Refrigerant type energy storage system based on safety and ultra-long service life

Abstract

The utility model relates to the field of energy storage, in particular to a gas energy storage technology. A refrigerant type energy storage system based on safety and ultra-long service life comprises a gas compression system and a gas expansion system, the gas expansion system is linked with a power generator, and a gas inlet of the gas compression system is connected to a low-pressure refrigerant gas storage chamber; a gas outlet of the gas compression system is connected to a high-pressure refrigerant gas storage tank; an outlet of the high-pressure refrigerant gas storage tank is connected to an input port of the gas expansion system through a valve; and an output port of the gas expansion system is connected to the low-pressure refrigerant gas storage chamber. The high-pressure refrigerant gas storage tank has the advantages that the gas-state refrigerant can be compressed into the liquid-state refrigerant with low pressure, so that the cost of the high-pressure refrigerant gas storage tank for storing the liquid-state refrigerant is reduced; and after the refrigerant is expanded and gasified, the low-pressure refrigerant is stored in the low-pressure refrigerant gas storage chamber reconstructed by the underground cave airtight structure, and the underground cave airtight structure has the beneficial effects of large utilization volume and low construction cost.

Description

Technical Field

[0001] This application relates to the field of energy storage, and specifically to gas energy storage technology. Background Art

[0002] In order to promote the green and low-carbon transformation of the economic society, achieve "carbon neutrality" and "energy structure adjustment", and at the same time enhance the international discourse power, respond to global climate change, and ensure energy security, China is encouraging the development of clean energy.

[0003] In clean energy technologies, such as the rapid development of wind power and photovoltaic power, they are greatly affected by the environment, and the power generation is unstable, which brings potential safety hazards to the safe operation of the power grid. In order to solve the problems of intermittency, volatility, and uncontrollability of renewable energy, improve energy utilization efficiency and power grid stability, energy storage technology, especially compressed air energy storage, has emerged as the times require. Compressed air energy storage technology can achieve large-scale energy storage, play a role in coordinating the peak shaving and valley filling of the power grid, and can also be used as a supporting facility for new energy power generation such as wind power and photovoltaic power, making up for its strong randomness and large volatility to a certain extent.

[0004] However, air is difficult to compress because the critical temperature of air is -140.7 degrees Celsius and the critical pressure is as high as 377 atmospheric pressures. In order to improve the energy storage efficiency, it is necessary to build a gas storage container with a huge storage volume and a pressure resistance of one to two hundred atmospheres. And higher pressure requires the gas storage container to have high sealing performance. Therefore, the construction of the gas storage container is difficult and the construction cost remains high, which affects the popularization of air energy storage technology. Utility Model Content

[0005] The purpose of this utility model is to provide a refrigerant-based energy storage system based on safety and ultra-long life to solve at least one of the above technical problems.

[0006] The technical problems solved by this utility model can be realized by the following technical solutions:

[0007] A refrigerant-based energy storage system based on safety and ultra-long life includes a gas compression system and a gas expansion system. The gas expansion system is linked to a generator. The intake port of the gas compression system is connected to a low-pressure refrigerant gas storage chamber; the outlet of the gas compression system is connected to a high-pressure refrigerant gas storage tank;

[0008] The outlet of the high-pressure refrigerant gas storage tank is connected to the input port of the gas expansion system through a valve; the output port of the gas expansion system is connected to the low-pressure refrigerant gas storage chamber;

[0009] The low-pressure refrigerant gas storage chamber includes an underground cave and an airtight structure arranged in the underground cave; the airtight structure of the pressure refrigerant gas storage chamber adopts a concrete layer; the inner wall of the airtight structure of the pressure refrigerant gas storage chamber is coated with a sealing layer.

[0010] In the above design, the energy storage medium is refrigerant. Common refrigerants are easily compressed into a liquid state at temperatures above zero degrees Celsius and at moderate pressures. For example, the commonly used refrigerant pentafluoropropane can be compressed and liquefied at 96 degrees Celsius and pressures of 8 to 12 MPa. Therefore, by consuming intermittent and fluctuating electrical energy through a gas compression system, the gaseous refrigerant is compressed into a high-pressure liquid refrigerant and stored in a high-pressure refrigerant tank, thereby achieving energy security and ultra-long-life storage in the refrigerant-based energy storage system.

[0011] When the power grid enters peak power consumption, the high-pressure refrigerant storage tank releases liquid refrigerant. The liquid refrigerant expands through the gas, driving the gas expander to rotate in the gas expansion system, thereby driving the generator to generate electricity and be incorporated into the power grid. The high-pressure refrigerant vaporizes and expands in this process, and after passing through the gas expander, it is collected in the low-pressure refrigerant storage chamber.

