Large temperature difference heat pump phase change energy storage system and energy storage method

Abstract

The application provides a large-temperature-difference heat pump phase change energy storage system and an energy storage method. The energy storage system comprises a gas compression module, a liquid phase storage module, and a power generation and gas supply module. The gas compression module compresses low-pressure gas into high-pressure gas by consuming electricity during valley electricity period and generates compression heat. The liquid phase storage module cools the high-pressure gas into low-temperature normal-pressure liquid air and stores the low-temperature normal-pressure liquid air, and utilizes part of the compression heat to warm the low-temperature normal-pressure liquid air into normal-temperature high-pressure air during peak electricity period. The power generation and gas supply module utilizes part of the compression heat to heat the normal-temperature high-pressure air into high-temperature high-pressure air, and generates power by means of the high-temperature high-pressure air. The low-pressure steam module is used for consuming part of the compression heat and preparing low-pressure steam. The large-temperature-difference heat pump phase change energy storage system and the energy storage method provided by the application are a distributed efficient green multi-supply and energy storage technology aiming at peak-valley electricity price, and can solve the problem of improving the power supply and demand condition while ensuring the production order and scale of centralized large-scale industrial and commercial power users, and can realize the problem of reducing cost and increasing efficiency by peak load shifting.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and in particular to a large temperature difference heat pump phase change energy storage system and energy storage method. Background Technology

[0002] To support the construction of a new power system primarily based on new energy sources and promote green and low-carbon energy development, the time-of-use pricing mechanism is becoming increasingly sophisticated, including wider peak-valley price differences, broader application scope, and clearer peak-valley time periods. Meanwhile, industrial and commercial electricity users often experience concentrated, time-sensitive, and diverse energy consumption and production, making it difficult to implement adaptive peak-shifting and flexibly adjust the load on energy systems.

[0003] However, centralized large-scale industrial and commercial electricity users have huge energy demands, concentrated energy consumption periods, and high energy costs due to the use of peak electricity prices. Their energy demands are diverse, including electricity, low-pressure steam, and compressed air. The conversion of high-grade electrical energy into medium- and low-grade heat energy results in significant energy quality loss and reduced production efficiency. Summary of the Invention

[0004] This invention provides a large temperature difference heat pump phase change energy storage system and energy storage method to solve the defects of the existing technology, such as the huge energy demand of centralized large-scale industrial and commercial power users, the concentrated energy consumption period, and the high energy cost caused by the use of peak electricity prices. It can improve the power supply and demand situation, and reduce costs and increase efficiency by shaving peaks and filling valleys.

[0005] This invention provides a large temperature difference heat pump phase change energy storage system, comprising:

[0006] The gas compression module compresses low-pressure gas into high-pressure gas by consuming electrical energy during off-peak hours, and generates heat of compression.

[0007] The liquid phase storage module cools the high-pressure gas to low-temperature atmospheric-pressure liquid air and stores it, and during peak power periods, it uses part of the heat of compression to reheat the low-temperature atmospheric-pressure liquid air to room-temperature high-pressure air;

[0008] The power generation and gas supply module uses part of the heat from compression to heat the room temperature high-pressure air to high temperature high-pressure air, and generates electricity using the high temperature high-pressure air;

[0009] A low-pressure steam module is used to consume part of the heat of compression to produce low-pressure steam.

[0010] According to the present invention, a large temperature difference heat pump phase change energy storage system further includes a heat storage module for storing a heat-conducting medium that absorbs part of the compression heat, so as to release the heat-conducting medium to the liquid phase storage module during peak power, so as to rewarm the low temperature atmospheric pressure liquid air into normal temperature high pressure air.

[0011] According to the present invention, a large temperature difference heat pump phase change energy storage system is provided, wherein the gas compression module includes:

[0012] A compressor is used to increase low-pressure gas to high-pressure gas.

[0013] A compression heat exchanger is connected to the outlet of the compressor. A heat transfer medium flows through the compression heat exchanger, and the heat transfer medium exchanges heat with the high-pressure gas. The heat transfer medium flows into the heat storage module or the low-pressure steam module.

[0014] According to the present invention, a large temperature difference heat pump phase change energy storage system is provided, wherein the liquid phase storage module includes:

[0015] Cold storage tanks are used to store cold energy;

[0016] The first air heat exchanger is connected to the cold storage tank and the compression heat exchanger to exchange heat between the cold energy and the high-pressure gas.

