Liquid Carbon Dioxide Energy Storage System and Microgrid System for Islands and Reefs

Abstract

The present invention provides a liquid carbon dioxide energy storage system and a microgrid system for island reefs. The liquid carbon dioxide energy storage system includes an energy storage module and a solar thermal module. The energy storage module includes a first liquid carbon dioxide storage tank, a first heat exchanger, a compression device, a cooling device, an expansion device, a second liquid carbon dioxide storage tank, a heating device, an energy release device, and a heat dissipation device. The cooling device includes a first cooler and a second cooler. The heating device includes a first heater and a second heater. The compression device is electrically connected to a new energy power generation system to store the electric energy of the new energy power generation system. The energy release device is electrically connected to an electricity consumption system to supply power to the electricity consumption system. The solar thermal module is communicated with another heat exchange chamber of the second heater. The present invention can meet the scenario requirements of island reefs for power generation, power storage, electricity consumption, and heat supply.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide energy storage, and particularly to a liquid carbon dioxide energy storage system and a microgrid system for island reefs. Background Art

[0002] Due to the limitations of energy supply and power consumption supply, the infrastructure construction of offshore island reefs is still subject to certain restrictions. At present, the production power supply of offshore island reefs mainly has two methods: long-distance submarine cable access and on-island self-provided diesel power generation system. The laying project of long-distance submarine cables is difficult and the operation and maintenance costs are high, and it is not suitable for long-distance island reefs; the diesel power generation system needs to consume fossil energy, and has serious noise pollution and large efficiency losses. Therefore, some offshore island reefs use photovoltaic power generation and wind power generation for power supply. However, since such energy is greatly affected by meteorological conditions and has significant uncertainty and volatility, problems such as large fluctuations in power generation power and insufficient power supply capacity occur. Therefore, the energy storage system has become an important part of constructing the microgrid in the offshore island reef area.

[0003] The electricity load of offshore island reefs is generally small. Therefore, a small and medium-sized, long-duration energy storage technology is required when matching new energy power generation methods. Conventional electrochemical energy storage technologies such as lithium batteries, sodium batteries, lead-acid batteries, etc. have short energy storage durations, and the system thermal management conditions are harsh, and there are great safety risks in applications on islands with extremely unstable natural conditions; the compressed air energy storage technology has low energy storage efficiency when the designed installed capacity is small. Therefore, a large gas storage volume and floor area are required, which has a great impact on the offshore island reefs with very limited area itself.

[0004] Therefore, there is an urgent need for an energy storage system that can solve the problems of long-term power shortage and instability faced by the microgrid of offshore island reefs. Summary of the Invention

[0005] The present invention provides a liquid carbon dioxide energy storage system and a microgrid system for island reefs to solve the problems of long-term power shortage and instability faced by the microgrid of offshore island reefs in the prior art.

[0006] The present invention provides a liquid carbon dioxide energy storage system for island reefs, comprising: an energy storage module and a solar thermal module; the energy storage module includes: a first liquid carbon dioxide storage tank, a first heat exchanger, a compression device, a cooling device, an expansion device, a second liquid carbon dioxide storage tank, a heating device, an energy release device, and a heat dissipation device; the cooling device includes a first cooler and a second cooler; the heating device includes a first heater and a second heater; the outlet of the first liquid carbon dioxide storage tank, one heat exchange chamber of the first heat exchanger, the compression device, one heat exchange chamber of the first cooler, one heat exchange chamber of the second cooler, the expansion device, the second liquid carbon dioxide storage tank, the first pump body, one heat exchange chamber of the first heater, one heat exchange chamber of the second heater, the energy release device, the heat dissipation device, the other heat exchange chamber of the first heat exchanger, and the inlet of the first liquid carbon dioxide storage tank are sequentially connected; the other heat exchange chamber of the second cooler is connected to the other heat exchange chamber of the first heater; the compression device is used to be electrically connected to a new energy power generation system to store the electric energy of the new energy power generation system; the energy release device is used to be electrically connected to an electricity consumption system to supply power to the electricity consumption system; the solar thermal module is connected to the other heat exchange chamber of the second heater.

[0007] According to the liquid carbon dioxide energy storage system for island reefs provided by the present invention, a plurality of the compression devices and the first coolers are provided, the number of the compression devices is the same as the number of the first coolers, and the compression devices and the first coolers are sequentially and alternately connected.

