Photo-thermal power generation system based on high-temperature heat pump and operation method

Abstract

The photo-thermal power generation system based on the high-temperature heat pump comprises a low-grade heat source system, a heat pump system and a high-grade heat source system, a first heat storage medium circulates in the low-grade heat source system, and the low-grade heat source system is configured to heat the first heat storage medium through a low-grade heat source; a heat pump medium circulates in the heat pump system, and the heat pump system is configured to heat and pressurize the heat pump medium; a second heat storage medium circulates in the high-grade heat source system, and the high-grade heat source system is configured to generate power through the second heat storage medium reaching the preset temperature; wherein the heated first heat storage medium in the low-grade heat source system is used for preheating the heat pump medium, and the heated and pressurized heat pump medium in the heat pump system is used for heating the second heat storage medium. Compared with a traditional photo-thermal power generation system in which all high-grade heat sources are generated by a high-grade heat source system, the efficiency of the system is improved to a certain degree, and meanwhile the investment cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar thermal power generation, and in particular relates to a high-temperature heat pump-based solar thermal power generation system and an operation method. Background Art

[0002] With the access of a large number of photovoltaic and wind power projects with characteristics such as randomness, volatility, and intermittency to the power system, as well as the gradual reduction of conventional base load and regulating power sources such as thermal power, the operation of the power system has been severely challenged. Since CSP has its own large-capacity energy storage system, the output is continuous and stable, and it can provide the rotational inertia and reactive support required for the safe and stable operation of the power system. The output can be adjusted quickly and deeply, and the regulation performance is better than that of conventional thermal power generating units. It promotes the absorption of random and volatile power sources such as wind power and photovoltaics, and is inherently friendly to the power system. However, the cost of CSP systems is still relatively high, and it is necessary to reduce costs and increase efficiency. Summary of the invention

[0003] To solve the above problems, the purpose of the present invention is to provide a solar thermal power generation system and operation method based on a high-temperature heat pump. The solar thermal power generation system includes a low-grade heat source system, a high-temperature heat pump system and a high-grade heat source system. Compared with the traditional solar thermal power generation system in which all high-grade heat sources are generated by the high-grade heat source system, the efficiency of the system is improved to a certain extent, while reducing the investment cost.

[0004] The technical solution provided by the present invention is: a solar thermal power generation system based on a high-temperature heat pump, comprising: A low-grade heat source system, wherein a first heat storage medium circulates in the low-grade heat source system, and the low-grade heat source system is configured to heat the first heat storage medium by means of a low-grade heat source; A heat pump system, wherein a heat pump medium circulates in the heat pump system, and the heat pump system is configured to increase the temperature and pressurize the heat pump medium; A high-grade heat source system, wherein a second heat storage medium circulates in the high-grade heat source system, and the high-grade heat source system is configured to generate electricity by heating the second heat storage medium to a preset temperature; The first heat storage medium heated in the low-grade heat source system is used to preheat the heat pump medium, and the heat pump medium heated and pressurized in the heat pump system is used to heat the second heat storage medium.

[0005] Preferably, the heat pump system comprises a heat charging heat exchanger, a heat releasing heat exchanger, and a thermal processing module; The inlet end of the thermal processing module is connected to the first output end of the heat charging heat exchanger, and the outlet end of the thermal processing module is connected to the second input end of the heat releasing heat exchanger; The second output end of the heat-releasing heat exchanger is connected to the first input end of the heat-charging heat exchanger; Wherein, the thermal processing module is configured to be powered by an energy device outside the solar thermal power generation system and to heat and pressurize the heat pump medium.

[0006] Preferably, the thermal processing module comprises a compressor and an electric drive system; The inlet end of the compressor is connected to the first output end of the heat charging heat exchanger, and the compressor heats up and pressurizes the heat pump medium after absorbing heat from the heat charging heat exchanger; The outlet end of the compressor is connected to the second input end of the heat release heat exchanger, and the heated and pressurized heat pump medium releases heat in the heat release heat exchanger to heat the second heat storage medium; The electric drive system is powered by an energy device outside the solar thermal power generation system to drive the compressor to increase the temperature and pressurize the heat pump medium after absorbing heat from the heat charging heat exchanger.

[0007] Preferably, the heat pump system further comprises an expander, which is arranged between the heat releasing heat exchanger and the heat charging heat exchanger, and the expander is mechanically connected to the compressor; The inlet end of the expander is connected to the second output end of the heat releasing heat exchanger, and the outlet end of the expander is connected to the first input end of the heat charging heat exchanger; The heat pump medium is adiabatically expanded in the expander to reduce temperature and pressure and perform external work to recover mechanical energy.

[0008] Preferably, the heat pump system further comprises a heat regenerator; The first input end of the regenerator is connected to the first output end of the heat charging heat exchanger, and the first output end of the regenerator is connected to the inlet end of the compressor; The second input end of the regenerator is connected to the second output end of the heat release heat exchanger, and the second output end of the regenerator is connected to the inlet end of the expander; The regenerator is configured to allow the heat pump medium to release heat for a second time after releasing heat once in the heat release heat exchanger, so as to heat the heat pump medium preheated by the low-grade heat source system.

