Coupling energy storage hot dry rock-solar energy combined power generation system and control method thereof

Abstract

The invention relates to a coupling energy storage hot dry rock-solar energy combined power generation system and a control method, geothermal water of a hot dry rock well enters a power generation unit after being regulated and controlled by an intelligent regulation and control device, and an organic working medium of the power generation unit exchanges heat with the geothermal water of a heat source unit for power generation; an organic working medium of the power generation unit exchanges heat with cooling water of the cooling unit; according to the geothermal water temperature of the hot dry rock well, it is judged that the hot dry rock-solar reheating peak shaving unit or the hot dry rock-solar coupling energy storage unit is started; the hot dry rock-solar reheating peak shaving unit controls terrestrial heat return water to enter the solar panel A to be heated again, and the hot dry rock-solar coupling energy storage unit controls terrestrial heat outlet water to enter the solar panel B and the energy storage device; the flow entering the evaporator from the heat source unit side is regulated and controlled according to the electricity demand of a user, and dynamic power generation is achieved. The system is simple in composition, small in initial investment, good in economical efficiency and capable of greatly improving the utilization rate and the application range of hot dry rock resources.

Description

Technical Field

[0001] The present invention belongs to the technical field of development and utilization of renewable resources, and in particular relates to a hot dry rock-solar energy combined power generation system coupled with energy storage and a control method thereof. Background Art

[0002] In recent years, under the dual carbon goals, renewable energy has been widely promoted and utilized. Geothermal energy has become an important alternative to traditional fossil energy due to its large reserves, wide distribution, and strong stability. As a type of geothermal energy resource, hot dry rock has the characteristics of high temperature, sustainable energy supply, and a wide range of applications, and has received widespread attention from the international community. The existing development and utilization methods of hot dry rock resources are mainly enhanced geothermal systems (CN205939792U) and closed-loop heat recovery systems (CN110863800A). The former is to create an artificial heat reservoir by obtaining fractures through large-scale fracturing. The heat recovery medium enters the fracture reservoir through an injection well and exchanges heat with the rock, and then flows out through a production well into the ground utilization system. Not only is the investment high, but there will also be serious loss of heat recovery medium, low recovery rate, and easy to induce geological disasters such as earthquakes; the latter is to install a coaxial casing in a hot dry rock well, and the heat recovery medium extracts heat from the heat reservoir through a closed circulation system. When running for a long time, there is a defect of insufficient heating capacity, which cannot meet the heat load demand during peak electricity consumption, limiting the promotion and application of hot dry rock resources. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art, provide a coupled energy storage hot dry rock-solar combined power generation system and a control method thereof, improve the utilization rate of hot dry rock resources, break through the application limitations of hot dry rocks caused by the attenuation of heat extraction capacity, and provide two operating schemes, namely, hot dry rock-solar reheating peak regulation and hot dry rock-solar coupled energy storage, for the two situations where the initial temperature conditions of the hot dry rock heat extraction system are good and the temperature conditions of the long-term operation are attenuated. The system can fully utilize the heat in the tail water after high-temperature hot dry rock power generation, and utilize solar energy to heat the low-temperature hot dry rock resources to the temperature required by the power generation system, thereby partially avoiding the problem of insufficient heat caused by the attenuation of the heating capacity of the hot dry rock under long-term operation; at the same time, the energy storage device is coupled in the system, which can fully utilize the difference between peak and valley electricity prices, reduce the system pump work, reduce the system operation cost, and further improve the economy of the power generation system.

[0004] The present invention solves the technical problem by the following technical solutions:

[0005] A hot dry rock-solar combined power generation system coupled with energy storage comprises a heat source unit, a power generation unit and a cooling unit. The heat source unit comprises a hot dry rock well, a geothermal water circulation pump, an intelligent control device and a heat source side circulation pump connected in sequence. The geothermal water of the hot dry rock well enters the power generation unit after being regulated by the intelligent control device. The organic working fluid of the power generation unit exchanges heat with the geothermal water of the heat source unit to generate electricity. The organic working fluid of the power generation unit exchanges heat with the cooling water of the cooling unit to cool.

