Indirect energy storage system based on heat pump circulation

Abstract

The invention discloses an indirect energy storage system based on a heat pump cycle. The system comprises a heat pump refrigerating and heating cycle, a heat engine power generation cycle, an indirect heat storage cycle and an indirect cold storage cycle. Off-peak electricity of a power station is adopted to drive a heat pump refrigeration and heating cycle to prepare a high-temperature heat load and a low-temperature cold load, and the high-temperature heat load and the low-temperature cold load are exchanged to an indirect heat storage cycle and an indirect cold storage cycle through a heat exchanger and are stored in a heat storage tank and a cold storage tank; in the peak period of power utilization, the energy storage working medium of the heat engine power generation cycle exchanges heat with the indirect heat storage cycle and the indirect cold storage cycle through the heat exchanger, the stored high-temperature heat load and the stored low-temperature cold load are absorbed, and the power generator is driven to generate power through the heat engine cycle. The indirect energy storage system based on heat pump circulation has the advantages of being simple in structure, low in cost, high in energy storage density, high in efficiency, suitable for power grid peak regulation and renewable energy power stations, free of greenhouse gas and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage, and relates to an energy storage system, and in particular to an indirect energy storage system based on a heat pump cycle, which is an energy storage system that stores energy based on a heat pump cycle and generates electrical energy using the stored energy. Technical Background

[0002] In recent years, renewable energy is gradually becoming an important source of electricity, and the grid structure and operation mode have undergone major changes. With the popularization of renewable energy and the urgent need for grid peak regulation, reliability improvement and quality improvement, the importance of power storage systems has become increasingly prominent. Power storage is an important component and key technical support for smart grids, energy systems with a high proportion of renewable energy, and energy Internet. Power storage can provide peak regulation, frequency regulation, backup, demand response support and other services for grid operation, and is an important means to improve the safety, flexibility and economy of traditional power systems; power storage can significantly improve the level of renewable energy consumption, support distributed power and microgrids, and is a key technology to promote the replacement of main energy from fossil energy to renewable energy; power storage can promote open sharing and flexible trading of energy production and consumption, and realize multi-energy synergy. It is the core technical foundation for building energy Internet, promoting power system reform and promoting the development of new energy formats.

[0003] At present, existing power energy storage technologies include pumped storage, compressed air storage, flywheel storage and supercapacitors. my country's energy storage is showing a good trend of diversified development: pumped storage is developing rapidly; compressed air storage, flywheel storage, and supercapacitors are accelerating their research and development and application; heat storage, cold storage, and hydrogen storage technologies have also made certain progress. Among them, physical methods represented by heat storage, pumped storage and compressed air storage are suitable for large-scale commercial applications due to their low cost and large energy storage capacity, accounting for about 99.5% of the world's total energy storage.

[0004] When the power system is in the valley load, the energy storage system of the pumped power station allows the motor to drive the water pump to pump the water from the low-level reservoir to the high-level reservoir through the pipeline to consume part of the electricity. When the peak load comes, the water in the high-level reservoir causes the pump and the motor to reverse through the pipeline drop to become the turbine and generator to output electricity, thereby playing the role of peak shaving and valley filling. The energy storage system of the pumped power station is technically mature and reliable, with high efficiency (about 70%) and large energy storage capacity. It has been widely used. However, the energy storage system of the pumped power station requires special geographical conditions to build two reservoirs, etc. The construction period is very long (generally about 7 to 15 years), and the initial investment is huge. What is more difficult is that the construction of large reservoirs will flood vegetation and even cities on a large scale, causing ecological and immigration problems. Therefore, the construction of energy storage systems for pumped power stations has been increasingly restricted.

[0005] During off-peak hours, traditional compressed air energy storage systems compress air and store it in an air storage chamber, converting electrical energy into the internal energy of air and storing it; during peak hours, high-pressure air is released from the air storage chamber, enters the combustion chamber of the gas turbine and burns with the fuel, and then drives the turbine to generate electricity. Compressed air energy storage systems have the advantages of large energy storage capacity, long energy storage cycle, high efficiency (50% to 70%), and relatively small unit investment. However, the energy storage density of compressed air energy storage technology is low, and the difficulty is that it requires a site where compressed air can be stored, such as a sealed cave. In addition, the compressed air energy storage system still relies on the combustion of fossil fuels to provide heat sources. On the one hand, it faces the threat of gradual depletion and price increases of fossil fuels. On the other hand, its combustion still produces various pollutants, which does not meet the requirements of zero-emission and renewable energy development.