[0009] Preferably, the low-grade heat source system comprises a low-grade heat source medium heat storage unit and a low-grade heat collection unit, wherein the low-grade heat collection unit is configured to heat the first heat storage medium by accumulated heat energy; The medium output end of the low-grade heat collection unit is connected to the high-temperature medium input end of the low-grade heat source medium heat storage unit, and the high-temperature medium output end of the low-grade heat source medium heat storage unit is connected to the second input end of the heat charging heat exchanger; The second output end of the heat charging heat exchanger is connected to the low-temperature medium input end of the low-grade heat source medium heat storage unit, and the low-temperature medium output end of the low-grade heat source medium heat storage unit is connected to the medium input end of the low-grade heat collection unit.

[0010] Preferably, the low-grade heat source system is a tower-type saturated water system, the low-grade heat collection unit is a tower-type saturated water heat collector, the low-grade heat source medium heat storage unit comprises a saturated water heat storage tank and a cold water storage tank, and a deaerator is further provided between the cold water storage tank and the tower-type saturated water heat collector; The inlet end of the deaerator is connected to the medium output end of the cold water storage tank, and the outlet end of the deaerator is connected to the medium input end of the tower saturated water collector.

[0011] Preferably, the high-grade heat source system comprises a high-grade heat source heat collection unit, a high-grade heat source medium heat storage unit, a high-grade heat exchange unit and a high-grade heat source power generation system; The first output end of the heat-releasing heat exchanger is connected to the high-temperature medium inlet end of the high-quality heat source medium heat storage unit, and the low-temperature medium outlet end of the high-quality heat source medium heat storage unit is connected to the first input end of the heat-releasing heat exchanger; The low-temperature medium outlet of the high-quality heat source medium heat storage unit is connected to the inlet of the high-quality heat source heat collection unit, and the outlet of the high-quality heat source heat collection unit is connected to the high-temperature medium inlet of the high-quality heat source medium heat storage unit; The high-temperature medium outlet end of the high-quality heat source medium heat storage unit is connected to the first input end of the high-quality heat exchange unit, and the first output end of the high-quality heat exchange unit is connected to the low-temperature medium inlet end of the high-quality heat source medium heat storage unit; The second output end of the high-grade heat exchange unit is connected to the medium input end of the high-grade heat source power generation system, and the medium output end of the high-grade heat source power generation system is connected to the second input end of the high-grade heat exchange unit.

[0012] Preferably, the high-grade heat source system is a tower molten salt system, the high-grade heat source heat collection unit is a tower molten salt collector, the high-grade heat source medium heat storage unit includes a hot salt tank and a cold salt tank, and the high-grade heat source power generation system is a tower molten salt power generation system.

[0013] A method for operating a photothermal power generation system based on a high-temperature heat pump is applied to the above-mentioned photothermal power generation system, wherein the low-grade heat source system heats the first heat storage medium in its circulation pipeline through a low-grade heat source, and the heated first heat storage medium is stored, or, The heated first heat storage medium is directly used to preheat the heat pump medium; When an external energy device supplies energy to the heat processing module in the heat pump system, the first heat storage medium heated in the low-grade heat source system is first introduced into the heat charging heat exchanger to exchange heat with the heat pump medium in the heat pump system, and then the heated heat pump medium is introduced into the heat processing module for heating and pressurization, and finally the heated and pressurized heat pump medium is introduced into the heat releasing heat exchanger to exchange heat with the second heat storage medium in the high-grade heat source system; the heated second heat storage medium is stored, or, The second heat storage medium after being heated is directly used for power generation.

[0014] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: The solar thermal power generation system based on high-temperature heat pump in the present invention combines the low-grade heat source system with the high-grade heat source system (generally referring to the traditional solar thermal power generation system) by setting up a heat pump system, so as to effectively reduce the scale of the mirror field under the condition of the same overall power of the power generation system; specifically, the low-grade heat source system heats the first heat storage medium through the low-grade heat source, and the heated first heat storage medium is used to preheat the heat pump medium. On this basis, the heat pump system further heats the heat pump medium by supplying energy through an external power device, and then the heat pump system heats the second heat storage medium in the high-grade heat source system through the heat pump medium. Finally, the second heat storage medium reaching the preset temperature is used in the high-grade heat source system to generate electricity, so as to realize a variety of heat collection and storage modes of the high-grade heat source system, that is, the high-grade heat source is stored in different time periods, instead of being fully stored in the same time period before being used at night or in the morning and evening peak hours. It only needs to be configured according to the partial heat storage energy demand, thereby effectively reducing the scale of the mirror field, improving the optical efficiency of the mirror field, and thus improving the overall efficiency of the system.

[0015] The heat pump system in the solar thermal power generation system based on high-temperature heat pumps in the present invention heats up and pressurizes the heat pump medium by utilizing the photovoltaic power and wind power abandonment from large-scale base projects themselves or photovoltaic power and wind power abandonment from other projects or low-cost valley electricity. It can not only promote the absorption and development of random, volatile and intermittent new energy such as photovoltaic and wind power, and realize the construction of a "new power system with new energy as the main body", but also effectively improve the utilization rate of energy by recovering and applying abandoned electricity.

[0016] (3) In the low-grade heat source system of the high-temperature heat pump-based solar thermal power generation system of the present invention, the working temperature of the first heat storage medium is lower than the working temperature of the second heat storage medium, so the requirements for the transportation pipeline material can be effectively reduced, thereby reducing the investment cost of the pipeline of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram of a solar thermal power generation system based on a high temperature heat pump according to the present invention; Figure 2 A schematic diagram of an embodiment of a solar thermal power generation system based on a high temperature heat pump according to the present invention; Figure 3 The figure is a simulated operation curve of an embodiment of a high-temperature heat pump-based solar thermal power generation system on a typical day.