[0006] Moreover, the heat source unit also includes a hot dry rock-solar reheating peak-shaving unit and a hot dry rock-solar coupling energy storage unit. The hot dry rock-solar reheating peak-shaving unit is installed on the return water pipeline of the hot dry rock well, and the hot dry rock-solar coupling energy storage unit is installed on the outlet water pipeline of the hot dry rock well. The hot dry rock-solar reheating peak-shaving unit includes a solar panel A and a solar circulation pump A connected in sequence. The geothermal water after heat exchange with the power generation unit is heated again by the solar panel A and then mixed with the geothermal water on the outlet water pipeline of the hot dry rock well through the solar circulation pump A and enters the intelligent control device, and enters the power generation unit under the regulation of the intelligent control device to generate electricity again;

[0007] The hot dry rock-solar coupled energy storage unit includes a solar panel B, a solar circulation pump B and an energy storage device. The solar panel B and the solar circulation pump B are arranged in parallel with the energy storage device. A part of the geothermal water in the hot dry rock well flows into the energy storage device, and the other part is heated by the solar panel B and then mixed with the geothermal water in the energy storage device through the solar circulation pump B to enter the intelligent control device, and enters the power generation unit to generate electricity under the regulation of the intelligent control device.

[0008] Moreover, the power generation unit includes an evaporator, a compressor, a generator and a condenser. The organic working fluid of the generator exchanges heat with the evaporator through a working fluid pump. The organic working fluid that fully absorbs heat in the evaporator enters the compressor and drives the generator to generate electricity after being pressurized.

[0009] Moreover, the cooling unit includes a cooling tower and a cooling water circulation pump. The organic working medium after power generation flows through the condenser and exchanges heat with the cooling water in the cooling tower under the action of the cooling water circulation pump. The organic working medium after releasing heat enters the evaporator for circulation again.

[0010] Moreover, the organic working fluid of the power generation unit is R134a or R245fa.

[0011] A control method for a hot dry rock-solar energy combined power generation system coupled with energy storage, the method comprising the following steps:

[0012] Determine whether to activate the hot dry rock-solar reheat peak-shaving unit or the hot dry rock-solar coupling energy storage unit according to the geothermal water temperature of the hot dry rock well;

[0013] The hot dry rock-solar reheat peak-shaving unit controls the geothermal return water to enter the solar panel A for reheating, and the hot dry rock-solar coupling energy storage unit controls the geothermal output water to enter the solar panel B and the energy storage device;

[0014] According to the user's electricity demand, the flow rate entering the evaporator from the heat source unit side is regulated to achieve dynamic power generation;

[0015] When the outlet temperature of the hot dry rock is good, the hot dry rock-solar reheat peak-shaving unit is activated. The geothermal water that fully absorbs heat in the hot dry rock well is intelligently controlled by the geothermal water circulation pump. The intelligent control device adjusts the power of the heat source side circulation pump according to the power load demand of the heat user to control the flow of geothermal water entering the evaporator. After fully exchanging heat with the organic working fluid of the power generation unit in the evaporator, a part of it directly enters the hot dry rock well to absorb heat at the bottom of the well again, and the other part enters the solar panel A. After being heated again in the solar panel A, it enters the intelligent control device through the solar circulation pump A, and enters the power generation unit again after mixing with the geothermal water; the organic working fluid that fully absorbs heat in the evaporator enters the compressor under the action of the working fluid pump, and drives the generator after pressurization to complete the power generation process; the organic working fluid after power generation flows through the condenser, exchanges heat with the cooling water in the cooling tower under the action of the cooling water circulation pump, and the organic working fluid after heat release enters the evaporator again and circulates in sequence;