[0006] In order to solve the main problems faced by traditional compressed air energy storage systems, scholars at home and abroad have carried out research on advanced adiabatic compressed air energy storage systems (AACAES), ground compressed air energy storage systems (SVCAES), compressed air energy storage systems with heat recovery (AACAES) and air-steam combined cycle compressed air energy storage systems (CASH) in recent years, so that compressed air energy storage systems can basically avoid the combustion of fossil fuels, but the energy density of compressed air energy storage systems is still very low, requiring large air storage chambers. Summary of the invention

[0007] In view of the above shortcomings and deficiencies of the prior art, the purpose of the present invention is to provide an indirect energy storage system based on a heat pump cycle, which includes a heat pump cooling and heating cycle, a heat engine power generation cycle, an indirect heat storage cycle and an indirect cold storage cycle. The power station off-peak electricity drives the heat pump cooling and heating cycle to produce high-temperature heat load and low-temperature cold load, and the high-temperature heat load and low-temperature cold load are exchanged to the indirect heat storage cycle and the indirect cold storage cycle through a heat exchanger, and stored in the heat storage tank and the cold storage tank; during the peak electricity consumption period, the energy storage medium of the heat engine power generation cycle exchanges heat with the indirect heat storage cycle and the indirect cold storage cycle through a heat exchanger, absorbs the stored high-temperature heat load and low-temperature cold load, and drives the generator to generate electricity through the heat engine cycle. The indirect energy storage system based on the heat pump cycle of the present invention has the advantages of simple structure, low cost, high energy storage density, high efficiency, suitable for power grid peak regulation and renewable energy power stations, and no greenhouse gas production.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] An indirect energy storage system based on a heat pump cycle, the system comprising an electric motor, an energy storage compressor, an energy storage expander, a cold storage cycle heat exchanger, a cold storage tank, a low-temperature circulation pump, a heat storage cycle heat exchanger, a heat storage cycle heat exchanger, a heat storage tank, a No. 1 high-pressure heat exchanger, a No. 2 high-pressure heat exchanger, an energy release compressor, an energy release expander, a generator, a No. 1 low-pressure heat exchanger, a No. 2 low-pressure heat exchanger, and No. 1 to No. 4 electric three-way valves.

[0010] in,

[0011] The motor is connected to the energy storage compressor, the energy storage compressor is connected to the energy storage expander, the energy release compressor is connected to the energy release expander, and the energy release expander is connected to the generator; the first to fourth electric three-way valves each include three interfaces, namely, interface 1#, interface 2#, and interface 3#;

[0012] It is characterized in that

[0013] The system is configured as a heat pump cooling and heating cycle, a heat engine power generation cycle, an indirect heat storage cycle and an indirect cold storage cycle, wherein:

[0014] In the heat pump cooling and heating cycle,

[0015] The exhaust port of the energy storage compressor is connected to the air inlet of the energy storage expander through a pipeline, in sequence, through the 1# interface and 2# interface of the 1# electric three-way valve, the hot side of the heat storage cycle heat exchanger, the 1# interface and 2# interface of the 2# electric three-way valve, and the hot side of the 1# high-pressure heat exchanger;

[0016] The exhaust port of the energy storage expander is connected to the air inlet of the energy storage compressor through a pipeline via the 1# interface and 2# interface of the No. 3 electric three-way valve, the cold side of the cold storage circulation heat exchanger, the 1# interface and 2# interface of the No. 4 electric three-way valve, and the cold side of the No. 1 low-pressure heat exchanger.

[0017] In the heat engine power generation cycle,

[0018] The exhaust port of the energy release compressor is connected to the air inlet of the energy release expander through a pipeline in sequence through the hot side of the No. 2 high-pressure heat exchanger, the 3# interface and the 1# interface of the No. 2 electric three-way valve, the hot side of the heat storage cycle heat exchanger, the 2# interface and the 3# interface of the No. 1 electric three-way valve;

[0019] The exhaust port of the energy release expander is connected to the air inlet of the energy release compressor through a pipeline via the cold side of the No. 2 low-pressure heat exchanger, the 3# interface and the 1# interface of the No. 4 electric three-way valve, the cold side of the cold storage cycle heat exchanger, the 2# interface and the 3# interface of the No. 3 electric three-way valve.

[0020] In the indirect heat storage cycle, the cold side of the heat storage cycle heat exchanger, the high-temperature circulation pump, and the heat storage tank are connected in sequence through pipelines to form a closed loop.

[0021] In the indirect cold storage cycle, the hot side of the cold storage cycle heat exchanger, the low-temperature circulation pump, and the cold storage tank are connected in sequence through pipelines to form a closed loop.

