CN221742823U - Compressed air energy storage system integrating solid electric heat storage - Google Patents

Abstract

The utility model provides a compressed air energy storage system integrating solid electric heat storage, which relates to the technical field of energy storage and comprises an air compression unit, a gas storage unit, a carbon dioxide compression unit, a carbon dioxide liquefying unit, a liquid storage unit, a carbon dioxide evaporating unit, an air heat regenerating unit and an air expansion unit. According to the energy storage system provided by the utility model, the volume change of the carbon dioxide phase change is utilized to enable the gas storage device to be always kept at constant pressure, and the carbon dioxide after energy release is stored at high pressure, so that the size of the flexible air bag is greatly reduced. The electric heat accumulator is used for heating high-pressure air before entering the air expander, so that the temperature of the working medium at the inlet of the air expander is increased, and the working capacity of the working medium with unit mass flow is improved. The compressed air energy storage system has the advantages of no limitation of geographical conditions, simple component design, low investment cost and the like.

Description

A compressed air energy storage system with integrated solid electric thermal storage

Technical Field

The utility model belongs to the field of renewable energy technology and compressed gas energy storage technology, and specifically relates to a compressed air energy storage system integrating solid electric heat storage.

Background Art

Compressed air energy storage technology has the advantages of high efficiency, environmental friendliness, and long life cycle. It is one of the effective technologies to ensure the large-scale and safe grid connection of renewable energy. The application of artificial storage tanks has freed the compressed air energy storage system from geographical restrictions, but the corresponding storage tanks are very expensive. Traditional compressed air energy storage systems are all constant volume, and the volume utilization rate of the gas storage device is low, resulting in a large amount of working fluid required. The storage tanks used are large in volume, high in pressure, and expensive. Constant pressure compressed air energy storage can improve the utilization rate of the gas storage device, thereby reducing the price of the storage tank, and can make the expander operate stably in its high efficiency state. On the other hand, most of the existing compressed air energy storage adopts adiabatic compression scheme, but due to the limitation of compressor technology, the actual outlet temperature of existing industrial compressors can only reach 400℃ at most, resulting in low power per unit mass of working fluid in the energy storage system, large volume of high-pressure gas storage tanks required, and a relatively complex system. A thermal energy storage system is required, and the investment cost is high.

Therefore, there is an urgent need for a compressed air energy storage technology with high economic value.

Utility Model Content

The purpose of the utility model is to provide a compressed air energy storage system with integrated solid electric thermal storage to solve one or more of the above-mentioned technical problems. The energy storage system provided by the utility model utilizes a solid electric thermal storage device to store high-temperature thermal energy (800-1600°C), greatly increases the amount of work done per unit of working fluid, and reduces the volume of high-pressure storage tanks required for the energy storage system at the same power level. The compressed air energy storage system of the utility model has the advantages of not being restricted by geographical conditions, simple component design, and low investment cost.

In order to achieve the above purpose, the utility model adopts the following technical solutions:

The utility model discloses a compressed air energy storage system with integrated solid electric heat storage, comprising: an air compression unit, a constant pressure storage tank, a voltage stabilizing unit, a regenerator, an electric heat storage device, and an air expander;

The air compression unit is used to compress air from the environment to a high pressure state;

The constant pressure storage tank is used to store compressed high-pressure air;

The pressure stabilizing unit is used to keep the air pressure in the constant pressure storage tank constant;

The regenerator is used to recover waste heat from the exhaust gas of the air expander;

The electric thermal storage is used to convert input electricity into high-temperature heat and store it;

The air expander is used to expand high-temperature and high-pressure air to perform work.

A further improvement of the utility model is that the air compression unit comprises: a plurality of air compressors and a plurality of coolers connected alternately in sequence, the air compressor at the front is connected to the environment, and the cooler at the back is connected to the inlet of the constant pressure storage tank;

Furthermore, the air compression unit includes a first air compressor, a first cooler, a second air compressor, a second cooler, a third air compressor, a third cooler, a fourth air compressor, a fourth cooler, a fifth air compressor, a fifth cooler, a sixth air compressor, and a sixth cooler connected in sequence;

The pressure stabilizing unit comprises: a flexible airbag, a carbon dioxide compressor, a condenser, a throttle valve, a liquid carbon dioxide storage tank, and an evaporator; the outlet of the flexible airbag is connected to the inlet of the liquid carbon dioxide storage tank through the carbon dioxide compressor, the hot side channel of the condenser, and the throttle valve, and the outlet of the liquid carbon dioxide storage tank is connected to the inlet of the flexible airbag through the cold side channel of the evaporator;

Furthermore, the throttle valve outlet is connected to the carbon dioxide compressor inlet;

Furthermore, the flexible airbag is placed inside the constant pressure storage tank to completely separate the air and carbon dioxide;

The outlet of the constant pressure storage tank is connected to the outside atmosphere through the cold side channel of the regenerator, the air channel of the electric heat accumulator, the air expander, and the hot side channel of the regenerator.

