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

Abstract

The invention provides a large-temperature-difference heat pump phase change energy storage system and method, and the energy storage system comprises a gas compression module which is used for compressing low-pressure gas into high-pressure gas by consuming the electric energy during the valley electricity period, and generating compression heat; the liquid phase storage module cools the high-pressure gas into low-temperature and normal-pressure liquid air and stores the low-temperature and normal-pressure liquid air, and reheats the low-temperature and normal-pressure liquid air into normal-temperature and high-pressure air by utilizing part of compression heat during the peak electricity period; the power generation and air supply module is used for heating normal-temperature and high-pressure air to high-temperature and high-pressure air by utilizing part of compression heat and generating power by virtue of the high-temperature and high-pressure air And the low-pressure steam module is used for consuming part of 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 invention are a distributed high-efficiency green multi-supply energy storage technology aiming at peak-valley electricity prices, and can solve the problems that centralized large-scale industrial and commercial power consumers guarantee the production order and scale, improve the power supply and demand conditions and realize cost reduction and benefit increase by peak load shifting while guaranteeing the production order and scale.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage systems, and in particular to a large temperature difference heat pump phase change energy storage system and an energy storage method. Background Art

[0002] In order to serve the construction of a new power system with new energy as the main body and promote the green and low-carbon development of energy, the time-of-use electricity price mechanism is becoming more and more perfect, including the increase of peak-valley price difference, the expansion of implementation scope and the clearer division of peak-valley time periods. At the same time, the energy production of industrial and commercial power users is often centralized, time-sensitive and diverse, making it difficult to adaptively stagger peak power consumption and flexibly adjust the energy system load.

[0003] However, centralized large-scale industrial and commercial electricity users have huge energy demands, concentrated energy consumption periods, and frequent use of peak electricity prices, which leads to high energy costs. Users' energy demands are diverse, including electricity, low-pressure steam, and compressed air. The use of high-grade electrical energy to convert medium- and low-grade thermal energy results in large energy quality losses, leading to reduced production efficiency. Summary of the invention

[0004] The present invention provides a large temperature difference heat pump phase change energy storage system and energy storage method, which are used to solve the defects in the prior art that large-scale centralized industrial and commercial power users have huge energy demands, concentrated energy use periods, and often use peak electricity prices, resulting in high energy costs, thereby improving the power supply and demand situation, shaving peaks and filling valleys to reduce costs and increase efficiency.

[0005] The present invention provides a large temperature difference heat pump phase change energy storage system, comprising: The gas compression module compresses low-pressure gas into high-pressure gas by consuming electricity during valley power periods and generates compression heat; A liquid phase storage module cools the high-pressure gas to low-temperature, normal-pressure liquid air and stores it, and during peak power periods, uses part of the compression heat to reheat the low-temperature, normal-pressure liquid air to normal-temperature, high-pressure air; A power generation and air supply module, which utilizes part of the compression heat to heat the normal temperature and high pressure air to high temperature and high pressure air, and generates electricity with the help of the high temperature and high pressure air; The low-pressure steam module is used to consume part of the compression heat to produce low-pressure steam.

[0006] A large temperature difference heat pump phase change energy storage system provided by the present invention also 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 periods, so as to reheat the low-temperature and normal-pressure liquid air to normal-temperature and high-pressure air.

[0007] According to a large temperature difference heat pump phase change energy storage system provided by the present invention, the gas compression module comprises: Compressors, used to raise low-pressure gas to high-pressure gas; A compression heat exchanger is connected to the outlet of the compressor. A heat transfer medium flows through the compression heat exchanger. 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.

[0008] According to a large temperature difference heat pump phase change energy storage system provided by the present invention, the liquid phase storage module comprises: Cold storage tank, used to store cold energy; a first air heat exchanger, connected to the cold storage tank and to the compression heat exchanger, so as to perform heat exchange between the cold energy and the high-pressure gas; A liquid expander, used for compressing the high-pressure gas into low-temperature liquid air; A liquid air storage tank, used for storing the cryogenic liquid air; A cryogenic pump, used to lift the cryogenic liquid air during peak power periods; 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 low-temperature liquid air to generate normal temperature and high pressure air, and the normal temperature and high pressure air is used by the power generation and air supply module.