[0022] Preferably, during off-peak electricity periods, the system utilizes the heat pump cooling and heating cycle to prepare high-temperature heat load and low-temperature cooling load, and stores the high-temperature heat load and low-temperature cooling load in the heat storage tank and the cold storage tank via the indirect heat storage cycle and the indirect cold storage cycle, respectively.

[0023] Furthermore, during the off-peak electricity period, the energy storage compressor and the energy storage expander are started, and the energy release compressor and the energy release expander are shut down; and the No. 1 electric three-way valve is controlled to connect its 1# interface with its 2# interface; the No. 2 electric three-way valve is controlled to connect its 1# interface with its 2# interface; the No. 3 electric three-way valve is controlled to connect its 1# interface with its 2# interface; and the No. 4 electric three-way valve is controlled to connect its 1# interface with its 2# interface.

[0024] Furthermore, during the off-peak period, in the heat pump cooling and heating cycle, the electric motor drives the energy storage compressor to compress the energy storage medium at room temperature and low pressure to a high temperature and high pressure state; the temperature of the high temperature and high pressure energy storage medium is reduced to room temperature through the heat storage cycle heat exchanger, and the high temperature heat load is stored in the heat storage medium of the heat storage tank through the indirect heat storage cycle; the temperature of the energy storage medium at room temperature and high pressure is reduced to near room temperature through the hot side of the No. 1 high pressure heat exchanger; the energy storage medium at room temperature and high pressure is further reduced to low temperature through the energy storage expander. The energy storage medium of room temperature and low pressure re-enters the inlet of the energy storage compressor to participate in the heat pump cycle, and the high-temperature heat load and the low-temperature cold load are continuously stored in the heat storage medium of the heat storage tank and the cold storage medium of the cold storage tank through the indirect cold storage cycle.

[0025] Preferably, during peak hours of electricity consumption, the system utilizes the high-temperature heat load and low-temperature cold load stored in the heat storage tank and the cold storage tank and drives the heat engine cycle to generate electricity with the help of the heat engine power generation cycle.

[0026] Furthermore, during the peak electricity consumption period, the energy release compressor and the energy release expander are started, and the energy storage compressor and the energy storage expander are shut down; and the No. 1 electric three-way valve is controlled to connect its 2# interface and 3# interface; the No. 2 electric three-way valve is controlled to connect its 1# interface and 3# interface; the No. 3 electric three-way valve is controlled to connect its 2# interface and 3# interface; and the No. 4 electric three-way valve is controlled to connect its 1# interface and 3# interface.

[0027] Furthermore, during the peak period of electricity consumption, the energy storage medium at room temperature and low pressure passes through the cold storage cycle heat exchanger, absorbs the low-temperature cold load stored in the cold storage tank, and then its temperature drops to low temperature and low pressure, and passes through the energy release compressor to compress the low-temperature and low-pressure energy storage medium to a normal temperature and high pressure state; the energy storage medium at room temperature and high pressure passes through the hot side of the No. 2 high-pressure heat exchanger, and its temperature drops to near room temperature; the energy storage medium at room temperature and high pressure passes through the heat storage cycle heat exchanger, and then its temperature rises to high temperature after absorbing the high-temperature heat load stored in the heat storage tank; the high-temperature and high-pressure energy storage medium further passes through the energy release expander to room temperature and low pressure; the energy storage medium at room temperature and low pressure passes through the No. 2 low-pressure heat exchanger and its temperature drops to near room temperature; the energy storage medium at room temperature and low pressure re-enters the inlet of the cold storage cycle heat exchanger to participate in the heat engine cycle, the energy release expander is driven and connected to the generator, and the energy release compressor is transmission-connected to the energy release expander, and this cycle is repeated to continuously convert the stored high-temperature heat load and low-temperature cold load into electrical energy output through the heat engine cycle.

[0028] Preferably, during the off-peak period of the indirect heat storage cycle, the high-temperature circulation pump drives the energy storage medium to circulate in the loop, the energy storage medium is heated when passing through the heat storage cycle heat exchanger and is cooled when passing through the heat storage tank, and the high-temperature heat load is stored in the heat storage medium in the heat storage tank; during the peak period of electricity consumption, the high-temperature circulation pump operates in reverse to drive the energy storage medium to circulate in the loop, the energy storage medium is heated when passing through the heat storage tank and is cooled when passing through the heat storage cycle heat exchanger, and the high-temperature heat load stored in the heat storage tank is exchanged to the heat engine working circuit.