A further improvement of the utility model is that the compressed air energy storage system with integrated solid electric thermal storage further comprises a cold storage unit, and the cold storage unit comprises: a first water tank, a second water tank;

The first water tank outlet is connected to the second water tank inlet through the low-temperature side channel of the condenser; the first water tank outlet is provided with a first water pump;

The second water tank outlet is connected to the first water tank inlet through the evaporator high temperature side channel; the second water tank outlet is provided with a second water pump.

A further improvement of the utility model is that the heat at the outlet of the cold side channel of each cooler is not stored, but is directly utilized for other purposes or directly dissipated into the atmosphere.

A further improvement of the utility model is that a high-temperature heat storage solid material containing an air channel is arranged inside the electric heat accumulator, a high-voltage resistance wire is arranged between the solid materials, and a high-temperature resistant heat-insulating ceramic is arranged outside.

In addition, the utility model provides an operating method of a compressed air energy storage system integrating solid electric thermal storage, comprising the following steps:

Energy storage process: air enters the compression unit from the environment and is compressed to a high-pressure state. It is cooled by the cooler and stored in a constant-pressure storage tank. The heat at the outlet of the cold-side channel of each cooler is not stored, but is directly used for other purposes or directly dissipated into the atmosphere. At the same time, the electricity input into the electric heat accumulator is converted into high-temperature heat by the resistance wire and stored in the solid heat storage material. The high-pressure air entering the constant-pressure storage tank discharges the carbon dioxide in the flexible airbag, and then the carbon dioxide is compressed and condensed by the water from the first water tank and then throttled to the storage pressure and stored in the liquid carbon dioxide storage tank. The water after absorbing the heat energy is stored in the second water tank.

Energy release process: The carbon dioxide liquid discharged from the liquid carbon dioxide storage tank enters the evaporator, is heated by the hot water in the second water tank into carbon dioxide gas, and then enters the flexible airbag for storage; at the same time, the air is discharged from the constant pressure storage tank, enters the air regenerator for preheating, and is further heated by the electric heat accumulator before entering the air expander to expand and generate electricity. The expanded air enters the air regenerator and exchanges heat with the high-pressure air discharged from the constant pressure storage tank before being discharged into the atmosphere.

A further improvement of the utility model is that during the operation of the energy storage system, the pressure in the constant pressure storage tank and the flexible airbag remains unchanged.

A further improvement of the utility model is that an electric heat accumulator is provided in front of the air expander, so that the inlet temperature of the air expander reaches above 800°C.

The beneficial effects of the utility model are:

1. The utility model is equipped with a high-temperature electric heat accumulator, which greatly increases the inlet temperature of the air expander (above 800°C), enhances the work capacity of the unit mass flow rate of the working fluid, reduces the high pressure required to be stored, and effectively reduces the investment cost of the high-pressure storage tank;

2. Compression heat no longer needs to be stored, and no complicated heat storage cycle is required. The system is simpler and easier to operate, while eliminating the investment in liquid heat storage materials and storage tanks.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only 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.

FIG1 is a schematic structural diagram of a compressed air energy storage system integrating solid electric thermal storage according to an embodiment of the present utility model;

Description of reference numerals:

1. The first air compressor; 2. The first cooler; 3. The second air compressor; 4. The second cooler; 5. The third air compressor; 6. The third cooler; 7. The fourth air compressor; 8. The fourth cooler; 9. The fifth air compressor; 10. The fifth cooler; 11. The sixth air compressor; 12. The sixth cooler; 13. The constant pressure storage tank; 14. The flexible air bag; 15. The carbon dioxide compressor; 16. The condenser; 17. The throttle valve; 18. The liquid carbon dioxide storage tank; 19. The evaporator; 20. The regenerator; 21. The electric heat accumulator; 22. The air expander; 23. The first water tank; 24. The first water pump; 25. The second water tank; 26. The second water pump.

