Photovoltaic-thermal integrated power generation system with high-temperature solid heat storage and operation method

Abstract

The application discloses a kind of photovoltaic photo-thermal integrated power generation system and operating method equipped with high-temperature solid heat storage, the system includes light collecting and heat collecting system, high-temperature solid heat storage system, CO2 power generation system, photovoltaic power generation system, the system is a kind of special for big photovoltaic small photo-thermal design can be consumed photovoltaic solar light electric energy power generation system.The characteristics are equipped with solid heat storage unit, solid material is widely available, while easily reach high temperature.The higher the operating temperature of CO2 cycle, the more obvious the advantage of its thermal efficiency can be embodied.In addition, the photo-thermal power generation and energy storage system is matched with photovoltaic power station, and the solid heat storage material can use an electric heater to achieve heat storage.The heat transfer fluid of the system uses air in nature, saving the cost of heat transfer fluid and the cost of storage equipment, solving the problems of high cost of battery energy storage, safety hazards, high cost of photo-thermal power station and complex construction difficulty in the existing power generation system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power generation systems, and relates to a photovoltaic-photothermal integrated power generation system equipped with high-temperature solid heat storage and an operation method. BACKGROUND

[0002] Under the background of energy shortage and environmental crisis, people pay more and more attention to improving energy utilization. Solar energy is a kind of inexhaustible clean energy. At the current stage, the technology of solar photovoltaic is relatively mature, and the price has been reduced a lot after years of development. At present, with the reduction of unit cost of photovoltaic, the state has gradually begun to reduce or even cancel the subsidy. However, the problem of energy storage of photovoltaic power generation has been difficult to solve. The relatively mature photovoltaic energy storage supporting mode is still battery energy storage, but the cost of battery energy storage is always too high, and it is difficult to avoid accidents such as fire. For large-scale energy storage demand of power plants of this power level, various types of battery energy storage are currently difficult to promote. Photothermal power station has the inherent advantage of using cheap heat storage method to store energy, so this technology is strongly supported. However, the cost of photothermal power generation system has been high, much higher than that of photovoltaic power generation. From the economic point of view, solar power generation is non-photovoltaic, but from the point of view of power grid fluctuation, a certain photothermal power station must be matched as a regulating power station, and the construction equipment is complex and difficult. In summary, the existing power generation system has the problems of high cost of battery energy storage, safety hazards, high cost of photothermal power station, and complex construction difficulty. SUMMARY

[0003] In view of the problems in the prior art, the application provides a photovoltaic-photothermal integrated power generation system equipped with high-temperature solid heat storage and an operation method, which solves the problems of high cost, safety hazards and complex construction difficulty of the existing power generation system, replaces the problems of high cost of battery energy storage and photothermal power station, and reduces the construction cost.

[0004] The application is realized by the following technical scheme:

[0005] A photovoltaic-photothermal integrated power generation system equipped with high-temperature solid heat storage, comprising,

[0006] a light-gathering and heat-collecting system, a high-temperature solid heat storage system, a CO2 power generation system and a photovoltaic power generation system;

[0007] The light-gathering and heat-collecting system comprises a mirror field and a heat collector; the mirror field and the heat collector cooperate to convert solar energy into heat energy;

[0008] The high-temperature solid heat storage system comprises a high-temperature solid heat storage heater, an air-CO2 heat exchanger, an air regenerator and a high-temperature fan, the air side outlet of the air-CO2 heat exchanger is communicated with the hot side inlet of the air regenerator, the outlet of the high-temperature fan is communicated with the low-temperature side inlet of the air regenerator, the low-temperature side outlet of the air regenerator is divided into two paths, one path is communicated with the inlet of the collector, the outlet of the collector is communicated with the inlet of the high-temperature solid heat storage heater, the other path of the low-temperature side outlet of the air regenerator is communicated with the inlet of the high-temperature solid heat storage heater, and the hot side outlet of the air regenerator is connected with the high-temperature fan; the photovoltaic power generation system is connected with the electrode in the high-temperature solid heat storage heater through a cable; and the CO2 power generation system is connected with the air-CO2 heat exchanger.

