A solar-assisted chemical chain heat pump energy storage system

Abstract

The present invention discloses a solar-assisted chemical-loop heat pump energy storage system, comprising a chemical-loop heat pump energy storage system and a tower solar thermal collector. In charging mode, low-pressure air output by a low-pressure air compressor is split into two streams. One stream is compressed into high-pressure air by a high-pressure air compressor and stored in a gas storage tank. The other stream is heated by a first regenerator and a tower solar thermal collector and then fed into a thermal storage reaction bed. High-valent metal oxygen carriers in the thermal storage reaction bed are decomposed into low-valent metal oxygen carriers by heat. The output reaction gas preheats the low-pressure air and then enters a charging-side expander to generate work, driving a first generator for power generation. In discharging mode, high-pressure air from the gas storage tank is heated by a second regenerator and then flows into the thermal storage reaction bed, reducing the low-valent metal oxygen carriers and releasing heat. The resulting high-temperature, high-pressure gas is fed into a discharge-side expander to generate work, driving a second generator for power generation. Exhaust gas is then used in the second regenerator to preheat the high-pressure air. This invention has the advantages of high energy storage density and high energy storage stability.

Description

Technical Field

[0001] The present invention belongs to the field of grid-level electricity storage and relates to a solar-assisted chemical chain heat pump electricity storage system. Specifically, it relates to a heat pump electricity storage system that uses a compressor and a tower-type solar collector to convert electrical energy and solar energy into thermal energy, and ultimately converts it into stable chemical energy in metal oxides for storage. Background Art

[0002] Currently, technologies that can achieve large-scale energy storage and peak regulation include pumped storage technology, compressed air energy storage technology, liquid air energy storage technology, hydrogen storage technology, and heat pump energy storage technology. Among them, pumped storage technology and compressed air energy storage technology are limited by geographical location and require large caves that can store compressed air or the construction of additional large-capacity gas storage tanks. Although liquid air energy storage technology and hydrogen storage technology have high energy storage density, their round-trip efficiency is relatively low. As a new type of energy storage technology, heat pump energy storage technology works by converting electrical energy into thermal energy through a heat pump cycle and storing energy in the form of sensible heat or latent heat. It not only has the characteristics of small footprint and no geographical restrictions, but also has the advantages of high round-trip efficiency and stable operation. However, sensible heat or latent heat energy storage itself also has disadvantages such as heat is not suitable for long-term storage and limited capacity density. Summary of the Invention

[0003] Purpose of the invention: The purpose of the present invention is to address the shortcomings of existing large-scale energy storage solutions and provide a solar-assisted chemical chain heat pump power storage system with high energy storage density and high energy storage stability.

[0004] Technical solution: The solar-assisted chemical chaining heat pump energy storage system of the present invention comprises a chemical chaining heat pump energy storage system and a tower solar collector. The chemical chaining heat pump energy storage system comprises a low-pressure air compressor, a high-pressure air compressor, a thermal storage reaction bed, a charging side expander, a first motor, a first generator, a gas storage tank, a discharge side expander, a second generator and a diverter valve. The thermal storage reaction bed is provided with a high-valent metal oxygen carrier MeO X The first motor is connected to the low-pressure air compressor and the high-pressure air compressor in sequence; the low-pressure air compressor is connected to the diverter valve inlet, the diverter valve first outlet, the tower solar collector, the thermal storage reaction bed and the charging side expansion machine are connected in sequence, and the charging side expansion machine is connected to the first generator; the diverter valve second outlet, the high-pressure air compressor, the gas storage tank, the thermal storage reaction bed and the discharge side expansion machine are connected in sequence, and the second generator is connected to the discharge side expansion machine and the power grid;

[0005] When the power generation is greater than the power load, it operates in charging mode:

[0006] The electric energy from photovoltaic, wind power or power grid drives the first motor to operate, and the first motor drives the low-pressure air compressor and the high-pressure air compressor to work. The low-pressure air compressor compresses the air from the external environment into low-pressure air; the high-pressure air compressor further compresses the low-pressure air from the second outlet of the diverter valve into high-pressure air and stores it in the air storage tank; the tower solar collector heats the low-pressure air from the first outlet of the diverter valve into high-temperature low-pressure air and inputs it into the heat storage reaction bed. The high-valent metal oxygen carrier MeO X Decomposed by heat into low-valent metal oxygen carrier MeO X-2 The first working gas flowing out of the thermal storage reaction bed is input into the charging side expander to perform work and drive the first generator to work, and the generated electric energy is supplied to the first motor;

