CN109026241A - A kind of heat pump compressed-air energy-storage system - Google Patents

Abstract

The invention discloses a heat pump compressed air energy storage system, which comprises a heat pump high-temperature heating cycle circuit and a compressed air energy storage-energy release circuit. Storage), use the heat pump high-temperature heating cycle to produce high-temperature heat and store it; at the peak of power consumption, high-pressure compressed air absorbs the stored compression heat and high-temperature heat in turn, and enters the expander to drive the generator to generate electricity. The heat pump compressed air energy storage system of the present invention has the advantages of simple structure, high efficiency, strong flexibility, suitable for power grid peak regulation and various renewable energy power stations, and does not generate greenhouse gases.

Description

A heat pump compressed air energy storage system

technical field

The invention belongs to the technical field of energy storage, and relates to a heat pump compressed air energy storage system, which is an energy storage system based on a heat pump cycle and compressed air to store energy and utilize the stored energy to generate electric energy.

Background technique

In recent years, renewable energy is gradually becoming an important source of new electricity, and major changes have taken place in the grid structure and operation mode. With the increasing popularity of renewable energy (wind energy, solar energy, etc.), and the urgent need for grid peak regulation, improving grid reliability, and improving power quality, the importance of power energy storage systems has become increasingly prominent. Energy storage is an important component and key supporting technology of smart grids, energy systems with a high proportion of renewable energy, and "Internet +" smart energy (hereinafter referred to as energy Internet). Energy storage can provide peak shaving, frequency regulation, backup, black start, demand response support and other services for power grid operation, and is an important means to improve the flexibility, economy and security of traditional power systems; The consumption level of renewable energy, supporting distributed power and micro-grid is the key technology to promote the replacement of main energy from fossil energy to renewable energy; energy storage can promote the open sharing and flexible transaction of energy production and consumption, and realize multi-energy coordination , is the core basis for building the energy Internet, promoting the reform of the power system and promoting the development of new energy formats.

At present, the existing power energy storage technologies include pumped water energy storage, compressed air energy storage, battery energy storage, superconducting magnetic energy, flywheel energy storage and supercapacitors. my country's energy storage is showing a good trend of diversified development: pumped storage is developing rapidly; compressed air energy storage, flywheel energy storage, superconducting energy storage and supercapacitors, lead storage batteries, lithium-ion batteries, sodium-sulfur batteries, flow batteries and other energy storage The application of technology research and development has accelerated; heat storage, cold storage, and hydrogen storage technologies have also made some progress. Among them, physical energy storage represented by pumped water storage, thermal energy storage and compressed air energy storage is suitable for large-scale commercial applications due to its low cost and large energy storage capacity, accounting for about 99.5% of the world's total energy storage.

The energy storage system of the pumped hydropower station allows the motor to drive the water pump to pump the water from the low reservoir to the high reservoir through the pipeline to consume part of the electric energy when the power system is at the valley load. When the peak load comes, the water in the high reservoir passes through the pipeline to make the water pump and the motor run in reverse, and then turns into a water turbine and a generator to generate electricity for the user, thus playing the role of peak shaving and valley filling. The energy storage system of the pumped hydropower station has the advantages of mature and reliable technology, high efficiency (~70%), and large energy storage capacity, and has been widely used at present. However, the pumped hydropower station energy storage system requires special geographical conditions to build two reservoirs and dams, the construction period is very long (generally about 7 to 15 years), and the initial investment is huge. What's more difficult is that the construction of large-scale reservoirs will flood vegetation and even cities in large areas, causing ecological and immigration problems, so the construction of pumped hydropower storage systems has been increasingly restricted.