[0012] Low-pressure refrigerant gas storage chambers can be converted into airtight structures by utilizing underground caves, such as abandoned mines, oil and gas field cavities, etc. The airtight structure is surrounded by a concrete layer to form a sealed space. The beneficial effect is that the underground cave has a large capacity and contains low-pressure refrigerant gas. Therefore, the low-pressure refrigerant gas storage chamber does not need to consider the pressure resistance problem, but only needs to ensure airtightness. A sealing layer can be simply coated on the inner wall of the airtight structure, thus having the beneficial effect of low construction cost.

[0013] The refrigerant energy storage system consumes electricity to compress the refrigerant storage during off-peak hours and releases high-pressure refrigerant to generate electricity and connect to the grid during peak hours, thereby coordinating the power grid's peak shaving and valley filling.

[0014] Furthermore, the refrigerant is pentafluoropropane.

[0015] Pentafluoropropane is environmentally friendly, highly efficient, does not damage the ozone layer, does not cause a greenhouse effect, and is also low-cost.

[0016] Furthermore, the bottom of the underground cave of the low-pressure refrigerant storage chamber is greater than 30m from the ground.

[0017] Below 30m from the ground, the seasonal temperature changes on the surface are unlikely to affect this depth, so this depth is a constant temperature zone, which is conducive to the storage of low-pressure refrigerant gas.

[0018] Furthermore, the sealing layer is a ceramic layer.

[0019] The sealing layer is a ceramic layer, which has the beneficial effect that the ceramic layer is dense and the refrigerant gas is not easy to leak.

[0020] Further, the sealing layer is made of a nano-scale silicone polymer coating, and the thickness of the coating is 7 - 12 μm.

[0021] After the coating reaches 7 - 12 μm, the nano-scale silicone polymer coating has an excellent airtight effect. Under a pressure of 0.5 MPa, the gas permeability is below 1 nD, and under a pressure of 4 MPa, the gas permeability is 4.5×10 -6 -5.5×10 -6 mD.

[0022] Further, the high-pressure refrigerant gas storage tank uses a gas storage tank with a pressure resistance of 12 - 15 Mpa.

[0023] The high-pressure refrigerant gas storage tank is used to store pentafluoropropane in a high-pressure liquefied state. The critical pressure of pentafluoropropane is 8 - 12 Mpa. Therefore, for the safety of high-pressure refrigerant storage, the pressure resistance of the gas storage tank needs to exceed the critical pressure of pentafluoropropane.

[0024] Further, the gas compression system includes at least two gas compressors and at least two coolers;

[0025] All the coolers use heat exchangers;

[0026] The outlet of the previous gas compressor is connected to the hot-end inlet of a cooler, and the hot-end outlet of the cooler is connected to the inlet of the next gas compressor;

[0027] The hot-end outlet of the cooler connected to the last-stage gas compressor is connected to the high-pressure refrigerant gas storage tank;

[0028] It also includes a heat storage system, which includes a container for containing a heat storage medium, and the container is provided with a cold-end outlet and a cold-end inlet;

[0029] The cold-end outlet of the heat storage system is connected to the cold-end inlets of each cooler through the drive of a fluid pump, and the cold-end outlets of each cooler are connected to the cold-end inlet of the heat storage system.

[0030] In the above design, heat is released during the compression and liquefaction process of the refrigerant. Therefore, behind each stage of the gas compressor, the compressed refrigerant needs to be cooled by a cooler, and the cooling is carried out by a heat exchanger. The high heat generated by the refrigerant is recovered and stored in the heat storage system through the heat storage medium in the heat exchanger.

[0031] Further, the gas expansion system includes at least two gas expanders and at least two reheaters;

[0032] All the reheaters use heat exchangers;

[0033] The cold-end inlet of the first reheater is used as the input port of the gas expansion system and is connected to the outlet of the high-pressure refrigerant gas storage tank;

[0034] The cold end outlet of each reheater is connected to the air supply port of a gas expander, and the exhaust port of the gas expander is connected to the cold end inlet of the next reheater.

[0035] The exhaust port of the last gas expander is used as the output port of the gas expansion system and is connected to the low-pressure refrigerant storage chamber.

[0036] It also includes a heat storage system provided with a heat storage medium container, and the container is provided with a hot end outlet and a hot end inlet.

[0037] The hot end outlet of the heat storage system is connected to the hot end inlet of each reheater through the drive of a fluid pump, and the hot end outlet of each reheater is connected to the hot end inlet of the heat storage system.