[0007] When the generated power is less than the power load, it operates in discharge mode:

[0008] High-pressure air from the gas tank flows into the thermal storage reaction bed and reacts with the low-valent metal oxygen carrier MeO X-2 Oxidation reaction occurs to generate high-valent metal oxygen carrier MeO X A large amount of heat is released, and the high-temperature and high-pressure second working gas generated flows out of the heat storage reaction bed and is input into the discharge side expander to perform work, driving the second generator to operate, and the generated electricity is supplied to the power grid.

[0009] Furthermore, the chemical chain heat pump energy storage system also includes a first regenerator, the first outlet of the diverter valve is connected to the cold side inlet of the first regenerator, and the tower solar collector is connected to the cold side outlet of the first regenerator; the heat storage reaction bed is connected to the hot side inlet of the first regenerator, and the charging side expander is connected to the hot side outlet of the first regenerator.

[0010] Furthermore, the chemical chain heat pump power storage system also includes a second regenerator, the gas storage tank is connected to the cold side inlet of the second regenerator, the thermal storage reaction bed is connected to the cold side outlet of the second regenerator; and the discharge side expander is connected to the hot side inlet of the second regenerator.

[0011] The present invention greatly improves the charging and discharging efficiency of the system by adding a regenerator to the system to recover waste heat.

[0012] Furthermore, the chemical linking heat pump power storage system also includes a waste heat utilization device, which is connected to the hot side outlet of the second regenerator.

[0013] Furthermore, the waste heat utilization methods of the waste heat utilization device include heating, organic Rankine cycle and seawater desalination.

[0014] Furthermore, high valence metal oxygen carrier MeO X Including Mn2O3, CuO and Co3O4.

[0015] Furthermore, the high-valent metal oxygen carrier MeO in the thermal storage reaction bed X A fixed bed arrangement is adopted, with fins or metal frames to enhance heat exchange, and direct contact heat exchange is carried out between air and metal oxides.

[0016] The direct heat exchange between air and energy storage material enhances the heat exchange effect, reduces the heat transfer temperature difference, and further improves the efficiency of the power storage system.

[0017] Furthermore, the low-pressure air compressor, the high-pressure air compressor and the charging-side expander are coaxially connected.

[0018] Furthermore, in the charging mode, the air flow rate flowing into the high-pressure air compressor must meet the air flow rate required for the oxidation reaction of the thermal storage reaction bed in the discharging mode; the electric energy generated by the first generator is less than the electric energy consumed by the first motor.

[0019] Furthermore, in the charging mode, the outlet pressure of the low-pressure air compressor is between 2 and 4 atm, and the outlet pressure of the high-pressure air compressor is above 5 atm.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0021] The tower solar collector and heat pump energy storage cycle converts solar energy and electrical energy into thermal energy and stores it in the form of stable chemical energy, which improves the capacity density and energy storage stability of conventional heat pump energy storage systems and has the following characteristics:

[0022] (1) Metal oxides are used as energy storage materials, air is used as working gas, and solar energy and electricity are used as energy inputs for the system. This is low-cost, clean, and pollution-free. At the same time, due to the extremely high stability and reaction enthalpy change of chemical energy, a set of energy storage solutions with higher flexibility, stability, and capacity density is provided.

[0023] (2) In the charging mode, by setting up low-pressure air compressors and high-pressure air compressors, the peak-shaving capacity of the power storage system is increased, and the ability to absorb renewable energy electricity is further improved.

[0024] (3) The system has a wide range of applications. It can be used in conjunction with new energy power plants to improve power generation stability; it can be used in conjunction with thermal power plants to meet the peak load demand of the power grid, and the use of the tiered electricity prices in the electricity market can also increase the profits of power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a solar-assisted chemical chaining heat pump power storage system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings.