[0017] A liquid expander is used to compress the high-pressure gas into cryogenic liquid air.

[0018] A liquid air storage tank for storing the cryogenic liquid air;

[0019] Cryogenic pumps are used to lift the cryogenic liquid air during peak power periods;

[0020] The second air heat exchanger is connected to the cryogenic pump and the cold storage tank, so that the compression heat absorbed by the cold energy heats the cryogenic liquid air to generate room temperature high-pressure air, which is then used by the power generation and gas supply module.

[0021] According to the present invention, a large temperature difference heat pump phase change energy storage system is provided, wherein the power generation and gas supply module includes:

[0022] A turbine heat exchanger is connected to the second air heat exchanger to allow the ambient temperature high-pressure air to exchange heat with the heat of compression, thereby transforming the ambient temperature high-pressure air into high-temperature high-pressure air.

[0023] The turbine uses high-temperature, high-pressure air to heat the air in the turbine, thereby increasing its power generation capacity.

[0024] According to the present invention, a large temperature difference heat pump phase change energy storage system is provided, wherein the low-pressure steam module comprises:

[0025] A first steam heat exchanger is connected to the heat storage module. The first steam heat exchanger is used for direct heat exchange between the heat pump working fluid and the heat transfer medium to steam.

[0026] The system consists of an evaporator, a steam compressor, a condenser, and an expansion valve. The heat pump working fluid absorbs heat from the low-temperature heat transfer oil flowing through the evaporator and turns into a gaseous state. It then passes through the steam compressor and becomes high-temperature and high-pressure steam. In the condenser, it exchanges heat with water to produce low-pressure steam, which finally flows through the expansion valve and becomes low-temperature and low-pressure steam.

[0027] According to the present invention, a large temperature difference heat pump phase change energy storage system is provided, wherein the gas compression module includes multiple compressors and multiple compression heat exchangers, and the compressors and the compression heat exchangers are arranged in a one-to-one correspondence.

[0028] According to the present invention, a large temperature difference heat pump phase change energy storage system is provided, wherein the power generation and gas supply module includes multiple turbine heat exchangers and multiple turbines, and the turbine heat exchangers and the turbines are arranged in a one-to-one correspondence.

[0029] This invention also provides a large temperature difference heat pump phase change energy storage method, comprising:

[0030] By consuming electrical energy during off-peak hours, low-pressure gas is compressed into high-pressure gas, generating heat of compression.

[0031] The high-pressure gas is cooled to low-temperature, atmospheric-pressure liquid air and stored.

[0032] During peak power periods, a portion of the aforementioned heat of compression is used to reheat the low-temperature, atmospheric-pressure liquid air into high-temperature, high-pressure air.

[0033] The power generation and gas supply module heats the high-temperature, high-pressure air and generates electricity.

[0034] A portion of the heat of compression is consumed to produce low-pressure steam.

[0035] According to the large temperature difference heat pump phase change energy storage method provided by the present invention, the consumption of a portion of the compression heat to produce low-pressure steam includes:

[0036] The high-temperature portion of the compression heat is used to produce low-pressure steam through direct heat exchange;

[0037] The low-temperature portion of the compression heat is used to produce low-pressure steam via a high-temperature heat pump.

[0038] The large temperature difference heat pump phase change energy storage system and method provided by this invention utilizes a gas compression module to consume electricity during off-peak hours to compress low-pressure gas into high-pressure gas, generating heat of compression. A liquid phase storage module cools the high-pressure gas to low-temperature, normal-pressure liquid air and stores it. During peak hours, a portion of the heat of compression is used to reheat the low-temperature, normal-pressure liquid air to normal-temperature, high-pressure air. A power generation and gas supply module uses a portion of the heat of compression to heat the normal-temperature, high-pressure air to high-temperature, high-pressure air, and generates electricity using this high-temperature, high-pressure air. A low-pressure steam module consumes a portion of the heat of compression to produce low-pressure steam. The large temperature difference heat pump phase change energy storage system provided by this invention is a decentralized, efficient, green, multi-supply energy storage technology for peak-valley electricity pricing. It can solve the problem of improving power supply and demand while ensuring production order and scale for centralized large-scale industrial and commercial power users, and achieving cost reduction and efficiency improvement by peak shaving and valley filling. In particular, the use of energy-saving and emission-reducing high-temperature heat pumps and liquid air energy storage technologies can better achieve flexible adjustment of the energy system load, while ensuring the safe, stable, and economical operation of the power system. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 This is a structural block diagram of the large temperature difference heat pump phase change energy storage system provided by the present invention.