[0038] In the above design, the high-pressure liquid refrigerant is heated and expanded through the reheater, and the gas after heating and expansion drives the gas expander to rotate to drive the generator to generate electricity. The heating is carried out by a heat exchanger, and the heat required for heating comes from the heat storage medium in the energy storage system, and the heat in the heat storage medium comes from the compression heat generated during the refrigerant compression process, so as to realize the recycling of heat.

[0039] The present utility model uses refrigerant as the energy storage medium, and its beneficial effects are as follows. First, the refrigerant is easier to be compressed and liquefied than air, and its critical pressure is low. Therefore, the pressure resistance of the high-pressure refrigerant storage tank is relatively lower than the pressure required for high-pressure air. Therefore, the manufacturing cost of the high-pressure refrigerant storage tank is low, and it can be stored more safely and with an ultra-long service life. Second, after the high-pressure refrigerant expands and generates electricity, its low-pressure refrigerant gas is stored in an underground cave. The low-pressure refrigerant storage chamber rebuilt from the airtight structure of the underground cave has the advantages of low construction cost and large available volume. Brief Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the description of the embodiments. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings. Among them:

[0041] Figure 1 is a schematic diagram of the present utility model;

[0042] Figure 2 is a schematic cross-sectional structure diagram of the airtight structure of the present utility model.

[0043] Symbol Explanation:

[0044] 1. Motor; 2. Gas compression system; 3. Cooler; 4. High-pressure refrigerant gas storage tank; 5. Reheater; 6. Gas expansion system; 7. Generator; 8. Heat storage system; 9. Low-pressure refrigerant gas storage chamber; 11. Hermetic structure; 12. Sealing layer. Detailed implementation mode

[0045] To make the above objects, features, and advantages of the present utility model more understandable, the following will describe in detail the specific implementation modes of the present utility model with reference to the accompanying drawings of the specification.

[0046] In the following description, many specific details are set forth to fully understand the present utility model. However, the present utility model can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present utility model. Therefore, the present utility model is not limited by the specific embodiments disclosed below.

[0047] Secondly, the present utility model will be described in detail with reference to the schematic diagrams. When describing the embodiments of the present utility model in detail, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally not in accordance with the general ratio, and the schematic diagrams are only examples and should not limit the scope of protection of the present utility model herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0048] Furthermore, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation mode of the present utility model. The "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is separate or selectively mutually exclusive with other embodiments.

[0049] Refer to Figure 1 、 Figure 2 As shown, a refrigerant-based energy storage system based on safety and ultra-long life includes a gas compression system 2 and a gas expansion system 6. The gas expansion system 6 is linked to a generator 7. The intake port of the gas compression system 2 is connected to a low-pressure refrigerant gas storage chamber 9; the outlet of the gas compression system 2 is connected to a high-pressure refrigerant gas storage tank 4;

[0050] The outlet of the high-pressure refrigerant gas storage tank 4 is connected to the input port of the gas expansion system 6 through a valve; the output port of the gas expansion system 6 is connected to the low-pressure refrigerant gas storage chamber 9;

[0051] The low-pressure refrigerant gas storage chamber 9 includes an underground cave and a hermetic structure 11 provided in the underground cave; the hermetic structure 11 of the refrigerant gas storage chamber adopts a concrete layer; the inner wall of the hermetic structure 11 of the refrigerant gas storage chamber is coated with a sealing layer 12.

[0052] In this embodiment, the energy storage medium is a refrigerant. Common refrigerants are generally easy to compress into a liquid state at temperatures above zero degrees Celsius and at moderate pressures. For example, the commonly used refrigerant pentafluoropropane can be compressed and liquefied at 96 degrees Celsius and a pressure of 8 to 12 MPa. Therefore, by consuming intermittent and fluctuating electrical energy through the gas compression system 2, the gaseous refrigerant is compressed into a high-pressure liquid refrigerant and stored in the high-pressure refrigerant storage tank 4, thereby achieving energy security and ultra-long-life storage in the refrigerant-based energy storage system.

[0053] When the power grid enters the peak of electricity consumption, the high-pressure refrigerant storage tank 4 releases liquid refrigerant. The liquid refrigerant expands through the gas, pushing the gas expander to rotate in the gas expansion system 6, and then driving the generator 7 to generate electricity and be incorporated into the power grid. The high-pressure refrigerant gasifies and expands in this process, and after passing through the gas expander, it is collected in the low-pressure refrigerant storage chamber 9.