The traditional compressed air energy storage system compresses the air and stores it in the gas storage chamber during the low electricity consumption, so that the electric energy is converted into the internal energy of the air and stored; during the peak power consumption, the high-pressure air is released from the gas storage chamber and enters the combustion chamber of the gas turbine at the same time. The fuel is burned together and drives a turbine to generate electricity. The compressed air energy storage system has the advantages of large energy storage capacity, long energy storage period, high efficiency (50%-70%) and relatively small unit investment. However, the energy storage density of compressed air energy storage technology is low, and the difficulty lies in the need for suitable places where compressed air can be stored, such as sealed caves or abandoned mines. Moreover, the compressed air energy storage system still relies on the burning of fossil fuels to provide heat sources. On the one hand, it faces the threat of the gradual depletion of fossil fuels and rising prices; Zero emissions), renewable energy development requirements.

In order to solve the main problems faced by traditional compressed air energy storage systems, domestic and foreign scholars have carried out advanced adiabatic compressed air energy storage systems (AACAES), surface compressed air energy storage systems (SVCAES), compressed air storage Energy storage system (AACAES) and air-steam combined cycle compressed air energy storage system (CASH), etc., make the compressed air energy storage system basically avoid burning fossil fuels, but the energy density of the compressed air energy storage system is still very low, requiring a large of the gas storage chamber.

Contents of the invention

In view of the above-mentioned shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a heat pump compressed air energy storage system, which uses power station low-peak power to compress the air to a high-pressure state and simultaneously stores compressed air heat, and uses the heat pump circulation system to produce High-temperature heat is stored in parallel; at the peak of power consumption, the compressed high-pressure absorbs the stored compression heat and high-temperature heat in turn, and enters the expander to drive the generator to generate electricity. Compared with the existing compressed air energy storage system, etc., the heat pump compressed air energy storage system of the present invention has the characteristics of simple structure, high temperature, high heat storage density, and strong flexibility, and can be suitable for various types of power stations.

For achieving the above object, technical solution of the present invention is:

A heat pump compressed air energy storage system, comprising a heat pump high-temperature heating cycle loop and a compressed air energy storage-energy release loop, characterized in that,

The heat pump high-temperature heating cycle is used to prepare high-temperature heat energy and store heat;

The compressed air energy storage-energy release circuit uses compressed air to store energy, and utilizes the compressed air and the high-temperature heat energy prepared by the heat pump high-temperature heating cycle circuit to release energy to perform external work;

in,

--The heat pump high-temperature heating cycle circuit includes a cycle compressor unit, a high-temperature heat storage/heat exchanger, a heat exchanger, and a heat pump cycle expansion unit. The cycle compressor unit is driven by a drive unit, and the cycle compressor unit is connected to the The heat pump cycle expansion unit is connected by transmission, and the cycle loop is filled with heat pump cycle gas working medium, wherein,

The exhaust port of the cyclic compressor unit communicates with the air inlet of the heat pump cyclic expansion unit via the high-temperature heat storage/heat exchanger and the hot side of the heat exchanger in sequence through pipelines,

The exhaust port of the heat pump cycle expansion unit communicates with the air inlet of the cycle compressor unit through a pipeline through the cold side of the heat exchanger;

--The compressed air energy storage-energy release circuit includes an air compressor unit, a medium-low temperature heat storage/heat exchanger, an air storage tank, the high-temperature heat storage/heat exchanger, an air expansion unit, and the air compressor unit Driven by a driving motor, the air expansion unit is driven and connected to a generator, wherein,

The air inlet of the air compressor unit communicates with the atmosphere, and the exhaust port communicates with the air inlet of the gas storage tank through the pipeline through the medium and low temperature heat storage/heat exchanger,

The gas outlet of the air storage tank communicates with the air inlet of the air expansion unit through the pipeline through the medium and low temperature heat storage/heat exchanger and the high temperature heat storage/heat exchanger. The exhaust port communicates with the atmosphere,

At least a valve is provided on the gas outlet pipeline of the gas storage tank.