[0016] When the hot dry rock outlet water temperature condition is poor, the hot dry rock-solar coupling energy storage unit is activated. When the geothermal water that has fully absorbed heat in the hot dry rock well flows out of the wellhead of the hot dry rock well, a part of it flows through the geothermal water circulation pump into the energy storage device, and the other part enters the solar panel B to be heated to the high temperature required by the power generation unit. After being mixed with the geothermal water in the energy storage device by the solar circulation pump B, it enters the intelligent control device. The intelligent control device adjusts the power of the heat source side circulation pump according to the power load demand of the heat user to control the flow of geothermal water entering the evaporator. After fully exchanging heat with the organic working fluid of the power generation unit in the evaporator, it flows back to the hot dry rock well to absorb heat again; the organic working fluid that has fully absorbed heat in the evaporator enters the compressor under the action of the working fluid pump, and drives the generator after pressurization to complete the power generation process; the organic working fluid after power generation flows through the condenser, exchanges heat with the cooling water in the cooling tower under the action of the cooling water circulation pump, and the organic working fluid after heat release enters the evaporator again and circulates in sequence.

[0017] The positive effects that the present invention can produce are:

[0018] 1. The hot dry rock-solar combined power generation system coupled with energy storage proposed in the present invention can not only make full use of the heat in the tail water after high-temperature hot dry rock power generation, but also use solar energy to heat the low-temperature hot dry rock resources to the temperature required by the power generation system, thereby avoiding the problem of insufficient heat caused by the attenuation of the heating capacity of the hot dry rock under long-term operation.

[0019] 2. The hot dry rock-solar combined power generation system coupled with energy storage proposed in the present invention couples an energy storage device in the system, which can fully utilize the difference between peak and valley electricity prices, reduce system pump work, reduce system operating costs, and further improve the economy of the power generation system.

[0020] 3. The hot dry rock-solar combined power generation system coupled with energy storage proposed in the present invention provides an intelligent control strategy for the system during operation. It can dynamically adjust the heat source flow entering the power generation system in real time according to the heating capacity of solar energy and hot dry rock resources and the user's electricity demand, which can effectively improve the efficiency of the power generation system.

[0021] 4. The coupled energy storage hot dry rock-solar combined power generation system proposed in the present invention overcomes the defects of unstable solar energy resource conditions and the attenuation of the heating capacity of hot dry rocks during long-term operation, cleverly complements the two renewable energy sources, and improves the utilization rate of renewable resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of a power generation system of the present invention;

[0023] Figure 2 It is a schematic diagram of the hot dry rock-solar energy reheat peak regulation unit of the present invention;

[0024] Figure 3 It is a schematic diagram of a hot dry rock-solar energy coupling storage unit of the present invention;

[0025] Figure 4 It is a control flow chart of the present invention.

[0026] Description of reference numerals:

[0027] 1. Hot dry rock well 2. Geothermal water circulation pump 3. Intelligent control device 4. Heat source side circulation pump 5. Evaporator 6. Solar panel A 7. Solar circulation pump A 8. Solar panel B 9. Solar circulation pump B 10. Energy storage device 11. Working fluid pump 12. Compressor 13. Generator 14. Condenser 15. Cooling water circulation pump 16. Cooling tower. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0029] like Figure 1As shown, a hot dry rock-solar combined power generation system coupled with energy storage, the innovation of which lies in: comprising a heat source unit, a power generation unit and a cooling unit, the heat source unit comprising a hot dry rock well 1, a geothermal water circulation pump 2, an intelligent control device 3, and a heat source side circulation pump 4 connected in sequence, the geothermal water of the hot dry rock well 1 enters the power generation unit after being regulated by the intelligent control device 3, the organic working fluid of the power generation unit exchanges heat with the geothermal water of the heat source unit to generate electricity, and the organic working fluid of the power generation unit exchanges heat with the cooling water of the cooling unit to cool.