[0008] According to the liquid carbon dioxide energy storage system for island reefs provided by the present invention, a plurality of the energy release devices and the second heaters are provided, the number of the energy release devices is the same as the number of the second heaters, and the energy release devices and the second heaters are sequentially and alternately connected.

[0009] According to the liquid carbon dioxide energy storage system for island reefs provided by the present invention, the energy storage module further includes: a first pump body, and the first pump body is arranged between the second liquid carbon dioxide storage tank and the first heater.

[0010] According to the liquid carbon dioxide energy storage system for island reefs provided by the present invention, the solar thermal module includes a solar collector, a heat storage tank, a working medium storage tank, and a second heat exchanger; the heat storage tank, the working medium storage tank, and one heat exchange chamber of the second heat exchanger are sequentially connected to form a first circulation loop, and the solar collector can be selectively connected to the first circulation loop; the other heat exchange chamber of the second heat exchanger is connected to the other heat exchange chamber of the second heater.

[0011] A liquid carbon dioxide energy storage system for island reefs provided by the present invention, the solar thermal module further includes: a second pump body and a third pump body; the second pump body is arranged between the solar collector and the working fluid storage tank, and the third pump body is arranged between the heat storage tank and the working fluid storage tank.

[0012] A liquid carbon dioxide energy storage system for island reefs provided by the present invention, the energy storage module further includes: a first chilled liquid tank and a second chilled liquid tank; the other heat exchange chamber of the second cooler, the first chilled liquid tank, the other heat exchange chamber of the first heater, and the second chilled liquid tank are connected in sequence to form a second heat exchange loop.

[0013] A liquid carbon dioxide energy storage system for island reefs provided by the present invention, one end of the other heat exchange chamber of the first cooler is used to communicate with the seawater introduction system, and the other end is used to communicate with the user heating system.

[0014] A liquid carbon dioxide energy storage system for island reefs provided by the present invention, the first circulating working fluid in the first heat exchange loop is carbon dioxide.

[0015] The present invention also provides a liquid carbon dioxide microgrid system for island reefs, including: a new energy power generation system, an electricity consumption system, and the liquid carbon dioxide energy storage system for island reefs described in any one of the above; the new energy power generation system is electrically connected to the compression device, and the electricity consumption system is electrically connected to the energy release device.

[0016] The liquid carbon dioxide energy storage system and microgrid system for island reefs provided by the present invention, on the one hand, by setting an energy storage module and a solar thermal module, connecting the new energy power generation system to the compression device, the electric energy of the new energy power generation system can be stored, and connecting the solar thermal module to the other heat exchange chamber of the second heater, so as to utilize solar thermal power generation through the solar thermal module. The above can store the electric energy of the new energy power generation system and the thermal energy of the solar thermal module of the solar energy, meet the scenario requirements of small-scale power generation, power storage, and power consumption, and realize the stable power supply of the island reef; on the other hand, by connecting the other heat exchange chamber of the second cooler to the other heat exchange chamber of the first heater, cooling and liquefying the first circulating working fluid flowing into the second liquid carbon dioxide storage tank. At the same time, by setting a heat dissipation device and a first heat exchanger, cooling and liquefying the first circulating working fluid flowing into the first liquid carbon dioxide storage tank, pure liquid storage of carbon dioxide can be realized. Compared with air compression energy storage, the floor area of the energy storage system is significantly reduced and the energy storage efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a liquid carbon dioxide microgrid system for island reefs provided by some embodiments of the present invention.

[0019] Reference numerals:

[0020] 1: Energy storage module; 101: First liquid carbon dioxide storage tank; 102: First heat exchanger; 103: Compression device; 104: Expansion device; 105: Second liquid carbon dioxide storage tank; 106: First pump body; 107: Energy release device; 108: Heat dissipation device; 109: First cold storage liquid tank; 110: Second cold storage liquid tank; 111: First valve body; 1121: First cooler; 1122: Second cooler; 1131: First heater; 1132: Second heater;

[0021] 2: Solar thermal module; 201: Solar collector; 202: Heat storage tank; 203: Working fluid storage tank; 204: Second heat exchanger; 205: Second pump body; 206: Third pump body; 207: Second valve body; 208: Third valve body; 209: Fourth valve body; 210: Fifth valve body; 211: Sixth valve body; 212: Seventh valve body;

[0022] 3: Generator. Detailed implementation manners

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention with reference to the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] The following combines Figure 1 to describe the liquid carbon dioxide energy storage system for island reefs of the present invention. As Figure 1 shown, the liquid carbon dioxide energy storage system provided by the present invention includes: an energy storage module 1 and a solar thermal module 2.