[0029] Preferably, during the off-peak electricity period of the indirect cold storage cycle, the low-temperature circulation pump drives the energy storage medium to circulate in the loop, the energy storage medium is cooled when passing through the cold storage cycle heat exchanger and is heated when passing through the cold storage tank, and the low-temperature cold load is stored in the cold storage medium in the cold storage tank; during the peak electricity consumption period of the indirect cold storage cycle, the low-temperature circulation pump operates in reverse to drive the energy storage medium to circulate in the loop, the energy storage medium is cooled when passing through the cold storage tank and is heated when passing through the cold storage cycle heat exchanger, and the low-temperature cold load stored in the cold storage tank is exchanged to the work circuit of the heat engine.

[0030] Preferably, the electric motor is a drive motor, which uses one or more of conventional power station off-peak electricity, nuclear power, wind power, solar power, hydropower or tidal power as power source.

[0031] Preferably, the total pressure ratio of the energy storage compressor or the energy release compressor is between 5 and 40; when the compressor is a plurality of compressors, the plurality of compressors are in a coaxial series form or a split-shaft parallel form; in the parallel form, each split shaft is dynamically connected to the main drive shaft.

[0032] Preferably, the energy storage expander or the energy release expander has a total expansion ratio between 5 and 40; when the expansion machine group consists of multiple expanders, the multiple expanders are in a coaxial series form or a split-shaft parallel form; in the parallel form, each split shaft is dynamically connected to the main drive shaft.

[0033] Preferably, the heat storage tank and the cold storage tank are cylindrical or rectangular. The heat storage medium and the cold storage medium are made of one or a combination of at least two materials such as water, rock, sand, metal particles, solid bricks, etc.

[0034] Preferably, in the indirect energy storage system based on the heat pump cycle, the energy storage working fluid in the heat pump cooling and heating cycle and the heat engine power generation cycle is one of argon, helium, hydrogen, nitrogen, oxygen or air, or a mixture of at least two of them.

[0035] Preferably, in the indirect energy storage system based on the heat pump cycle, the energy storage working fluid in the indirect heat storage cycle and the indirect cold storage cycle is one of argon, helium, hydrogen, nitrogen, oxygen or air, or a mixture of at least two of them.

[0036] Compared with the prior art, the indirect energy storage system based on the heat pump cycle of the present invention adopts the off-peak electricity of the power station to drive the heat pump refrigeration and heating cycle to produce high-temperature heat load and low-temperature cold load, and stores them in the heat storage and cold storage tanks through the indirect heat exchange cycle; during the peak electricity consumption period, the high and low temperature loads inside the heat storage and cold storage tanks are exchanged to the energy release power generation cycle through the indirect heat exchange cycle and the indirect heat storage and cold storage cycle heat exchanger, and the generator is driven to generate electricity through the heat engine cycle. The indirect energy storage system based on the heat pump cycle of the present invention has the advantages of simple structure, low cost, high energy storage density, high efficiency, suitable for power grid peak regulation and renewable energy power stations, and no greenhouse gas production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the indirect energy storage system based on the heat pump cycle of the present invention. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0039] like Figure 1As shown, the indirect energy storage system based on the heat pump cycle of the present invention is composed of a motor 1, an energy storage compressor 2, an energy storage expander 3, a cold storage cycle heat exchanger 4, a cold storage tank 5, a low-temperature circulation pump 6, a heat storage cycle heat exchanger 7, a high-temperature circulation pump 8, a heat storage tank 9, a No. 1 high-pressure heat exchanger 10, a No. 2 high-pressure heat exchanger 11, an energy release compressor 12, an energy release expander 13, a generator 14, a No. 1 low-pressure heat exchanger 15, a No. 2 low-pressure heat exchanger 16, a No. 1 electric three-way valve 17, a No. 2 electric three-way valve 18, a No. 3 electric three-way valve 19, a No. 4 electric three-way valve 20, and a plurality of pipelines (1) to (20) and other components. Among them, the electric three-way valves No. 1 to No. 4 17~20 each include three interfaces, namely interface 1#, interface 2#, and interface 3#; the energy storage compressor 2 is drivingly connected to the motor 1, the energy release expander 13 is drivingly connected to the generator 14, the energy storage compressor 2 is drivingly connected to the energy storage expander 3, and the energy release compressor 12 is drivingly connected to the energy release expander 13.

[0040] The above-mentioned indirect energy storage system based on the heat pump cycle composed of multiple parts of the present invention can be divided into four circuits, namely, a heat pump cooling and heating cycle, a heat engine power generation cycle, an indirect heat storage cycle and an indirect cold storage cycle.

