Cold storage and cold exchange integrated air energy storage system and energy conversion method
By integrating the accumulator and cooler of a multi-stage cold storage air energy storage system into a single cold storage cooler, the problems of system miniaturization and flexible application are solved, resulting in more efficient energy utilization and lower system costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-03-27
AI Technical Summary
The use of accumulators and coolers in multi-stage cold storage air energy storage systems limits the flexibility of their application scenarios and miniaturized deployment, especially the miniaturized deployment on the user side, which is not conducive to distributed utilization.
By integrating the accumulator and cooler of a multi-stage cold storage air energy storage system into a single cold storage cooler, the system can be miniaturized and modularized, simplifying system process design, reducing system investment costs, and improving energy utilization.
This enables more flexible applications of multi-stage cold storage air energy storage systems, especially in user-side and microgrid construction, improving energy utilization and reducing system costs.
Smart Images
Figure CN121738718A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of energy storage technology, and in particular to an integrated air energy storage system and energy conversion method for cold storage and heat exchange. Background Technology
[0002] Faced with the urgent demands of new power systems for peak shaving and reliability, air energy storage, as a core technology for large-scale, long-term energy storage, is playing an irreplaceable role. Currently, this field primarily utilizes high-pressure gaseous storage (compressed air energy storage) and cryogenic liquid storage (liquid air energy storage). These two technologies, through physical transformation, achieve efficient energy storage and release, providing crucial technical support for improving power quality and ensuring the safe operation of the power grid. Current air energy storage systems are all multi-stage thermal storage types, with accumulators typically employing single-tank or dual-tank systems. Common heat transfer media include water, thermal oil, and molten salt. However, heat exchange between the compressor and expander stages requires a separate heat exchanger for the recovery and release of compression heat. The process requires the simultaneous storage of air as the medium and high-temperature thermal energy to ensure sufficient heat source to drive turbine expansion during the energy release phase. However, this dual dependence on the "medium-thermal energy" limitation restricts its distributed utilization. Multi-stage cold storage systems, by first cooling and then compressing air in a multi-stage series system, and then expanding and then cooling it back, ensure that the final stage of energy storage only involves air storage without the need for a large-scale thermal storage system. This enables longer-term storage, distributed storage, and resource utilization. However, the use of cold storage units and multi-stage heat exchangers in multi-stage cold storage systems limits their application flexibility and diversity, particularly hindering miniaturized deployment on the user side. Therefore, making multi-stage cold storage air energy storage systems more compact and simple is a pressing issue that needs to be addressed. Summary of the Invention
[0003] To address the above problems, the purpose of this invention is to provide an integrated cold storage and heat exchange air energy storage system and energy conversion method. The invention aims to integrate the cold storage and heat exchanger of a multi-stage cold storage air energy storage system into a single cold storage and heat exchanger, thereby enabling the multi-stage cold storage air energy storage system to be more easily miniaturized, modularized, or integrated, and to achieve flexible applications in more scenarios.
[0004] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides an integrated cold storage and heat exchange air energy storage system, comprising a compressor unit, an expander unit, an inlet pipeline, an outlet pipeline, a cold storage and heat exchanger, and an air energy storage device; A cold storage and heat exchanger is a container for storing cold energy and has a heat exchange function. The intake pipe is divided into: One end is connected to the outside, and the other end is connected to the air inlet section of the cold storage and heat exchanger; In addition, one end of the intake section is connected to the intake section 1 inside the cold storage and heat exchanger, and the other end is connected to the intake section 2 of the compressor unit. And, one end is connected to the compressor unit outlet, and the other end is connected to the air inlet section three of the cold storage and heat exchanger; And, one end is connected to the air intake section three inside the cold storage and heat exchanger, and the other end is connected to the air intake section four at the inlet of the air storage device; The exhaust pipe is divided into: One end is connected to the outlet of the air energy storage device, and the other end is connected to the air outlet section of the cold storage and heat exchanger. In addition, one end is connected to the first outlet section inside the cold storage and heat exchanger, and the other end is connected to the second outlet section at the inlet of the expander unit. And, one end is connected to the outlet of the expander unit, and the other end is connected to the outlet section of the cold storage and heat exchanger; In addition, one end is connected to the third air outlet section inside the cold storage and heat exchanger, and the other end is connected to the fourth air outlet section to the outside. The compressor unit is powered by an electric motor. The expander unit is connected to an external generator set for power generation.
