Coupling heat pump, cascade compression and multi-tank molten salt Carnot cell system and method

Abstract

The invention discloses a heat pump coupling, cascade compression and multi-tank salt melting Carnot battery system, which comprises a power generator, the power generator is connected with a steam Rankine cycle unit, the steam Rankine cycle unit is sequentially connected with a double-salt multi-tank heat storage unit and a Brayton heat pump cycle unit, and the invention also discloses a control method of the system. The system structure is reasonably designed, the structure of an existing Carnot battery system is modified, redundant electricity is converted into heat to be stored in the power grid power supply valley period, stored heat is converted into electricity to be released in the power grid power supply peak period, heat is supplied to heat pump side cold source air in the process, environment heat can be better used, and the heat pump side cold source air can be recycled. The efficiency of the Brayton heat pump cycle is higher, the overall system efficiency is improved, and the system is improved. And meanwhile, multi-stage compression series connection change is conducted on heat pump side heat storage, more heat is generated, the efficiency of the Brayton heat pump cycle is higher, and the overall system efficiency is improved.

Description

Technical Field

[0001] The present invention relates to a Carnot battery system and method for coupling a heat pump, cascade compression, and multiple molten salt tanks, and belongs to the technical field of Carnot batteries. Background Art

[0002] As chemical energy sources continue to decline and new energy systems rapidly develop, traditional thermal power plants are gradually transitioning to renewable energy power generation systems. During this conversion process, renewable energy sources are highly unstable, and this instability can lead to excessive power curtailment, resulting in unstable power systems. This requires not only regulating peak demand but also addressing the utilization of curtailed renewable energy. To address this issue, research is underway on large-scale power stations such as the Carnot battery. The Carnot battery is a novel energy storage technology that can be configured with both low-temperature and high-temperature heat sources to convert electricity into heat. It consists of three components: electricity-to-heat, electricity storage, and heat-to-electricity. Specific implementations vary, including the molten salt-based Carnot battery. This system couples a thermal power plant with energy storage technology. Through a heat pump cycle or direct electrical heating of molten salt, it converts off-peak electricity and curtailed renewable energy into heat. The high-temperature molten salt serves as the heat source to drive a steam turbine for power generation, making it a novel energy storage system for large-scale electricity storage.

[0003] For abandoned thermal power plants, their power generation components can be reused, retaining their generators and equipped with power-to-heat and energy storage systems. These systems can be transformed into large-scale energy storage systems. For example, these systems consist of three components: charging, storage, and discharge. The charging component converts electrical energy into thermal energy through a heat pump cycle, the storage component enables large-scale storage, and the discharge component uses high-temperature molten salt to drive a Rankine cycle for power generation. In practical applications, the charging process can also be accomplished by directly electrically heating the molten salt. Furthermore, the power plant can extract steam from the turbine to heat the molten salt storage medium for peak load regulation and heat storage. The boilers in this system are unloaded and do not participate in the energy storage process. Summary of the Invention

[0004] The purpose of the present invention is to provide a Carnot battery system coupled with a heat pump, cascade compression, and multiple tanks of molten salt, and also to provide a control method for a Carnot battery system coupled with a heat pump, cascade compression, and multiple tanks of molten salt. The present invention transforms the structure of the existing Carnot battery system by rationally designing the system structure. When the power grid is low, excess electricity is converted into heat storage, and when the power grid is high, the stored heat is converted into electricity and released. In this process, heating the cold source air on the heat pump side can better utilize ambient heat, making the Brayton heat pump cycle more efficient, increasing the overall system efficiency, and improving the system. At the same time, the heat storage on the heat pump side is compressed in series with multiple stages, generating more heat, making the Brayton heat pump cycle more efficient, and increasing the overall system efficiency.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt system, including a generator, the generator is connected to a steam Rankine cycle unit, the steam Rankine cycle unit is sequentially connected to a dual-salt multi-tank heat storage unit and a Brayton heat pump cycle unit, the steam Rankine cycle unit includes a multi-stage steam turbine unit, a superheater, an evaporator, and a preheater connected in sequence, the generator is connected to the multi-stage steam turbine unit, the dual-salt multi-tank heat storage unit includes a solar salt molten salt heat storage tank and a salt molten salt heat storage tank, the solar salt molten salt heat storage tank is respectively connected to the superheater and the evaporator, H The itec salt molten salt heat storage tank is respectively connected to the superheater, evaporator and preheater. The Brayton heat pump circulation unit includes a multi-stage compressor, an air-molten salt heat exchanger, an air-propane heat exchanger A, an expander and an air-propane heat exchanger B. The multi-stage compressor is respectively connected to the air-molten salt heat exchanger and the air-propane heat exchanger A. The air-molten salt heat exchanger is respectively connected to the solar salt molten salt heat storage tank and the Hitec salt molten salt heat storage tank. The air-molten salt heat exchanger is connected to the air-propane heat exchanger A. The air-propane heat exchanger A is connected to the expander, and the air-propane heat exchanger B is connected to the air-propane heat exchanger A.

[0006] The aforementioned Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks, the multi-stage steam turbine unit includes a steam turbine high-pressure cylinder, a steam turbine intermediate-pressure cylinder, and a steam turbine low-pressure cylinder connected in sequence, the steam turbine high-pressure cylinder and the steam turbine intermediate-pressure cylinder are respectively connected to the superheater, the steam turbine low-pressure cylinder is connected to the generator, and the steam turbine low-pressure cylinder is connected to a condenser.

[0007] The aforementioned Carnot battery system with coupled heat pump, cascade compression and multi-tank molten salt, the steam Rankine cycle unit also includes a low-pressure heater group and a high-pressure heater group, the high-pressure cylinder of the steam turbine is connected to the high-pressure heater group, the low-pressure cylinder of the steam turbine is connected to the low-pressure heater group, and the intermediate-pressure cylinder of the steam turbine is respectively connected to the low-pressure heater group and the high-pressure heater group.

[0008] The aforementioned coupled heat pump, cascade compression, and multi-tank molten salt Carnot battery system, the steam Rankine cycle unit also includes a deaerator, which is respectively connected to the turbine intermediate pressure cylinder, the low pressure heater group, and the high pressure heater group.