Preferably, during the low electricity consumption period, the system utilizes the heat pump high-temperature heating cycle loop to prepare high-temperature heat energy and store heat, specifically: the drive unit drives the heat pump cycle compressor unit to compress the medium-temperature and low-pressure heat pump cycle gas working medium to a high-temperature and high-pressure state; use the high-temperature heat storage/heat exchanger to reduce the temperature of the high-temperature and high-pressure heat pump cycle gas to a medium temperature, and store high-temperature heat energy in the heat storage medium of the high-temperature heat storage/heat exchanger The medium-temperature and high-pressure heat pump cycle gas working medium passes through the hot side of the heat exchanger and then transforms into medium-low temperature and high pressure; the medium-low temperature and high-pressure heat pump cycle gas working medium further passes through the heat pump cycle expansion unit to low temperature and low pressure; the low-temperature and low-pressure heat pump The temperature of the circulating gas working medium rises to medium temperature after passing through the cold side of the heat exchanger; the medium-temperature and low-pressure heat pump circulating gas working medium re-enters the inlet of the heat pump circulating compressor unit to participate in the heat pump cycle. stored in the heat storage medium of the high temperature heat storage/heat exchanger;

Further, during the period of low power consumption, the compressed air energy storage-energy release circuit stores energy, and uses the power station's low power to drive the air compressor unit to compress the air into medium-low temperature and high-pressure air; the medium-low temperature and high-pressure air passes through the medium The temperature is lowered after the hot side of the low temperature thermal storage/exchanger and stored in the air storage tank.

Further, during the peak period of electricity consumption, the compressed air energy storage-energy release circuit releases energy, and the compressed air in the air storage tank passes through the medium and low temperature heat storage/heat exchanger and the high temperature heat storage/heat exchange successively. After the device, the temperature continues to rise until it turns into high-temperature and high-pressure air; the high-temperature and high-pressure air expands in the air expansion unit to do work, driving the generator to generate electricity.

Preferably, the heat pump cycle gas working medium is a mixture of one or more of monoatomic molecular gas, diatomic molecular gas or polyatomic molecular gas.

Preferably, the heat pump cycle gas working fluid of the monatomic molecular gas is one or a mixture of helium and argon.

Preferably, the driving unit is a driving motor or a wind turbine. When the driving unit is a driving motor, one or more of conventional power station low power, nuclear power, wind power, solar power, hydropower or tidal power power supply.

Preferably, the compressed air energy storage-energy release circuit is also equipped with air purification and purification equipment, the air purification and purification equipment is integrated in the air compressor unit or the medium and low temperature heat storage/heat exchanger, the air Purification and purification equipment is used to purify and purify the air in the process of air compression and cooling, and remove solids and impurity gases in the air.

Preferably, the total pressure ratio of the air compressor unit is between 36 and 340; when the air compressor unit is composed of multiple compressors, the multiple compressors are in the form of coaxial series or split-shaft parallel connection; the parallel form Among them, each sub-shaft is dynamically connected with the main drive shaft.

Preferably, the total expansion ratio of the air expansion unit is between 38 and 340, and the exhaust gas of the final expander is close to normal pressure; when the air expansion unit has multiple expanders, the multiple expanders are coaxial and connected in series In the parallel connection mode, each sub-shaft is dynamically connected with the main drive shaft; the intake air of the expanders at all levels is first heated by the heat storage/heat exchanger.

Preferably, the total pressure ratio of the heat pump cycle compressor unit is between 5 and 40; when the heat pump cycle compressor unit is composed of multiple compressors, the multiple compressors are in the form of coaxial series or split shaft parallel; In the parallel mode, each branch shaft is dynamically connected with the main drive shaft.

Preferably, the total expansion ratio of the heat pump cyclic expansion unit is between 5 and 40; when the heat pump cyclic expansion unit is a plurality of expanders, the plurality of expanders are in the form of coaxial series connection or split shaft parallel connection; In the parallel mode, each branch shaft is dynamically connected with the main drive shaft.

Preferably, the air compressor, air expander, heat pump cycle compressor, and/or heat pump cycle expander are piston type, axial flow type, centrifugal type, screw type or hybrid type.

Preferably, the multiple compressors and expanders are respectively distributed on one drive shaft or multiple drive shafts; the heat pump cycle compressors and heat pump cycle expanders are distributed on one drive shaft, or on multiple drive shafts connected through a gearbox.