[0009] According to a large temperature difference heat pump phase change energy storage system provided by the present invention, the power generation and gas supply module comprises: a turbine heat exchanger connected to the second air heat exchanger so as to exchange heat between the normal temperature and high pressure air and the compression heat so as to convert the normal temperature and high pressure air into high temperature and high pressure air; The turbine increases the temperature of the air in the turbine by using the high-temperature and high-pressure air to increase the power generation capacity.

[0010] According to a large temperature difference heat pump phase change energy storage system provided by the present invention, the low-pressure steam module comprises: A first steam heat exchanger is connected to the heat storage module, and the first steam heat exchanger is used for directly exchanging heat between the heat pump working fluid and the heat transfer medium into steam; Evaporator, water vapor compressor, condenser and expansion valve. The heat pump working fluid absorbs the heat of the low-temperature heat transfer oil flowing through the evaporator and becomes gaseous, then becomes high temperature and high pressure through the water vapor compressor, exchanges heat with water in the condenser to produce low-pressure steam, and finally flows through the expansion valve to become low temperature and low pressure.

[0011] According to a large temperature difference heat pump phase change energy storage system provided by the present invention, the gas compression module includes a plurality of compressors and a plurality of compression heat exchangers, and the compressors and the compression heat exchangers are arranged in a one-to-one correspondence.

[0012] According to a large temperature difference heat pump phase change energy storage system provided by the present invention, the power generation and air supply module includes a plurality of turbine heat exchangers and a plurality of turbine machines, and the turbine heat exchangers and the turbine machines are arranged in a one-to-one correspondence.

[0013] The present invention also provides a large temperature difference heat pump phase change energy storage method, comprising: The low-pressure gas is compressed into high-pressure gas by consuming the electric energy during valley power, and compression heat is generated; Cooling the high-pressure gas to low-temperature, normal-pressure liquid air and storing it; During peak power periods, part of the compression heat is used to reheat the low-temperature, normal-pressure liquid air into high-temperature, high-pressure air; The power generation and air supply module heats up the high temperature and high pressure air and generates electricity; Part of the compression heat is consumed to produce low-pressure steam.

[0014] According to the large temperature difference heat pump phase change energy storage method provided by the present invention, the consumption of part of the compression heat to produce low-pressure steam includes: The high-temperature part of the compression heat is used to produce low-pressure steam by direct heat exchange; The low-temperature part of the compression heat is used to produce low-pressure steam through a high-temperature heat pump.

[0015] The large temperature difference heat pump phase change energy storage system and energy storage method provided by the present invention consume the electric energy during the valley power period to compress the low-pressure gas into high-pressure gas and generate compression heat through the gas compression module, the liquid phase storage module cools the high-pressure gas to low-temperature normal-pressure liquid air and stores it, and uses part of the compression heat to reheat the low-temperature normal-pressure liquid air to normal-temperature high-pressure air during the peak power period, the power generation and air supply module uses part of the compression heat 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 consumes part of the compression heat to produce low-pressure steam. The large temperature difference heat pump phase change energy storage system provided by the present invention is a decentralized, efficient, green, multi-supply energy storage technology for peak and valley electricity prices, which can solve the problem of centralized large-scale industrial and commercial power users ensuring production order and scale while improving the power supply and demand situation, and shaving peaks and filling valleys to achieve cost reduction and efficiency improvement. In particular, the use of green and efficient energy-saving technologies such as energy-saving and emission-reduction high-temperature heat pumps and liquid air energy storage can better realize the flexible adjustment of energy consumption system loads, while ensuring the safe, stable and economical operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a structural block diagram of the large temperature difference heat pump phase change energy storage system provided by the present invention.

[0018] Reference numerals: 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. Water vapor compressor; 44. Condenser; 45. Expansion valve. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and 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 devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0021] Combine the following Figure 1 The 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.

[0022] 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.

[0023] Electricity consumption is achieved through the gas compression module 1. During the valley electricity price period, the gas compression module 1 compresses the low-pressure gas into high-pressure gas by consuming the electricity of the valley electricity price period (i.e. the period of low electricity demand and low electricity price), and generates compression heat.

[0024] The liquid phase storage module 2 receives high-pressure gas from the gas compression module 1, cools the high-pressure gas to low-temperature, normal-pressure liquid air and stores it. During peak electricity prices, it uses part of the compression heat to reheat the liquid air to normal-temperature, high-pressure air, in preparation for the power generation gas supply module 3.