[0030] like Figure 2 , 3 As shown, the heat source unit also includes a hot dry rock-solar reheating peak-shaving unit and a hot dry rock-solar coupling energy storage unit. The hot dry rock-solar reheating peak-shaving unit is installed on the return water pipeline of the hot dry rock well 1, and the hot dry rock-solar coupling energy storage unit is installed on the outlet water pipeline of the hot dry rock well 1. The hot dry rock-solar reheating peak-shaving unit includes a solar panel A6 and a solar circulation pump A7 connected in sequence. The geothermal water after heat exchange with the power generation unit is heated again by the solar panel A6 and then mixed with the geothermal water on the outlet water pipeline of the hot dry rock well 1 through the solar circulation pump A7 to enter the intelligent control device 3, and enters the power generation unit under the regulation of the intelligent control device 3 to generate electricity again;

[0031] The hot dry rock-solar coupled energy storage unit includes a solar panel B8, a solar circulation pump B9 and an energy storage device 10. The solar panel B8 and the solar circulation pump B9 are arranged in parallel with the energy storage device 10. A part of the geothermal water in the hot dry rock well 1 flows into the energy storage device 10, and the other part is heated by the solar panel B8 and then mixed with the geothermal water in the energy storage device 10 through the solar circulation pump B9 and enters the intelligent control device 3. Under the regulation of the intelligent control device 3, it enters the power generation unit to generate electricity.

[0032] The power generation unit includes an evaporator 5, a compressor 12, a generator 13 and a condenser 14. The organic working fluid of the generator 13 exchanges heat with the evaporator 5 through a working fluid pump 11. The organic working fluid that fully absorbs heat in the evaporator 5 enters the compressor 12 and drives the generator 13 to generate electricity after being pressurized.

[0033] The cooling unit includes a cooling tower 16 and a cooling water circulation pump 15. The organic working medium after power generation flows through the condenser 14 and exchanges heat with the cooling water in the cooling tower 16 under the action of the cooling water circulation pump 15. The organic working medium after releasing heat enters the evaporator 5 for circulation again.

[0034] The organic working fluid of the power generation unit is R134a or R245fa.

[0035] like Figure 4As shown, a control method for a hot dry rock-solar energy combined power generation system coupled with energy storage is innovative in that the steps of the method are:

[0036] Determine whether to activate the hot dry rock-solar reheat peak-shaving unit or the hot dry rock-solar coupling energy storage unit according to the geothermal water temperature of the hot dry rock well 1;

[0037] The hot dry rock-solar reheat peak-shaving unit controls the geothermal return water to enter the solar panel A6 for reheating, and the hot dry rock-solar coupling energy storage unit controls the geothermal output water to enter the solar panel B8 and the energy storage device 10;

[0038] According to the user's electricity demand, the flow rate entering the evaporator 5 from the heat source unit side is regulated to achieve dynamic power generation;

[0039] When the outlet water temperature of the hot dry rock is good (≥80℃), the hot dry rock-solar reheat peak-shaving unit is activated. The geothermal water that fully absorbs heat in the hot dry rock well 1 is intelligently controlled by the geothermal water circulation pump 2. The intelligent control device 3 adjusts the power of the heat source side circulation pump 4 according to the power load demand of the heat user to control the flow of geothermal water entering the evaporator 5. After fully exchanging heat with the organic working fluid of the power generation unit in the evaporator 5, a part of it directly enters the hot dry rock well 1 to absorb heat at the bottom of the well again, and the other part enters the solar energy. In the panel A6, after being heated again in the solar panel A6, the organic working fluid enters the intelligent control device 3 through the solar circulation pump A7, and enters the power generation unit again after mixing with the geothermal water; the organic working fluid that fully absorbs heat in the evaporator 5 enters the compressor 12 under the action of the working fluid pump 11, and drives the generator 13 after being pressurized to complete the power generation process; the organic working fluid after power generation flows through the condenser 14, and exchanges heat with the cooling water in the cooling tower 16 under the action of the cooling water circulation pump 15, and the organic working fluid after releasing heat enters the evaporator 5 again, and circulates in sequence;