Preferably, the heat storage form of the medium-low temperature heat storage/heat exchanger and the high-temperature heat storage/heat exchanger is one or more of sensible heat, latent heat or chemical reaction heat, and the heat exchange form is high-pressure air Direct contact with the heat storage material or heat exchange with the heat storage material through the heat exchange surface; the heat storage medium used is water, paraffin, biomass oil, inorganic crystalline hydrated salt, molten salt, metal and its alloy, organic fatty acid, stone , rock or concrete, the thermal storage medium is stored in an insulated container.

Preferably, the heat exchanger is in the form of one or more combinations of shell-and-tube, tube-fin, plate-fin, or plate-type.

Compared with the prior art, the heat pump-compressed air energy storage system of the present invention uses low-peak power of the power station to compress the air to a high-pressure state and simultaneously stores air compressed heat, and uses the heat pump cycle system to produce high-temperature heat and store it; , the compression high pressure sequentially absorbs the stored compression heat and high temperature heat energy, and enters the expander to drive the generator to generate electricity. Compared with the existing compressed air energy storage system, etc., the heat pump compressed air energy storage system of the present invention has the characteristics of simple structure, high temperature, high heat storage density, and strong flexibility, and can be suitable for various types of power stations.

Description of drawings

Fig. 1 is a structural schematic diagram of Embodiment 1 of the heat pump-compressed air energy storage system of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

As shown in Figure 1, the heat pump compressed air energy storage system of the present invention consists of an air compressor unit 1, a medium and low temperature heat storage/heat exchanger 2, an air storage tank 3, a high temperature heat storage/heat exchanger 4, an air expansion unit 5, Heat pump cycle compressor unit 6, heat pump cycle expansion unit 7, heat exchanger 8, drive motor 9, generator 10, heat pump drive motor 11, valve 14 and multiple pipelines 12, 13, 15-22.

Heat pump cycle compressor unit 6, high temperature heat storage/heat exchanger 4, heat exchanger 8, heat pump cycle expansion unit 7 and pipelines 18, 19, 20, 21, 22 form a heat pump high temperature heating loop. The heat pump drive motor 11 is fixedly connected to the common transmission shaft of the heat pump cycle compressor unit 6 and the heat pump cycle expansion unit 7, and the exhaust port of the cycle compressor unit 6 passes through the pipeline in turn through the heat of the high-temperature heat storage/heat exchanger 4 and the heat exchanger 8. The side is connected with the air inlet of the heat pump cycle expansion unit 7, and the exhaust port of the heat pump cycle expansion unit 7 is connected with the air inlet of the cycle compressor unit 6 through the cold side of the heat exchanger 8 through the pipeline.

Air compressor unit 1, medium and low temperature heat storage/heat exchanger 2, air storage tank 3, high temperature heat storage/heat exchanger 4, air expansion unit 5 and pipelines 12, 13, 15, 16, 17 form air energy storage-release can loop. The air compressor unit 1 is driven by a drive motor 9 , and the air expansion unit 5 is driven and connected to a generator 10 . The air inlet of the air compressor unit 1 communicates with the atmosphere A, the exhaust port communicates with the air inlet of the gas storage tank 3 through the medium and low temperature heat storage/heat exchanger 2 through the pipeline, and the gas outlet of the gas storage tank 3 passes through the pipeline through the middle The low-temperature heat storage/heat exchanger 2 and the high-temperature heat storage/heat exchanger 4 are connected to the air inlet of the air expansion unit 5, and the exhaust port of the air expansion unit 5 is connected to the atmosphere, at least in the outlet line of the gas storage tank 3 There is a valve 14 on it.