[0018] Description of reference numerals: 1. Low-grade heat source system; 101. Low-grade heat collection unit; 102. Low-grade heat source low-temperature heat storage unit; 103. Low-grade heat source high-temperature heat storage unit; 2. Heat pump system; 201. Heat charging heat exchanger; 202. Expander; 203. Compressor; 204. Electric drive system; 205. Heat dissipation heat exchanger; 206. Regenerator; 3. High-grade heat source system; 301. High-grade heat collection unit; 302. High-grade heat source low-temperature heat storage unit; 303. High High-quality heat source high-temperature heat storage unit; 304, high-quality heat exchange unit; 305, high-quality heat source power generation system; 1a, tower saturated water system; 1a01, tower saturated water collector; 1a02, cold water storage tank; 1a03, saturated water heat storage tank; 1a04, deaerator; 3a, tower molten salt system; 3a01, tower molten salt collector; 3a02, cold salt tank; 3a03, hot salt tank; 3a04, tower molten salt heat exchange unit; 3a05, tower molten salt power generation system. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0020] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0021] First embodiment like Figure 1 As shown, this embodiment provides a solar thermal power generation system based on a high temperature heat pump, comprising: A low-grade heat source system 1, wherein a first heat storage medium circulates in the low-grade heat source system 1, and the low-grade heat source system 1 is configured to heat the first heat storage medium by the low-grade heat source; A heat pump system 2, wherein a heat pump medium circulates in the heat pump system 2, and the heat pump system 2 is configured to increase the temperature and pressurize the heat pump medium; A high-grade heat source system 3, wherein a second heat storage medium circulates in the high-grade heat source system 3, and the high-grade heat source system 3 is configured to generate electricity by heating the second heat storage medium to a preset temperature; The first heat storage medium heated in the low-grade heat source system 1 is used to preheat the heat pump medium, and the heat pump medium heated and pressurized in the heat pump system 2 is used to heat the second heat storage medium.

[0022] In this embodiment, the second heat storage medium that reaches the preset temperature is the second heat storage medium after heat exchange with the heat pump medium after heating and pressurizing in the heat pump system, and / or, the second heat storage medium after being heated by the high-grade heat source. The technical solution of this embodiment is different from the traditional solar thermal power generation system, and a low-grade heat source system 1 and a heat pump system 2 are also configured in combination. The low-grade heat source system 1 preheats the heat pump medium in the heat pump system 2, and the heat pump system 2 further heats the heat pump medium by supplying energy through an external power device on this basis, and then the heat pump system 2 heats the second heat storage medium in the high-grade heat source system 3 through the heat pump medium. Generally, the high-grade heat source system 3 refers to the traditional solar thermal power generation system. By combining the low-grade heat source system 1 and the heat pump system 2, the overall power of the high-grade heat source power generation system 305 is the same, which can effectively reduce the scale of the mirror field, which is beneficial to improving the optical efficiency of the mirror field and can improve the overall efficiency of the system. The external power device mentioned here can be photovoltaic power, wind power abandonment from large base projects, photovoltaic power, wind power abandonment from other projects, or low-cost valley power, so as to promote the consumption and development of random, volatile, and intermittent new energy such as photovoltaic power and wind power, and is beneficial to the construction of a "new power system with new energy as the main body". Among them, in other embodiments, the first heat storage medium is a metal compound, a molten salt (molten salt refers to a molten body of one, two or more salt compounds), water or one of other heat transfer fluids; the second heat storage medium is a metal compound, a molten salt (molten salt refers to a molten body of one, two or more salt compounds), water or one of other heat transfer fluids. In this embodiment, the first heat storage medium is water, and the second heat storage medium is molten salt.

[0023] It should be noted that the low-grade heat source system 1 in the present invention is a system with low cost, but the heat source quality it generates is also low. In some embodiments, the low-grade heat source system 1 can be a concentrated heat collection system using saturated water as the first heat storage medium. The heat pump system 2 uses the low-grade heat source generated by the low-grade heat source system 1 and the electric energy provided by the electric power device outside the system to generate a high-grade heat source to power the high-grade heat source system 3, forming a flexible multi-stage heat utilization effect, thereby making the entire system more flexible and able to more efficiently cooperate with the dispatch of the power grid.

[0024] In a preferred embodiment, the heat pump system 2 includes a heat charging heat exchanger 201, a heat releasing heat exchanger 205, and a thermal processing module; The inlet end of the thermal processing module is connected to the first output end of the heat charging heat exchanger 201, and the outlet end of the thermal processing module is connected to the second input end of the heat releasing heat exchanger 205; The second output end of the heat releasing heat exchanger 205 is connected to the first input end of the heat charging heat exchanger 201; Among them, the thermal processing module is configured to be powered by an energy device outside the solar thermal power generation system and to heat and pressurize the heat pump medium.