[0009] Preferably, a filter is arranged at the outlet of the high-temperature solid heat storage heater, the outlet of the high-temperature solid heat storage heater is communicated with the inlet of the filter, and the outlet of the filter is communicated with the air side inlet of the air-CO2 heat exchanger.

[0010] Preferably, the hot side outlet of the air regenerator is divided into two paths, one path is communicated with the inlet of the high-temperature fan through a buffer tank, and the other path is connected with an exhaust pipeline.

[0011] Preferably, the high-temperature solid heat storage system further comprises a make-up air fan, and the outlet of the make-up air fan is communicated with the air supplementing port of the buffer tank.

[0012] Preferably, the high-temperature solid heat storage heater comprises a solid heat storage material, and the solid heat storage material comprises a plurality of independent solid heat storage units, each of which contains an independent heating electrode, and the solid heat storage unit can be heated by the heating electrode or by hot air.

[0013] Preferably, the CO2 power generation system comprises a high-temperature regenerator, a low-temperature regenerator, a main compressor and a secondary compressor,

[0014] The outlet of the CO2 turbine is communicated with the low-pressure side inlet of the high-temperature regenerator, the low-pressure side outlet of the high-temperature regenerator is communicated with the low-pressure side inlet of the low-temperature regenerator, the outlet of the main compressor is communicated with the high-pressure side inlet of the low-temperature regenerator, the high-pressure side outlet of the low-temperature regenerator is communicated with the high-pressure side inlet of the high-temperature regenerator, the low-pressure side outlet of the low-temperature regenerator is divided into another path and is communicated with the inlet of the secondary compressor, the outlet of the secondary compressor is communicated with the high-pressure side inlet of the high-temperature regenerator, and the high-pressure side outlet of the high-temperature regenerator is communicated with the CO2 inlet of the air-CO2 heat exchanger.

[0015] Preferably, the CO2 power generation system further comprises a pre-cooler, and the low-pressure side outlet of the low-temperature regenerator is divided into two paths, one path is communicated with the CO2 side inlet of the pre-cooler, and the CO2 side outlet of the pre-cooler is communicated with the inlet of the main compressor.

[0016] Preferably, the air-CO2 heat exchanger CO2 side is provided with a CO2 turbine, the outlet of the CO2 turbine is communicated with the high-temperature regenerator low-pressure side inlet, and the air-CO2 heat exchanger CO2 outlet is communicated with the CO2 turbine inlet.

[0017] Preferably, a valve is arranged between the air regenerator low-temperature side outlet and the high-temperature solid heat storage heater inlet.

[0018] A running method of a photovoltaic-thermal integrated power generation system equipped with a high-temperature solid heat storage, comprising,

[0019] When the photovoltaic power generation system generates sufficient power during the day, the concentrated heat collection system and the photovoltaic power generation system work simultaneously, the concentrated heat collection system converts solar energy into heat energy and transmits the heat energy to the air sent by the air regenerator, the hot air after being heated by the heat collector enters the high-temperature solid heat storage heater, and then enters the air-CO2 heat exchanger, but does not release heat, at this time, the CO2 power generation system does not work, and the high-temperature hot air then enters the air regenerator, and then the air enters the air regenerator after being pressurized by the high-temperature air blower to absorb heat to complete a cycle.

[0020] When the photovoltaic power generation system stops generating at night, the air sent by the air regenerator is disconnected from the heat collector, the air releases heat in the air-CO2 heat exchanger, and the air gradually heats the CO2 in the air-CO2 heat exchanger by the heat of the high-temperature solid heat storage heater, and the CO2 power generation system starts to work.

[0021] Compared with the prior art, the present application has the following beneficial technical effects:

[0022] The present application provides a photovoltaic-thermal integrated power generation system equipped with a high-temperature solid heat storage and a running method, which is designed for large photovoltaic and small photothermal and can consume photovoltaic solar energy. The system is composed of a concentrated heat collection system, a high-temperature solid heat storage system, a CO2 power generation system and a photovoltaic power generation system, and solves the problems of high cost, safety hazards, high cost, complex construction and difficulty of photothermal power station. The photothermal power generation and energy storage system is designed for photovoltaic power station, and the heat transfer fluid is air, which saves the cost of heat transfer fluid and storage equipment. At the same time, the supercritical CO2 cycle is applied to the photothermal power generation system, which can greatly improve the heat conversion efficiency and reduce the equipment size, and has high economic efficiency. The running method of the present application is simple, efficient and low in running cost.