[0041] Figure label:

[0042] 1. Gas compression module; 2. Liquid phase storage module; 3. Power generation and gas supply module; 4. Low-pressure steam module; 5. Heat storage module; 11. Compressor; 12. Compression heat exchanger; 21. Cold storage tank; 22. First air heat exchanger; 23. Liquid expander; 24. Liquid air storage tank; 25. Cryogenic pump; 26. Second air heat exchanger; 31. Turbine heat exchanger; 32. Turbine; 41. First steam heat exchanger; 42. Evaporator; 43. Steam compressor; 44. Condenser; 45. Expansion valve. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0044] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] The following is combined Figure 1 The present invention describes a large temperature difference heat pump phase change energy storage system, including power consumption, phase change cold storage, thermal energy utilization and distribution, high temperature heat pump, and multi-energy supply.

[0046] like Figure 1 As shown, the present invention provides a large temperature difference heat pump phase change energy storage system, including a gas compression module 1, a liquid phase storage module 2, a power generation and gas supply module 3, and a low-pressure steam module 4.

[0047] Electricity consumption is achieved through the gas compression module 1. During off-peak electricity price periods, the gas compression module 1 consumes the electricity during off-peak electricity price periods (i.e., periods with low electricity demand and low electricity prices) to compress low-pressure gas into high-pressure gas and generate compression heat.

[0048] The liquid storage module 2 receives high-pressure gas from the gas compression module 1, cools the high-pressure gas to low-temperature atmospheric pressure liquid air and stores it. During peak electricity price periods, it uses part of the heat of compression to reheat the liquid air to room temperature high-pressure air, preparing it for the power generation gas supply module 3.

[0049] The power generation and gas supply module 3 uses part of the compression heat to heat the normal temperature high pressure air to high temperature high pressure air. The high temperature high pressure air enters the power generation equipment and drives the power generation equipment to generate electricity, realizing the conversion and output of energy.

[0050] Low-pressure steam module 4 consumes part of the heat of compression to produce low-pressure steam through a steam generator. This low-pressure steam can be used for various purposes such as heating, industrial heating, and sterilization, improving the overall energy efficiency of the system.

[0051] The large temperature difference heat pump phase change energy storage system provided by this invention, during off-peak electricity pricing periods, uses a gas compression module 1 to consume low-cost electricity to compress low-pressure gas into high-pressure gas and generate heat of compression. The high-pressure gas then enters a liquid storage module 2 where it is cooled into a liquid state for storage. Part of the heat of compression is used to reheat the liquid air to room-temperature, high-pressure air, while another part is used to heat the power generation gas supply module 3 and the low-pressure steam module 4, respectively. The room-temperature, high-pressure air is further heated into high-temperature, high-pressure air for power generation, while the remaining heat of compression is used to produce low-pressure steam for other applications.

[0052] This invention addresses the challenges of decentralized, efficient, green, and multi-supply energy storage technology for peak-valley electricity pricing. It can solve the problem of improving the power supply and demand situation while ensuring production order and scale for centralized large-scale industrial and commercial power users, and achieving cost reduction and efficiency improvement by peak shaving and valley filling. In particular, the use of energy-saving and emission-reducing high-temperature heat pumps and liquid air energy storage technologies can better achieve flexible adjustment of the load of the energy system, while ensuring the safe, stable, and economical operation of the power system.

[0053] In one feasible embodiment of the invention, a heat storage module 5 is further included to store a heat-conducting medium that absorbs part of the heat of compression, so as to release the heat-conducting medium to the liquid phase storage module 2 during peak electricity periods, thereby rewarming the low-temperature, atmospheric-pressure liquid air to room-temperature, high-pressure air. During off-peak electricity periods, the heat storage module 5 receives and stores part of the heat of compression from the gas compression module 1. This heat is stored in a medium with high thermal conductivity, such as molten salt or heat transfer oil. During peak electricity periods, when it is necessary to rewarm the low-temperature, atmospheric-pressure liquid air, the heat storage module 5 releases the stored heat-conducting medium to the liquid phase storage module 2. The heat in the heat-conducting medium is transferred to the liquid air, rewarming it to room-temperature, high-pressure air, preparing for the subsequent power generation process.