[0025] The technical solution of this embodiment preferably introduces a thermal processing module in the heat pump system 2, and the thermal processing module is powered by an energy device outside the solar thermal power generation system to heat and pressurize the heat pump medium after absorbing heat from the heat exchanger. That is to say, the heat pump system 2 of this embodiment introduces an external energy device for primary heating. In another embodiment, for example, when other projects generate photovoltaic power abandonment, wind power abandonment or low-cost valley electricity, the heat pump system 2 of the solar thermal power generation system of the present invention can use this electric energy to heat the heat pump medium and further store it in a high-grade heat source high-temperature heat storage unit, thereby promoting the consumption and development of random, volatile and intermittent new energy such as photovoltaic and wind power, which is beneficial to the construction of a "new power system with new energy as the main body".

[0026] In a preferred embodiment, the thermal processing module includes a compressor 203 and an electric drive system 204. The inlet end of the compressor 203 is connected to the first output end of the heat charging heat exchanger 201, and the heat pump medium after absorbing heat from the heat charging heat exchanger 201 is heated and pressurized. The outlet end of the compressor 203 is connected to the second input end of the heat releasing heat exchanger 205. The heat pump medium after heating and pressurization releases heat in the heat releasing heat exchanger 205 to heat the second heat storage medium. The electric drive system 204 is powered by an energy device outside the solar thermal power generation system to drive the compressor to heat and pressurize the heat pump medium. Of course, in other embodiments, the solar thermal power generation system can also provide energy, and the specific energy supply can be designed according to specific circumstances.

[0027] In this preferred embodiment, the heat processing module uses a combination of a compressor 203 and an electric drive system 204. The configuration of the electric drive system 204 in the heat pump system 2 can utilize the wind power abandonment or low-cost valley electricity at night to make the high-grade heat source system 3 store heat energy in time periods, that is, it is not used at night or during peak hours in the morning and evening after the storage is full in the same time period, which means that the heat storage system only needs to be configured according to part of the heat storage energy demand. Compared with the traditional solar thermal power generation system, the scale of the high-grade heat source system 3 can be effectively reduced, and the requirements for the materials of the low-grade heat source high-temperature heat storage unit 103 and / or the low-grade heat source low-temperature heat storage unit 102 of the low-grade heat source system 1 can be reduced, thereby reducing the investment cost of the entire system. In addition, due to the configuration of the electric drive system 204 in the heat pump system 2, part of the energy comes from the photovoltaic, wind power abandonment of the large base project itself or the photovoltaic, wind power abandonment of other projects, or low-cost valley electricity. Compared with the traditional solar thermal power generation system, the scale of the high-grade heat source system 3 can be effectively reduced, thereby reducing the investment cost of the entire system. According to preliminary calculations, if a 300MW solar thermal power station adopts the solution based on the high-temperature heat pump system of the present invention, the static investment can be reduced by 10% to 15%.

[0028] In a preferred embodiment, the heat pump system further comprises an expander 202, which is disposed between the heat releasing heat exchanger 205 and the heat charging heat exchanger 201, and the expander 202 is mechanically connected to the compressor 203; The inlet end of the expander 202 is connected to the second output end of the heat releasing heat exchanger 205, and the outlet end of the expander 202 is connected to the first input end of the heat charging heat exchanger 201; The heat pump medium expands adiabatically in the expander 202 to reduce temperature and pressure and perform work externally to recover mechanical energy.

[0029] In this embodiment, the high-temperature and high-pressure heat pump medium output from the compressor 203 is used to heat the second heat storage medium in the heat release heat exchanger 205. The temperature of the heat pump medium drops after heat release, but it still has a large pressure potential energy. The heat pump medium with a large pressure potential energy is passed into the expander 202 to recover mechanical energy, thereby forming a closed circulation path, which can not only continuously generate high-quality heat sources, but also improve energy utilization.

[0030] In a preferred embodiment, the heat pump system 2 further includes a regenerator 206; The second input end of the regenerator 206 is connected to the second output end of the heat releasing heat exchanger 205, and the second output end of the regenerator 206 is connected to the inlet end of the expander 202; The first input end of the regenerator 206 is connected to the first output end of the heat charging heat exchanger 201, and the first output end of the regenerator 206 is connected to the inlet end of the compressor 203; The regenerator 206 is configured to allow the heat pump medium that has released heat once in the heat release heat exchanger 205 to release heat for a second time, so as to heat the heat pump medium that has been preheated by the low-grade heat source system.

[0031] In this embodiment, a regenerator 206 is also provided between the heat release heat exchanger 205 and the expander 202. The heat pump medium output from the heat release heat exchanger 205 is used as a heating source, and the heat pump medium preheated in the heat charging heat exchanger 201 is used as a heated object, that is, the heat pump medium after being heated and pressurized in the compressor 203 releases heat once through the heat release heat exchanger 205 and releases heat twice through the regenerator 206, so as to fully utilize the heat energy. After releasing heat twice, the heat pump medium still has a large pressure potential energy, and then recovers mechanical energy by expanding and doing work in the high-temperature heat pump expander 202, and further reduces the temperature of the heat pump medium to become a low-temperature and low-pressure heat pump medium. At the same time, since the heat pump medium output from the heat charging heat exchanger 201 is further heated, the performance requirements of the low-grade heat source system 1 can be reduced, and the compatibility of the entire system can be improved.

