CN216278062U

CN216278062U - Heat pump electricity storage system integrated with thermochemical conversion

Info

Publication number: CN216278062U
Application number: CN202122229168.8U
Authority: CN
Inventors: 许诚; 庞劲松; 许宏宇
Original assignee: North China Electric Power University
Current assignee: North China Electric Power University
Priority date: 2021-09-15
Filing date: 2021-09-15
Publication date: 2022-04-12
Anticipated expiration: 2031-09-15

Abstract

The utility model discloses a heat pump electricity storage system integrating thermochemical conversion, belonging to the field of power grid-level energy storage. The system mainly comprises a compressor, an expander, a heat exchanger, a reaction vessel, a cold storage layer, a steam generator, a generator and the like. In the system, during charging, the electric energy drives the compressor to compress the working fluid to a high-temperature and high-pressure state, the working fluid releases heat in the reaction container and causes the calcium hydroxide to be decomposed to generate calcium oxide; during discharging, the working fluid in a low-temperature and low-pressure state is compressed by the compressor and then mixed with water vapor to flow into the reaction container, the water vapor reacts with calcium oxide to release heat, the working fluid absorbs heat to reach a high-temperature and high-pressure state and then enters the expansion machine to do work, and the expansion machine drives the generator to generate electricity. Through the complete set of charging and discharging cycles, the problems of poor stability and periodic fluctuation of the new energy power are well solved, and a new scheme is provided for the development of the new energy.

Description

Heat pump electricity storage system integrated with thermochemical conversion

Technical Field

The utility model belongs to the field of power grid-level electricity storage, and particularly relates to a heat pump electricity storage system integrating thermochemical conversion, in particular to a novel electricity storage system which converts electric energy into heat energy by using a compressor and finally converts the heat energy into stable chemical energy in calcium oxide for storage.

Background

With the exhaustion of fossil energy, new energy such as solar energy, wind energy and the like is regarded as a solution scheme of future electric power due to the excellent characteristics of wide distribution, rich reserves, cleanness and no pollution; meanwhile, the problems of poor stability, periodic fluctuation and the like of solar energy, wind energy and the like also greatly limit the development and stable operation of the solar energy, wind energy and the like. Energy storage is an important means for solving renewable energy power. At present, mature electricity storage schemes meeting the requirements of power grid level electricity storage and discharge include pumped storage, compressed air energy storage and the like. However, both of these electricity storage schemes are limited by geographical locations, the former requiring large reservoirs with large drop heights, and the latter requiring large caverns capable of storing compressed air; in order to better meet the development of renewable power in the future, more flexible and practical energy storage technology needs to be developed.

The heat pump energy storage is a relatively novel electricity storage technology, based on reverse power circulation, the electric energy is converted into heat energy by using a compressor and stored in a heat storage medium in the form of sensible heat or latent heat, and the heat pump energy storage has the advantages of no geographical position limitation, high reciprocating efficiency, stable work and the like, however, the sensible heat or latent heat energy storage also has the defects of heat unsuitability for long-term storage, limited capacity density and the like.

The heat pump electricity storage system integrated with thermochemical conversion has a power cycle similar to that of a heat pump energy storage system, but replaces less stable sensible heat or latent heat storage with more stable chemical energy storage, so that the heat pump electricity storage system has the advantages of a heat pump energy storage technology and higher energy storage stability. Meanwhile, the electricity storage technology takes air as working fluid, calcium hydroxide as energy storage material and concrete as cold storage layer, adopts direct heat exchange, has low cost, safety and high efficiency, does not cause any pollution to the environment, has high capacity density which is several times or more than ten times of that of heat pump energy storage, and can well meet the development requirement of future renewable power.

Disclosure of Invention

The utility model aims to provide a heat pump energy storage system integrated with thermochemical conversion aiming at the defects of the existing power grid level energy storage scheme, and is characterized in that in a charging mode, a power grid is connected with a No. 1 motor, the No. 1 motor is connected with a No. 1 compressor, the No. 1 motor is driven to operate by electric energy from the power grid, and the No. 1 motor drives the No. 1 compressor to work; the No. 1 compressor and the No. 1 turboexpander are connected to the same shaft; the reaction vessel is connected with a No. 1 compressor; the No. 1 heat exchanger is connected with the reaction container through a No. 1 compressor, and the reaction container is connected with the No. 1 compressor and the No. 1 heat exchanger and is connected with the No. 1 turboexpander through the No. 1 heat exchanger; the No. 1 generator and the cold storage layer are respectively connected with the No. 1 turbine expander; in the discharging mode, the cold storage layer is connected with the No. 2 heat exchanger through the No. 2 compressor; the No. 2 motor is connected with the No. 2 compressor; the No. 2 compressor is connected with the No. 2 heat exchanger; the steam generator is connected with the flow control valve; the No. 2 heat exchanger and the flow control valve are simultaneously connected with the reaction container through the flow merging valve; the reaction vessel is connected with the No. 2 heat exchanger through the No. 2 turboexpander; the No. 2 generator is connected with the No. 2 turboexpander, generates electric energy and returns to a power grid; the waste heat comprehensive utilization device is connected with the No. 2 heat exchanger.