[0054] In a feasible embodiment of the present invention, the gas compression module 1 includes a compressor 11 and a compression heat exchanger 12. The compressor 11 is used to increase the low-pressure gas to a high-pressure gas. During this process, the internal energy of the gas increases, the temperature rises, and a large amount of compression heat is generated. The compression heat exchanger 12 is connected to the outlet of the compressor 11. A heat transfer medium flows inside the compression heat exchanger 12. After the high-pressure gas enters the compression heat exchanger 12, the high-pressure gas exchanges heat with the heat transfer medium. After absorbing the heat from the high-pressure gas, the temperature of the heat transfer medium rises, and it is then transported to other systems that require heat energy, such as the heat transfer medium flowing into the heat storage module 5 or the low-pressure steam module 4.

[0055] In a feasible embodiment of the present invention, the liquid phase storage module 2 includes a cold storage tank 21, a first air heat exchanger 22, a liquid expander 23, a liquid air storage tank 24, a cryogenic pump 25, and a second air heat exchanger 26. The cold storage tank 21 is used to store cold energy. The first air heat exchanger 22 is connected to the cold storage tank 21 and to the compression heat exchanger 12. The function of the first air heat exchanger 22 is to exchange heat between the high-pressure gas from the compressor 11 and the cold energy in the cold storage tank 21, thereby reducing the temperature of the high-pressure gas. When the high-pressure gas passes through the first air heat exchanger 22, it exchanges heat with the cold energy released from the cold storage tank 21, and the gas temperature drops rapidly, preparing for the subsequent liquefaction process.

[0056] The liquid expander 23 utilizes the adiabatic expansion of high-pressure gas to generate a low-temperature effect, thereby further cooling and liquefying the gas, and compressing the high-pressure gas into low-temperature liquid air.

[0057] The liquid air storage tank 24 is used to store cryogenic liquid air. The liquid air storage tank 24 has good thermal insulation properties to prevent the liquid air from heating up and re-vaporizing during storage.

[0058] The cryogenic pump 25 is used to extract cryogenic liquid air from the liquid air storage tank 24 and increase its pressure during peak power periods; the cryogenic pump 25 can operate stably in a low-temperature environment, ensuring that the liquid air remains at a low temperature during transportation.

[0059] The second air heat exchanger 26 is connected to the cryogenic pump 25 and the cold storage tank 21, so that the compression heat absorbed by the cold energy heats the cryogenic liquid air to generate room temperature high-pressure air, which is then supplied to the power generation and gas supply module 3. The function of the second air heat exchanger 26 is to use the remaining cold energy in the cold storage tank 21 and the compression heat from the heat storage module 5 to heat the cryogenic liquid air, so that it is reheated to room temperature high-pressure air.

[0060] The liquid phase storage module 2 provided in this embodiment realizes energy storage and release through the phase change of air. During the energy storage process, the air is cooled to a low temperature and normal pressure liquid state to achieve high density and safe storage at normal pressure. During the power generation process, the air is reset to normal temperature and high pressure air, and high-grade cold energy is stored by the cold storage tank 21.

[0061] In a feasible embodiment of the present invention, the power generation and gas supply module 3 includes a turbine heat exchanger 31 and a turbine 32. The turbine heat exchanger 31 connects the second air heat exchanger 26 and the turbine 32. The turbine heat exchanger 31 exchanges heat between the ambient temperature high-pressure air output from the second air heat exchanger 26 and the compressed heat in the system, raising the temperature of the ambient temperature high-pressure air to a high temperature and high pressure state. The turbine 32 is the core component of the power generation and gas supply module 3. The turbine of the turbine 32 is driven to rotate by the high temperature and high pressure air, thereby generating electrical energy through the generator and increasing the power generation capacity.