[0054] The low-pressure refrigerant storage chamber 9 can be converted into an airtight structure by utilizing underground caves, such as abandoned mines, oil and gas field cavities, etc. The airtight structure 11 is surrounded by a concrete layer to form a sealed space. The beneficial effect is that the underground cave has a large capacity and contains low-pressure refrigerant gas. Therefore, the low-pressure refrigerant storage chamber 9 does not need to consider the pressure resistance problem, but only needs to ensure airtightness. It can simply adopt the method of coating the sealing layer 12 on the inner wall of the airtight structure 11, so it has the beneficial effect of low construction cost.

[0055] The refrigerant energy storage system consumes electricity to compress the refrigerant storage during off-peak hours and releases high-pressure refrigerant to generate electricity and connect to the grid during peak hours, thereby coordinating the power grid's peak shaving and valley filling.

[0056] Furthermore, the refrigerant is pentafluoropropane.

[0057] In this embodiment, pentafluoropropane is environmentally friendly and highly efficient, does not damage the ozone layer, and does not cause a greenhouse effect. It also has the advantage of low cost.

[0058] Furthermore, the bottom of the underground cave of the low-pressure refrigerant storage chamber 9 is below 30 m from the ground.

[0059] In this embodiment, the bottom of the underground cave is below 30m from the ground. The temperature changes of the four seasons at this depth are difficult to affect the ground surface. Therefore, this depth is a constant temperature zone, which is conducive to the long-term storage of low-pressure refrigerant gas.

[0060] Furthermore, the sealing layer 12 is a ceramic layer.

[0061] In this embodiment, the sealing layer 12 is a ceramic layer, which has the beneficial effect that the ceramic layer is dense and the refrigerant gas is not easily leaked.

[0062] Further, the sealing layer 12 is made of a nano-scale silicone polymer coating, and the thickness of the coating is 7-12 μm.

[0063] In this embodiment, after the coating of the nano-scale silicone polymer coating reaches 7-12 μm, it has an excellent airtight effect. Under a pressure of 0.5 MPa, the gas permeability is below 1 nD, and under a pressure of 4 MPa, the gas permeability is 4.5×10 -6 -5.5×10 -6 mD.

[0064] Further, the high-pressure refrigerant gas storage tank 4 uses a gas storage tank with a pressure resistance of 12-15 Mpa.

[0065] In this embodiment, the high-pressure refrigerant gas storage tank 4 is a gas storage tank for storing pentafluoropropane in a high-pressure liquefied state. The critical pressure of pentafluoropropane is 8-12 Mpa. Therefore, for the safety of high-pressure refrigerant storage, the pressure resistance of the gas storage tank needs to exceed the critical pressure of pentafluoropropane.

[0066] Further, the gas compression system 2 includes at least two gas compressors and at least two coolers 3;

[0067] All of the coolers 3 use heat exchangers;

[0068] The outlet of the previous gas compressor is connected to the hot end inlet of a cooler 3, and the hot end outlet of the cooler 3 is connected to the inlet of the next gas compressor;

[0069] The hot end outlet of the cooler 3 connected to the last-stage gas compressor is connected to the high-pressure refrigerant gas storage tank 4;

[0070] It further includes a heat storage system 8, and the heat storage system 8 includes a container for containing a heat storage medium, and the container is provided with a cold end outlet and a cold end inlet;

[0071] The cold end outlet of the heat storage system 8 is connected to the cold end inlets of each cooler 3 through the drive of a fluid pump, and the cold end outlets of each cooler 3 are connected to the cold end inlet of the heat storage system 8.

[0072] In this embodiment, the motor 1 drives the gas compressor to compress the refrigerant. The refrigerant will release heat during the compression and liquefaction process. Therefore, behind each stage of the gas compressor, the compressed refrigerant needs to be cooled by the cooler 3. The cooling is carried out by a heat exchanger, and the high heat generated by the refrigerant is recovered and stored in the heat storage system 8 through the heat storage medium in the heat exchanger.

[0073] Further, the gas expansion system 6 includes at least two gas expanders and at least two reheaters 5;

[0074] All of the reheaters 5 use heat exchangers;

[0075] The cold-end inlet of the first reheater 5 is connected to the outlet of the high-pressure refrigerant gas storage tank 4 as the input port of the gas expansion system 6;

[0076] The cold-end outlet of each reheater 5 is connected to the air supply port of a gas expander, and the exhaust port of this gas expander is connected to the cold-end inlet of the next reheater 5;

[0077] The exhaust port of the last gas expander is connected to the low-pressure refrigerant gas storage chamber 9 as the output port of the gas expansion system 6.