DETAILED DESCRIPTION

In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the technical scheme in the specific embodiments of the utility model is clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

It should be noted that the technical terms used in the specification and claims of the utility model should have the usual meanings understood by people with ordinary skills in the technical field to which the utility model belongs. The words "including" or "comprising" and the like used in the specification and claims mean that the parts or objects appearing before "including" or "comprising" include the parts or objects listed after "including" or "comprising" and their equivalent parts, and do not exclude other parts or objects. The words "connected" or "connected" and the like are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

The utility model is further described in detail below with reference to the accompanying drawings:

Please refer to FIG1 , a compressed air energy storage system with integrated solid electric heat storage of the utility model comprises: an air compression unit, a constant pressure storage tank 13, a voltage stabilizing unit, a regenerator 20, an electric heat storage device 21, and an air expander 22;

The air compression unit is used to compress air from the environment to a high pressure state;

The constant pressure storage tank 13 is used to store compressed high-pressure air;

The pressure stabilizing unit is used to keep the air pressure in the constant pressure storage tank 13 constant;

The regenerator 20 is used to recover the waste heat of the exhaust gas of the air expander;

The electric heat storage device 21 is used to convert the input electricity into high-temperature heat and store it;

The air expander 22 is used to expand high-temperature and high-pressure air to perform work.

Optionally, the air compression unit of the utility model comprises: a plurality of air compressors and a plurality of coolers connected alternately in sequence, the air compressor at the front is connected to the environment, and the cooler at the back is connected to the inlet of the constant pressure storage tank 13;

It can be understood that the plurality of air compressors and the plurality of coolers can be 4, 5, 6, 7 or 8, preferably 6. Referring to FIG1 , the air compression unit in the optional embodiment includes a first air compressor 1, a first cooler 2, a second air compressor 3, a second cooler 4, a third air compressor 5, a third cooler 6, a fourth air compressor 7, a fourth cooler 8, a fifth air compressor 9, a fifth cooler 10, a sixth air compressor 11, and a sixth cooler 12 connected in sequence;

The pressure stabilizing unit includes: a flexible airbag 14, a carbon dioxide compressor 15, a condenser 16, a throttle valve 17, a liquid carbon dioxide storage tank 18, and an evaporator 19; the outlet of the flexible airbag 14 is connected to the inlet of the liquid carbon dioxide storage tank 18 through the carbon dioxide compressor 15, the hot side channel of the condenser 16, and the throttle valve 17, and the outlet of the liquid carbon dioxide storage tank 18 is connected to the inlet of the flexible airbag 14 through the cold side channel of the evaporator 19;

It can be understood that the saturated gas at the outlet of the throttle valve 17 is refluxed and connected to the inlet of the carbon dioxide compressor 15;

It can be understood that the flexible airbag 14 is placed inside the constant pressure storage tank 13 to completely separate the air and carbon dioxide. The flexible airbag is made of rubber material and its volume can be freely changed.

The outlet of the constant pressure storage tank 13 is connected to the outside atmosphere through the cold side channel of the regenerator 20, the air channel of the electric heat accumulator 21, the air expander 22, and the hot side channel of the regenerator 20.

Optionally, in the embodiment of the utility model, the compressed air energy storage system with integrated solid electric thermal storage further comprises a cold storage unit, and the cold storage unit comprises: a first water tank 23, a second water tank 25;

The outlet of the first water tank 23 is connected to the inlet of the second water tank 25 through the low temperature side channel of the condenser 16; the outlet of the first water tank 23 is provided with a first water pump 24;

The outlet of the second water tank 25 is connected to the inlet of the first water tank 23 through the high temperature side channel of the evaporator 19 ; a second water pump 26 is provided at the outlet of the second water tank 25 .

Optionally, in an embodiment of the utility model, the heat at the outlet of the cold side channel of each cooler is not stored, but is directly utilized for other purposes or directly dissipated into the atmosphere.

Optionally, in the embodiment of the utility model, the electric heat accumulator 21 is provided with a high-temperature heat storage solid material containing an air channel, a high-voltage resistance wire is provided between the solid materials, and a high-temperature resistant heat-insulating ceramic is provided on the outside.

The utility model is provided with a high-temperature electric heat accumulator, which greatly increases the inlet temperature of the air expander (above 800°C), enhances the work capacity of the working fluid per unit mass flow rate, reduces the high pressure required to be stored, and effectively reduces the investment cost of the high-pressure storage tank; compression heat no longer needs to be stored, and no complicated heat storage cycle is required, the system is simpler and easier to operate, and at the same time, the investment in liquid heat storage materials and storage tanks is reduced.