[0062] The overall workflow of the power generation and gas supply module 3 is as follows: Normal temperature, high-pressure air enters the turbine heat exchanger 31 from the second air heat exchanger 26. In the turbine heat exchanger 31, the normal temperature, high-pressure air exchanges heat with the compression heat in the system, significantly increasing its temperature and transforming into high-temperature, high-pressure air. This high-temperature, high-pressure air enters the turbine 32, driving the turbine to rotate, which in turn generates electricity through the generator. The turbine 32 discharges low-temperature, low-pressure air from its exhaust port, which can be further processed and discharged according to system requirements.

[0063] In one feasible embodiment of the present invention, the low-pressure steam module 4 includes a first steam heat exchanger 41, an evaporator 42, a steam compressor 43, a condenser 44, and an expansion valve 45.

[0064] The first steam heat exchanger 41 is connected to the heat storage module 5. The first steam heat exchanger 41 is used for direct heat exchange between the heat pump working fluid (a fluid circulating in the heat pump system for absorbing and releasing heat) and the heat transfer medium from the heat storage module 5.

[0065] The system comprises an evaporator 42, a steam compressor 43, a condenser 44, and an expansion valve 45. In the evaporator 42, the heat pump working fluid exists in liquid form and exchanges heat with the low-temperature heat transfer oil flowing through it. The low-temperature heat transfer oil releases its heat to the heat pump, causing it to evaporate from liquid to gas. During this process, the temperature of the low-temperature heat transfer oil decreases, while the operating temperature and pressure of the heat pump increase. The steam compressor 43 compresses the gaseous heat pump working fluid output from the evaporator 42, significantly increasing its temperature and pressure. During this process, the internal energy of the heat pump working fluid increases, providing energy for subsequent steam generation. In the condenser 44, the high-temperature, high-pressure heat pump working fluid exchanges heat with water. The heat pump working fluid releases its heat to the water, raising its temperature and causing partial vaporization to form low-pressure steam. Simultaneously, the temperature and pressure of the heat pump working fluid decrease, transforming it into a liquid or gas-liquid mixture. The expansion valve 45 limits the flow rate of the heat pump working fluid and reduces its pressure by reducing the cross-sectional area of ​​the flow channel. In this way, the heat pump working fluid becomes a low temperature and low pressure state after flowing through the expansion valve 45, and is ready to enter the evaporator 42 again for the next cycle.

[0066] It should be noted that the storage and distribution of compressed heat and steam are achieved through high and low temperature storage tanks, which have the characteristics of being readily available and always in use.

[0067] In one feasible embodiment of the present invention, the gas compression module 1 includes multiple compressors 11 and multiple compression heat exchangers 12, with each compressor 11 and compression heat exchanger 12 configured in a one-to-one correspondence. Since each compressor 11 is equipped with an independent compression heat exchanger 12, it can be ensured that the heat generated during each compression process is dissipated in a timely and effective manner, avoiding energy efficiency degradation and equipment overheating problems caused by heat accumulation. By precisely controlling the operating status of each compressor 11 and compression heat exchanger 12, refined management of the entire gas compression process can be achieved, thereby further improving the system's energy efficiency ratio and reducing energy consumption.

[0068] In one feasible embodiment of the present invention, the power generation and gas supply module 3 includes multiple turbine heat exchangers 31 and multiple turbines 32, with each turbine heat exchanger 31 and turbine 32 configured in a one-to-one correspondence. This one-to-one correspondence ensures that each turbine 32 receives a fully preheated working medium, thereby improving energy conversion efficiency. This configuration reduces energy loss during transmission and makes the entire system more stable and reliable in operation.

[0069] Therefore, the large temperature difference heat pump phase change energy storage system provided by the present invention can realize multiple energy supply. The reheated high temperature and high pressure air is used to generate electricity through a turbine during peak power periods to supply industrial production or grid connection. At the same time, the outlet compressed air and low pressure steam prepared by the heat of compression are supplied to phase energy application occasions.

[0070] A second aspect of the present invention provides an energy storage method for a large temperature difference heat pump phase change energy storage system, comprising:

[0071] S1. By consuming electrical energy during off-peak hours, low-pressure gas is compressed into high-pressure gas, generating heat of compression.

[0072] During off-peak electricity demand (off-peak electricity periods), electricity prices are relatively low. At this time, electricity is used to drive compressors, compressing low-pressure gases (such as air) into high-pressure gases. During compression, the gas's internal energy increases, and its temperature rises, generating a significant amount of heat during compression. This heat of compression is a crucial heat source for subsequent steps.