[0040] When the hot dry rock outlet water temperature condition is poor (<80°C), the hot dry rock-solar coupled energy storage unit is activated. When the geothermal water that has fully absorbed heat in the hot dry rock well 1 flows out of the wellhead of the hot dry rock well 1, part of it flows through the geothermal water circulation pump 2 into the energy storage device 10, and the other part enters the solar panel B8 to be heated to the high temperature required by the power generation unit, and then enters the intelligent control device 3 after being mixed with the geothermal water in the energy storage device 10 by the solar circulation pump B9. The intelligent control device 3 adjusts the heat source side circulation according to the power load demand of the heat user. The power of the pump 4 is used to control the flow rate of the geothermal water entering the evaporator 5. After fully exchanging heat with the organic working fluid of the power generation unit in the evaporator 5, the geothermal water flows back to the hot dry rock well to absorb heat again. The organic working fluid that has fully absorbed heat in the evaporator 5 enters the compressor 12 under the action of the working fluid pump 11, and drives the generator 13 after being pressurized to complete the power generation process. The organic working fluid after power generation flows through the condenser 14, exchanges heat with the cooling water in the cooling tower 16 under the action of the cooling water circulation pump 15, and the organic working fluid after releasing heat enters the evaporator 5 again and circulates in sequence.

[0041] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A hot dry rock-solar combined power generation system coupled with energy storage, characterized in that: The invention comprises a heat source unit, a power generation unit and a cooling unit. The heat source unit comprises a hot dry rock well (1), a geothermal water circulation pump (2), an intelligent control device (3) and a heat source side circulation pump (4) which are connected in sequence. The geothermal water of the hot dry rock well (1) enters the power generation unit after being regulated by the intelligent control device (3). The organic working fluid of the power generation unit exchanges heat with the geothermal water of the heat source unit to generate electricity. The organic working fluid of the power generation unit exchanges heat with the cooling water of the cooling unit to cool the unit.

2. The hot dry rock-solar energy combined power generation system coupled with energy storage according to claim 1 is characterized in that: The heat source unit also includes a hot dry rock-solar reheating peak-shaving unit and a hot dry rock-solar coupling energy storage unit. The hot dry rock-solar reheating peak-shaving unit is installed on the return water pipeline of the hot dry rock well (1). The hot dry rock-solar coupling energy storage unit is installed on the outlet water pipeline of the hot dry rock well (1). The hot dry rock-solar reheating peak-shaving unit includes a solar panel A (6) and a solar circulation pump A (7) connected in sequence. The geothermal water after heat exchange with the power generation unit is heated again by the solar panel A (6) and then passed through the solar circulation pump A (7) and mixed with the geothermal water on the outlet water pipeline of the hot dry rock well (1) to enter the intelligent control device (3). Under the regulation of the intelligent control device (3), the geothermal water enters the power generation unit to generate electricity again. The hot dry rock-solar coupled energy storage unit comprises a solar panel B (8), a solar circulation pump B (9) and an energy storage device (10). The solar panel B (8) and the solar circulation pump B (9) are arranged in parallel with the energy storage device (10). A portion of the geothermal water in the hot dry rock well (1) flows into the energy storage device (10), and the other portion is heated by the solar panel B (8) and then mixed with the geothermal water in the energy storage device (10) through the solar circulation pump B (9) and enters the intelligent control device (3). Under the regulation of the intelligent control device (3), the geothermal water enters the power generation unit to generate electricity.

3. The hot dry rock-solar energy combined power generation system coupled with energy storage according to claim 1 is characterized in that: The power generation unit comprises an evaporator (5), a compressor (12), a generator (13) and a condenser (14); the organic working fluid of the generator (13) exchanges heat with the evaporator (5) through a working fluid pump (11); the organic working fluid that has fully absorbed heat in the evaporator (5) enters the compressor (12) and, after being pressurized, drives the generator (13) to complete power generation.