The utility model has the beneficial effects that: the electric energy is converted into heat energy through the heat pump energy storage circulation, and the heat energy is stored in the form of stable chemical energy in calcium oxide, so that the capacity density and the energy storage stability are improved; meanwhile, by adding heat exchange equipment, the charge-discharge efficiency of the system is greatly increased, and the system has the following characteristics:

(1) by adopting charging and discharging circulation respectively at the peak and trough periods of the new energy power, the effect of peak clipping and trough filling can be achieved, the adverse effect of the fluctuation of the new energy power on a power grid is greatly reduced, the stability of the power grid is improved, and a basic guarantee is provided for the development of the new energy power.

(2) The calcium hydroxide is used as an energy storage substance, the air is used as a working fluid, the concrete is used as a cold storage layer, the cost is low, the cleaning and the pollution are avoided, and meanwhile, the flexibility, the stability and the capacity density of the system are greatly improved due to the fact that the chemical energy has high stability and reaction enthalpy change.

(3) The heat pump energy storage circulation is adopted, the principle is clear, the equipment is simple, the work is stable, and the charge and discharge efficiency is higher.

(4) By adding the heat exchanger in the system, the adverse effect of the exhaust temperature on the system is reduced, and the charge-discharge efficiency of the system is greatly increased; the working fluid and the energy storage material adopt direct heat exchange, so that the heat exchange effect is enhanced, the heat transfer temperature difference is reduced, and the system efficiency is further improved.

(5) The system has wide application range and obvious effect, can be matched with a wind power plant or a solar power plant for use, and improves the power generation stability; the device can be matched with a thermal power plant or a gas power plant for use, the peak regulation requirement of a power grid is met, and the profit of the power plant can be increased by utilizing the stepped electricity price in the power market; in addition, the system can be applied to an island distributed energy system, stable power supply to a remote island is realized with low cost, and meanwhile, low-temperature waste heat generated by the system can also be applied to heating or seawater desalination and the like.

Drawings

FIG. 1 is a schematic diagram of a heat pump electric storage system integrated with thermochemical conversion.

In the figure: the system comprises a power grid 1, a motor 2-1, a compressor 3-1, a reaction vessel 4, a heat exchanger 5-1, a turboexpander 6-1, a shaft 7-1, a generator 8-1, a cold storage layer 9, a compressor 10-2, a motor 11-2, a heat exchanger 12-2, a steam generator 13, a flow control valve 14, a flow converging valve 15, a turboexpander 16-2, a generator 17-2, a shaft 18-2 and a waste heat comprehensive utilization device 19.

Detailed Description

The utility model provides a heat pump electricity storage system integrated with thermochemical conversion, which is described below by combining with the accompanying drawings.

In the heat pump electricity storage system integrating thermochemical conversion as shown in fig. 1, in a charging mode, an electric network 1 is connected with a No. 1 motor 2, the No. 1 motor 2 is connected with a No. 1 compressor 3, the No. 1 motor 2 is driven to operate by electric energy from the electric network 1, and the No. 1 motor 2 drives the No. 1 compressor 3 to work; the No. 1 compressor 3 and the No. 1 turboexpander 6 are connected to the same shaft 7; the reaction vessel 4 is connected with a No. 1 compressor 3; the No. 1 heat exchanger 5 is connected with the reaction container 4 through the No. 1 compressor 3, meanwhile, the reaction container 4 is connected with the No. 1 compressor 3 and the No. 1 heat exchanger 5, and is connected with the No. 1 turboexpander 6 through the No. 1 heat exchanger 5; the No. 1 generator 8 and the cold storage layer 9 are respectively connected with the No. 1 turbo expander 6; in the discharging mode, the cold storage layer 9 is connected with the No. 2 heat exchanger 12 through the No. 2 compressor 10; the No. 2 motor 11 is connected with the No. 2 compressor 10; the No. 2 compressor 10 is connected with the No. 2 heat exchanger 12; the steam generator 13 is connected with a flow control valve 14; the No. 2 heat exchanger 12 and the flow control valve 14 are simultaneously connected with the reaction vessel 4 through the confluence valve 15; the reaction vessel 4 is connected with a No. 2 heat exchanger 12 through a No. 2 turboexpander 16; the No. 2 generator 17 is connected with the No. 2 turboexpander 16, generates electric energy and returns to the power grid 1; the waste heat comprehensive utilization device 19 is connected with the No. 2 heat exchanger 12.