[0009] The aforementioned Carnot battery system with coupled heat pump, cascade compression and multiple molten salt tanks, the Hitec salt molten salt heat storage tanks include Hitec salt molten salt high-temperature heat storage tanks, Hitec salt molten salt medium-temperature heat storage tanks and Hitec salt molten salt low-temperature heat storage tanks, and the solar salt molten salt heat storage tanks include solar salt molten salt high-temperature heat storage tanks and solar salt molten salt low-temperature heat storage tanks.

[0010] The aforementioned Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks, wherein the multi-stage compressor includes a first-stage compressor and a second-stage compressor, and multiple sets of air-molten salt heat exchangers are provided, wherein one set of air-molten salt heat exchangers is placed between the first-stage compressor and the second-stage compressor; the first-stage compressor and the second-stage compressor are connected in series.

[0011] In the aforementioned Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks, the expander is a scroll expander.

[0012] In the aforementioned Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks, both the first-stage compressor and the second-stage compressor are centrifugal compressors.

[0013] The control method of the aforementioned Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks is to open the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side when the power consumption of the power grid is low. The Brayton heat pump circulation unit uses low-cost electricity to act on the multi-stage compressor, so that the multi-stage compressor works to pressurize the low-temperature and low-pressure air to high-pressure and high-temperature gas. The air then passes through the air-molten salt heat exchanger and the A air-propane heat exchanger, and the high-temperature heat is stored in the solar salt molten salt heat storage tank, and the low-temperature heat is stored in the Hitec salt molten salt heat storage tank. After expansion and environmental heating, the air then enters the multi-stage compressor for circulation. At this time, the coal-fired power generation unit stops working;

[0014] During peak power consumption in the grid, the turbine side passage and the heat exchange passages between the molten salt side and the heat pump side are opened, heat is released through the molten salt, and steam is used to pass through the superheater, evaporator, and preheater to heat the working fluid in the steam Rankine cycle unit, causing the multi-stage steam turbine unit to operate and generate electricity. At this time, the Brayton heat pump cycle unit stops working.

[0015] The aforementioned method of coupling a heat pump, cascade compression, and a Carnot battery system with multiple molten salt tanks, in the Brayton heat pump circulation unit, the air passes through the first-stage compressor and then passes through the air-molten salt heat exchanger and the salt molten salt heat storage tank in turn to enter the second-stage compressor, and then the air passes through the hot side of the air-molten salt heat exchanger and the solar salt molten salt heat storage tank, the hot side of the air-molten salt heat exchanger and the Hitec salt molten salt heat storage tank, the hot side of the air-molten salt heat exchanger and the Hitec salt molten salt heat storage tank, and the hot side of the A air-propane heat exchanger and then communicates with the expander inlet, and the steam passes through the expander through the cold side of the B air-propane heat exchanger and is connected to the inlet of the compressor supporting the B air-propane heat exchanger. Propane is used in the compression heat pump, and the propane comes out from the hot side of the B air-propane heat exchanger, passes through the compressor supporting the B air-propane heat exchanger, and exchanges heat with the air on the heat pump side, and finally exchanges heat with the ambient air again;

[0016] In the steam Rankine cycle unit, after the steam comes out of the superheater, it passes through the high-pressure cylinder of the steam turbine, the intermediate-pressure cylinder of the steam turbine, and the low-pressure cylinder of the steam turbine in sequence to generate electricity. The steam coming out of the high-pressure cylinder of the steam turbine goes to the intermediate-pressure cylinder of the steam turbine, and then part of it enters the low-pressure cylinder of the steam turbine. After doing work, it passes through the condenser and the low-pressure heater group and then enters the deaerator. After passing through the deaerator, part of it enters the preheater, evaporator, and superheater in sequence to exchange heat with the dual-salt multi-tank heat storage unit;

[0017] The dual-salt multi-tank heat storage unit is in the solar salt molten salt heat storage tank. After the steam comes out of the cold side of the air-molten salt heat exchanger and the solar salt molten salt high-temperature heat storage tank, the heat is stored in the solar salt molten salt high-temperature heat storage tank. At the peak, the steam passes through the superheater to release the stored heat into the steam Rankine cycle unit and then enters the solar salt molten salt low-temperature heat storage tank; after the steam comes out of the cold side of the air-molten salt heat exchanger and the Hitec salt molten salt high-temperature heat storage tank, the heat is stored in the Hitec salt molten salt high-temperature heat storage tank. At the peak, the steam passes through the evaporator to release the stored heat into the steam Rankine cycle unit and then enters the Hitec salt molten salt medium-temperature heat storage tank; after the steam comes out of the cold side of the air-molten salt heat exchanger and the Hitec salt molten salt medium-temperature heat storage tank, the heat is stored in the Hitec salt molten salt medium-temperature heat storage tank. At the peak, the steam passes through the evaporator to release the stored heat into the steam Rankine cycle unit and then enters the Hitec salt molten salt low-temperature heat storage tank.

[0018] Compared with the prior art, the present invention is beneficial in that:

[0019] 1. The present invention uses a compression heat pump to heat the air cooling source temperature on the heat pump side, and uses a large amount of ambient heat, so that less electricity is consumed to obtain the same amount of heat, resulting in a significant increase in the efficiency of the heat pump side and the overall system round-trip efficiency.

[0020] 2. The heat storage system of the present invention adopts dual salt species and dual molten salt storage tanks of solar salt molten salt and molten salt, which expands the temperature range of heat storage, better matches the high-temperature heat and low-temperature heat generated by the heat pump side, and has higher heat storage efficiency;

[0021] 3. The heat pump side of the present invention uses a multi-stage compression series method to convert electricity into heat. Under the condition of the same electricity consumption, the heat generated is increased, which increases the efficiency of the Brayton heat pump cycle and the overall round-trip efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a connection relationship diagram between the generator of the present invention and the steam Rankine cycle unit, the dual-salt multi-tank heat storage unit and the Brayton heat pump cycle unit.