[0005] As a further preferred option, the air energy storage device is a gas storage chamber for storing high-pressure, room-temperature gas, with inlet section four connected to the gas storage chamber inlet and outlet section one connected to the gas storage chamber outlet.
[0006] As a further preferred option, the air energy storage device includes a throttle valve, a cryogenic pump, and a storage tank for storing cryogenic liquid gas. The fourth air intake section connects to the inlet of the liquid storage tank, and the first air outlet section connects to the outlet of the liquid storage tank. The throttle valve is located on the fourth section of the intake, and the cryogenic pump is located on the first section of the outlet.
[0007] As a further preferred option, the compressor unit includes a multi-stage compressor, with one compressor corresponding to one intake section two and one intake section three; intake sections three and two in adjacent compressor stages are connected in a cold storage heat exchanger.
[0008] As a further preferred option, the expander unit includes a multi-stage expander, with one expander corresponding to one outlet section two and one outlet section three; the outlet sections three and two in two adjacent expanders are connected in a cold storage and heat exchanger.
[0009] As a further preferred option, the storage tank is also equipped with a gas discharge pipe for discharging unliquefied gas, and the gas discharge pipe is connected to the gas outlet section four via a cold storage and heat exchanger.
[0010] An energy conversion method for an integrated air energy storage system that combines cold storage and heat exchange includes the following steps: Step 1: Air enters the cold storage and heat exchanger through intake section 1 to cool down, then enters the compressor through intake section 2 to be pressurized and heated, forming room temperature high pressure gas, and then exits through intake section 3 of the compressor to the cold storage and heat exchanger for cooling down again, forming low temperature high pressure gas. Step 2: The low-temperature high-pressure gas enters the next stage compressor through the second inlet section of the next stage compressor for pressurization and heating, forming room-temperature high-pressure gas. It then passes through the third inlet section of the next stage compressor and is output to the cold storage and heat exchanger for further cooling. This process continues until the low-temperature high-pressure gas enters the fourth inlet section and passes through the throttle valve to form liquid air, which is stored in the liquid storage tank. At this point, the electrical energy storage process is complete, and the refrigerant in the cold storage and heat exchanger is consumed. Step 3: The liquid air in the storage tank is pumped into the first outlet section by the cryogenic pump, and enters the cold storage heat exchanger to be heated. The cold storage heat exchanger absorbs the cold energy, and the liquid air forms a vaporous cryogenic gas. Step 4: The gaseous low-temperature gas enters the previous stage expander through the second outlet section of the previous stage expander to do work and generate electricity, and then is output to the cold storage and heat exchanger through the third outlet section of the previous stage compressor, where the cold energy is transferred to the cold storage and heat exchanger again. Step 5: The gaseous low-temperature gas, still retaining its cold energy, enters the next stage expander through the second outlet section to generate electricity. Then, it is output again through the third outlet section of the next stage compressor to the cold storage and heat exchanger, where the remaining cold energy is transferred. Finally, it is discharged through the fourth outlet section. At this point, the energy release and cold energy recovery processes are complete.
[0011] As a further preferred option, the cryogenic gas that has not been liquefied after passing through the throttle valve is discharged through a gas discharge pipe, which transfers the cooling capacity of this portion of cryogenic gas to a cold storage heat exchanger.
[0012] This invention integrates the accumulator and the heat exchanger of a multi-stage cold storage air energy storage system into a cold storage heat exchanger, making it easier to miniaturize, modularize, or integrate the multi-stage cold storage air energy storage system. In addition to conventional deployment on the power grid source side, it can also be flexibly applied in user-side scenarios, microgrid construction, and other fields. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention. Detailed Implementation
[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0015] The present invention provides an integrated cold storage and heat exchange air energy storage system, comprising: a compressor unit 1, an expander unit 2, an air inlet pipeline 3, an air outlet pipeline 4, a cold storage and heat exchanger 5, and an air energy storage device. The cold storage and heat exchanger 5 contains refrigerant and serves as a cold storage container. It has a heat exchange function, and the cold energy of the refrigerant will enter the air of the compressor unit 1 for pre-cold storage. Air energy storage devices are used to store air energy; Intake pipe 3 is divided into: One end is connected to the outside, and the other end is connected to the air inlet section 31 of the cold storage and heat exchanger; And, one end is connected to the inlet section 31 in the cold storage and heat exchanger, and the other end is connected to the inlet section 32 of the compressor unit 1. And, one end is connected to the outlet of compressor unit 1, and the other end is connected to the inlet section 33 of the cold storage and heat exchanger; And, one end is connected to the air intake section 33 in the cold storage and heat exchanger, and the other end is connected to the air intake section 4 34 at the inlet of the air storage device. Air outlet pipe 4 is divided into: One end is connected to the outlet of the air energy storage device, and the other end is connected to the air outlet section 41 of the cold storage and heat exchanger. And, one end is connected to the outlet section 41 inside the cold storage and heat exchanger, and the other end is connected to the outlet section 42 at the inlet of the expander unit 2. And, one end is connected to the outlet of expander unit 2, and the other end is connected to the outlet section 3 43 of the cold storage and heat exchanger; And, one end is connected to the outlet section 3 43 inside the cold storage and heat exchanger, and the other end is connected to the outlet section 4 44 to the outside. Compressor unit 1 is powered by electric motor unit 6. Compressor unit 1 is used to compress air and generate temperature. Expander unit 2 is connected to generator unit 7 to generate electricity. Expander unit 2 is used to perform work, output electrical energy, and provide refrigeration.
