and an expansion valve that are sequentially connected in series through a second working medium circulation pipe to form a closed loop. The condenser is installed on the heat network pipe. The second working medium circulation pipe in the condenser can heat the heat network water in the heat network pipe so as to supply heat to users through the heat network pipe; A circulating water pipe and a circulating pump. At least part of the circulating water pipe is coiled in the condenser. The circulating water in the circulating water pipe can be heated by the first working medium return pipe in the condenser. The circulating pump and the evaporator are sequentially connected in series on the circulating water pipe.

7. The low-temperature cogeneration system integrating solar energy with geothermal energy according to claim 6, characterized in that, The second compressor is electrically connected to the generator.

8. A low-temperature cogeneration method coupling solar energy and geothermal energy, characterized in that, Determine the working mode of the low-temperature cogeneration system coupling solar energy and geothermal energy according to the actual light conditions, wherein, When the light intensity is relatively high, the first working fluid enters the solar collector through the first working fluid supply pipe and absorbs solar heat to evaporate into superheated steam. The superheated steam is divided into two paths at the outlet end of the solar collector. One path enters the bypass pipe and is pressurized by the first compressor to condense and release heat in the geothermal heat exchange pipe, store heat in the underground soil, and then return to the solar collector. The other path enters the turbine through the first working fluid outlet pipe to expand and do work to drive the generator to generate electricity; When the light intensity is relatively low, the first working fluid is divided into two paths at the outlet end of the first working fluid supply pipe and enters the solar collector and the geothermal heat exchange pipe respectively. The first working fluid absorbs solar heat and geothermal heat to evaporate into superheated steam. The superheated steam enters the turbine through the first working fluid outlet pipe to expand and do work to drive the generator to generate electricity; When there is no light at night, the first working fluid enters the geothermal heat exchange pipe through the first working fluid supply pipe and absorbs geothermal heat to evaporate into superheated steam. The superheated steam enters the turbine through the first working fluid outlet pipe to expand and do work to drive the generator to generate electricity.

9. The low-temperature cogeneration method of solar energy coupled with geothermal energy according to claim 8, characterized in that, The low-temperature cogeneration method coupling solar energy and geothermal energy further includes determining the working mode of the low-temperature cogeneration system coupling solar energy and geothermal energy according to the user's usage requirements, where When electricity and heating are required on the user side, the electricity generated by the generator supplies power to both the user and the second compressor at the same time. The circulating water in the circulating water pipe is heated by the first working fluid return pipe in the condenser. The circulating pump pumps the heated circulating water to the evaporator as the low-temperature heat source of the evaporator. The second working fluid in the second working fluid circulation pipe is heated by the low-temperature heat source and enters the condenser after being pressurized and heated again by the second compressor. The heated and pressurized second working fluid heats the heat network water in the heat network pipe in the condenser, and the heat network pipe supplies heat to the user; When there is no electricity or heating required on the user side, the first working fluid enters the solar collector through the first working fluid supply pipe and absorbs solar heat to evaporate into superheated steam. The superheated steam is pressurized by the first compressor and then condenses and releases heat in the geothermal heat exchange pipe, storing heat in the underground soil.

10. The low-temperature cogeneration method of solar energy coupled with geothermal energy according to claim 9, characterized in that, When there are fluctuations in user heating, adjust the input power of the second compressor to change the heating power of the compression heat pump jointly composed of the evaporator, the second compressor, the condenser, and the expansion valve to ensure the user's heating demand.

Images