[0024] Reference numerals: 1-generator, 2-steam Rankine cycle unit, 3-dual salt multi-tank heat storage unit, 4-Brayton heat pump cycle unit, 5-multi-stage steam turbine unit, 6-superheater, 7-evaporator, 8-preheater, 9-solar salt molten salt high temperature heat storage tank, 10-Hitec salt molten salt heat storage tank, 11-multi-stage compressor, 12-air-molten salt heat exchanger, 13-A air-propane heat exchanger, 14-expander, 15-B air-propane heat exchanger, 16 -Steam turbine high-pressure cylinder, 17-Steam turbine intermediate-pressure cylinder, 18-Steam turbine low-pressure cylinder, 19-Condenser, 20-Low-pressure heater group, 21-High-pressure heater group, 22-Deaerator, 23-Hitec salt molten salt high-temperature heat storage tank, 24-Hitec salt molten salt medium-temperature heat storage tank, 25-Hitec salt molten salt low-temperature heat storage tank, 26-First-stage compressor, 27-Second-stage compressor, 28-Solar salt molten salt low-temperature heat storage tank, 29-Solar salt molten salt heat storage tank.

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0026] Embodiment 1 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt comprises a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 being respectively connected to the superheater 6 and the evaporator 7, the Hitec salt molten salt heat storage tank 10 being respectively connected to the superheater 6 and the evaporator 7, They are respectively connected to the superheater 6, the evaporator 7, and the preheater 8. The Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15. The multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 12 and the A air-propane heat exchanger 13. The air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10. The air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13. The A air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13.

[0027] Embodiment 2 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and multi-tank molten salt comprises a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump circulation unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 being respectively connected to the superheater 6 and the evaporator 7, the Hitec salt molten salt heat storage tank 10 being respectively connected to the superheater 6, the evaporator 7, and the preheater 8, the Brayton heat pump circulation unit 4 comprising a multi-stage compressor 11, an air-molten salt heat exchanger 12, A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15, the multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 12 and the A air-propane heat exchanger 13, the air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10, the air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13, the A air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13; the multi-stage steam turbine unit 5 includes a steam turbine high-pressure cylinder 16, a steam turbine intermediate-pressure cylinder 17 and a steam turbine low-pressure cylinder 18 connected in sequence, the steam turbine high-pressure cylinder 16 and the steam turbine intermediate-pressure cylinder 17 are respectively connected to the superheater 6, the steam turbine low-pressure cylinder 18 is connected to the generator 1, and the steam turbine low-pressure cylinder 18 is connected to the condenser 19.

[0028] Embodiment 3 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt system, comprising a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar The salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 are respectively connected to the superheater 6 and the evaporator 7, the salt molten Hitec salt heat storage tank 10 are respectively connected to the superheater 6, the evaporator 7, and the preheater 8, the Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15, the multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 1 2. A air-propane heat exchanger 13 and an air-molten salt heat exchanger 12 are connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10 respectively, the air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13, the A air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13; the multi-stage steam turbine unit 5 includes a steam turbine high-pressure cylinder 16, a steam turbine intermediate-pressure cylinder 17 and a steam turbine low-pressure cylinder connected in sequence. 18, the turbine high-pressure cylinder 16 and the turbine intermediate-pressure cylinder 17 are respectively connected to the superheater 6, the turbine low-pressure cylinder 18 is connected to the generator 1, and the turbine low-pressure cylinder 18 is connected to the condenser 19; the steam Rankine cycle unit 2 also includes a low-pressure heater group 20 and a high-pressure heater group 21, the turbine high-pressure cylinder 16 is connected to the high-pressure heater group 21, the turbine low-pressure cylinder 18 is connected to the low-pressure heater group 20, and the turbine intermediate-pressure cylinder 17 is respectively connected to the low-pressure heater group 20 and the high-pressure heater group 21.

[0029] Embodiment 4 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt system, comprising a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec The salt molten salt heat storage tank 10 and the solar salt molten salt heat storage tank 29 are respectively connected to the superheater 6 and the evaporator 7. The Hitec salt molten salt heat storage tank 10 is respectively connected to the superheater 6, the evaporator 7 and the preheater 8. The Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15. The multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 12, the A air-propane heat exchanger 13, the air-molten salt heat exchanger 12 is respectively connected to the solar The molten salt heat storage tank 29 is connected to the Hitec molten salt heat storage tank 10, the air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13, the A air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13; the multi-stage steam turbine unit 5 includes a steam turbine high-pressure cylinder 16, a steam turbine intermediate-pressure cylinder 17 and a steam turbine low-pressure cylinder 18 connected in sequence, the steam turbine high-pressure cylinder 16 and the steam turbine intermediate-pressure cylinder 17 are respectively connected to the superheater 6, and the steam turbine low-pressure cylinder 18 is connected to the generator 1 The steam Rankine cycle unit 2 further comprises a low-pressure heater group 20 and a high-pressure heater group 21, the steam turbine high-pressure cylinder 16 is connected to the high-pressure heater group 21, the steam turbine low-pressure cylinder 18 is connected to the low-pressure heater group 20, and the steam turbine intermediate-pressure cylinder 17 is respectively connected to the low-pressure heater group 20 and the high-pressure heater group 21; the steam Rankine cycle unit 2 further comprises a deaerator 22, which is respectively connected to the steam turbine intermediate-pressure cylinder 17, the low-pressure heater group 20 and the high-pressure heater group 21.