According to the principle of the heat pump electricity storage system integrating thermochemical conversion, when the generated power is greater than the electricity load, the charging mode is operated; the electric energy from the power grid 1 drives the No. 1 motor 2 to operate, the No. 1 motor 2 drives the No. 1 compressor 3 to work, and compresses the air from the No. 1 heat exchanger 5 to enable the air to reach a certain temperature and pressure, the high-temperature and high-pressure air flows into the reaction container 4 filled with calcium hydroxide and is in direct contact with the reaction container, and the calcium hydroxide is decomposed by heat absorption to generate calcium oxide and water vapor; the working fluid flows out of the reaction container 4 and then flows into the No. 1 heat exchanger 5 to heat the air from the environment A, then enters the No. 1 turbo expander 6 to continuously do work and drive the No. 1 generator 8 to work, and the generated electric energy is used for supplying the No. 1 compressor 3; the low-temperature low-pressure fluid flowing out of the No. 1 turbo expander 6 flows into the cold storage layer 9 to exchange heat with a cold storage medium, absorb heat and store cold therein; finally, the working fluid which is recovered to be close to the environmental state returns to the environment A again, and the charging process is finished; when the generated power is less than the electricity load, the discharging mode is operated; air from the environment A flows into the cold storage layer 9 and exchanges heat, and the air enters the No. 2 compressor 10 to be compressed after releasing heat; the working fluid flows out of the No. 2 compressor 10, enters the No. 2 heat exchanger 12, exchanges heat with the exhaust gas of the No. 2 turboexpander 12, absorbs heat, flows into the flow merging valve 15 together with the steam which is generated by the steam generator 13 and flows through the flow control valve 14, is mixed and flows into the reaction vessel 4; the water vapor and calcium oxide in the reaction vessel 4 are subjected to chemical combination reaction to generate calcium hydroxide and release a large amount of heat; the working fluid absorbs heat in the reaction container 4 and then reaches a high-temperature and high-pressure state, then flows into the No. 2 turboexpander 16 to do work, a small part of the made work is used for driving the No. 2 motor 11 to operate and driving the No. 2 compressor 10 to operate, and the rest part of the made work is used for driving the No. 2 generator 17 to operate, so that electric energy is generated and supplied to the power grid 1; the working fluid flows out of the turbo expander 16 No. 2 and then flows into the heat exchanger 12 No. 2, exchanges heat with the incoming air and releases heat, and then flows into the comprehensive waste heat utilization device 19, and is discharged into the environment a after the final step of waste heat utilization is completed, so that the discharge process is completed.

Claims

1. The heat pump electricity storage system integrating thermochemical conversion is characterized in that in a charging mode, an electric network (1) is connected with a No. 1 motor (2), the No. 1 motor (2) is connected with a No. 1 compressor (3), the No. 1 motor (2) is driven to operate by electric energy from the electric network (1), and the No. 1 motor (2) drives the No. 1 compressor (3) to work; the No. 1 compressor (3) and the No. 1 turboexpander (6) are connected to the same shaft (7); the reaction container (4) is connected with a No. 1 compressor (3); the heat exchanger (5) No. 1 is connected with the reaction container (4) through the compressor (3) No. 1, and the reaction container (4) is connected with the compressor (3) No. 1 and the heat exchanger (5) No. 1 and is connected with the turboexpander (6) No. 1 through the heat exchanger (5) No. 1; the No. 1 generator (8) and the cold storage layer (9) are respectively connected with the No. 1 turbo expander (6); in the discharge mode, the cold storage layer (9) is connected with the No. 2 heat exchanger (12) through the No. 2 compressor (10); the No. 2 motor (11) is connected with the No. 2 compressor (10); the No. 2 compressor (10) is connected with the No. 2 heat exchanger (12); the steam generator (13) is connected with a flow control valve (14); the No. 2 heat exchanger (12) and the flow control valve (14) are simultaneously connected with the reaction vessel (4) through a flow merging valve (15); the reaction vessel (4) is connected with the No. 2 heat exchanger (12) through a No. 2 turbo expander (16); the No. 2 generator (17) is connected with the No. 2 turboexpander (16) and used for generating electric energy and returning the electric energy to the power grid (1); the waste heat comprehensive utilization device (19) is connected with the No. 2 heat exchanger (12).