[0041] See also Figure 1 In the indirect energy storage system based on the heat pump cycle of the present invention, the heat pump cooling and heating cycle includes an energy storage compressor 2, an energy storage expander 3, a heat storage cycle heat exchanger 7, a No. 1 high-pressure heat exchanger 10, a No. 2 high-pressure heat exchanger 11, a cold storage cycle heat exchanger 4, a No. 1 low-pressure heat exchanger 15, and a No. 2 low-pressure heat exchanger 16. The heat pump cooling and heating cycle is filled with a heat pump cycle energy storage medium, wherein,

[0042] The exhaust port of the energy storage compressor 2 is connected to the air inlet of the energy storage expander 3 through a pipeline, in sequence, through the 1# interface and 2# interface of the 1# electric three-way valve 17, the hot side of the heat storage cycle heat exchanger 7, the 1# interface and 2# interface of the 2# electric three-way valve 18, and the hot side of the 1# high-pressure heat exchanger 10.

[0043] The exhaust port of the energy storage expander 3 is connected to the air inlet of the energy storage compressor 2 through a pipeline in sequence through the 1# interface and 2# interface of the No. 3 electric three-way valve 19, the cold side of the cold storage circulation heat exchanger 4, the 1# interface and 2# interface of the No. 4 electric three-way valve 20, and the cold side of the No. 1 low-pressure heat exchanger 15.

[0044] See also Figure 1In the indirect energy storage system based on the heat pump cycle of the present invention, the heat engine power generation cycle includes an energy-discharging compressor 12, a heat storage cycle heat exchanger 7, a second high-pressure heat exchanger 11, a cold storage cycle heat exchanger 4, an energy-discharging expander 13, and a second low-pressure heat exchanger 16. The heat engine power generation cycle is filled with a circulating energy storage medium, wherein:

[0045] The exhaust port of the energy release compressor 12 is connected to the air inlet of the energy release expander 13 through a pipeline in sequence through the hot side of the No. 2 high-pressure heat exchanger 11, the 3# interface and the 1# interface of the No. 2 electric three-way valve 18, the hot side of the heat storage cycle heat exchanger 7, the 2# interface and the 3# interface of the No. 1 electric three-way valve 17;

[0046] The exhaust port of the energy release expander 13 is connected to the air inlet of the energy release compressor 12 through a pipeline via the cold side of the No. 2 low-pressure heat exchanger 16, the 3# interface and the 1# interface of the No. 4 electric three-way valve 20, the cold side of the cold storage cycle heat exchanger 4, the 2# interface and the 3# interface of the No. 3 electric three-way valve 19.

[0047] See also Figure 1 In the indirect energy storage system based on the heat pump cycle of the present invention, the heat storage cycle heat exchanger 7, the high temperature circulation pump 8, the heat storage tank 9 and the pipelines (19) and (20) constitute an indirect heat storage cycle. The cold side of the heat storage cycle heat exchanger 7, the high temperature circulation pump 8 and the heat storage tank 9 are connected in sequence through pipelines to form a closed loop.

[0048] See also Figure 1 In the indirect energy storage system based on heat pump cycle of the present invention, the cold storage cycle heat exchanger 4, the low temperature circulation pump 6, the cold storage tank 5 and the pipelines (17) and (18) constitute an indirect cold storage cycle. The hot side of the cold storage cycle heat exchanger 4, the low temperature circulation pump 6 and the cold storage tank 5 are connected in sequence through pipelines to form a closed loop.

[0049] See also Figure 1When the indirect energy storage system based on the heat pump cycle of the present invention is storing energy, the first electric three-way valve 17 is controlled to connect its 1# interface with the 2# interface, so that pipeline (1) is connected with pipeline (3) and pipeline (14) is cut off; the second electric three-way valve 18 is controlled to connect its 1# interface with the 2# interface, so that pipeline (4) is connected with pipeline (5) and pipeline (13) is cut off; the fourth electric three-way valve 20 is controlled to connect its 1# interface with the 2# interface, so that pipeline (9) is connected with pipeline (10) and pipeline (16) is cut off; the third electric three-way valve 19 is controlled to connect its 1# interface with the 2# interface, so that pipeline (7) is connected with pipeline (8) and pipeline (11) is cut off. By operating the valves, the energy storage compressor 2, the heat storage cycle heat exchanger 7, the first high-pressure heat exchanger 10, the energy storage expander 3, the cold storage cycle heat exchanger 4, the first low-pressure heat exchanger 15 and the pipelines (1) to (10) form a heat pump cooling and heating cycle. The motor 1 is fixedly connected to the common transmission shaft of the energy storage compressor 2 and the energy storage expander 3.