During the low electricity consumption period, the system uses the heat pump high-temperature heating cycle loop to prepare high-temperature heat energy and store heat, specifically: use the drive unit 11 to drive the heat pump cycle compressor unit 6, and compress a certain amount of medium-temperature and low-pressure heat pump cycle gas working fluid to high temperature and high pressure state; through the high-temperature heat storage/heat exchanger 4, the temperature is lowered to medium temperature, and at the same time, the high-temperature heat energy is stored in the high-temperature heat storage/heat exchanger 4; the medium-temperature and high-pressure heat pump circulation gas is cooled to medium-low temperature and high pressure through the heat exchanger 8; The low-temperature and high-pressure heat pump cycle gas further passes through the heat pump cycle expansion unit 7 to low temperature and low pressure, and at the same time generates expansion work to supplement the work consumed by the compressor unit; The inlet that re-enters the compressor unit 6 of the heat pump cycle participates in the heat pump cycle.

During the period of low electricity consumption, when the compressed air energy storage-energy release circuit stores energy, the low-valley (low price) electric drive motor 9 drives the compressor unit, and the air A enters the air compressor unit 1 to be compressed to a medium-low temperature and high-pressure state, and the air compressor exits the air Enter the medium and low temperature heat storage/heat exchanger 2 through the pipeline 12, and the air at the outlet of the medium and low temperature heat storage/heat exchanger 2 drops to normal temperature and enters the air storage tank 3 through the pipeline 13 for storage.

During the peak period of electricity consumption, when the compressed air energy storage-energy release circuit releases energy, the valve 14 is opened, and the high-pressure air in the air storage tank 3 enters the medium and low temperature heat storage/heat exchanger 2 through the pipeline 15 to heat up to the medium and low temperature, and further enters the high temperature The heat storage/heat exchanger 4 heats up to a high temperature, and the high-temperature and high-pressure air after the temperature rise is injected into the air expansion unit 5 through the pipeline 17 to expand and perform work.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of the present invention within.

Claims (11)