[0030] Embodiment 5 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt comprises a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 being respectively connected to the superheater 6, evaporator 7, Hitec salt molten salt heat storage tank 10 is respectively connected to superheater 6, evaporator 7, preheater 8, the Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15, the multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 12, the A air-propane heat exchanger 13, the air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10, the air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13, the A The air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13; the multi-stage steam turbine unit 5 includes a steam turbine high-pressure cylinder 16, a steam turbine intermediate-pressure cylinder 17 and a steam turbine low-pressure cylinder 18 connected in sequence, the steam turbine high-pressure cylinder 16 and the steam turbine intermediate-pressure cylinder 17 are respectively connected to the superheater 6, the steam turbine low-pressure cylinder 18 is connected to the generator 1, and the steam turbine low-pressure cylinder 18 is connected to the condenser 19; the steam Rankine cycle unit 2 also includes a low-pressure heater group 20 and a high-pressure heater group 21, the steam turbine high-pressure cylinder 16 is connected to the high-pressure heater group 21, the steam turbine low-pressure The cylinder 18 is connected to the low-pressure heater group 20, and the turbine intermediate-pressure cylinder 17 is respectively connected to the low-pressure heater group 20 and the high-pressure heater group 21; the steam Rankine cycle unit 2 also includes a deaerator 22, which is respectively connected to the turbine intermediate-pressure cylinder 17, the low-pressure heater group 20 and the high-pressure heater group 21; the Hitec salt molten salt heat storage tank 10 includes a Hitec salt molten salt high-temperature heat storage tank 23, a Hitec salt molten salt medium-temperature heat storage tank 24 and a Hitec salt molten salt low-temperature heat storage tank 25, and the solar salt molten salt heat storage tank 29 includes a solar salt molten salt high-temperature heat storage tank 9 and a solar salt molten salt low-temperature heat storage tank 28.

[0031] Embodiment 6 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt comprises a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 being respectively connected to the superheater 6, the evaporator 7, and the Hitec salt molten salt heat storage tank 10 are respectively connected to the superheater 6, the evaporator 7, and the preheater 8. The Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15. The multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 12 and the A air-propane heat exchanger 13. The air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10. The air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13. The A air-propane heat exchanger 13 is connected to the expander 14. The B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger. The multi-stage steam turbine unit 5 includes a steam turbine high-pressure cylinder 16, a steam turbine intermediate-pressure cylinder 17 and a steam turbine low-pressure cylinder 18 connected in sequence, the steam turbine high-pressure cylinder 16 and the steam turbine intermediate-pressure cylinder 17 are respectively connected to the superheater 6, the steam turbine low-pressure cylinder 18 is connected to the generator 1, and the steam turbine low-pressure cylinder 18 is connected to the condenser 19; the steam Rankine cycle unit 2 also includes a low-pressure heater group 20 and a high-pressure heater group 21, the steam turbine high-pressure cylinder 16 is connected to the high-pressure heater group 21, the steam turbine low-pressure cylinder 18 is connected to the low-pressure heater group 20, and the steam turbine intermediate-pressure cylinder 17 is respectively connected to the low-pressure heater group 20 and the high-pressure heater group 21; the steam Rankine cycle unit 2 It also includes a deaerator 22, which is respectively connected to the turbine intermediate pressure cylinder 17, the low pressure heater group 20 and the high pressure heater group 21; the Hitec salt molten salt heat storage tank 10 includes a Hitec salt molten salt high temperature heat storage tank 23, a Hitec salt molten salt medium temperature heat storage tank 24 and a Hitec salt molten salt low temperature heat storage tank 25, and the solar salt molten salt heat storage tank 29 includes a solar salt molten salt high temperature heat storage tank 9 and a solar salt molten salt low temperature heat storage tank 28; the multi-stage compressor 11 includes a first-stage compressor 26 and a second-stage compressor 27, and multiple sets of air-molten salt heat exchangers 12 are provided, one set of air-molten salt heat exchangers 12 is placed between the first-stage compressor 26 and the second-stage compressor 27.

[0032] Embodiment 7 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt comprises a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 being respectively connected to the superheater 6 and the evaporator 7, and the Hitec salt molten salt heat storage tank 10 being respectively Connected to the superheater 6, the evaporator 7, and the preheater 8, the Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15, the multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 12 and the A air-propane heat exchanger 13, the air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10, the air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13, the A air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13; The multi-stage steam turbine unit 5 includes a steam turbine high-pressure cylinder 16, a steam turbine intermediate-pressure cylinder 17 and a steam turbine low-pressure cylinder 18 connected in sequence. The steam turbine high-pressure cylinder 16 and the steam turbine intermediate-pressure cylinder 17 are respectively connected to the superheater 6, the steam turbine low-pressure cylinder 18 is connected to the generator 1, and the steam turbine low-pressure cylinder 18 is connected to the condenser 19; the steam Rankine cycle unit 2 also includes a low-pressure heater group 20 and a high-pressure heater group 21, the steam turbine high-pressure cylinder 16 is connected to the high-pressure heater group 21, the steam turbine low-pressure cylinder 18 is connected to the low-pressure heater group 20, and the steam turbine intermediate-pressure cylinder 17 is respectively connected to the low-pressure heater group 20 and the high-pressure heater group 21; the steam Rankine cycle unit 2 also includes a deaerator 22, a deaerator 22 are respectively connected to the turbine intermediate pressure cylinder 17, the low pressure heater group 20 and the high pressure heater group 21; the Hitec salt molten salt heat storage tank 10 includes a Hitec salt molten salt high temperature heat storage tank 23, a Hitec salt molten salt medium temperature heat storage tank 24 and a Hitec salt molten salt low temperature heat storage tank 25, and the solar salt molten salt heat storage tank 29 includes a solar salt molten salt high temperature heat storage tank 9 and a solar salt molten salt low temperature heat storage tank 28; the multi-stage compressor 11 includes a first-stage compressor 26 and a second-stage compressor 27, and the air-molten salt heat exchanger 12 is provided with multiple sets, one of which is placed between the first-stage compressor 26 and the second-stage compressor 27; the expander 14 adopts a scroll expander.