[0016] The compressor unit 1 includes a multi-stage compressor, with one compressor corresponding to one intake section 2 32 and one intake section 33; the intake sections 33 and 2 32 in two adjacent compressor stages are connected in a cold storage and heat exchanger.
[0017] Correspondingly, the expander unit 2 includes a multi-stage expander, with one expander corresponding to one outlet section 2 42 and one outlet section 3 43; the outlet sections 3 43 and 2 42 in two adjacent expanders are connected in a cold storage and heat exchanger.
[0018] The centralized cold storage and heat exchanger 5 of this invention can simultaneously realize cold storage and heat exchange, which can simplify the system process design, reduce system investment costs, and eliminate energy loss due to the absence of redundant external heat exchangers, resulting in higher energy utilization. Example 1
[0019] Reference Figure 1 The air storage device is a storage chamber 12 for storing high-pressure room temperature gas. The inlet section 4 34 is connected to the inlet of the storage chamber 12, and the outlet section 41 is connected to the outlet of the storage chamber 12. Example 2
[0020] Reference Figure 2 The air energy storage device includes a throttle valve 8, a cryogenic pump 9, and a liquid storage tank 13 for storing cryogenic liquid gas; the inlet section 44 is connected to the inlet of the liquid storage tank 13, and the outlet section 41 is connected to the outlet of the liquid storage tank 13; the throttle valve 8 is located on the inlet section 44, and the cryogenic pump 9 is located on the outlet section 41, which can realize both cold storage and cold exchange at the same time. The operating temperature of the system can be any operating temperature range above -200 degrees Celsius. The storage tank 13 is also equipped with a gas discharge pipe 10 for discharging unliquefied gas. The gas discharge pipe 10 is connected to the gas outlet section 44 via the cold storage and heat exchanger 5.
[0021] Example 2 illustrates the working principle of an integrated air energy storage system for storing and releasing electrical energy: Step 1: Air enters the cold storage and heat exchanger 5 through the first intake section 31 to cool down, then enters the first stage compressor through the second intake section 32 to be pressurized and heated to form room temperature high pressure gas, and then passes through the third intake section 33 of the first stage compressor to be output to the cold storage and heat exchanger 5 for cooling down again to form low temperature high pressure gas. Step 2: The low-temperature high-pressure gas enters the next stage compressor through the second intake section 32 and is pressurized and heated to form room temperature high-pressure gas. Then, it is output through the third intake section 33 of the next stage compressor to the cold storage and heat exchanger 5 for further cooling. This process continues until the low-temperature high-pressure gas enters the fourth intake section 34 and passes through the throttle valve 8 to form liquid air, which is stored in the liquid storage tank 13. At this point, the electrical energy storage process is completed, and the refrigerant in the cold storage and heat exchanger 5 is consumed. Specifically, after filtration, the outside air is first cooled to a cryogenic state by passing through the cold storage and heat exchanger 5. Then, it enters the first-stage compressor inside the compressor unit 1 for compression, after which the air temperature recovers from cryogenic to room temperature. Before entering each stage of the compressor, the compressed air passes through the cold storage and heat exchanger 5 to exchange heat with the working fluid before entering the next stage compressor for compression, resulting in high-pressure, room-temperature air. This high-pressure, room-temperature air is then cooled again to a high-pressure cryogenic state by the cold storage and heat exchanger 5. The high-pressure cryogenic air then passes through the throttling valve 8, where most of it becomes liquid air and is stored in the liquid storage tank 13. A small portion of the compressed air enters the cold storage and heat exchanger 5 through the gas discharge pipe 10 to recover cold energy before being discharged into the environment. When the liquid storage tank 13 reaches the required liquid air storage capacity, the energy storage process ends. At this time, all the cold energy in the cold storage heat exchanger 5 is released, and the cold storage medium in the cold storage heat exchanger 5 is at room temperature. During this process, the electric motor unit 6 supplies power to the compressor unit 1, and the electrical energy and the cold energy in the cold storage heat exchanger 5 are converted into the internal energy of the liquid air and stored.