[0025] The power generation air supply module 3 uses part of the compression heat to heat the normal temperature and high pressure air to high temperature and high pressure air. The high temperature and high pressure air enters the power generation equipment, drives the power generation equipment to generate electricity, and realizes energy conversion and output.

[0026] The low-pressure steam module 4 consumes part of the compression heat and produces low-pressure steam through a steam generator. The low-pressure steam can be used for heating, heating in industrial production, disinfection and other purposes, thereby improving the comprehensive energy utilization efficiency of the system.

[0027] In the large temperature difference heat pump phase change energy storage system provided by the present invention, during the valley electricity price period, the gas compression module 1 consumes low-priced electricity, compresses the low-pressure gas into high-pressure gas and produces compression heat, and the high-pressure gas then enters the liquid phase storage module 2 to be cooled into liquid storage. Part of the compression heat is used to reheat the liquid air to normal temperature high-pressure air, and the other part is used for the heating needs of the power generation air supply module 3 and the low-pressure steam module 4. The normal temperature high-pressure air is further heated to high-temperature high-pressure air for power generation, and the remaining compression heat is used to produce low-pressure steam for other purposes.

[0028] The distributed, efficient, green, multi-supply energy storage technology for peak-valley electricity prices of the present invention can solve the difficult problem of ensuring production order and scale for centralized large-scale industrial and commercial electricity users while improving the electricity supply and demand situation, and reducing peaks and filling valleys to achieve cost reduction and efficiency improvement. In particular, the use of green and efficient energy-saving technologies such as energy-saving and emission-reduction high-temperature heat pumps and liquid air energy storage can better realize flexible adjustment of the energy system load, while ensuring safe, stable and economical operation of the power system.

[0029] In a feasible embodiment of the present invention, a heat storage module 5 is also included, which is used to store the heat-conducting medium that absorbs part of the compression heat, so as to release the heat-conducting medium to the liquid phase storage module 2 during the peak power period, so that the low-temperature normal-pressure liquid air can be reheated to normal-temperature high-pressure air. During the valley electricity price period, the heat storage module 5 receives and stores part of the compression heat from the gas compression module 1. This heat is stored in a medium with high thermal conductivity, such as molten salt, thermal oil, etc. During the peak electricity price period, when the low-temperature normal-pressure liquid air needs to be reheated, 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, so that it can be reheated to normal-temperature high-pressure air, in preparation for the subsequent power generation process.

[0030] 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 high-pressure gas. In 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 in 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 the heat transfer medium absorbs the heat of the high-pressure gas, the temperature rises and is then transported to other systems that require thermal energy, such as the heat transfer medium flowing into the heat storage module 5 or the low-pressure steam module 4.

[0031] 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 heat exchange the high-pressure gas from the compressor 11 with 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 in the cold storage tank 21, and the gas temperature drops rapidly, preparing for the subsequent liquefaction process.

[0032] The liquid expander 23 utilizes the adiabatic expansion of the high-pressure gas to produce a cryogenic effect, thereby further cooling and liquefying the gas, and is used to compress the high-pressure gas into cryogenic liquid air.

[0033] The liquid air storage tank 24 is used to store low-temperature liquid air. The liquid air storage tank 24 has good thermal insulation properties to prevent the liquid air from heating up and re-gasifying during storage.

[0034] The cryogenic pump 25 is used to extract cryogenic liquid air from the liquid air storage tank 24 and increase the pressure during peak power periods; the cryogenic pump 25 can operate stably in a low-temperature environment to ensure that the liquid air remains in a low-temperature state during transportation.

[0035] 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 low-temperature liquid air to generate normal-temperature high-pressure air, which is used by the power generation air 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 low-temperature liquid air and reheat it to normal-temperature high-pressure air.

[0036] The liquid phase storage module 2 provided in this embodiment realizes the storage and release of energy through the phase change of air. During the power storage process, the air is cooled to a low-temperature and normal-pressure liquid to achieve high-density, normal-pressure safe storage. During the power generation process, the air is reset to normal-temperature and high-pressure air, and high-quality cold energy is stored in the cold storage tank 21.