4. The hot dry rock-solar energy combined power generation system coupled with energy storage according to claim 1 is characterized in that: The cooling unit comprises a cooling tower (16) and a cooling water circulation pump (15). The organic working medium after power generation flows through the condenser (14) and exchanges heat with the cooling water in the cooling tower (16) under the action of the cooling water circulation pump (15). The organic working medium after releasing heat enters the evaporator (5) for circulation again.

5. The hot dry rock-solar energy combined power generation system coupled with energy storage according to claim 1 is characterized in that: The organic working fluid of the power generation unit is R134a or R245fa.

6. A control method for a hot dry rock-solar energy combined power generation system coupled with energy storage as claimed in any one of claims 1 to 5, characterized in that: The steps of the method are: Determine whether to activate a hot dry rock-solar reheat peak-shaving unit or a hot dry rock-solar coupling energy storage unit according to the geothermal water temperature of the hot dry rock well (1); The hot dry rock-solar reheat peak-shaving unit controls the geothermal return water to enter the solar panel A (6) for reheating, and the hot dry rock-solar coupling energy storage unit controls the geothermal output water to enter the solar panel B (8) and the energy storage device (10); According to the user's electricity demand, the flow rate entering the evaporator (5) from the heat source unit side is regulated to achieve dynamic power generation; When the hot dry rock outlet water temperature condition is good, the hot dry rock-solar energy reheating peak regulation unit is activated. The geothermal water fully absorbs heat in the hot dry rock well (1). Under the action of the geothermal water circulation pump (2), the intelligent control device (3) adjusts the power of the heat source side circulation pump (4) according to the power load demand of the heat user to control the flow rate of the geothermal water entering the evaporator (5). After fully exchanging heat with the organic working fluid of the power generation unit in the evaporator (5), a part of the geothermal water directly enters the hot dry rock well (1) to absorb heat at the bottom of the well again, and the other part enters the solar panel A (6). After being heated again in the solar panel A (6), the organic working fluid enters the intelligent control device (3) through the solar circulation pump A (7), and enters the power generation unit again after being mixed with the geothermal water; the organic working fluid that has fully absorbed heat in the evaporator (5) enters the compressor (12) under the action of the working fluid pump (11), and after being pressurized, drives the generator (13) to complete the power generation process; the organic working fluid after power generation flows through the condenser (14), and exchanges heat with the cooling water in the cooling tower (16) under the action of the cooling water circulation pump (15), and the organic working fluid after releasing heat enters the evaporator (5) again, and circulates in sequence; When the hot dry rock outlet temperature condition is poor, the hot dry rock-solar coupled energy storage unit is activated. When the geothermal water that has fully absorbed heat in the hot dry rock well (1) flows out of the wellhead of the hot dry rock well (1), a part of it flows through the geothermal water circulation pump (2) and enters the energy storage device (10), and the other part enters the solar panel B (8) to be heated to the high temperature required by the power generation unit. After being mixed with the geothermal water in the energy storage device (10) by the solar circulation pump B (9), it enters the intelligent control device (3). The intelligent control device (3) adjusts the heat source side circulation pump (4) according to the power load demand of the heat user. The power is used to control the flow rate of geothermal water entering the evaporator (5); after fully exchanging heat with the organic working fluid of the power generation unit in the evaporator (5), the water flows back to the hot dry rock well to absorb heat again; the organic working fluid that has fully absorbed heat in the evaporator (5) enters the compressor (12) under the action of the working fluid pump (11), and after being pressurized, it drives the generator (13) to complete the power generation process; the organic working fluid after power generation flows through the condenser (14), exchanges heat with the cooling water in the cooling tower (16) under the action of the cooling water circulation pump (15), and the organic working fluid after releasing heat enters the evaporator (5) again, and circulates in sequence.

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