[0050] When discharging energy to generate electricity, the first electric three-way valve 17 is controlled to connect its 2# interface with the 3# interface, so that pipeline (3) is connected to pipeline (14) and pipeline (1) is cut off; the second electric three-way valve 18 is controlled to connect its 1# interface with the 3# interface, so that pipeline (4) is connected to pipeline (13) and pipeline (5) is cut off; the fourth electric three-way valve 20 is controlled to connect its 1# interface with the 3# interface, so that pipeline (9) is connected to pipeline (16) and pipeline (10) is cut off; The No. 3 electric three-way valve 19 is controlled to connect its No. 2 interface and No. 3 interface, so that pipeline (8) is connected to pipeline (11) and pipeline (7) is closed; when discharging energy to generate electricity, the energy discharging compressor 12, No. 2 high-pressure heat exchanger 11, heat storage cycle heat exchanger 7, energy discharging expander 13, No. 2 low-pressure heat exchanger 16, cold storage cycle heat exchanger 4 and pipelines (8), (9), (11), (12), (13), (4), (3), (14), (15) and (16) form a heat engine power generation cycle. The generator 14 is fixedly connected to the common transmission shaft of the energy discharging compressor 12 and the energy discharging expander 13.

[0051] During the off-peak period, the motor 1 drives the energy storage compressor 2 to compress the energy storage medium at room temperature and low pressure to a high temperature and high pressure state; the temperature of the high temperature and high pressure energy storage medium is reduced to room temperature through the heat storage cycle heat exchanger 7; at the same time, the energy storage medium in the indirect heat storage cycle is driven by the high temperature circulation pump 8, and after being heated by the heat storage cycle heat exchanger 7, it is cooled by the heat storage tank 9, and at the same time, the high temperature heat load is stored in the heat storage medium of the heat storage tank 9; the temperature of the energy storage medium at room temperature and high pressure is reduced to near room temperature through the hot side of the No. 1 high pressure heat exchanger 10; the energy storage medium at room temperature and high pressure is further expanded to low temperature and low pressure through the energy storage expander 3; the energy storage medium at low temperature and low pressure After passing through the cold storage cycle heat exchanger 4, the temperature of the low-temperature and low-pressure energy storage medium is increased to normal temperature. At the same time, the energy storage medium in the indirect cold storage cycle is driven by the low-temperature circulation pump 6, and after being cooled through the cold storage cycle heat exchanger 4, it is heated through the cold storage tank 5, and at the same time, the low-temperature cold load is stored in the cold storage medium of the cold storage tank 5; the temperature of the normal temperature and low-pressure energy storage medium is increased to near room temperature after passing through the No. 1 low-pressure heat exchanger 15; the room temperature and low-pressure energy storage medium re-enters the inlet of the energy storage compressor 2 to participate in the heat pump cycle, and this cycle is repeated, continuously storing the high-temperature heat load and the low-temperature cold load in the heat storage medium of the heat storage tank 9 and the cold storage medium of the cold storage tank 5.

[0052] During the peak period of electricity consumption, the low-temperature circulation pump 6 in the indirect cold storage cycle rotates in the opposite direction, and the energy storage medium in the indirect cold storage cycle is driven by the low-temperature circulation pump 6, passes through the cold storage tank 5 to absorb the low-temperature cold load stored in the cold storage medium in the cold storage tank 5, and is then heated by the cold storage cycle heat exchanger 4; the normal temperature and low-pressure energy storage medium in the heat engine power generation cycle passes through the cold storage cycle heat exchanger 4, absorbs the low-temperature cold load, and the temperature drops to low temperature and low pressure, and passes through the energy release compressor 12 to compress the low temperature and low pressure energy storage medium to a normal temperature and high pressure state; the normal temperature and high pressure energy storage medium passes through the hot side temperature of the No. 2 low-pressure heat exchanger 16 to drop to near room temperature; at the same time, the indirect heat storage The high-temperature circulation pump 8 in the cycle rotates in the opposite direction, and the energy storage medium in the indirect heat storage cycle is driven by the high-temperature circulation pump 8, passes through the heat storage tank 9 to absorb the high-temperature heat load stored in the heat storage medium of the heat storage tank 9, and then passes through the heat storage cycle heat exchanger 7 to be cooled; the energy storage medium passes through the heat storage cycle heat exchanger 7 to raise the temperature of the high-pressure energy storage medium at room temperature to high temperature; the high-temperature and high-pressure energy storage medium further passes through the energy release expansion unit 13 to normal temperature and low pressure; the normal temperature and low pressure heat pump cycle gas medium passes through the second low-pressure heat exchanger 16 and the temperature is close to room temperature; the room temperature and low pressure gas medium re-enters the inlet of the cold storage circuit heat exchanger 4 to participate in the heat engine cycle. The energy release expansion machine 13 is driven to connect to the generator 14, and the energy release compressor 12 is connected to the energy release expansion machine 13 in a transmission manner. This cycle is repeated, and the stored high-temperature heat load and low-temperature cold load are continuously converted into electrical energy output through the heat engine cycle.