In addition, the utility model provides an operating method of a compressed air energy storage system integrating solid electric thermal storage, comprising the following steps:

Energy storage process: air enters the compression unit from the environment and is compressed to a high-pressure state, and is stored in the constant-pressure storage tank 13 after being cooled by the cooler. The heat at the outlet of the cold-side channel of each cooler is not stored, but is directly used for other purposes or directly dissipated into the atmosphere; at the same time, the electricity input into the electric heat accumulator 21 is converted into high-temperature heat by the resistance wire and stored in the solid heat storage material; the high-pressure air entering the constant-pressure storage tank 13 discharges the carbon dioxide in the flexible airbag 14, and then the carbon dioxide is compressed and condensed by the water from the first water tank 23 and then throttled to the storage pressure and stored in the liquid carbon dioxide storage tank 18, and the water after absorbing the heat energy is stored in the second water tank 25;

Energy release process: the carbon dioxide liquid discharged from the liquid carbon dioxide storage tank 18 enters the evaporator 19, is heated by the hot water in the second water tank 25 into carbon dioxide gas, and then enters the flexible airbag 14 for storage; at the same time, the air is discharged from the constant pressure storage tank 13, enters the air regenerator 20 for preheating, and is further heated by the electric heat accumulator 21 before entering the air expander 22 for expansion to generate power. The expanded air enters the air regenerator 20 for heat exchange with the high-pressure air discharged from the constant pressure storage tank 13 and then is discharged into the atmosphere.

Optionally, in an embodiment of the utility model, during the operation of the energy storage system, the pressure in the constant pressure storage tank 13 and the flexible airbag 14 remains constant.

Optionally, in the embodiment of the utility model, an electric heat accumulator 21 is provided in front of the air expander 22 so that the inlet temperature of the air expander 22 reaches above 800°C.

The advantages of the operation method of the compressed air energy storage system with integrated solid electric thermal storage over the prior art are the same as those of the compressed air energy storage system with integrated solid electric thermal storage, which will not be repeated here.

Although the utility model is disclosed as above, the protection scope of the utility model is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the utility model, and these changes and modifications will fall within the protection scope of the utility model.

Claims (5)

1. A compressed air energy storage system integrating solid electrical heat storage, comprising: the device comprises an air compression unit, a constant-pressure storage tank (13), a pressure stabilizing unit, a heat regenerator (20), an electric heat accumulator (21) and an air expander (22);

The air compression unit is used for compressing air from the environment to a high pressure state;

the constant pressure storage tank (13) is used for storing compressed high-pressure air;

The pressure stabilizing unit is used for keeping the air pressure in the constant-pressure storage tank (13) constant;

-the regenerator (20) is used for recovering waste heat of the exhaust gas of the air expander (22);

The electric heat accumulator (21) is used for converting input electricity into high-temperature heat and storing the high-temperature heat;

The air expander (22) is used for expanding high-temperature high-pressure air to do work.

2. The integrated solid state electrically regenerative compressed air energy storage system of claim 1, wherein said air compression unit comprises: the air compressors and the coolers are alternately connected in sequence, the foremost air compressor is connected with the environment, and the last cooler is connected with the inlet of the constant-pressure storage tank (13);

The voltage stabilizing unit includes: a flexible air bag (14), a carbon dioxide compressor (15), a condenser (16), a throttle valve (17), a liquid carbon dioxide storage tank (18) and an evaporator (19); the outlet of the flexible air bag (14) is connected to the inlet of the liquid carbon dioxide storage tank (18) through the carbon dioxide compressor (15), the hot side channel of the condenser (16) and the throttle valve (17), and the outlet of the liquid carbon dioxide storage tank (18) is connected to the inlet of the flexible air bag (14) through the cold side channel of the evaporator (19); -said throttle valve (17) outlet is connected to said carbon dioxide compressor (15) inlet; the flexible air bag (14) is arranged inside the constant pressure storage tank (13) and is used for completely separating air and carbon dioxide;

The outlet of the constant-pressure storage tank (13) is connected to the external atmosphere through the cold side channel of the heat regenerator (20), the air channel of the electric heat accumulator (21), the air expander (22) and the hot side channel of the heat regenerator (20).

3. The integrated solid state electrically regenerative compressed air energy storage system of claim 2, further comprising a regenerative unit, said regenerative unit comprising: a first water tank (23) and a second water tank (25);

The outlet of the first water tank (23) is connected to the inlet of the second water tank (25) through a low-temperature side passage of the condenser (16); the outlet of the first water tank (23) is provided with a first water pump (24);

The outlet of the second water tank (25) is connected to the inlet of the first water tank (23) through a high-temperature side channel of the evaporator (19); and a second water pump (26) is arranged at the outlet of the second water tank (25).

4. An integrated solid state electrically regenerative compressed air energy storage system according to claim 2, wherein the heat at the cold side channel outlet of each cooler is not stored and is directly utilized by other uses or is directly dissipated to the atmosphere.

5. The compressed air energy storage system integrating solid electric heat storage according to claim 2, wherein the electric heat storage device (21) is internally provided with high-temperature heat storage solid materials containing air channels, high-voltage resistance wires are arranged between the solid materials, and high-temperature resistant heat insulation ceramics are arranged outside the solid materials.