[0025] The energy storage module 1 includes: a first liquid carbon dioxide storage tank 101, a first heat exchanger 102, a compression device 103, a cooling device, an expansion device 104, a second liquid carbon dioxide storage tank 105, a heating device, an energy release device 107, and a heat dissipation device 108; the cooling device includes a first cooler 1121 and a second cooler 1122; the heating device includes a first heater 1131 and a second heater 1132.

[0026] The outlet of the first liquid carbon dioxide storage tank 101, one heat exchange chamber of the first heat exchanger 102, the compression device 103, one heat exchange chamber of the first cooler 1121, one heat exchange chamber of the second cooler 1122, the expansion device 104, the second liquid carbon dioxide storage tank 105, one heat exchange chamber of the first heater 1131, one heat exchange chamber of the second heater 1132, the energy release device 107, the heat dissipation device 108, the other heat exchange chamber of the first heat exchanger 102, and the inlet of the first liquid carbon dioxide storage tank 101 are connected in sequence to form a first heat exchange loop.

[0027] The other heat exchange chamber of the second cooler 1122 is connected to the other heat exchange chamber of the first heater 1131; the compression device 103 is used to be electrically connected to a new energy power generation system to store the electric energy of the new energy power generation system; the energy release device 107 is used to be electrically connected to an electricity consumption system to supply power to the electricity consumption system; the solar thermal module 2 is connected to the other heat exchange chamber of the second heater 1132.

[0028] Among them, the first circulating working medium in the first heat exchange loop can be carbon dioxide. The compression device 103 uses compressed carbon dioxide energy storage technology to store the electric energy of the new energy power generation system.

[0029] Among them, the new energy power generation system includes wind power generation and a photovoltaic power generation system.

[0030] The new energy power generation system is the power production source of the island reef, and the generated electricity is used for industrial and living use. During the low electricity consumption period, the electric energy is input into the energy storage module 1, that is, energy storage is realized by the power consumption of the compression device 103.

[0031] Among them, the solar thermal module 2 is related to the expansion and energy release process in the energy storage module 1, and is used to provide heat energy for the carbon dioxide that does work for the energy release device 107.

[0032] The solar thermal module 2 is used to store solar energy and use solar energy to heat the first circulating working medium in the second cooler 1122 to realize solar thermal power generation.

[0033] Among them, the electricity consumption system includes a generator 3, and the energy release device 107 is connected to the generator 3 and is used for expansion power generation.

[0034] The electricity consumption system includes electricity consumption systems such as military, production, and life.

[0035] In related technologies, when the designed installed capacity of compressed air energy storage technology is small, the energy storage efficiency is not high, and a large gas storage volume and floor area are required, which has a great impact on military reefs with very limited area itself.

[0036] The present invention provides a liquid carbon dioxide energy storage system for reefs. On the one hand, by setting up an energy storage module 1 and a solar thermal module 2, connecting a new energy power generation system to a compression device 103, the electric energy of the new energy power generation system can be stored. Connecting the solar thermal module 2 to another heat exchange chamber of a second heater 1132, so as to utilize solar thermal power generation through the solar thermal module 2. The above can store the electric energy of the new energy power generation system and the thermal energy of the solar thermal module 2 of solar energy, meet the scenario requirements of small-scale power generation, power storage, and power consumption, and achieve stable power supply on reefs. On the other hand, by connecting another heat exchange chamber of a second cooler 1122 to another heat exchange chamber of a first heater 1131, cooling and liquefying the first circulating working medium flowing into a second liquid carbon dioxide storage tank 105. At the same time, by setting up a heat dissipation device 108 and a first heat exchanger 102, cooling and liquefying the first circulating working medium flowing into a first liquid carbon dioxide storage tank 101, pure liquid storage of carbon dioxide can be realized. Compared with air compression energy storage, the floor area of the energy storage system is significantly reduced and the energy storage efficiency is improved.

[0037] Among them, the first liquid carbon dioxide storage tank 101 and the second liquid carbon dioxide storage tank 105 are used to store liquid carbon dioxide.

[0038] The first liquid carbon dioxide storage tank 101 and the second liquid carbon dioxide storage tank 105 can be liquid carbon dioxide storage tanks well-known in the art. For example, low-pressure pressure vessels made of cast iron or steel can be used.