[0032] In one embodiment, see Figure 1 , the low-grade heat source system 1 comprises a low-grade heat source medium heat storage unit and a low-grade heat collection unit 101, the low-grade heat collection unit 101 is configured to heat the first heat storage medium by the accumulated heat energy; The medium output end of the low-grade heat collection unit 101 is connected to the high-temperature medium input end of the low-grade heat source medium heat storage unit, and the high-temperature medium output end of the low-grade heat source medium heat storage unit is connected to the second input end of the heat charging heat exchanger 201; The second output end of the heat charging heat exchanger 201 is connected to the low-temperature medium input end of the low-grade heat source medium heat storage unit, and the low-temperature medium output end of the low-grade heat source medium heat storage unit is connected to the medium input end of the low-grade heat collection unit 101.

[0033] In this embodiment, the low-grade heat source system 1 includes a low-grade heat source medium heat storage unit and a low-grade heat collection unit 101. The low-grade heat source medium heat storage unit includes a low-grade heat source low-temperature heat storage unit 102 and a low-grade heat source high-temperature heat storage unit 103. The low-grade heat collection unit 101 gathers heat in the low-grade heat source to heat the low-grade heat source medium. The high-temperature first heat storage medium heated by the low-grade heat collection unit 101 is stored in the low-grade heat source high-temperature heat storage unit 103, realizing the primary storage of thermal energy; when necessary, the heat pump medium used to preheat the heat pump system 2 is pumped out, which is conducive to the realization of multi-level energy storage of the entire system and improves the output flexibility of the entire system; of course, in other embodiments, when the heat pump system receives photovoltaic, wind power abandonment or other photovoltaic, wind power abandonment, or low-cost valley electricity from the large base project itself, the high-temperature first heat storage medium heated by the low-grade heat collection unit 101 can also be directly introduced into the heat charging heat exchanger 201 to exchange heat with the heat pump medium.

[0034] In one embodiment, see Figure 1 , the high-grade heat source system 3 includes a high-grade heat source heat collection unit 301, a high-grade heat source medium heat storage unit, a high-grade heat exchange unit 304 and a high-grade heat source power generation system 305, and the high-grade heat source medium heat storage unit includes a high-grade heat source high-temperature heat storage unit 303 and a high-grade heat source low-temperature heat storage unit 302; The first output end of the heat-releasing heat exchanger 205 is connected to the inlet end of the high-quality heat source high-temperature heat storage unit 303, and the outlet end of the high-quality heat source low-temperature heat storage unit 302 is connected to the first input end of the heat-releasing heat exchanger 205; The outlet end of the high-quality heat source heat collection unit 301 is connected to the inlet end of the high-quality heat source high-temperature heat storage unit 303, and the outlet end of the high-quality heat source low-temperature heat storage unit 302 is connected to the inlet end of the high-quality heat source heat collection unit 301; The outlet end of the high-quality heat source high-temperature heat storage unit 303 is connected to the first input end of the high-quality heat exchange unit 304, and the first output end of the high-quality heat exchange unit 304 is connected to the inlet end of the high-quality heat source low-temperature heat storage unit 302; The second output end of the high-grade heat exchange unit 304 is connected to the medium input end of the high-grade heat source power generation system 305 , and the medium output end of the high-grade heat source power generation system 305 is connected to the second input end of the high-grade heat exchange unit 304 .

[0035] In this embodiment, since the high-grade heat source system 3 is also equipped with a high-grade heat source heat collection unit 301, it is possible to realize a variety of heat collection and storage modes of the high-grade heat source system 3, and to store the high-grade heat source in different time periods, that is, it is not necessary to store it fully in the same time period before using it at night or during peak hours in the morning and evening. It only needs to be configured according to part of the heat storage energy demand. Compared with the traditional solar thermal power generation system, the scale of the high-grade heat storage system can be effectively reduced. Moreover, the working temperature of the first heat storage medium is lower than the working temperature of the second heat storage medium, thereby reducing the requirements for the materials of the heat storage unit of the low-grade heat storage system, thereby reducing the investment cost of the heat storage system.

[0036] In some embodiments, the low-grade heat collection unit 101 heats the low-grade heat source medium flowing through the low-grade heat collection unit 101 by concentrating and collecting heat, converting solar radiation energy into low-grade heat energy and storing it in the high-temperature heat storage unit of the low-grade heat source system 1, so as to be used to preheat the heat pump medium when needed. In this embodiment, the working temperature of the first heat storage medium is lower than the working temperature of the second heat storage medium. Compared with the traditional solar thermal power generation system, under the same power generation scale, it is not necessary to design all pipelines according to the working temperature of the second heat storage medium in the high-grade heat source system 3. Especially when the system scale is large and it is necessary to design long-distance pipelines according to the working temperature of the second heat storage medium in the high-grade heat source system 3, the pipelines in the low-grade heat source system 1 in the scheme of the present invention only need to be designed according to the working temperature requirements of the first heat storage medium in the low-grade heat source system 1. The long-distance pipeline can effectively reduce the requirements for the material of the transportation pipeline, thereby reducing the investment cost of the pipeline.

[0037] In a specific embodiment, see Figure 2 , showing a schematic diagram of an embodiment of a solar thermal power generation system based on a high-temperature heat pump. The low-grade heat source system 1 is a tower-type saturated water system 1a, the low-grade heat collection unit 101 is a tower-type saturated water collector 1a01, the low-grade heat source high-temperature heat storage unit 103 is a saturated water heat storage tank 1a03, the low-grade heat source low-temperature heat storage unit 102 is a cold water storage tank 1a02, and a deaerator 1a04 is also provided between the cold water storage tank 1a02 and the tower-type saturated water collector 1a01; The inlet end of the deaerator 1a04 is connected to the medium output end of the cold water storage tank 1a02, and the outlet end of the deaerator 1a04 is connected to the medium input end of the tower saturated water collector 1a01.