[0037] In a feasible embodiment of the present invention, the power generation air supply module 3 includes a turbine heat exchanger 31 and a turbine 32. The turbine heat exchanger 31 is connected to the second air heat exchanger 26 and the turbine 32. The turbine heat exchanger 31 exchanges the normal temperature and high pressure air output by the second air heat exchanger 26 with the compression heat in the system to raise the temperature of the normal temperature and high pressure air to a high temperature and high pressure state. The turbine 32 is the core component of the power generation air supply module 3. The high temperature and high pressure air drives the turbine of the turbine 32 to rotate, thereby generating electrical energy through the generator to increase the power generation power.

[0038] The overall working process of the power generation and air supply module 3 is that the normal temperature and 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 and high pressure air exchanges heat with the compression heat in the system, and the temperature is significantly increased, and it is converted into high temperature and high pressure air. The high temperature and high pressure air enters the turbine 32, drives the turbine to rotate, and then generates electricity through the generator. The exhaust port of the turbine 32 discharges low temperature and low pressure air, which can be further processed and discharged according to system requirements.

[0039] In a feasible embodiment of the present invention, the low-pressure steam module 4 includes a first steam heat exchanger 41 , an evaporator 42 , a water vapor compressor 43 , a condenser 44 and an expansion valve 45 .

[0040] The first steam heat exchanger 41 is connected to the heat storage module 5 , and is used for direct heat exchange between a heat pump working medium (a fluid circulating in a heat pump system for absorbing and releasing heat) and a heat transfer medium from the heat storage module 5 .

[0041] Evaporator 42, water vapor compressor 43, condenser 44 and expansion valve 45. In evaporator 42, the heat pump working fluid exists in liquid form and exchanges heat with the low-temperature heat-conducting oil flowing through evaporator 42. The low-temperature heat-conducting oil releases its heat to the heat pump, causing it to evaporate from liquid to gas. In this process, the temperature of the low-temperature heat-conducting oil decreases, while the temperature and pressure of the heat pump operation increase. The water vapor compressor 43 compresses the gaseous heat pump working fluid output by the evaporator 42, causing its temperature and pressure to increase significantly. In 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 and high-pressure heat pump working fluid exchanges heat with water. The heat pump working fluid releases its heat to the water, causing its temperature to increase and partially vaporize to form low-pressure steam. At the same time, the temperature and pressure of the heat pump working fluid decrease, converting it into a liquid state or a gas-liquid mixed state. The expansion valve 45 limits the flow of the heat pump working fluid by reducing the cross-sectional area of ​​the flow channel and reduces its pressure. 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.

[0042] It should be noted that the storage and distribution of compression heat and steam are achieved through high and low temperature storage tanks, which have the characteristics of on-demand use and all-time availability.

[0043] In a feasible embodiment of the present invention, 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 one by one. Since each compressor 11 is equipped with an independent compression heat exchanger 12, it can be ensured that the heat generated in each compression process can be dissipated in a timely and effective manner, thereby avoiding the problem of energy efficiency reduction and equipment overheating caused by heat accumulation. By accurately controlling the operating status of each compressor 11 and compression heat exchanger 12, the entire gas compression process can be managed in a refined manner, thereby further improving the energy efficiency ratio of the system and reducing energy consumption.

[0044] In a feasible embodiment of the present invention, the power generation and air supply module 3 includes a plurality of turbine heat exchangers 31 and a plurality of turbines 32, and the turbine heat exchangers 31 and the turbines 32 are arranged one by one. The one-to-one arrangement of the turbine heat exchangers 31 and the turbines 32 ensures that each turbine 32 can receive a fully preheated working medium, thereby improving the efficiency of energy conversion. This configuration reduces the loss of energy during transmission and makes the operation of the entire system more stable and reliable.

[0045] Therefore, the large temperature difference heat pump phase change energy storage system provided by the present invention can realize multi-energy supply. The reheated high-temperature and high-pressure air is supplied to industrial production or grid connection through turbine power generation during peak power periods. At the same time, the exported compressed air and low-pressure steam prepared by compression heat are supplied to relevant energy application occasions.

[0046] The second aspect of the present invention provides an energy storage method for a large temperature difference heat pump phase change energy storage system, comprising: S1. Compress low-pressure gas into high-pressure gas by consuming the electrical energy during valley power period and generate compression heat.