[0073] S2. Cool the high-pressure gas to low-temperature, normal-pressure liquid air and store it.

[0074] The compressed, high-temperature, high-pressure gas is cooled by a cooling system, lowering its temperature below the critical temperature of liquid air and its pressure to near atmospheric pressure, thus transforming it into low-temperature, atmospheric-pressure liquid air. This liquid air has high density and high energy density, facilitating storage and transportation. During storage, the liquid air is injected into specialized storage tanks, awaiting subsequent use.

[0075] S3. During peak power periods, some of the heat from compression is used to reheat the low-temperature, normal-pressure liquid air into high-temperature, high-pressure air.

[0076] When electricity demand reaches its peak (during peak electricity periods), electricity prices are relatively high. At this time, the previously stored heat of compression is used to heat the low-temperature, normal-pressure liquid air, allowing it to reheat and revert to high-temperature, high-pressure air. In this process, the heat of compression is effectively utilized, reducing dependence on external energy sources.

[0077] S4, the power generation and gas supply module 3 heats up the air at high temperature and high pressure and generates electricity.

[0078] After the high-temperature, high-pressure air enters the power generation and gas supply module, it first exchanges heat with the heat pump working fluid through the turbine heat exchanger 31, further increasing its temperature and pressure. Subsequently, this high-temperature, high-pressure air drives the turbine to rotate, which in turn drives the generator to generate electricity. In this process, the internal energy of the air is converted into electrical energy output. At the same time, the exhaust port of the turbine 32 can output gas at a certain temperature and pressure for other industrial or civil needs.

[0079] S5. Consumes part of the compression heat to produce low-pressure steam.

[0080] While the power generation and gas supply module is operating, the remaining heat of compression can also be used to produce low-pressure steam. This is typically achieved through a steam generator or similar equipment, which transfers some of the heat of compression to water or other working fluids, causing them to vaporize and produce low-pressure steam.

[0081] In step S5, consuming a portion of the heat of compression to produce low-pressure steam includes:

[0082] S501, the high-temperature part of the compression heat is used to produce low-pressure steam through direct heat exchange.

[0083] The high-temperature heat of compression generated during the compression process has a relatively high temperature and can be directly exchanged with water or other working fluids through a heat exchanger. In this process, the high-temperature heat of compression is rapidly transferred to the water, causing it to heat up rapidly and partially vaporize, thereby directly producing low-pressure steam.

[0084] S502, the low-temperature part of the compression heat is used to produce low-pressure steam through a high-temperature heat pump.

[0085] The low-temperature heat of compression generated during the compression process is relatively low, and directly using it to produce low-pressure steam may be inefficient. Therefore, a high-temperature heat pump system can be used to further increase the temperature of this heat and then use it to produce low-pressure steam. A high-temperature heat pump consumes a small amount of electricity to raise the temperature of the low-temperature heat source (i.e., the low-temperature heat of compression) to a higher level, and then transfers it to water or other working fluids to produce steam. Although this method requires some electricity, it can more fully utilize the low-temperature heat of compression, improving overall energy efficiency.

[0086] Therefore, the large temperature difference heat pump phase change energy storage method provided by this invention is a decentralized, efficient, green, and multi-supply energy storage technology for peak-valley electricity pricing. It can solve the problem of improving the power supply and demand situation while ensuring the production order and scale of centralized large-scale industrial and commercial power users, and achieving cost reduction and efficiency improvement by peak shaving and valley filling. In particular, the use of energy-saving and emission-reducing high-temperature heat pumps and liquid air energy storage and other green, efficient, and energy-saving technologies can better achieve flexible adjustment of the load of the energy system, while ensuring the safe, stable, and economical operation of the power system.