[0038] Continue to see Figure 2, and also shows a schematic diagram of another embodiment of a solar thermal power generation system based on a high-temperature heat pump. In this embodiment, the high-grade heat source system 3 is a tower molten salt system 3a, the high-grade heat source heat collection unit 301 is a tower molten salt collector 3a01, the high-grade heat source high-temperature heat storage unit 303 is a hot salt tank 3a03, the high-grade heat source low-temperature heat storage unit 302 is a cold salt tank 3a02, and the high-grade heat source power generation system 305 is a tower molten salt power generation system 3a05.

[0039] Second embodiment Based on the same concept, this embodiment provides a method for operating a CSP system based on a high-temperature heat pump, which is applied to any CSP system of the first embodiment; The low-grade heat source system 1 heats the first heat storage medium in its circulation pipeline through the low-grade heat source, and stores the heated first heat storage medium, or, The heated first heat storage medium is directly used to preheat the heat pump medium; When the external energy device supplies energy to the heat processing module in the heat pump system 2, the first heat storage medium heated in the low-grade heat source system 1 is first introduced into the heat charging heat exchanger 201 to exchange heat with the heat pump medium in the heat pump system 2, and then the heated heat pump medium is introduced into the heat processing module to increase temperature and pressurize, and finally the heated and pressurized heat pump medium is introduced into the heat releasing heat exchanger 205 to exchange heat with the second heat storage medium in the high-grade heat source system; The second heat storage medium reaching the preset temperature is stored, or the second heat storage medium reaching the preset temperature is directly used for power generation.

[0040] In another embodiment, the low-grade heat source system 1 heats the first heat storage medium in its circulation pipeline and stores the heated first heat storage medium in the low-grade heat source high-temperature heat storage unit 103 of the low-grade heat source system 1; When necessary, the low-temperature and low-pressure heat pump medium in the heat pump system 2 is preheated by the first heat storage medium in the low-grade heat source high-temperature heat storage unit 103 of the low-grade heat source system 1; The compressor 203 in the heat pump system 2 is driven by the electric drive system 204 in the heat pump system 2 powered by an electric device outside the solar thermal power generation system to increase the temperature and pressurize the preheated heat pump medium; The heated and pressurized heat pump medium heats the second heat storage medium in the high-grade heat source system 3. On the other hand, the heated second heat storage medium is stored in the high-grade heat source system high-temperature storage tank 303 so as to supply energy and generate electricity when power is needed.

[0041] In the technical solution of this embodiment, the low-grade heat source system 1 preheats the heat pump medium in the heat pump system 2, and the heat pump system 2 further heats the heat pump medium by supplying energy through an external power device on this basis, and then the heat pump system 2 heats the second heat storage medium in the high-grade heat source system 3 through the heat pump medium. The high-grade heat source system 3 here can be a traditional solar thermal power generation system. By combining the low-grade heat source system 1 and the heat pump system 2, the overall power of the high-grade heat source power generation system 305 is the same, which can effectively reduce the scale of the mirror field, which is beneficial to improving the optical efficiency of the mirror field and can improve the overall efficiency of the system.

[0042] Preferably, it also includes: The heat pump medium after heat exchange with the second heat storage medium in the high-grade heat source system 3 is further heat exchanged with the heat pump medium after preheating by the first heat storage medium in the regenerator 206. The heat pump medium after releasing heat in the regenerator 206 enters the expander 202 to expand and perform work to recover mechanical energy.

[0043] In this embodiment, a regenerator 206 is also provided between the heat release heat exchanger 205 and the expander 202. The heat pump medium output from the heat release heat exchanger 205 is used as a heating source, and the heat pump medium preheated in the heat charging heat exchanger 201 is used as a heated object, that is, the heat pump medium after being heated and pressurized in the compressor 203 releases heat once through the heat release heat exchanger 205 and releases heat twice through the regenerator 206, so as to fully utilize the heat energy. After releasing heat twice, the heat pump medium still has a large pressure potential energy, and then recovers mechanical energy by expanding and doing work in the high-temperature heat pump expander 202, and further reduces the temperature of the heat pump medium to become a low-temperature and low-pressure heat pump medium. At the same time, since the heat pump medium output from the heat charging heat exchanger 201 is further heated, the performance requirements of the low-grade heat source system 1 can be reduced, and the compatibility of the entire system can be improved.

[0044] Preferably, it also includes: The low-grade heat source collector 101 heats the first heat storage medium by concentrating and collecting heat through a mirror field, and the high-grade heat source collector 301 heats the second heat storage medium by concentrating and collecting heat through a mirror field. The working temperature of the first heat storage medium is lower than the working temperature of the second heat storage medium. The power supply device of the electric drive system 204 of the heat pump system 2 is photovoltaic power abandonment, wind power abandonment, or low-cost valley power.