[0053] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims

1. An indirect energy storage system based on a heat pump cycle, the system comprising an electric motor, an energy storage compressor, an energy storage expander, a cold storage cycle heat exchanger, a cold storage tank, a low-temperature circulation pump, a heat storage cycle heat exchanger, a heat storage cycle heat exchanger, a heat storage tank, a No. 1 high-pressure heat exchanger, a No. 2 high-pressure heat exchanger, an energy release compressor, an energy release expander, a generator, a No. 1 low-pressure heat exchanger, a No. 2 low-pressure heat exchanger, and No. 1 to No. 4 electric three-way valves. in, The motor is connected to the energy storage compressor, the energy storage compressor is connected to the energy storage expander, the energy release compressor is connected to the energy release expander, and the energy release expander is connected to the generator; the first to fourth electric three-way valves each include three interfaces, namely, interface 1#, interface 2#, and interface 3#; It is characterized in that The system is configured as a heat pump cooling and heating cycle, a heat engine power generation cycle, an indirect heat storage cycle and an indirect cold storage cycle, wherein: In the heat pump cooling and heating cycle, the exhaust port of the energy storage compressor is connected to the air inlet of the energy storage expander through a pipeline, in sequence through the 1# interface and 2# interface of the No. 1 electric three-way valve, the hot side of the heat storage cycle heat exchanger, the 1# interface and 2# interface of the No. 2 electric three-way valve, and the hot side of the No. 1 high-pressure heat exchanger; the exhaust port of the energy storage expander is connected to the air inlet of the energy storage compressor through a pipeline, in sequence through the 1# interface and 2# interface of the No. 3 electric three-way valve, the cold side of the cold storage cycle heat exchanger, the 1# interface and 2# interface of the No. 4 electric three-way valve, and the cold side of the No. 1 low-pressure heat exchanger. In the heat engine power generation cycle, the exhaust port of the energy release compressor is connected to the air inlet of the energy release expander through a pipeline in sequence via the hot side of the No. 2 high-pressure heat exchanger, the 3# interface and the 1# interface of the No. 2 electric three-way valve, the hot side of the heat storage cycle heat exchanger, the 2# interface and the 3# interface of the No. 1 electric three-way valve; the exhaust port of the energy release expander is connected to the air inlet of the energy release compressor through a pipeline in sequence via the cold side of the No. 2 low-pressure heat exchanger, the 3# interface and the 1# interface of the No. 4 electric three-way valve, the cold side of the cold storage cycle heat exchanger, the 2# interface and the 3# interface of the No. 3 electric three-way valve. In the indirect heat storage cycle, the cold side of the heat storage cycle heat exchanger, the high-temperature circulation pump, and the heat storage tank are connected in sequence through pipelines to form a closed loop. In the indirect cold storage cycle, the hot side of the cold storage cycle heat exchanger, the low-temperature circulation pump, and the cold storage tank are connected in sequence through pipelines to form a closed loop.

2. The indirect energy storage system based on the heat pump cycle according to the above claims is characterized in that: During off-peak electricity periods, the system uses the heat pump cooling and heating cycle to prepare high-temperature heat load and low-temperature cold load, and stores the high-temperature heat load and low-temperature cold load in the heat storage tank and the cold storage tank via the indirect heat storage cycle and the indirect cold storage cycle, respectively.

3. The indirect energy storage system based on heat pump cycle according to claim 2 is characterized in that: During the off-peak period, the energy storage compressor and the energy storage expander are started, and the energy release compressor and the energy release expander are shut down; and the No. 1 electric three-way valve is controlled to connect its 1# interface with its 2# interface; the No. 2 electric three-way valve is controlled to connect its 1# interface with its 2# interface; the No. 3 electric three-way valve is controlled to connect its 1# interface with its 2# interface; and the No. 4 electric three-way valve is controlled to connect its 1# interface with its 2# interface.