[0033] Embodiment 8 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt, comprising a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 being respectively connected to the superheater 6 and the evaporator 7, and the Hitec salt molten salt heat storage tank 10 being respectively connected to the superheater 6 , evaporator 7, preheater 8, the Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15, the multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 12, the A air-propane heat exchanger 13, the air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10, the air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13, the A air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13; the multi-stage steam turbine unit 5 includes a plurality of heat exchangers connected in sequence. The steam turbine high-pressure cylinder 16, the steam turbine intermediate-pressure cylinder 17 and the steam turbine low-pressure cylinder 18 are connected to the superheater 6 respectively, the steam turbine low-pressure cylinder 18 is connected to the generator 1, and the steam turbine low-pressure cylinder 18 is connected to the condenser 19; the steam Rankine cycle unit 2 also includes a low-pressure heater group 20 and a high-pressure heater group 21, the steam turbine high-pressure cylinder 16 is connected to the high-pressure heater group 21, the steam turbine low-pressure cylinder 18 is connected to the low-pressure heater group 20, and the steam turbine intermediate-pressure cylinder 17 is respectively connected to the low-pressure heater group 20 and the high-pressure heater group 21; the steam Rankine cycle unit 2 also includes a deaerator 22, which is respectively connected to the steam turbine intermediate-pressure cylinder 17 and the low-pressure heater group 20 and high-pressure heater group 21; the Hitec salt molten salt heat storage tank 10 includes a Hitec salt molten salt high-temperature heat storage tank 23, a Hitec salt molten salt medium-temperature heat storage tank 24 and a Hitec salt molten salt low-temperature heat storage tank 25, and the solar salt molten salt heat storage tank 29 includes a solar salt molten salt high-temperature heat storage tank 9 and a solar salt molten salt low-temperature heat storage tank 28; the multi-stage compressor 11 includes a primary compressor 26 and a secondary compressor 27, and the air-molten salt heat exchanger 12 is provided with multiple sets, one of which is placed between the primary compressor 26 and the secondary compressor 27; the expander 14 adopts a scroll expander; the primary compressor 26 and the secondary compressor 27 both adopt centrifugal compressors.

[0034] Embodiment 9 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and multi-tank molten salt, comprising a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 being respectively connected to the superheater 6 and the evaporator 7, and the Hitec salt molten salt heat storage tank 10 being respectively connected to the superheater 6 , evaporator 7, preheater 8, the Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15, the multi-stage compressor 11 is respectively connected to the air-molten salt heat exchanger 12, the A air-propane heat exchanger 13, the air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10, the air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13, the A air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13; the multi-stage steam turbine unit 5 includes a plurality of heat exchangers connected in sequence. The steam turbine high-pressure cylinder 16, the steam turbine intermediate-pressure cylinder 17 and the steam turbine low-pressure cylinder 18 are connected to the superheater 6 respectively, the steam turbine low-pressure cylinder 18 is connected to the generator 1, and the steam turbine low-pressure cylinder 18 is connected to the condenser 19; the steam Rankine cycle unit 2 also includes a low-pressure heater group 20 and a high-pressure heater group 21, the steam turbine high-pressure cylinder 16 is connected to the high-pressure heater group 21, the steam turbine low-pressure cylinder 18 is connected to the low-pressure heater group 20, and the steam turbine intermediate-pressure cylinder 17 is respectively connected to the low-pressure heater group 20 and the high-pressure heater group 21; the steam Rankine cycle unit 2 also includes a deaerator 22, which is respectively connected to the steam turbine intermediate-pressure cylinder 17 and the low-pressure heater group 20 and high-pressure heater group 21; the Hitec salt molten salt heat storage tank 10 includes a Hitec salt molten salt high-temperature heat storage tank 23, a Hitec salt molten salt medium-temperature heat storage tank 24 and a Hitec salt molten salt low-temperature heat storage tank 25, and the solar salt molten salt heat storage tank 29 includes a solar salt molten salt high-temperature heat storage tank 9 and a solar salt molten salt low-temperature heat storage tank 28; the multi-stage compressor 11 includes a primary compressor 26 and a secondary compressor 27, and the air-molten salt heat exchanger 12 is provided with multiple sets, one of which is placed between the primary compressor 26 and the secondary compressor 27; the expander 14 adopts a scroll expander; the primary compressor 26 and the secondary compressor 27 are both centrifugal compressors;The molten salt high-temperature heat storage tank 23 contains Hitec salt at a temperature of 400-420°C, the Hitec salt molten salt medium-temperature heat storage tank 24 contains Hitec salt at a temperature of 350-370°C, the Hitec salt molten salt low-temperature heat storage tank 25 contains Hitec salt at a temperature of 200-220°C, the solar salt molten salt high-temperature heat storage tank 9 contains solar salt at a temperature of 555-590°C, and the solar salt molten salt low-temperature heat storage tank 28 contains solar salt at a temperature of 400-420°C. The number of air-propane heat exchangers B 15 and air-propane heat exchangers A 13 can be set according to actual operating conditions.