[0078] It also includes a heat storage system 8 provided with a heat storage medium container, and the container is provided with a hot-end outlet and a hot-end inlet;

[0079] The hot-end outlet of the heat storage system 8 is connected to the hot-end inlets of each reheater 5 through the drive of a fluid pump, and the hot-end outlets of each reheater 5 are connected to the hot-end inlet of the heat storage system 8.

[0080] In this embodiment, the high-pressure liquid refrigerant is heated and expanded through the reheater 5, and the heated and expanded gas drives the gas expander to rotate to drive the generator 7 to generate electricity. The heating is carried out by a heat exchanger, and the heat required for heating comes from the heat storage medium in the energy storage system, and the heat in the heat storage medium comes from the compression heat generated during the refrigerant compression process, thereby realizing the recycling of heat.

[0081] In addition, to provide a concise description of the exemplary embodiments, all features of the actual embodiments may not be described, that is, those features that are not relevant to the best mode of the present invention or those features that are not relevant to the implementation of the present invention.

[0082] It should be understood that in the development process of any actual implementation, such as in any engineering or design project, a large number of specific implementation decisions can be made. Such development efforts may be complex and time-consuming, but for those ordinary technicians who benefit from this disclosure, without excessive experimentation, the development efforts will be a routine work of design, manufacturing, and production.

[0083] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A refrigerant energy storage system based on safety and ultra-long life, including a gas compression system and a gas expansion system, the gas expansion system being linked to a generator, characterized in that: The intake port of the gas compression system is connected to a low-pressure refrigerant gas storage chamber; The outlet port of the gas compression system is connected to a high-pressure refrigerant gas storage tank; The outlet of the high-pressure refrigerant gas storage tank is connected to the input port of the gas expansion system through a valve; The output port of the gas expansion system is connected to the low-pressure refrigerant gas storage chamber; The low-pressure refrigerant gas storage chamber includes an underground cave and an airtight structure provided in the underground cave; The airtight structure of the refrigerant gas storage chamber adopts a concrete layer; The inner wall of the airtight structure of the refrigerant gas storage chamber is coated with a sealing layer.

2. The refrigerant energy storage system based on safety and ultra-long life according to claim 1, wherein The refrigerant used is pentafluoropropane.

3. The refrigerant energy storage system based on safety and ultra-long life according to claim 1, wherein The bottom of the underground cave of the low-pressure refrigerant gas storage chamber is more than 30 m away from the ground.

4. The refrigerant energy storage system based on safety and ultra-long life according to claim 1, characterized in that, The sealing layer adopts a ceramic layer.

5. The refrigerant energy storage system based on safety and ultra-long life according to claim 1, wherein The sealing layer adopts a nano-level silicone polymer coating, and the thickness of the coating is 7-12 μm.

6. The refrigerant-based energy storage system based on safety and ultra-long life according to claim 1, characterized in that, The high-pressure refrigerant gas storage tank adopts a gas storage tank with a pressure resistance of 12-15 Mpa.

7. The refrigerant energy storage system based on safety and ultra-long life according to claim 1, wherein The gas compression system includes at least two gas compressors and at least two coolers; All the coolers adopt heat exchangers; The outlet port of the previous gas compressor is connected to the hot-end inlet of a cooler, and the hot-end outlet of the cooler is connected to the intake port of the next gas compressor; The hot-end outlet of the cooler connected to the last-stage gas compressor is connected to the high-pressure refrigerant gas storage tank; It also includes a heat storage system, the heat storage system including a container for containing a heat storage medium, and the container is provided with a cold-end outlet and a cold-end inlet; The cold-end outlet of the heat storage system is connected to the cold-end inlets of each cooler through the drive of a fluid pump, and the cold-end outlets of each cooler are connected to the cold-end inlet of the heat storage system.

8. The refrigerant-based energy storage system based on safety and ultra-long life according to claim 1, characterized in that, The gas expansion system includes at least two gas expanders and at least two reheaters; All the reheaters adopt heat exchangers; The cold-end inlet of the first reheater is used as the input port of the gas expansion system and is connected to the outlet of the high-pressure refrigerant gas storage tank; The cold-end outlet of each reheater is connected to the air supply port of a gas expander, and the exhaust port of this gas expander is connected to the cold-end inlet of the next reheater; The exhaust port of the last gas expander is used as the output port of the gas expansion system and is connected to the low-pressure refrigerant gas storage chamber; It also includes a heat storage system provided with a container for containing a heat storage medium, and the container is provided with a hot-end outlet and a hot-end inlet; The hot-end outlet of the heat storage system is connected to the hot-end inlets of each reheater through the drive of a fluid pump, and the hot-end outlets of each reheater are connected to the hot-end inlet of the heat storage system.

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