[0023] Further, by being equipped with high-temperature solid heat storage heater, the solid heat storage material is widely available, and the solid heat storage material can be stored by using an electric heater, and high temperature can be easily achieved, the heat storage efficiency is improved, and the advantage of high operating temperature of the CO2 cycle can be more obviously embodied.

[0024] Further, the application sets a buffer tank in the high-temperature solid heat storage system, and in the hot air circulation heating process, the exhaust pipeline of the hot side outlet of the air regenerator is controlled by detecting the temperature of the buffer tank, and when the temperature of the buffer tank exceeds the limited value, the exhaust pipeline is opened to discharge part of the hot air, so as to ensure the safe operation of the high-temperature fan, and the start and stop of the air supplement fan is controlled by detecting the pressure of the buffer tank, and when the pressure of the buffer tank is too low, the air supplement fan is opened to supplement air into the buffer tank, so as to further ensure the stable and safe operation of the equipment and improve the working efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a schematic diagram of a photovoltaic and photothermal integrated power generation system equipped with high-temperature solid heat storage.

[0026] In the figure: mirror field system 1, heat collector 2, high-temperature solid heat storage heater 3, filter 4, air-CO2 heat exchanger 5, air regenerator 6, buffer tank 7, high-temperature fan 8, air supplement fan 9, CO2 turbine 10, high-temperature regenerator 11, low-temperature regenerator 12, pre-cooler 13, main compressor 14, auxiliary compressor 15, photovoltaic power generation system 16. DETAILED DESCRIPTION

[0027] The application will be described in further detail below with specific embodiments, which are an explanation of the application rather than a limitation.

[0028] In order to enable the personnel in the technical field to better understand the application scheme, the technical solutions in the embodiments of the application will be clearly and completely described below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the application.

[0029] Currently, the photo-thermal power generation needs to realize the heat-electricity conversion through a heat cycle. Among the numerous heat cycles, the supercritical Brayton cycle is the most advantageous cycle form. The new CO2 supercritical working medium has the innate advantages of high energy density, high heat transfer efficiency, and simple system, can greatly improve the heat work conversion efficiency, reduce the equipment size, and has high economic efficiency. It is the best choice to replace the existing water vapor heat cycle system and the development trend of future heat-electricity system. Therefore, it is very suitable to apply the supercritical CO2 cycle to the photo-thermal power generation system.

[0030] As shown in Figure 1 A photovoltaic-thermal integrated power generation system equipped with high-temperature solid heat storage and a running method, characterized in that it comprises a light-collecting and heat-collecting system, a high-temperature solid heat storage system, a CO2 power generation system, and a photovoltaic power generation system.

[0031] A photovoltaic-thermal integrated power generation system equipped with high-temperature solid heat storage and a running method, characterized in that it comprises a light-collecting and heat-collecting system, a high-temperature solid heat storage system, a CO2 power generation system, and a photovoltaic power generation system.

[0032] The light-collecting and heat-collecting system comprises a mirror field system 1 and a heat collector 2. The mirror field system 1 reflects sunlight to the heat collector 2 for heat collection.

[0033] The high-temperature solid heat storage system comprises a high-temperature solid heat storage heater 3, a filter 4, an air-CO2 heat exchanger 5, an air heat regenerator 6, a buffer tank 7, a high-temperature fan 8, and a make-up air fan 9. The outlet of the high-temperature solid heat storage heater 3 is connected to the inlet of the filter 4. The outlet of the filter 4 is connected to the air side inlet of the air-CO2 heat exchanger 5. The air side outlet of the air-CO2 heat exchanger 5 is connected to the hot side inlet of the air heat regenerator 6. The hot side outlet of the air heat regenerator 6 is divided into two paths. One path is connected to the inlet of the buffer tank 7, and the other path is connected to an air exhaust pipeline. The outlet of the buffer tank 7 is connected to the inlet of the high-temperature fan 8. The outlet of the high-temperature fan 8 is connected to the low-temperature side inlet of the air heat regenerator 6. The low-temperature side outlet of the air heat regenerator 6 is divided into two paths. One path is connected to the inlet of the heat collector 2, and the other path is directly connected to the inlet of the high-temperature solid heat storage heater 3. The outlet of the make-up air fan 9 is connected to the air inlet of the buffer tank 7.