[0035] Embodiment 10 of the present invention: A Carnot battery system coupled with a heat pump, cascade compression, and a multi-tank molten salt, comprising a generator 1, the generator 1 being connected to a steam Rankine cycle unit 2, the steam Rankine cycle unit 2 being sequentially connected to a dual-salt multi-tank heat storage unit 3 and a Brayton heat pump cycle unit 4, the steam Rankine cycle unit 2 comprising a multi-stage steam turbine unit 5, a superheater 6, an evaporator 7, and a preheater 8 connected in sequence, the generator 1 being connected to the multi-stage steam turbine unit 5, the dual-salt multi-tank heat storage unit 3 comprising a solar salt molten salt heat storage tank 29 and a Hitec salt molten salt heat storage tank 10, the solar salt molten salt heat storage tank 29 being respectively connected to the superheater 6 and the evaporator 7, and the Hitec salt molten salt heat storage tank 10 being respectively connected to the superheater 6, evaporator 7, preheater 8, the Brayton heat pump circulation unit 4 includes a multi-stage compressor 11, an air-molten salt heat exchanger 12, an A air-propane heat exchanger 13, an expander 14 and a B air-propane heat exchanger 15, the multi-stage compressor 11 is connected to the air-molten salt heat exchanger 12, the A air-propane heat exchanger 13, the air-molten salt heat exchanger 12 is connected to the solar salt molten salt heat storage tank 29 and the Hitec salt molten salt heat storage tank 10, the air-molten salt heat exchanger 12 is connected to the A air-propane heat exchanger 13, the A air-propane heat exchanger 13 is connected to the expander 14, and the B air-propane heat exchanger 15 is connected to the A air-propane heat exchanger 13; the multi-stage steam turbine unit 5 includes a plurality of steps connected in sequence. The steam turbine high-pressure cylinder 16, the steam turbine intermediate-pressure cylinder 17 and the steam turbine low-pressure cylinder 18 are connected. The steam turbine high-pressure cylinder 16 and the steam turbine intermediate-pressure cylinder 17 are respectively connected to the superheater 6, the steam turbine low-pressure cylinder 18 is connected to the generator 1, and the steam turbine low-pressure cylinder 18 is connected to the condenser 19; the steam Rankine cycle unit 2 also includes a low-pressure heater group 20 and a high-pressure heater group 21, the steam turbine high-pressure cylinder 16 is connected to the high-pressure heater group 21, the steam turbine low-pressure cylinder 18 is connected to the low-pressure heater group 20, and the steam turbine intermediate-pressure cylinder 17 is respectively connected to the low-pressure heater group 20 and the high-pressure heater group 21; the steam Rankine cycle unit 2 also includes a deaerator 22, which is respectively connected to the steam turbine intermediate-pressure cylinder 17 and the low-pressure heater group 21. The Hitec salt molten salt heat storage tank 10 includes a Hitec salt molten salt high-temperature heat storage tank 23, a Hitec salt molten salt medium-temperature heat storage tank 24 and a Hitec salt molten salt low-temperature heat storage tank 25, and the solar salt molten salt heat storage tank 29 includes a solar salt molten salt high-temperature heat storage tank 9 and a solar salt molten salt low-temperature heat storage tank 28; the multi-stage compressor 11 includes a primary compressor 26 and a secondary compressor 27, and the air-molten salt heat exchanger 12 is provided with multiple sets, wherein one set of air-molten salt heat exchanger 12 is placed between the primary compressor 26 and the secondary compressor 27; the expander 14 adopts a scroll expander; the primary compressor 26 and the secondary compressor 27 both adopt centrifugal compressors;Among them, the Hitec salt molten salt high temperature heat storage tank 23 contains Hitec salt with a temperature of 410°C, the salt molten salt medium temperature heat storage tank 24 contains Hitec salt with a temperature of 360°C, the Hitec salt molten salt low temperature heat storage tank 25 contains Hitec salt with a temperature of 210°C, the solar salt molten salt high temperature heat storage tank 9 contains solar salt with a temperature of 558°C, and the solar salt molten salt low temperature heat storage tank 28 contains solar salt with a temperature of 410°C. The steam Rankine cycle unit 2 also includes a diverter and a reheater. The diverter controls the flow of water into the process. The heat ratio of the superheater and reheater is as follows: After exiting the superheater, the steam passes through the turbine high-pressure cylinder 16, the turbine intermediate-pressure cylinder 17, and the turbine low-pressure cylinder 18 in sequence to generate electricity. The steam exiting the turbine high-pressure cylinder 16 passes through the reheater to the turbine intermediate-pressure cylinder 17, and then a portion enters the turbine low-pressure cylinder 18. After performing work, it passes through the condenser 19 and the low-pressure heater and enters the deaerator 22. A portion of the steam passes through the deaerator 22 and then enters the preheater 8, evaporator 7, and superheater 6 in sequence to exchange heat with the dual-salt multi-tank thermal storage unit 3.

[0036] Embodiment 11 of the present invention: Control method of a Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks,

[0037] When the power grid is in a low power consumption period, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened. The Brayton heat pump circulation unit 4 uses low-cost electricity to act on the multi-stage compressor 11, so that the multi-stage compressor 11 works to pressurize the low-temperature and low-pressure air into high-pressure and high-temperature gas. The air then passes through the air-molten salt heat exchanger 12 and the A air-propane heat exchanger 13, and the high-temperature heat is stored in the solar salt molten salt heat storage tank 29, and the low-temperature heat is stored in the Hitec salt molten salt heat storage tank 10. After expansion and environmental heating, the air enters the multi-stage compressor 11 for circulation. At this time, the coal-fired power generation unit stops working;

[0038] During peak power consumption in the power grid, the steam turbine side passage and the heat exchange passages between the molten salt side and the heat pump side are opened to release heat through the molten salt. Steam is used to pass through the superheater 6, the evaporator 7, and the preheater 8 to heat the working medium in the steam Rankine cycle unit 2, so that the multi-stage steam turbine unit 5 works to generate electricity. At this time, the Brayton heat pump circulation unit 4 stops working.

[0039] Embodiment 12 of the present invention: Control method of a Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks,

[0040] When the power grid is in a low power consumption period, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened. The Brayton heat pump circulation unit 4 uses low-cost electricity to act on the multi-stage compressor 11, so that the multi-stage compressor 11 works to pressurize the low-temperature and low-pressure air into high-pressure and high-temperature gas. The air then passes through the air-molten salt heat exchanger 12 and the A air-propane heat exchanger 13, and the high-temperature heat is stored in the solar salt molten salt heat storage tank 29, and the low-temperature heat is stored in the Hitec salt molten salt heat storage tank 10. After expansion and environmental heating, the air enters the multi-stage compressor 11 for circulation. At this time, the coal-fired power generation unit stops working;

[0041] During peak power consumption in the grid, the steam turbine side passage and the heat exchange passage between the molten salt side and the heat pump side are opened, heat is released through the molten salt, and steam is used to pass through the superheater 6, evaporator 7, and preheater 8 to heat the working medium in the steam Rankine cycle unit 2, so that the multi-stage steam turbine unit 5 is operated to generate electricity. At this time, the Brayton heat pump cycle unit 4 stops working;

[0042] Among them, in the Brayton heat pump circulation unit 4, the air passes through the first-stage compressor 26 and then passes through the air-molten salt heat exchanger 12 and the Hitec salt molten salt heat storage tank 10 for heat exchange and enters the second-stage compressor 27, and then the air passes through the hot side of the air-molten salt heat exchanger 12 and the solar salt molten salt heat storage tank 29 for heat exchange, the hot side of the air-molten salt heat exchanger 12 and the Hitec salt molten salt heat storage tank 10, and the air-molten salt heat exchanger 12 and the Hitec salt molten salt heat storage tank The hot side of the 10-phase heat exchange, the hot side of the A air-propane heat exchanger 13, is then connected to the inlet of the expander 14. After passing through the expander 14, the steam passes through the cold side of the B air-propane heat exchanger 15 and is connected to the inlet of the compressor associated with the B air-propane heat exchanger 15. The compression heat pump uses propane. The propane comes out of the hot side of the B air-propane heat exchanger 15, passes through the compressor associated with the B air-propane heat exchanger 15, exchanges heat with the air on the heat pump side, and finally exchanges heat with the ambient air again.