1. A heat pump compressed air energy storage system, comprising a heat pump high temperature heating cycle loop and a compressed air energy storage-energy release loop, characterized in that, The heat pump high-temperature heating cycle is used to prepare high-temperature heat energy and store heat; The compressed air energy storage-energy release circuit uses compressed air to store energy, and utilizes the compressed air and the high-temperature heat energy prepared by the heat pump high-temperature heating cycle circuit to release energy to perform external work; in, --The heat pump high-temperature heating cycle circuit includes a cycle compressor unit, a high-temperature heat storage/heat exchanger, a heat exchanger, and a heat pump cycle expansion unit. The cycle compressor unit is driven by a drive unit, and the cycle compressor unit is connected to the The heat pump cycle expansion unit is connected by transmission, and the cycle loop is filled with heat pump cycle gas working medium, wherein, The exhaust port of the cyclic compressor unit communicates with the air inlet of the heat pump cyclic expansion unit via the high-temperature heat storage/heat exchanger and the hot side of the heat exchanger in sequence through pipelines, The exhaust port of the heat pump cycle expansion unit communicates with the air inlet of the cycle compressor unit through a pipeline through the cold side of the heat exchanger; --The compressed air energy storage-energy release circuit includes an air compressor unit, a medium-low temperature heat storage/heat exchanger, an air storage tank, the high-temperature heat storage/heat exchanger, an air expansion unit, and the air compressor unit Driven by a driving motor, the air expansion unit is driven and connected to a generator, wherein, The air inlet of the air compressor unit communicates with the atmosphere, and the exhaust port communicates with the air inlet of the gas storage tank through the pipeline through the medium and low temperature heat storage/heat exchanger, The gas outlet of the air storage tank communicates with the air inlet of the air expansion unit through the pipeline through the medium and low temperature heat storage/heat exchanger and the high temperature heat storage/heat exchanger. The exhaust port communicates with the atmosphere, At least a valve is provided on the gas outlet pipeline of the gas storage tank. 2. The heat pump compressed air energy storage system according to claim 1, characterized in that: during the low power consumption period, the system uses the heat pump high temperature heating cycle to prepare high temperature heat energy and store heat, specifically: the drive unit Drive the heat pump cycle compressor unit to compress the medium-temperature and low-pressure heat pump cycle gas working medium to a high-temperature and high-pressure state; use the high-temperature heat storage/heat exchanger to reduce the temperature of the high-temperature and high-pressure heat pump cycle gas The thermal energy is stored in the heat storage medium of the high-temperature heat storage/heat exchanger; the medium-temperature and high-pressure heat pump circulating gas working fluid passes through the hot side of the heat exchanger and is transformed into a medium-low temperature and high-pressure working fluid; the medium-low temperature and high-pressure heat pump circulating gas working medium The substance further passes through the heat pump cycle expansion unit to low temperature and low pressure; the temperature of the low temperature and low pressure heat pump cycle gas working fluid passes through the cold side of the heat exchanger and then rises to medium temperature; the medium temperature and low pressure heat pump cycle gas working medium re-enters the heat pump The inlet of the cycle compressor unit participates in the heat pump cycle, so that the cycle repeats, and the high-temperature heat energy is continuously stored in the heat storage medium of the high-temperature heat storage/heat exchanger. 3. The heat pump compressed air energy storage system according to claim 1 or 2, characterized in that: during the low power consumption period, the compressed air energy storage-energy release circuit stores energy, and the low power of the power station is used to drive the air compressor The unit compresses the air into medium-low temperature and high-pressure air; the temperature of the medium-low temperature and high-pressure air passes through the medium-low temperature heat storage/heat exchanger and is stored in the air storage tank. 4. The heat pump compressed air energy storage system according to claim 1, 2 or 3, characterized in that: during the peak period of electricity consumption, the compressed air energy storage-energy release circuit releases energy, and the compressed air in the air storage tank After successively passing through the medium and low temperature heat storage/heat exchanger and the high temperature heat storage/heat exchanger, the temperature continues to rise until it turns into high temperature and high pressure air; the high temperature and high pressure air expands in the air expansion unit to do work, driving the generator to generate electricity. 5. The heat pump compressed air energy storage system according to claim 1, characterized in that: the heat pump cycle gas working medium is one or more of monoatomic molecular gas, diatomic gas molecule or polyatomic molecular gas mix. 6. The heat pump compressed air energy storage system according to claim 4, characterized in that the heat pump cycle gas working medium of the monoatomic molecular gas is one or a mixture of helium and argon. 7. The heat pump compressed air energy storage system according to claim 1, characterized in that: the drive unit is a drive motor or a wind turbine; One or more of wind power, solar power, hydropower or tidal power is the power source. 8. The heat pump compressed air energy storage system according to claim 1, characterized in that: the compressed air energy storage-energy release circuit is also equipped with air purification and purification equipment, and the air purification and purification equipment is integrated in the In the air compressor unit or medium-low temperature heat storage/heat exchanger, the air purification and purification equipment is used to purify and purify the air during the air compression and cooling process, and remove solids and impurity gases in the air. 9. The heat pump compressed air energy storage system according to claim 1, characterized in that: the total pressure ratio of the air compressor unit is between 36 and 340; when the air compressor unit consists of multiple compressors, more The two compressors are in the form of coaxial series connection or split shaft parallel connection; in the parallel connection mode, each split shaft is dynamically connected with the main drive shaft. 10. The heat pump compressed air energy storage system according to claim 1, characterized in that: the total expansion ratio of the air expansion unit is between 38 and 340, and the exhaust gas of the final expander is close to normal pressure; when the air When the expansion unit consists of multiple expanders, the multiple expanders are in the form of coaxial series connection or split shaft parallel connection; in the parallel connection mode, each split shaft is dynamically connected with the main drive shaft; The heat/heat exchanger heats up. 11. The heat pump compressed air energy storage system according to claim 1, characterized in that: the total pressure ratio of the heat pump cycle compressor unit is between 5 and 40; when the heat pump cycle compressor unit is composed of multiple compressors , Multiple compressors are in the form of coaxial series connection or sub-shaft parallel connection; in the parallel connection form, each sub-axis is dynamically connected with the main drive shaft.