[0034] The CO2 power generation system comprises a CO2 turbine 10, a high-temperature regenerator 11, a low-temperature regenerator 12, a pre-cooler 13, a main compressor 14, and a secondary compressor 15. The outlet of the CO2 turbine 10 is connected to the low-pressure side inlet of the high-temperature regenerator 11. The low-pressure side outlet of the high-temperature regenerator 11 is connected to the low-pressure side inlet of the low-temperature regenerator 12. The low-pressure side outlet of the low-temperature regenerator 12 is divided into two paths. One path is connected to the CO2 side inlet of the pre-cooler 13. The CO2 side outlet of the pre-cooler 13 is connected to the inlet of the main compressor 14. The outlet of the main compressor 14 is connected to the high-pressure side inlet of the low-temperature regenerator 12. The high-pressure side outlet of the low-temperature regenerator 12 is connected to the high-pressure side inlet of the high-temperature regenerator 11. The other path of the low-pressure side outlet of the low-temperature regenerator 12 is connected to the inlet of the secondary compressor 15. The outlet of the secondary compressor 15 is connected to the high-pressure side inlet of the high-temperature regenerator 11. The high-pressure side outlet of the high-temperature regenerator 11 is connected to the CO2 inlet of the air-CO2 heat exchanger 5. The CO2 outlet of the air-CO2 heat exchanger 5 is connected to the inlet of the CO2 turbine 10.

[0035] The photovoltaic power generation system 16 is connected to the electrode in the high-temperature solid heat storage heater 3 through a cable. The photovoltaic power generation system 16 comprises a solar cell group, a solar controller, and a storage battery group. It is a device system for directly converting solar energy into electric energy by using a battery assembly. Under the condition of light, the solar cell assembly generates a certain electromotive force. The series and parallel connection of the assembly forms a solar cell square array, so that the square array voltage meets the requirement of the system input voltage. The system is output to the high-temperature solid heat storage heater 3 through a cable.

[0036] The high-temperature solid heat storage heater 3 integrates the functions of electric heating and air heating. The solid heat storage material is composed of a plurality of independent heat storage units. Each heat storage unit contains an independent heating electrode. The solid heat storage unit can be heated by the heating electrode or hot air.

[0037] The specific operation process is as follows:

[0038] When the photovoltaic system generates sufficient electricity during the day, the solar-thermal system works simultaneously, and the solar energy is converted into heat energy by the mirror field 1 and the collector 2 and is transmitted to the air sent by the air regenerator 6, at this time, the pipeline connecting the low-temperature side outlet of the air regenerator 6 and the high-temperature solid heat storage heater 3 is closed, the hot air after being heated by the collector 2 enters the high-temperature solid heat storage heater 3, the solid heat storage material is heated and then enters the filter 4, since the solid heat storage material inevitably produces some ash during the long-term operation, it needs to be filtered in the filter 4, and then enters the air-CO2 heat exchanger 5, but the flow does not release heat, at this time, the CO2 power generation system does not work, the hot air with a still high temperature then enters the air regenerator 6, the heat is transmitted to the low-temperature air and then enters the buffer tank 7, the buffer tank 7 plays a role in stabilizing the air pressure, and then the air enters the high-temperature air blower 8, the high-temperature air blower 8 plays a role in increasing the air pressure to overcome the flow resistance, and the pressurized air then enters the air regenerator 6 to absorb heat to complete a cycle. During this period, the temperature of the buffer tank 7 is detected to control the exhaust pipeline of the hot side outlet of the air regenerator 6, when the temperature of the buffer tank 7 exceeds the limited value, the exhaust pipeline is opened to discharge part of the high-temperature air to ensure the safe operation of the high-temperature air blower, and the pressure of the buffer tank 7 is detected to control the start and stop of the air supplement blower 9, when the pressure of the buffer tank 7 is too low, the air supplement blower 9 is opened to supplement air into the buffer tank 7. At the same time, the electric heater also consumes the excess electricity of the photovoltaic system to convert it into heat energy to heat the solid heat storage unit, the electric heater will select the heating object according to the temperature of the heat storage unit, when the solid heat storage unit reaches the designed temperature, the heating of the unit is stopped, and the heating of other units is turned on. At this time, the CO2 power generation system does not work.