[0043] In the steam Rankine cycle unit 2, after the steam comes out of the superheater 6, it passes through the turbine high-pressure cylinder 16, the turbine intermediate-pressure cylinder 17, and the turbine low-pressure cylinder 18 in sequence to generate electricity. The steam coming out of the turbine high-pressure cylinder 16 goes to the turbine intermediate-pressure cylinder 17, and then a part of it enters the turbine low-pressure cylinder 18. After doing work, it passes through the condenser 19 and the low-pressure heater group 20 and enters the deaerator 22. After passing through the deaerator 22, a part of it enters the preheater 8, the evaporator 7, and the superheater 6 in sequence to exchange heat with the dual-salt multi-tank heat storage unit 3;

[0044] The dual-salt multi-tank heat storage unit 3 is in the solar salt molten salt heat storage tank 29. After the air comes out from the cold side of the air-molten salt heat exchanger 12 and the solar salt molten salt high-temperature heat storage tank 9, the heat is stored in the solar salt molten salt high-temperature heat storage tank 9. At the peak time, the air passes through the superheater 6 and releases the stored heat into the steam Rankine cycle unit 2, and then enters the solar salt molten salt low-temperature heat storage tank 28; after the air comes out from the cold side of the air-molten salt heat exchanger 12 and the Hitec salt molten salt high-temperature heat storage tank 23, the heat is stored in the Hitec salt molten salt high-temperature heat storage tank 28. In the salt high-temperature heat storage tank 23, at peak times, the stored heat is released into the steam Rankine cycle unit 2 through the evaporator 7, and then enters the Hitec salt molten salt medium-temperature heat storage tank 24; the steam comes out from the cold side of the air-molten salt heat exchanger 12 and the Hitec salt molten salt medium-temperature heat storage tank 24 after heat exchange, and stores the heat in the Hitec salt molten salt medium-temperature heat storage tank 24. At peak times, the steam passes through the evaporator 7, releases the stored heat into the steam Rankine cycle unit 2, and then enters the Hitec salt molten salt low-temperature heat storage tank 25.

[0045] The working principle of an embodiment of the present invention is as follows:

[0046] When the present invention works:

[0047] When the power grid is in a low power consumption period, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened. The Brayton heat pump circulation unit 4 uses low-cost electricity to act on the multi-stage compressor 11, so that the multi-stage compressor 11 works to pressurize the low-temperature and low-pressure air into high-pressure and high-temperature gas. The air then passes through the air-molten salt heat exchanger 12 and the A air-propane heat exchanger 13, and the high-temperature heat is stored in the solar salt molten salt heat storage tank 29, and the low-temperature heat is stored in the Hitec salt molten salt heat storage tank 10. After expansion and environmental heating, the air enters the multi-stage compressor 11 for circulation. At this time, the coal-fired power generation unit stops working;

[0048] During peak power consumption in the power grid, the steam turbine side passage and the heat exchange passages between the molten salt side and the heat pump side are opened to release heat through the molten salt. Steam is used to pass through the superheater 6, the evaporator 7, and the preheater 8 to heat the working medium in the steam Rankine cycle unit 2, so that the multi-stage steam turbine unit 5 works to generate electricity. At this time, the Brayton heat pump circulation unit 4 stops working.

Claims

1. A Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks, comprising a generator (1), characterized in that: The generator (1) is connected to a steam Rankine cycle unit (2), and a dual-salt multi-tank heat storage unit (3) and a Brayton heat pump circulation unit (4) are sequentially connected to the steam Rankine cycle unit (2), and the steam Rankine cycle unit (2) includes a multi-stage steam turbine unit (5), a superheater (6), an evaporator (7), and a preheater (8) connected in sequence. The generator (1) is connected to the multi-stage steam turbine unit (5), and the dual-salt multi-tank heat storage unit (3) includes a solar salt molten salt heat storage tank (29) and a Hitec salt molten salt heat storage tank (10), and the solar salt molten salt heat storage tank (29) is respectively connected to the superheater (6) and the evaporator (7), and the Hitec salt molten salt heat storage tank (10) is respectively connected to the superheater (6), the evaporator (7), and the preheater (8), the Brayton heat pump circulation unit (4) includes a multi-stage compressor (11), an air-molten salt heat exchanger (12), an air-propane heat exchanger A (13), an expander (14) and an air-propane heat exchanger B (15), the multi-stage compressor (11) is respectively connected to the air-molten salt heat exchanger (12) and the air-propane heat exchanger A (13), the air-molten salt heat exchanger (12) is respectively connected to the solar salt molten salt heat storage tank (29) and the Hitec salt molten salt heat storage tank (10), the air-molten salt heat exchanger (12) is connected to the air-propane heat exchanger A (13), the air-propane heat exchanger A (13) is connected to the expander (14), and the air-propane heat exchanger B (15) is connected to the air-propane heat exchanger A (13).

2. The Carnot battery system coupled with heat pump, cascade compression and multi-tank molten salt according to claim 1 is characterized in that: The multi-stage steam turbine unit (5) comprises a steam turbine high-pressure cylinder (16), a steam turbine intermediate-pressure cylinder (17) and a steam turbine low-pressure cylinder (18) connected in sequence, wherein the steam turbine high-pressure cylinder (16) and the steam turbine intermediate-pressure cylinder (17) are respectively connected to the superheater (6), the steam turbine low-pressure cylinder (18) is connected to the generator (1), and the steam turbine low-pressure cylinder (18) is connected to a condenser (19).