[0039] The pressures of the first liquid carbon dioxide storage tank 101 and the second liquid carbon dioxide storage tank 105 can be the same or different.

[0040] Among them, the first heat exchanger 102, the cooling device, the heating device, and the heat dissipation device 108 are all heat exchange devices with heat exchange functions well-known in the art, and the types of heat exchange devices used are specifically selected according to the use scenario.

[0041] For example, the first heat exchanger 102 can be a cold storage heat exchanger. The first circulating working medium in the first heat exchange loop is cooled to a liquid state in the first heat exchanger 102.

[0042] The cooling device can be a cooler well-known in the art, and the first circulating working medium in the energy storage module 1 exchanges heat and is cooled in the cooling device.

[0043] The first circulating working fluid in the first heat exchange loop exchanges heat with the solar thermal module 2 in the second heater 1132 and is heated by the high-temperature second circulating working fluid in the solar thermal module 2.

[0044] The heat dissipation device 108 can be a radiator well-known in the art, and the heat dissipation method can adopt liquid cooling or air cooling.

[0045] When the compression device 103 stores the excess electric energy of the new energy power generation system, heat is released, causing the temperature of the flowing first circulating working fluid to rise. The cooling device is used to cool the high-temperature first circulating working fluid flowing out of the compression device 103 so that the first circulating working fluid becomes cooled and liquefied and is stored in the second liquid carbon dioxide storage tank 105.

[0046] Among them, the solar thermal module 2, the heating device and the energy release device 107 utilize solar thermal power generation to realize the energy storage and utilization of solar energy.

[0047] Among them, the second circulating working fluid in the solar thermal module 2 can be a heat exchange working fluid well-known in the art. For example, it can be water and water vapor, or other heat exchange working fluids such as heat-conducting oil.

[0048] It should be noted that compared with gas-liquid mixture or supercritical state storage, pure liquid storage further reduces the volume of the compression device, and thus further reduces the floor area of the energy storage module.

[0049] Among them, the first cooler 1121 and the second heater 1132 can be heat exchangers well-known in the art, such as shell-and-tube heat exchangers, plate heat exchangers, and finned heat exchangers, etc.

[0050] Among them, the other heat exchange chamber of the second cooler 1122 is communicated with the other heat exchange chamber of the first heater 1131 to form a second heat exchange loop.

[0051] The second circulating working fluid flowing through the second heat exchange loop can be a cold storage working fluid well-known in the art. For example, it can be methanol or other low-temperature liquid cold storage working fluids.

[0052] Among them, the power consumption system includes a generator 3, and the energy release device 107 is connected to the generator 3 for expansion work power generation.

[0053] Further, as Figure 1 shown, both the compression device 103 and the first cooler 1121 are provided with a plurality of them. The number of the compression devices 103 is the same as the number of the first coolers 1121, and the compression devices 103 and the first coolers 1121 are alternately connected in sequence.

[0054] In this embodiment, by designing a multi-stage compression device 103 and a multi-stage first cooler 1121, the excess electric energy generated by the new energy power generation system is fully compressed and stored, and the compression heat is fully discharged through the first cooler 1121 to further reduce the temperature of the first circulating working fluid, realizing the full utilization of energy.

[0055] Further, the compression device 103 includes a compressor. The compressor is used to be electrically connected to the new energy power generation system for compression energy storage.

[0056] In some embodiments, the compression device 103 is provided with 2 compressors, and the first cooler 1121 is provided with 2. Carbon dioxide sequentially passes through the first compressor, the first first cooler 1121, the second compressor and the second first cooler 1121 and enters the second cooler 1122, and the carbon dioxide is cooled and liquefied by the second cooler 1122.

[0057] Among them, the first compressor and the second compressor fully store and consume the excess electric energy generated by the new energy power generation system to realize compression energy storage. In this process, carbon dioxide is compressed into a high-temperature and high-pressure supercritical state, and at the same time, the compression heat is discharged through the two first coolers 1121.

[0058] Among them, the supercritical state refers to the state where carbon dioxide is above the critical temperature and critical pressure and close to the critical point. Carbon dioxide being compressed into a high-temperature and high-pressure supercritical state means that carbon dioxide is in a dense gaseous state close to the liquid state.