[0039] When the photovoltaic system stops generating electricity at night, the air is disconnected from the collector, the air releases heat in the air-CO2 heat exchanger 5, and the air gradually heats the CO2 in the air-CO2 heat exchanger 5 with the heat of the high-temperature solid heat storage heater 3, and the CO2 power generation system starts to work.

[0040] The above specific embodiments further illustrate the purpose, technical solutions and advantages of the present application, and it should be understood that the above description is only a specific embodiment of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

[0041] It should be noted that when a component is referred to as "fixed to" another component, it can be directly on the other component or there can be a middle component. When a component is referred to as "connected to" another component, it can be directly connected to the other component or there can be a middle component. When a component is referred to as "provided on" another component, it can be directly provided on the other component or there can be a middle component.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] The above descriptions are only the preferred embodiments of the present application, not intended to limit the present application in any form. Any person skilled in the art can easily implement the present application according to the drawings and the above descriptions. However, any equivalent changes, modifications and evolutions made by those skilled in the art within the scope of the technical solutions of the present application, using the above disclosed technical contents, are equivalent embodiments of the present application. Meanwhile, any equivalent changes, modifications and evolutions made by those skilled in the art according to the essential technology of the above embodiments are still within the protection scope of the technical solutions of the present application.

Claims

1. A photovoltaic-photothermal integrated power generation system equipped with high-temperature solid heat storage, characterized by, The application relates to a solar energy power generation system, which comprises a light-gathering and heat-collecting system, a high-temperature solid heat storage system, a CO2 power generation system and a photovoltaic power generation system. The light-gathering and heat-collecting system comprises a mirror field (1) and a heat collector (2); the mirror field (1) and the heat collector (2) cooperate to convert solar energy into heat energy. The high-temperature solid heat storage system comprises a high-temperature solid heat storage heater (3), an air-CO2 heat exchanger (5), an air regenerator (6) and a high-temperature fan (8); the air side outlet of the air-CO2 heat exchanger (5) is communicated with the hot side inlet of the air regenerator (6); the outlet of the high-temperature fan (8) is communicated with the low-temperature side inlet of the air regenerator (6); the low-temperature side outlet of the air regenerator (6) is divided into two paths, one of which is communicated with the inlet of the heat collector (2), the outlet of the heat collector (2) is communicated with the inlet of the high-temperature solid heat storage heater (3), the other path of the low-temperature side outlet of the air regenerator (6) is communicated with the inlet of the high-temperature solid heat storage heater (3), and the hot side outlet of the air regenerator (6) is connected with the high-temperature fan (8); the photovoltaic power generation system (16) is connected with the electrode in the high-temperature solid heat storage heater (3) through a cable; and the CO2 power generation system is connected with the air-CO2 heat exchanger (5). The hot side outlet of the air regenerator (6) is divided into two paths, one of which is communicated with the inlet of the high-temperature fan (8) through a buffer tank (7), and the other path is connected with an air exhaust pipeline. The CO2 power generation system comprises a high-temperature regenerator (11), a low-temperature regenerator (12), a main compressor (14) and a secondary compressor (15). The outlet of a CO2 turbine (10) is communicated with the low-pressure side inlet of the high-temperature regenerator (11), the low-pressure side outlet of the high-temperature regenerator (11) is communicated with the low-pressure side inlet of the low-temperature regenerator (12), the outlet of the main compressor (14) is communicated with the high-pressure side inlet of the low-temperature regenerator (12), the high-pressure side outlet of the low-temperature regenerator (12) is communicated with the high-pressure side inlet of the high-temperature regenerator (11), the low-pressure side outlet of the low-temperature regenerator (12) is divided into another path which is communicated with the inlet of the secondary compressor (15), the outlet of the secondary compressor (15) is communicated with the high-pressure side inlet of the high-temperature regenerator (11), and the high-pressure side outlet of the high-temperature regenerator (11) is communicated with the CO2 inlet of the air-CO2 heat exchanger (5). A filter (4) is arranged at the outlet of the high-temperature solid heat storage heater (3); the outlet of the high-temperature solid heat storage heater (3) is communicated with the inlet of the filter (4), and the outlet of the filter (4) is communicated with the air side inlet of the air-CO2 heat exchanger (5).