3. The Carnot battery system coupled with heat pump, cascade compression and multi-tank molten salt according to claim 2 is characterized in that: The steam Rankine cycle unit (2) further comprises a low-pressure heater group (20) and a high-pressure heater group (21), the high-pressure cylinder (16) of the steam turbine is connected to the high-pressure heater group (21), the low-pressure cylinder (18) of the steam turbine is connected to the low-pressure heater group (20), and the intermediate-pressure cylinder (17) of the steam turbine is respectively connected to the low-pressure heater group (20) and the high-pressure heater group (21).

4. The Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks according to claim 3 is characterized in that: The steam Rankine cycle unit (2) further comprises a deaerator (22), which is respectively connected to the steam turbine intermediate pressure cylinder (17), the low pressure heater group (20) and the high pressure heater group (21).

5. The Carnot battery system coupled with heat pump, cascade compression and multi-tank molten salt according to claim 1 is characterized in that: The Hitec salt molten salt heat storage tank (10) includes a Hitec salt molten salt high-temperature heat storage tank (23), a salt molten Hitec salt medium-temperature heat storage tank (24) and a Hitec salt molten salt low-temperature heat storage tank (25), and the solar salt molten salt heat storage tank (29) includes a solar salt molten salt high-temperature heat storage tank (9) and a solar salt molten salt low-temperature heat storage tank (28).

6. The Carnot battery system coupled with heat pump, cascade compression and multi-tank molten salt according to claim 1 is characterized in that: The multi-stage compressor (11) includes a primary compressor (26) and a secondary compressor (27), and multiple sets of air-molten salt heat exchangers (12) are provided, wherein one set of air-molten salt heat exchangers (12) is placed between the primary compressor (26) and the secondary compressor (27).

7. The Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks according to claim 1 is characterized in that: The expander (14) is a scroll expander.

8. The Carnot battery system coupled with a heat pump, cascade compression, and multiple molten salt tanks according to claim 6, characterized in that: The first-stage compressor (26) and the second-stage compressor (27) are both centrifugal compressors.

9. A control method for the system according to claim 1-8, characterized in that: When the power grid is in low power consumption, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened, and the Brayton heat pump circulation unit (4) uses low-cost electricity to act on the multi-stage compressor (11), so that the multi-stage compressor (11) works to pressurize the low-temperature and low-pressure air into high-pressure and high-temperature gas, and then the air passes through the air-molten salt heat exchanger (12) and the A air-propane heat exchanger (13), and the high-temperature heat is stored in the solar salt molten salt heat storage tank (29), and the low-temperature heat is stored in the Hitec salt molten salt heat storage tank (10), and then enters the multi-stage compressor (11) for circulation after expansion and environmental heating. At this time, the coal-fired power generation unit stops working; During peak power consumption in the power grid, the steam turbine side passage and the heat exchange passages between the molten salt side and the heat pump side are opened, heat is released through the molten salt, and steam is used to pass through the superheater (6), the evaporator (7), and the preheater (8) to heat the working medium in the steam Rankine cycle unit (2), thereby causing the multi-stage steam turbine unit (5) to operate and generate electricity. At this time, the Brayton heat pump cycle unit (4) stops working.

10. The control method according to claim 9, characterized in that: In the Brayton heat pump circulation unit (4), the air passes through the first-stage compressor (26) and then sequentially passes through the air-molten salt heat exchanger (12) and the Hitec salt molten salt heat storage tank (10) for heat exchange and enters the second-stage compressor (27). Then, the air sequentially passes through the hot side of the air-molten salt heat exchanger (12) and the solar salt molten salt heat storage tank (29), the hot side of the air-molten salt heat exchanger (12) and the Hitec salt molten salt heat storage tank (10), the hot side of the air-molten salt heat exchanger (12) and the Hitec salt molten salt heat storage tank ( 10) The hot side of the phase heat exchange and the hot side of the A air-propane heat exchanger (13) are connected to the inlet of the expander (14). After passing through the expander (14), the air passes through the cold side of the BB air-propane heat exchanger (15) and is connected to the inlet of the compressor matched with the BB air-propane heat exchanger (15). Propane is used in the compression heat pump. The propane comes out from the hot side of the BB air-propane heat exchanger (15), passes through the compressor matched with the BB air-propane heat exchanger (15), exchanges heat with the air on the heat pump side, and finally exchanges heat with the ambient air again. In the steam Rankine cycle unit (2), after steam comes out of the superheater (6), it passes through the high-pressure cylinder (16) of the steam turbine, the intermediate-pressure cylinder (17) of the steam turbine, and the low-pressure cylinder (18) of the steam turbine in sequence to generate electricity. The steam coming out of the high-pressure cylinder (16) of the steam turbine enters the intermediate-pressure cylinder (17) of the steam turbine, and then a part of it enters the low-pressure cylinder (18) of the steam turbine. After doing work, it passes through the condenser (19) and the low-pressure heater group (20) and then enters the deaerator (22). A part of it passes through the deaerator (22) and then enters the preheater (8), the evaporator (7), and the superheater (6) in sequence to exchange heat with the double-salt multi-tank heat storage unit (3); The dual-salt multi-tank heat storage unit (3) is in the solar salt molten salt heat storage tank (29). After the air comes out from the cold side of the air-molten salt heat exchanger (12) and the solar salt molten salt high-temperature heat storage tank (9), the heat is stored in the solar salt molten salt high-temperature heat storage tank (9). At the peak time, the air passes through the superheater (6) and releases the stored heat into the steam Rankine cycle unit (2), and then enters the solar salt molten salt low-temperature heat storage tank (28); The air comes out from the cold side of the air-molten salt heat exchanger (12) and the molten salt high temperature heat storage tank (23) and stores the heat in the molten salt high temperature heat storage tank (23). At the peak time, the air passes through the evaporator (7) and releases the stored heat into the steam Rankine cycle unit (2), and then enters the Hitec molten salt medium temperature heat storage tank (24); The air comes out from the cold side of the air-molten salt heat exchanger (12) and the Hitec salt molten salt medium temperature heat storage tank (24) and stores the heat in the Hitec salt molten salt medium temperature heat storage tank (24). At the peak time, the air passes through the evaporator (7) and releases the stored heat into the steam Rankine cycle unit (2), and then enters the Hitec salt molten salt low temperature heat storage tank (25).

Images