[0047] During the low electricity demand period (off-peak period), the electricity price is relatively low. At this time, the electric energy is used to drive the compressor to compress the low-pressure gas (such as air) into high-pressure gas. During the compression process, the internal energy of the gas increases and the temperature rises, thereby generating a large amount of compression heat. This compression heat is an important heat source in the subsequent steps.

[0048] S2. Cool the high-pressure gas to low-temperature, normal-pressure liquid air and store it.

[0049] The compressed high-temperature and high-pressure gas is cooled by a cooling system to reduce its temperature to below the critical temperature of liquid air, and its pressure is also reduced to near normal pressure, thus transforming into low-temperature and normal-pressure liquid air. This liquid air has high density and high energy storage density, making it easy to store and transport. During storage, the liquid air is injected into a special storage tank and waits for subsequent use.

[0050] S3. During peak power periods, part of the compression heat is used to reheat the low-temperature, normal-pressure liquid air into high-temperature, high-pressure air.

[0051] When the demand for electricity reaches its peak (during peak electricity demand), the electricity price is relatively high. At this time, the previously stored compression heat is used to heat the low-temperature and normal-pressure liquid air, so that it can be reheated and turned into high-temperature and high-pressure air again. In this process, the compression heat is effectively utilized, reducing the dependence on external energy.

[0052] S4, the power generation air supply module 3 heats up and generates electricity through high-temperature and high-pressure air.

[0053] After the high-temperature and high-pressure air enters the power generation air supply module, it first exchanges heat with the heat pump working fluid through the turbine heat exchanger 31 to further increase its temperature and pressure. Subsequently, this high-temperature and high-pressure air drives the turbine to rotate, thereby driving 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 of a certain temperature and pressure for other industrial or civilian needs.

[0054] S5. Consume part of the compression heat to produce low-pressure steam.

[0055] While the power generation and gas supply module is running, the remaining compression heat can also be used to produce low-pressure steam. This is usually achieved through a steam generator or similar equipment, which transfers part of the compression heat to water or other working fluids to vaporize them and produce low-pressure steam.

[0056] Wherein, in step S5, part of the compression heat is consumed to produce low-pressure steam, including: S501. The high-temperature part of the compression heat is used to produce low-pressure steam through direct heat exchange.

[0057] The high-temperature compression heat generated during the compression process has a high temperature and can be directly exchanged with water or other working fluids through a heat exchanger. In this process, the high-temperature compression heat is quickly transferred to water, causing it to quickly heat up and partially vaporize, thereby directly producing low-pressure steam.

[0058] S502. The low-temperature part of the compression heat is used to produce low-pressure steam through a high-temperature heat pump.

[0059] As for the low-temperature compression heat generated during the compression process, it may not be efficient to use it directly to produce low-pressure steam because its temperature is relatively low. Therefore, a high-temperature heat pump system can be used to further increase the temperature of this part of heat and use it to produce low-pressure steam. The high-temperature heat pump consumes a small amount of electrical energy to raise the heat in the low-temperature heat source (i.e., the low-temperature compression heat) to a higher temperature level, and then transfers it to water or other working fluids to produce steam. Although this method requires a certain amount of electrical energy, it can make more full use of the compression heat of the low-temperature part and improve the overall energy utilization efficiency.

[0060] Therefore, the large temperature difference heat pump phase change energy storage method provided by the present invention is a decentralized, efficient, green, multi-supply energy storage technology for peak and valley electricity prices. It can solve the problem of ensuring production order and scale for centralized large-scale industrial and commercial electricity users while improving the electricity supply and demand situation, and reducing peaks and filling valleys to achieve cost reduction and efficiency improvement. In particular, the use of green and efficient energy-saving technologies such as energy-saving and emission-reduction high-temperature heat pumps and liquid air energy storage can better realize the flexible adjustment of the energy system load, while ensuring the safe, stable and economical operation of the power system.

[0061] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions 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: A gas compression module (1) compresses low-pressure gas into high-pressure gas by consuming electric energy during valley power supply, and generates compression heat; A liquid phase storage module (2) cools the high-pressure gas to low-temperature, normal-pressure liquid air and stores it, and during peak power periods, uses part of the compression heat to reheat the low-temperature, normal-pressure liquid air to normal-temperature, high-pressure air; A power generation and air supply module (3) utilizes part of the compression heat to heat the normal temperature and high pressure air to high temperature and high pressure air, and generates electricity with the help of the high temperature and high pressure air; The low-pressure steam module (4) is used to consume part of the compression heat to produce low-pressure steam.