[0027] Attachment Figure 1 The reference numerals in the figures are as follows:

[0028] 1. Low-pressure air compressor; 2. High-pressure air compressor; 3. First regenerator; 4. Tower solar collector; 5. Thermal storage reaction bed; 6. Charge-side expander; 7. First electric motor; 8. First generator; 9. Gas storage tank; 10. Second regenerator; 11. Discharge-side expander; 12. Second generator; 13. Waste heat utilization device; 14. Photovoltaic, wind power or power grid; 15. Diverter valve.

[0029] like Figure 1 As shown, an embodiment of the present invention provides a solar-assisted chemical chain heat pump power storage system, including a chemical chain heat pump power storage system and a tower solar collector 4. The chemical chain heat pump power storage system includes a low-pressure air compressor 1, a high-pressure air compressor 2, a first regenerator 3, a thermal storage reaction bed 5, a charging side expander 6, a first motor 7, a first generator 8, a gas storage tank 9, a second regenerator 10, a discharge side expander 11, a second generator 12, a waste heat utilization device 13 and a diverter valve 15.

[0030] First motor 7 is connected to photovoltaic, wind power, or the power grid 14. It is also connected sequentially to low-pressure air compressor 1 and high-pressure air compressor 2. Low-pressure air compressor 1, high-pressure air compressor 2, and charging-side expander 6 are coaxially connected. Low-pressure air compressor 1 is connected to the inlet of diverter valve 15. The first outlet of diverter valve 15 is connected to the cold-side inlet of first regenerator 3. Tower solar collector 4 is connected to the cold-side outlet of first regenerator 3. Thermal storage reactor bed 5 is connected to the hot-side inlet of first regenerator 3. Charging-side expander 6 is connected to the hot-side outlet of first regenerator 3. Charging-side expander 6 is connected to first generator 8.

[0031] The second outlet of the diverter valve 15, the high-pressure air compressor 2 and the air storage tank 9 are connected in sequence, the air storage tank 9 is connected to the cold side inlet of the second regenerator 10, the cold side outlet of the second regenerator 10, the thermal storage reaction bed 5 and the discharge side expander 11 are connected in sequence, the discharge side expander 11 is connected to the hot side inlet of the second regenerator 10, the waste heat utilization device 13 is connected to the hot side outlet of the second regenerator 10, and the second generator 12 is connected to the discharge side expander 11 and the power grid.

[0032] The thermal storage reaction bed 5 is provided with a high-valent metal oxygen carrier MeO X , specifically Mn2O3, CuO and Co3O4 and other metal oxides that can be used in the power storage system. The high-valent metal oxygen carrier MeO in the thermal storage reaction bed 5 XA fixed bed arrangement is adopted, with fins or metal frames to enhance heat transfer, and direct contact heat exchange is carried out between air and metal oxides to maximize the heat transfer effect.

[0033] The working principle of the solar-assisted chemical looping heat pump power storage system provided in an embodiment of the present invention is as follows.

[0034] When the power generation is greater than the power load, it operates in charging mode:

[0035] The electric energy from photovoltaic, wind power or grid 14 (which can be called source side) drives the first motor 7 to operate, and the first motor 7 drives the low-pressure air compressor 1 and the high-pressure air compressor 2 to work. The low-pressure air compressor 1 compresses the air from the external environment into low-pressure air; the high-pressure air compressor 2 further compresses the low-pressure air from the second outlet of the diverter valve 15 into high-pressure air and stores it in the air storage tank 9; the low-pressure air from the first outlet of the diverter valve 15 is heated by the first regenerator 3 and the tower solar collector 4 to become high-temperature low-pressure air. The high-temperature low-pressure air is input into the thermal storage reaction bed 5 and reacts with the high-valent metal oxygen carrier MeO X Direct contact, high valence metal oxygen carrier MeO X Decomposed by heat into low-valent metal oxygen carrier MeO X-2 The formed first working gas flows out of the thermal storage reaction bed 5 and is input into the first regenerator 3 to heat the low-pressure air from the first outlet of the diverter valve 15. Then, it enters the charging side expander 6 to perform work and drive the first generator 8 to work. The generated electric energy is supplied to the first motor 7; the first working gas flowing out of the charging side expander 6 is close to the ambient state and is directly discharged to the external environment, and the charging process is completed.