[0022] Step 3: The liquid air in the storage tank 13 is pumped into the outlet section 41 by the cryogenic pump 9, and enters the cold storage heat exchanger 5 to be heated. The cold storage heat exchanger 5 absorbs the cold energy, and the liquid air forms a vaporized low-temperature gas. Step 4: The gaseous low-temperature gas enters the previous stage expander through the second outlet section 42 of the previous stage expander to do work and generate electricity, and then is output to the cold storage and heat exchanger 5 through the third outlet section 43 of the previous stage compressor, and the cold energy is transferred to the cold storage and heat exchanger 5 again. Step 5: The gaseous low-temperature gas, still retaining its cold energy, enters the next stage expander through the second outlet section 42 to generate electricity. Then, it is output again through the third outlet section 43 of the next stage compressor to the cold storage and heat exchanger 5, where the remaining cold energy is transferred. Finally, it is discharged through the fourth outlet section 44. At this point, the energy release process and the cold energy recovery process are completed.
[0023] Specifically, the liquid air stored in the storage tank 13 is pressurized by the cryogenic pump 9 and enters the cold storage and heat exchanger 5 to exchange cold energy with the heat exchange medium. After being heated and vaporized, it enters the first stage expander of the expander unit 2 through the second outlet section 42 for expansion. After expansion, it becomes compressed air in a cryogenic state and returns to the cold storage and heat exchanger 5 through the third outlet section 43 to cool the heat exchange medium and restore it to near room temperature. Then, through multi-stage expansion and inter-stage heat exchange, it finally returns to the cold storage and heat exchanger 5 through the third outlet section 43 of the last stage expander for final heat exchange, and finally is discharged into the atmosphere through the fourth outlet section 44.
[0024] When the liquid air in the storage tank 13 is consumed to a certain extent, the energy release process ends. The internal energy of the liquid air in the storage tank 13 does work through the expander and drives the generator set 7 to generate electricity. Part of it is converted into electrical energy and output to the outside, and part of it is converted into cold energy and stored in the cold storage and heat exchanger 5 for the next electrical energy storage process.
[0025] The unliquefied low-temperature gas after passing through the throttle valve 8 is discharged through the gas discharge pipe 10, and the gas discharge pipe 10 transfers the cold energy of this portion of the low-temperature gas to the cold storage heat exchanger 5.
[0026] This invention is easier to integrate with air separation systems and LNG gasification systems for development and utilization, thereby achieving greater economic benefits.
[0027] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. An integrated air energy storage system for cold storage and heat exchange, characterized in that: Includes: compressor unit (1), expander unit (2), intake pipe (3), outlet pipe (4), cold storage and heat exchanger (5), and air storage device; The cold storage and heat exchanger (5) is a cold storage container with heat exchange function; The intake pipe (3) is divided into: One end is connected to the outside, and the other end is connected to the air inlet section (31) of the cold storage and heat exchanger (5). And, one end is connected to the first intake section (31) in the cold storage and heat exchanger (5), and the other end is connected to the second intake section (32) at the inlet of the compressor unit (1). And, one end is connected to the outlet of the compressor unit (1), and the other end is connected to the inlet section three (33) of the cold storage and heat exchanger (5). And, one end is connected to the air intake section three (33) inside the cold storage and heat exchanger (5), and the other end is connected to the air intake section four (34) at the inlet of the air storage device. The exhaust pipe (4) is divided into: One end is connected to the outlet of the air storage device, and the other end is connected to the outlet section (41) of the cold storage and heat exchanger (5). And, one end is connected to the first outlet section (41) inside the cold storage and heat exchanger (5), and the other end is connected to the second outlet section (42) at the inlet of the expander unit (2). And, one end is connected to the outlet of the expander unit (2), and the other end is connected to the outlet section three (43) of the cold storage and heat exchanger (5). In addition, one end is connected to the third air outlet section (43) inside the cold storage and heat exchanger (5), and the other end is connected to the fourth air outlet section (44) outside. The compressor unit (1) is powered by the electric motor unit (6); The expander unit (2) is connected to an external generator set (7) for power generation.