2. The large temperature difference heat pump phase change energy storage system according to claim 1, characterized in that: It also includes a heat storage module (5) 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 (2) during peak power periods, so as to restore the low-temperature and normal-pressure liquid air to normal-temperature and high-pressure air.

3. The large temperature difference heat pump phase change energy storage system according to claim 2, characterized in that: The gas compression module (1) comprises: A compressor (11) for increasing the pressure of 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, and the heat transfer medium flows into the heat storage module (5) or the low-pressure steam module (4).

4. The large temperature difference heat pump phase change energy storage system according to claim 3 is characterized in that: The liquid phase storage module (2) comprises: A cold storage tank (21) for storing cold energy; A first air heat exchanger (22) is connected to the cold storage tank (21) and to the compression heat exchanger (12) so as to perform heat exchange between the cold energy and the high-pressure gas; A liquid expander (23), used for compressing the high-pressure gas into low-temperature liquid air; A liquid air storage tank (24), used for storing the cryogenic liquid air; A cryogenic pump (25) for lifting the cryogenic liquid air during peak power periods; The second air heat exchanger (26) is connected to the cryogenic pump (25) and to the cold storage tank (21), so that the compression heat absorbed by the cold energy heats the low-temperature liquid air to generate normal-temperature high-pressure air, and the normal-temperature high-pressure air is used by the power generation air supply module (3).

5. The large temperature difference heat pump phase change energy storage system according to claim 4, characterized in that: The power generation and gas supply module (3) comprises: a turbine heat exchanger (31) connected to the second air heat exchanger (26) so as to exchange heat between the normal temperature and high pressure air and the compression heat, so that the normal temperature and high pressure air becomes high temperature and high pressure air; The turbine (32) heats the air of the turbine (32) by using the high-temperature and high-pressure air to increase the power generation capacity.

6. The large temperature difference heat pump phase change energy storage system according to claim 3, characterized in that: The low-pressure steam module (4) comprises: A first steam heat exchanger (41) connected to the heat storage module (5), the first steam heat exchanger (41) being used for directly exchanging heat between the heat pump working fluid and the heat transfer medium to form steam; An evaporator (42), a water vapor compressor (43), a condenser (44) and an expansion valve (45); the heat pump working fluid absorbs the heat of the low-temperature heat transfer oil flowing through the evaporator (42) and becomes gaseous, then passes through the water vapor compressor (43) and becomes high-temperature and high-pressure, exchanges heat with water in the condenser (44) to produce low-pressure steam, and finally passes through the expansion valve (45) and becomes low-temperature and low-pressure.

7. The large temperature difference heat pump phase change energy storage system according to claim 3, characterized in that: The gas compression module (1) comprises a plurality of the compressors (11) and a plurality of the compression heat exchangers (12), and the compressors (11) and the compression heat exchangers (12) are arranged in a one-to-one correspondence.

8. The large temperature difference heat pump phase change energy storage system according to claim 5, characterized in that: The power generation and air supply module (3) comprises a plurality of the turbine heat exchangers (31) and a plurality of the turbine machines (32), and the turbine heat exchangers (31) and the turbine machines (32) are arranged in a one-to-one correspondence.

9. An energy storage method using the large temperature difference heat pump phase change energy storage system according to any one of claims 1 to 8, characterized in that: include: The low-pressure gas is compressed into high-pressure gas by consuming the electric energy during valley power, and compression heat is generated; Cooling the high-pressure gas to low-temperature, normal-pressure liquid air and storing it; During peak power periods, part of the compression heat is used to reheat the low-temperature, normal-pressure liquid air into high-temperature, high-pressure air; The power generation and air supply module heats up the high temperature and high pressure air and generates electricity; Part of the compression heat is consumed to produce low-pressure steam.

10. The large temperature difference heat pump phase change energy storage method according to claim 9, characterized in that: The method of consuming part of the compression heat to produce low-pressure steam comprises: The high-temperature part of the compression heat is used to produce low-pressure steam by direct heat exchange; The low-temperature part of the compression heat is used to produce low-pressure steam through a high-temperature heat pump.

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