4. The indirect energy storage system based on heat pump cycle according to claim 2 is characterized in that: During the off-peak period, in the heat pump cooling and heating cycle, the motor drives the energy storage compressor to compress the energy storage medium at room temperature and low pressure to a high temperature and high pressure state; the temperature of the high temperature and high pressure energy storage medium is reduced to room temperature through the heat storage cycle heat exchanger, and the high temperature heat load is stored in the heat storage medium of the heat storage tank through the indirect heat storage cycle; the energy storage medium at room temperature and high pressure is reduced to near room temperature through the hot side temperature of the No. 1 high pressure heat exchanger; the energy storage medium at room temperature and high pressure is further reduced to low temperature and low pressure through the energy storage expander. pressure; the temperature of the low-temperature and low-pressure energy storage medium rises to room temperature after passing through the cold storage cycle heat exchanger, and the low-temperature cold load is stored in the cold storage medium of the cold storage tank through the indirect cold storage cycle; the temperature of the normal temperature and low-pressure energy storage medium rises to near room temperature after passing through the No. 1 low-pressure heat exchanger; the room temperature and low-pressure energy storage medium re-enters the inlet of the energy storage compressor to participate in the heat pump cycle, and this cycle is repeated to continuously store the high-temperature heat load and the low-temperature cold load in the heat storage medium of the heat storage tank and the cold storage medium of the cold storage tank.

5. The indirect energy storage system based on the heat pump cycle according to the above claims is characterized in that: During peak hours of electricity consumption, the system utilizes the high-temperature heat load and low-temperature cold load stored in the heat storage tank and the cold storage tank and drives the heat engine cycle to generate electricity with the help of the heat engine power generation cycle.

6. The indirect energy storage system based on heat pump cycle according to claim 5 is characterized in that: During the peak electricity consumption period, the energy release compressor and the energy release expander are started, and the energy storage compressor and the energy storage expander are shut down; and the No. 1 electric three-way valve is controlled to connect its 2# interface and 3# interface; the No. 2 electric three-way valve is controlled to connect its 1# interface and 3# interface; the No. 3 electric three-way valve is controlled to connect its 2# interface and 3# interface; and the No. 4 electric three-way valve is controlled to connect its 1# interface and 3# interface.

7. The indirect energy storage system based on heat pump cycle according to claim 5, characterized in that: During the peak period of electricity consumption, the energy storage medium at normal temperature and low pressure passes through the cold storage cycle heat exchanger, absorbs the low-temperature cold load stored in the cold storage tank, and then its temperature drops to low temperature and low pressure, and passes through the energy release compressor to compress the low-temperature and low-pressure energy storage medium to a normal temperature and high pressure state; the energy storage medium at normal temperature and high pressure passes through the hot side of the No. 2 high-pressure heat exchanger, and its temperature drops to near room temperature; the energy storage medium at room temperature and high pressure passes through the heat storage cycle heat exchanger, and then its temperature rises to high temperature after absorbing the high-temperature heat load stored in the heat storage tank; the energy storage medium at high temperature and high pressure further passes through the energy release expander to normal temperature and low pressure; the energy storage medium at normal temperature and low pressure passes through the No. 2 low-pressure heat exchanger, and its temperature drops to near room temperature; the energy storage medium at room temperature and low pressure re-enters the inlet of the cold storage cycle heat exchanger to participate in the heat engine cycle, the energy release expander is driven and connected to the generator, and the energy release compressor is transmission-connected to the energy release expander, and this cycle is repeated to continuously convert the stored high and high temperature heat load and low temperature cold load into electrical energy output through the heat engine cycle.

8. The indirect energy storage system based on the heat pump cycle according to the above claims is characterized in that: During the off-peak period of the indirect heat storage cycle, the high-temperature circulation pump drives the energy storage medium to circulate in the loop, the energy storage medium is heated when passing through the heat storage cycle heat exchanger and is cooled when passing through the heat storage tank, and the high-temperature heat load is stored in the heat storage medium in the heat storage tank; during the peak period of electricity consumption, the high-temperature circulation pump operates in reverse to drive the energy storage medium to circulate in the loop, the energy storage medium is heated when passing through the heat storage tank and is cooled when passing through the heat storage cycle heat exchanger, and the high-temperature heat load stored in the heat storage tank is exchanged to the heat engine working circuit.

9. The indirect energy storage system based on the heat pump cycle according to the above claims is characterized in that: During the off-peak period of the indirect cold storage cycle, the low-temperature circulation pump drives the energy storage medium to circulate in the loop, the energy storage medium is cooled when passing through the cold storage cycle heat exchanger and is heated when passing through the cold storage tank, and the low-temperature cold load is stored in the cold storage medium in the cold storage tank; during the peak period of electricity consumption, the low-temperature circulation pump operates in reverse to drive the energy storage medium to circulate in the loop, the energy storage medium is cooled when passing through the cold storage tank and is heated when passing through the cold storage cycle heat exchanger, and the low-temperature cold load stored in the cold storage tank is exchanged to the heat engine working circuit.

10. The indirect energy storage system based on the heat pump cycle according to the above claims is characterized in that: The electric motor is a driving motor, which uses one or more of conventional power station off-peak electricity, nuclear power, wind power, solar power, hydropower or tidal power as power source.

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