2. The integrated air energy storage system for cold storage and heat exchange according to claim 1, characterized in that: The air storage device is a gas storage chamber (12) for storing high-pressure normal temperature gas. The fourth air inlet section (34) is connected to the inlet of the gas storage chamber (12), and the first air outlet section (41) is connected to the outlet of the gas storage chamber (12).
3. The integrated air energy storage system for cold storage and heat exchange according to claim 1, characterized in that: The air storage device includes a throttle valve (8), a cryogenic pump (9), and a storage tank (13) for storing cryogenic liquid gas. The fourth air intake section (34) is connected to the inlet of the liquid storage tank (13), and the first air outlet section (41) is connected to the outlet of the liquid storage tank (13); The throttle valve (8) is located on the fourth section (34) of the air intake, and the cryogenic pump (9) is located on the first section (41) of the air outlet.
4. The integrated air energy storage system for cold storage and heat exchange according to claim 3, characterized in that: The compressor unit (1) includes a multi-stage compressor, with one compressor corresponding to one intake section two (32) and one intake section three (33); the intake sections three (33) and two (32) in adjacent compressor stages are connected in a cold storage and heat exchanger.
5. The integrated air energy storage system for cold storage and heat exchange according to claim 4, characterized in that: The expander unit (2) includes a multi-stage expander, with one expander corresponding to one outlet section two (42) and one outlet section three (43); the outlet sections three (43) and two (42) in adjacent expanders are connected in a cold storage and heat exchanger.
6. The integrated air energy storage system for cold storage and heat exchange according to claim 5, characterized in that: The storage tank (13) is also equipped with a gas discharge pipe (10) for discharging unliquefied gas. The gas discharge pipe (10) is connected to the gas outlet section four (44) via the cold storage and heat exchanger (5).
7. The energy conversion method of an integrated air energy storage system for cold storage and heat exchange according to claim 6, characterized in that, Includes the following steps: Step 1: Air enters the cold storage and heat exchanger (5) through the first intake section (31) to cool down, and then enters the first compressor through the second intake section (32) to be pressurized and heated to form room temperature high pressure gas. Then it is output to the cold storage and heat exchanger (5) through the third intake section (33) of the first compressor to cool down again and form low temperature high pressure gas. Step 2: The low-temperature high-pressure gas enters the second inlet section (32) of the next stage compressor and is pressurized and heated to form room temperature high-pressure gas. Then, it is output to the cold storage and heat exchanger (5) through the third inlet section (33) of the next stage compressor to cool down again. This process is repeated until the low-temperature high-pressure gas enters the fourth inlet section (34), passes through the throttle valve (8) to form liquid air, and is stored in the liquid storage tank (13). At this time, the electrical energy storage process is completed, and the refrigerant in the cold storage and heat exchanger (5) is consumed. Step 3: The liquid air in the storage tank (13) is pumped into the first gas outlet section (41) by the cryogenic pump (9), enters the cold storage heat exchanger (5) to be heated, the cold storage heat exchanger (5) absorbs the cold energy, and the liquid air forms a vaporized low-temperature gas; Step 4: The gaseous low-temperature gas enters the first-stage expander through the second outlet section (42) of the first-stage expander to do work and generate electricity, and then is output to the cold storage and heat exchanger (5) through the third outlet section (43) of the first-stage compressor, and the cold energy is transferred to the cold storage and heat exchanger (5) again. Step 5: The gaseous low-temperature gas that still retains its cold energy enters the next stage expander through the second (42) outlet section of the next stage expander to generate electricity. Then, it is output again through the third (43) outlet section of the next stage compressor to the cold storage and heat exchanger (5), where the remaining cold energy is transferred to the cold storage and heat exchanger (5) again. Finally, it is discharged through the fourth (44) outlet section. At this time, the process of releasing electrical energy and recovering cold energy is completed.
8. The energy conversion method of an integrated air energy storage system for cold storage and heat exchange according to claim 7, characterized in that: The low-temperature gas that has not been liquefied after passing through the throttle valve (8) is discharged through the gas discharge pipe (10), and the gas discharge pipe (10) transfers the cold energy of this part of the low-temperature gas to the cold storage heat exchanger (5).