[0036] When the generated power is less than the power load, it operates in discharge mode:

[0037] The high-pressure air from the gas storage tank 9 flows into the second regenerator 10 and exchanges heat with the exhaust of the discharge side expander 11. The high-pressure air after absorbing heat flows into the thermal storage reaction bed 5 and reacts with the low-valent metal oxygen carrier MeO X-2 Oxidation reaction occurs to generate high-valent metal oxygen carrier MeO X The high-temperature, high-pressure second working gas released by the discharge-side expander 11 generates a large amount of heat, flowing out of the thermal storage reaction bed 5 and into the discharge-side expander 11 to perform work, driving the second generator 12. The generated electricity is then supplied to the grid. The second working gas flowing out of the discharge-side expander 11 is fed into the second regenerator 10, heating the high-pressure air from the gas storage tank 9. It then flows into the waste heat recovery device 13, which utilizes the waste heat of the second working gas before being discharged to the outside environment, completing the discharge process.

[0038] In charging mode, the power generated by first generator 8 is less than the power consumed by first motor 7. The air flow rate flowing into high-pressure air compressor 2 must meet the air flow required for the oxidation reaction in thermal storage reaction bed 5 during discharge mode. The outlet pressure of low-pressure air compressor 1 is between 2 and 4 atm, while the outlet pressure of high-pressure air compressor 2 is generally above 5 atm.

[0039] In charging mode, the air is heated to over 1000°C by the tower solar collector 4. The high-valent metal oxygen carrier in the thermal storage reaction bed 5 typically decomposes at temperatures exceeding 800°C. The inlet temperature of the thermal storage reaction bed 5 must be higher than the decomposition temperature of the high-valent metal oxygen carrier. The entry of low-pressure air into the thermal storage reaction bed 5 reduces the oxygen partial pressure in the air, further lowering the decomposition temperature of the high-valent metal oxygen carrier.

[0040] In the discharge mode, the high-pressure air heated by the second regenerator 10 reacts with the low-valent metal oxygen carrier in the thermal storage reaction bed 5 and releases heat. The working gas reaches a temperature of 550-750°C after absorbing heat. By adjusting the mass flow rate of the working gas, the temperature of the working gas after absorbing heat can be changed. By lowering the decomposition temperature of the high-valent metal oxygen carrier in the charging mode and increasing the heat absorption temperature of the working gas and the reaction pressure of the thermal storage reaction bed 5 in the discharge mode, the charging and discharging efficiency of the system can be improved.

[0041] In charging mode, the addition of the first regenerator 3 reduces the exhaust temperature of the charge-side expander 6, improving charging efficiency. In discharging mode, the addition of the second regenerator 10 increases the temperature of the working gas entering the thermal storage reaction bed 5, increasing the reaction rate. Simultaneously, the exhaust waste heat of the discharge-side expander 11 is utilized, reducing losses and improving the system's discharge efficiency.

[0042] In the charging mode, the provision of the low-pressure air compressor 1 and the high-pressure air compressor 2 improves the peak-shaving capacity of the power storage system.

[0043] In the discharge mode, the air flowing out of the second regenerator 10 still contains low-temperature waste heat, which can be utilized by the waste heat utilization device 13. The waste heat utilization device 13 can be implemented in various ways, and the waste heat can be utilized through heating, organic Rankine cycle, seawater desalination, and other methods.