[0045] The technical solution of this embodiment is to set a regenerator 206 between the heat release heat exchanger 205 and the expander 202. The heat pump medium output from the heat release heat exchanger 205 is used as a heating source, and the heat pump medium preheated in the heat charging heat exchanger 201 is used as a heated object, that is, the heat pump medium after being heated and pressurized in the compressor 203 is subjected to a first heat release through the heat release heat exchanger 205 and a second heat release through the regenerator 206, so as to fully utilize the heat energy. After the two heat releases, the heat pump medium still has a large pressure potential energy, and then recovers mechanical energy by expanding and doing work in the high-temperature heat pump expander 202, and further reduces the temperature of the heat pump medium to become a low-temperature and low-pressure heat pump medium. At the same time, since the heat pump medium output from the heat charging heat exchanger 201 is further heated, the performance requirements of the low-grade heat source system 1 can be reduced, and the compatibility of the entire system can be improved.

[0046] In a specific embodiment, during the day, the tower saturated water system 1a produces saturated water through the tower saturated water collector 1a01 and stores it in the saturated water storage tank 1a03. During the non-generating time of 10:00 ~ 16:00 and the low-load operation time of 0:00 ~ 5:00 in the tower molten salt power generation system 3a05, the high-temperature heat pump system 2 utilizes the project's own photovoltaic, wind power abandonment or other projects' photovoltaic, wind power abandonment, or low-cost valley electricity to transfer the energy in the saturated water to molten salt, generating high-temperature molten salt stored in the tower molten salt system 3a hot salt tank 3a03. At the same time, the tower molten salt system 3a produces high-temperature molten salt through the tower molten salt collector 3a01, which is also stored in the tower molten salt system hot salt tank 3a03, and uses the tower molten salt heat exchange unit 3a04 and the tower molten salt power generation system 3a05 to operate at full load as much as possible from 5:00 to 10:00 and 16:00 to 24:00, and operate at low load with a load rate of 15% from 0:00 to 5:00.

[0047] Figure 3 yes Figure 2 The simulated operation curve of a 300MW CSP system based on a high-temperature heat pump on a typical day. The rated power generation power of the tower molten salt power generation system 3a05 is 300MW, and the installed capacity of the high-temperature heat pump system 2 is 300MW, that is, the rated power consumption of the high-temperature heat pump power drive system 204 is 300MW.

[0048] The power generation operation mode of the high-grade heat source system 3 is set as follows: Utilize the energy in the high-grade heat source system 3 and run it at full capacity as much as possible from 5:00 to 10:00 and 16:00 to 24:00; Using the energy from the high-grade heat source system 3, it operates at a low load rate of 15% from 0:00 to 5:00; 10:00 ~ 16:00 The unit is shut down and does not operate; Set the operation mode of heat pump system 2: 0:00 ~ 5:00, 10:00 ~ 16:00 to utilize the low-grade heat source generated by the low-grade heat source system 1, as well as the photovoltaic and wind power abandonment of the large base project itself or the photovoltaic and wind power abandonment of other projects, or low-cost valley electricity, to generate high-grade heat source, and store it in the high-grade heat source high-temperature heat storage unit 303.

[0049] The power generation operation mode of the high-grade heat source system 3 and the operation mode of the high-temperature heat pump system 2 are set here for illustrative purposes only and can be optimized according to factors such as resource conditions and electricity price conditions at the project location.

[0050] In addition, the power supply for the electric drive system 204 of the heat pump system 2 is provided by photovoltaic power and wind power abandonment of the large-scale base project itself, photovoltaic power and wind power abandonment of other projects, or low-cost valley electricity, thereby promoting the absorption and development of random, volatile, and intermittent new energy sources such as photovoltaic power and wind power, and is beneficial to the construction of a "new power system with new energy as the main body".

[0051] Those skilled in the art can clearly understand that, for the sake of convenience and brevity in description, the identification content specifically executed by the above-described system and device can refer to the corresponding process in the aforementioned method embodiment.

[0052] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the protection scope of the present invention.

Claims

1. A solar thermal power generation system based on a high temperature heat pump, characterized in that: include: A low-grade heat source system, wherein a first heat storage medium circulates in the low-grade heat source system, and the low-grade heat source system is configured to heat the first heat storage medium by means of a low-grade heat source; A heat pump system, wherein a heat pump medium circulates in the heat pump system, and the heat pump system is configured to increase the temperature and pressurize the heat pump medium; A high-grade heat source system, wherein a second heat storage medium circulates in the high-grade heat source system, and the high-grade heat source system is configured to generate electricity by heating the second heat storage medium to a preset temperature; The first heat storage medium heated in the low-grade heat source system is used to preheat the heat pump medium, and the heat pump medium heated and pressurized in the heat pump system is used to heat the second heat storage medium.

2. The solar thermal power generation system based on a high temperature heat pump according to claim 1, characterized in that: The heat pump system includes a heat charging heat exchanger, a heat releasing heat exchanger, and a heat processing module; The inlet end of the thermal processing module is connected to the first output end of the heat charging heat exchanger, and the outlet end of the thermal processing module is connected to the second input end of the heat releasing heat exchanger; The second output end of the heat-releasing heat exchanger is connected to the first input end of the heat-charging heat exchanger; Wherein, the thermal processing module is configured to be powered by an energy device outside the solar thermal power generation system and to heat and pressurize the heat pump medium.