[0087] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0088] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "method," "specific method," or "some methods," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or method is included in at least one embodiment or method of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or method. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or methods. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or methods described in this specification, as well as the features of different embodiments or methods.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A large temperature difference heat pump phase change energy storage system, characterized in that, include: The gas compression module (1) compresses low-pressure gas into high-pressure gas by consuming electrical energy during off-peak hours and generates heat of compression. The liquid storage module (2) cools the high-pressure gas to low-temperature atmospheric pressure liquid air and stores it, and during peak power, it uses part of the heat of compression to reheat the low-temperature atmospheric pressure liquid air to room temperature high-pressure air; The power generation and gas supply module (3) uses part of the heat of compression to heat the normal temperature high pressure air to high temperature high pressure air, and generates electricity with the help of the high temperature high pressure air; The low-pressure steam module (4) is used to consume part of the heat of compression to produce low-pressure steam; It also includes a heat storage module (5) for storing a heat-conducting medium that absorbs part of the heat of compression, so as to release the heat-conducting medium to the liquid phase storage module (2) during peak electricity, so as to reheat the low-temperature atmospheric pressure liquid air into room temperature high pressure air; The gas compression module (1) includes: Compressor (11) is used to increase low-pressure gas to high-pressure gas; A compression heat exchanger (12) is connected to the outlet of the compressor (11). A heat transfer medium flows through the compression heat exchanger (12). The heat transfer medium exchanges heat with the high-pressure gas. The heat transfer medium flows into the heat storage module (5) or the low-pressure steam module (4). The liquid phase storage module (2) includes: Cold storage tank (21) is used to store cold energy; The first air heat exchanger (22) is connected to the cold storage tank (21) and the compression heat exchanger (12) to exchange heat between the cold energy and the high-pressure gas. A liquid expander (23) is used to compress the high-pressure gas into cryogenic liquid air; A liquid air storage tank (24) is used to store the cryogenic liquid air; A cryogenic pump (25) is used to lift the cryogenic liquid air during peak power periods; The second air heat exchanger (26) is connected to the cryogenic pump (25) and the cold storage tank (21) so that the compression heat absorbed by the cold energy heats the cryogenic liquid air to generate room temperature high pressure air, which is used by the power generation and gas supply module (3). The power generation and gas supply module (3) includes: A turbine heat exchanger (31) is connected to the second air heat exchanger (26) so that the ambient temperature high pressure air exchanges heat with the compression heat, so that the ambient temperature high pressure air becomes high temperature high pressure air; The turbine (32) heats the air in the turbine (32) by means of the high temperature and high pressure air, thereby increasing the power generation capacity; The low-pressure steam module (4) includes: The first steam heat exchanger (41) is connected to the heat storage module (5). The first steam heat exchanger (41) is used for the heat pump working fluid to directly exchange heat with the heat transfer medium to steam. Evaporator (42), steam compressor (43), condenser (44) and expansion valve (45). The heat pump working fluid absorbs the heat from the low-temperature heat transfer oil flowing through the evaporator (42) and becomes gaseous. Then it is transformed into high temperature and high pressure by the steam compressor (43). In the condenser (44), it exchanges heat with water to produce low-pressure steam. Finally, it flows through the expansion valve (45) and becomes low temperature and low pressure.

2. The large temperature difference heat pump phase change energy storage system according to claim 1, characterized in that, The gas compression module (1) includes a plurality of compressors (11) and a plurality of compression heat exchangers (12), and the compressors (11) and the compression heat exchangers (12) are arranged in a one-to-one correspondence.

3. The large temperature difference heat pump phase change energy storage system according to claim 1, characterized in that, The power generation and gas supply module (3) includes multiple turbine heat exchangers (31) and multiple turbines (32), and the turbine heat exchangers (31) and the turbines (32) are arranged in a one-to-one correspondence.

4. An energy storage method utilizing the large temperature difference heat pump phase change energy storage system according to any one of claims 1-3, characterized in that, include: By consuming electrical energy during off-peak hours, low-pressure gas is compressed into high-pressure gas, generating heat of compression. The high-pressure gas is cooled to low-temperature, atmospheric-pressure liquid air and stored. During peak power periods, a portion of the aforementioned heat of compression is used to reheat the low-temperature, atmospheric-pressure liquid air into high-temperature, high-pressure air. The power generation and gas supply module heats the high-temperature, high-pressure air and generates electricity. A portion of the heat of compression is consumed to produce low-pressure steam.

5. The energy storage method according to claim 4, characterized in that, The consumption of a portion of the compression heat to produce low-pressure steam includes: The high-temperature portion of the compression heat is used to produce low-pressure steam through direct heat exchange; The low-temperature portion of the compression heat is used to produce low-pressure steam via a high-temperature heat pump.

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