Claims

1. A solar-assisted chemical chaining heat pump energy storage system, characterized in that: The invention comprises a chemical chain heat pump power storage system and a tower solar thermal collector (4), wherein the chemical chain heat pump power storage system comprises a low-pressure air compressor (1), a high-pressure air compressor (2), a thermal storage reaction bed (5), a charging side expander (6), a first motor (7), a first generator (8), a gas storage tank (9), a discharge side expander (11), a second generator (12) and a diverter valve (15), and a high-valent metal oxygen carrier MeO is provided in the thermal storage reaction bed (5). X The first motor (7) is connected to the low-pressure air compressor (1) and the high-pressure air compressor (2) in sequence; the low-pressure air compressor (1) is connected to the inlet of the diverter valve (15); the first outlet of the diverter valve (15), the tower solar collector (4), the thermal storage reaction bed (5) and the charging side expansion machine (6) are connected in sequence, and the charging side expansion machine (6) is connected to the first generator (8); the second outlet of the diverter valve (15), the high-pressure air compressor (2), the gas storage tank (9), the thermal storage reaction bed (5) and the discharge side expansion machine (11) are connected in sequence, and the second generator (12) is connected to the discharge side expansion machine (11) and the power grid; When the power generation is greater than the power load, it operates in charging mode: The electric energy from photovoltaic, wind power or power grid (14) drives the first motor (7) to operate, and the first motor (7) drives the low-pressure air compressor (1) and the high-pressure air compressor (2) to operate. The low-pressure air compressor (1) compresses the air from the external environment into low-pressure air; the high-pressure air compressor (2) further compresses the low-pressure air from the second outlet of the diverter valve (15) into high-pressure air and stores it in the air storage tank (9); the tower solar collector (4) heats the low-pressure air from the first outlet of the diverter valve (15) into high-temperature low-pressure air and inputs it into the heat storage reaction bed (5). The high-valent metal oxygen carrier MeO X Decomposed by heat into low-valent metal oxygen carrier MeO X-2 The first working gas flowing out of the thermal storage reaction bed (5) is input into the charging side expander (6) to perform work and drive the first generator (8) to work, and the generated electric energy is supplied to the first motor (7); When the generated power is less than the power load, it operates in discharge mode: High-pressure air from the gas storage tank (9) flows into the thermal storage reaction bed (5) and reacts with the low-valent metal oxygen carrier MeO X-2 Oxidation reaction occurs to generate high-valent metal oxygen carrier MeO X A large amount of heat is released, and the generated high-temperature and high-pressure second working gas flows out of the thermal storage reaction bed (5) and is input into the discharge side expander (11) to perform work, driving the second generator (12) to operate, and the generated electric energy is supplied to the power grid.

2. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: The chemical chain heat pump power storage system further comprises a first regenerator (3), a first outlet of a diverter valve (15) connected to a cold side inlet of the first regenerator (3), a tower solar collector (4) connected to the cold side outlet of the first regenerator (3); a thermal storage reaction bed (5) connected to a hot side inlet of the first regenerator (3), and a charging side expander (6) connected to a hot side outlet of the first regenerator (3).

3. The solar-assisted chemical chaining heat pump power storage system according to claim 1 or 2, characterized in that: The chemical chain heat pump power storage system further comprises a second regenerator (10), a gas storage tank (9) connected to a cold side inlet of the second regenerator (10), a thermal storage reaction bed (5) connected to a cold side outlet of the second regenerator (10), and a discharge side expander (11) connected to a hot side inlet of the second regenerator (10).

4. The solar-assisted chemical chaining heat pump power storage system according to claim 3, characterized in that: The chemical chain heat pump power storage system further comprises a waste heat utilization device (13), and the waste heat utilization device (13) is connected to the hot side outlet of the second regenerator (10).

5. The solar-assisted chemical chaining heat pump power storage system according to claim 4, characterized in that: The waste heat utilization method of the waste heat utilization device (13) includes heating, organic Rankine cycle and seawater desalination.

6. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: High-valent metal oxygen carrier MeO X Including Mn2O3, CuO and Co3O4.

7. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: High-valent metal oxygen carrier MeO in the thermal storage reaction bed (5) X A fixed bed arrangement is adopted, with fins or metal frames to enhance heat exchange, and direct contact heat exchange is carried out between air and metal oxides.

8. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: The low-pressure air compressor (1), the high-pressure air compressor (2) and the charging-side expander (6) are coaxially connected.

9. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: In the charging mode, the air flow rate flowing into the high-pressure air compressor (2) must meet the air flow rate required for the oxidation reaction of the thermal storage reaction bed (5) in the discharging mode; and the electric energy generated by the first generator (8) is less than the electric energy consumed by the first motor (7).

10. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: In the charging mode, the outlet pressure of the low-pressure air compressor (1) is between 2 and 4 atm, and the outlet pressure of the high-pressure air compressor (2) is above 5 atm.

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