3. The solar thermal power generation system based on a high temperature heat pump according to claim 2, characterized in that: The thermal processing module includes a compressor and an electric drive system; The inlet end of the compressor is connected to the first output end of the heat charging heat exchanger, and the compressor heats up and pressurizes the heat pump medium after absorbing heat from the heat charging heat exchanger; The outlet end of the compressor is connected to the second input end of the heat release heat exchanger, and the heated and pressurized heat pump medium releases heat in the heat release heat exchanger to heat the second heat storage medium; The electric drive system is powered by an energy device outside the solar thermal power generation system to drive the compressor to increase the temperature and pressurize the heat pump medium after absorbing heat from the heat charging heat exchanger.

4. The solar thermal power generation system based on a high temperature heat pump according to claim 3, characterized in that: The heat pump system further comprises an expander, which is arranged between the heat releasing heat exchanger and the heat charging heat exchanger, and the expander is mechanically connected to the compressor; The inlet end of the expander is connected to the second output end of the heat releasing heat exchanger, and the outlet end of the expander is connected to the first input end of the heat charging heat exchanger; The heat pump medium expands adiabatically in the expander to reduce temperature and pressure and perform work externally to recover mechanical energy.

5. The solar thermal power generation system based on a high temperature heat pump according to claim 4, characterized in that: The heat pump system also includes a regenerator; The first input end of the regenerator is connected to the first output end of the heat charging heat exchanger, and the first output end of the regenerator is connected to the inlet end of the compressor; The second input end of the regenerator is connected to the second output end of the heat release heat exchanger, and the second output end of the regenerator is connected to the inlet end of the expander; The regenerator is configured to allow the heat pump medium to release heat for a second time after releasing heat once in the heat release heat exchanger, so as to heat the heat pump medium preheated by the low-grade heat source system.

6. The solar thermal power generation system based on a high temperature heat pump according to claim 2, characterized in that: The low-grade heat source system comprises a low-grade heat source medium heat storage unit and a low-grade heat collection unit, wherein the low-grade heat collection unit is configured to heat the first heat storage medium by accumulated heat energy; The medium output end of the low-grade heat collection unit is connected to the high-temperature medium input end of the low-grade heat source medium heat storage unit, and the high-temperature medium output end of the low-grade heat source medium heat storage unit is connected to the second input end of the heat charging heat exchanger; The second output end of the heat charging heat exchanger is connected to the low-temperature medium input end of the low-grade heat source medium heat storage unit, and the low-temperature medium output end of the low-grade heat source medium heat storage unit is connected to the medium input end of the low-grade heat collection unit.

7. The solar thermal power generation system based on a high temperature heat pump according to claim 6, characterized in that: The low-grade heat source system is a tower-type saturated water system, the low-grade heat collection unit is a tower-type saturated water heat collector, the low-grade heat source medium heat storage unit comprises a saturated water heat storage tank and a cold water storage tank, and a deaerator is further provided between the cold water storage tank and the tower-type saturated water heat collector; The inlet end of the deaerator is connected to the medium output end of the cold water storage tank, and the outlet end of the deaerator is connected to the medium input end of the tower saturated water collector.

8. The solar thermal power generation system based on a high temperature heat pump according to claim 2, characterized in that: The high-grade heat source system includes a high-grade heat source heat collection unit, a high-grade heat source medium heat storage unit, a high-grade heat exchange unit and a high-grade heat source power generation system; The first output end of the heat-releasing heat exchanger is connected to the high-temperature medium inlet end of the high-quality heat source medium heat storage unit, and the low-temperature medium outlet end of the high-quality heat source medium heat storage unit is connected to the first input end of the heat-releasing heat exchanger; The low-temperature medium outlet of the high-quality heat source medium heat storage unit is connected to the inlet of the high-quality heat source heat collection unit, and the outlet of the high-quality heat source heat collection unit is connected to the high-temperature medium inlet of the high-quality heat source medium heat storage unit; The high-temperature medium outlet end of the high-quality heat source medium heat storage unit is connected to the first input end of the high-quality heat exchange unit, and the first output end of the high-quality heat exchange unit is connected to the low-temperature medium inlet end of the high-quality heat source medium heat storage unit; The second output end of the high-grade heat exchange unit is connected to the medium input end of the high-grade heat source power generation system, and the medium output end of the high-grade heat source power generation system is connected to the second input end of the high-grade heat exchange unit.

9. The solar thermal power generation system based on a high temperature heat pump according to claim 8, characterized in that: The high-grade heat source system is a tower molten salt system, the high-grade heat source heat collection unit is a tower molten salt collector, the high-grade heat source medium heat storage unit includes a hot salt tank and a cold salt tank, and the high-grade heat source power generation system is a tower molten salt power generation system.

10. A method for operating a CSP system based on a high temperature heat pump, applied to the CSP system described in claim 2, characterized in that: The low-grade heat source system heats the first heat storage medium in its circulation pipeline by means of a low-grade heat source, and stores the heated first heat storage medium, or, The heated first heat storage medium is directly used to preheat the heat pump medium; When an external energy device supplies energy to the heat processing module in the heat pump system, the first heat storage medium heated in the low-grade heat source system is first introduced into the heat charging heat exchanger to perform heat exchange with the heat pump medium in the heat pump system, and then the heated heat pump medium is introduced into the heat processing module to increase temperature and pressurize, and finally the heated and pressurized heat pump medium is introduced into the heat releasing heat exchanger to perform heat exchange with the second heat storage medium in the high-grade heat source system; The second heat storage medium reaching a preset temperature is stored, or, The second heat storage medium reaching the preset temperature is directly used for power generation.

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