2. The photovoltaic-thermal integrated power generation system equipped with high-temperature solid heat storage according to claim 1, characterized in that, The high-temperature solid heat storage system further comprises a make-up air fan (9), and the outlet of the make-up air fan (9) is communicated with the air inlet of the buffer tank (7).

3. The photovoltaic-thermal integrated power generation system equipped with high-temperature solid heat storage according to claim 1, characterized in that, The high-temperature solid heat storage heater (3) comprises a solid heat storage material, and the solid heat storage material comprises a plurality of independent solid heat storage units, each of which contains an independent heating electrode; the solid heat storage unit can be heated by the heating electrode or by hot air.

4. The photovoltaic-thermal integrated power generation system equipped with high-temperature solid heat storage according to claim 1, characterized in that, ​ 5. The photovoltaic-thermal integrated power generation system equipped with high-temperature solid heat storage according to claim 1, characterized in that, The CO2 power generation system further comprises a pre-cooler (13), and the low-pressure side outlet of the low-temperature regenerator (12) is divided into two paths, one of which is connected to the CO2 side inlet of the pre-cooler (13), and the CO2 side outlet of the pre-cooler (13) is connected to the inlet of the main compressor (14).

6. The photovoltaic-thermal integrated power generation system equipped with high-temperature solid heat storage according to claim 5, characterized in that, The CO2 side of the air-CO2 heat exchanger (5) is provided with a CO2 turbine (10) on the low-pressure side of the high-temperature regenerator (11), the outlet of the CO2 turbine (10) is connected to the inlet of the low-pressure side of the high-temperature regenerator (11), and the CO2 outlet of the air-CO2 heat exchanger (5) is connected to the inlet of the CO2 turbine (10).

7. The photovoltaic-thermal integrated power generation system equipped with high-temperature solid heat storage according to claim 1, characterized in that, The low-temperature side outlet of the air regenerator (6) is provided with a valve between the inlet of the high-temperature solid heat storage heater (3).

8. A method for operating a high-temperature solid thermal storage equipped photovoltaic and photo-thermal integrated power generation system based on the high-temperature solid thermal storage equipped photovoltaic and photo-thermal integrated power generation system according to any one of claims 1-7, characterized in that, The application further relates to a high-temperature air-CO2 heat storage power generation system comprising the high-temperature air-CO2 heat storage power generation system and a CO2 power generation system. When the photovoltaic power generation system generates sufficient power during the day, the concentrated heat collection system and the photovoltaic power generation system work simultaneously, the concentrated heat collection system converts solar energy into heat energy and transmits the heat energy to the air sent by the air regenerator (6), the hot air heated by the heat collector (2) enters the high-temperature solid heat storage heater (3), and then enters the air-CO2 heat exchanger (5), but does not flow and release heat at this time, the CO2 power generation system does not work, and the high-temperature hot air then enters the air regenerator (6), and then the air enters the high-temperature air blower (8) to be pressurized and then enters the air regenerator (6) to absorb heat and complete a cycle; When the photovoltaic power generation system stops generating power at night, the air sent by the air regenerator (6) is disconnected from the heat collector (2), the air releases heat in the air-CO2 heat exchanger (5), and the air gradually heats the CO2 in the air-CO2 heat exchanger (5) by using the heat of the high-temperature solid heat storage heater (3), and the CO2 power generation system starts to work.

Images