[0059] Further, a plurality of energy release devices 107 and second heaters 1132 are provided. The number of the energy release devices 107 and the second heaters 1132 is the same, and the energy release devices 107 and the second heaters 1132 are alternately connected in sequence.

[0060] In some embodiments, the energy release device 107 includes an expander. The expander is used to be electrically connected to the power consumption system to supply power to the power consumption system.

[0061] Power generation during the expansion process is used for military, production, and living electricity on the island.

[0062] In this embodiment, carbon dioxide is heated and vaporized and drives the two-stage expander to do work and generate electricity to realize expansion energy release. In this process, carbon dioxide is heated to a certain temperature by the high-temperature water from the solar thermal module 2 through the second heater 1132 at the inlet of each stage of the expander, which helps to improve the expansion work.

[0063] In this embodiment, by designing a multi-stage energy release device 107 and a second heater 1132, expansion energy release is fully carried out to realize the full optimization of energy.

[0064] In some embodiments, such as Figure 1As shown, the energy release device 107 is provided with two expanders, and the second heater 1132 is provided with two. The carbon dioxide flowing out of the first heater 1131 sequentially passes through the first second heater 1132, the first expander, the second second heater 1132, and the second expander and enters the heat dissipation device 108, where the carbon dioxide is cooled to room temperature by the heat dissipation device 108.

[0065] It can be understood that the compression device 103 and the energy release device 107 are not limited to two stages and can also be set in a multi-stage form. Correspondingly, a multi-stage first cooler 1121 and a multi-stage second heater 1132 can also be provided to achieve full storage and utilization of energy, which can be specifically set according to actual needs.

[0066] Furthermore, the energy storage module further includes: a first pump body, which is arranged between the second liquid carbon dioxide storage tank and the first heater, and the first pump body is used to drive the first circulating working medium to flow.

[0067] Furthermore, the energy storage module further includes: a first valve body 111, and the first valve body 111 can be a pressure stabilizing valve well-known in the art.

[0068] In some embodiments, the first valve body 111 is a throttle valve.

[0069] Furthermore, the energy storage module 1 further includes: a first cold storage liquid tank 109 and a second cold storage liquid tank 110; the other heat exchange chamber of the second cooler 1122, the first cold storage liquid tank 109, the other heat exchange chamber of the first heater 1131, and the second cold storage liquid tank 110 are sequentially connected.

[0070] Among them, the first cold storage liquid tank 109 and the second cold storage liquid tank 110 are used to store the second circulating working medium. The high-pressure normal-temperature carbon dioxide coming out of the first cooler 1121 is cooled by the low-temperature second circulating working medium coming out of the first cold storage liquid tank 109 through the second cooler 1122.

[0071] The liquid carbon dioxide stored in the second liquid carbon dioxide storage tank 105 increases in pressure through the first pump body 106, and at the same time, the temperature slightly rises, and then enters the first heater 1131 to transfer the low-temperature cold quantity to the medium-temperature second circulating working medium coming out of the second cold storage liquid tank 110, and then the temperature of the carbon dioxide rises significantly.

[0072] In this embodiment, by setting the second heat exchange loop in which the other heat exchange chamber of the second cooler 1122, the first cold storage liquid tank 109, the other heat exchange chamber of the first heater 1131, and the second cold storage liquid tank 110 are sequentially connected, heat exchange can be carried out using the heat energy of the first heat exchange loop itself to achieve pure liquid storage of carbon dioxide.

[0073] Further, another heat exchange chamber of the first cooler 1121 is used to communicate with the seawater introduction system and the user heating system.

[0074] Among them, the low-temperature seawater or desalinated seawater by-products in the seawater introduction system are used as a cooling medium, and sequentially enter the multi-stage first cooler 1121 to absorb heat. The obtained high-temperature water can be used to supply heat to users through the user heating system.

[0075] Currently, heat supply facilities also need to be set up for heating in island areas, resulting in complex energy supply problems in the already limited island areas.

[0076] In this embodiment, by connecting another heat exchange chamber of the first cooler 1121 with the seawater introduction system and the user heating system, the compression heat generated by the energy storage medium is recovered to solve the heating problem on the reefs, and the application scenarios of the liquid carbon dioxide energy storage system in the present invention are increased.

[0077] Further, as Figure 1 shown, the solar thermal module 2 includes a solar collector 201, a heat storage tank 202, a working fluid storage tank 203, and a second heat exchanger 204; a heat exchange chamber of the heat storage tank 202, the working fluid storage tank 203, and the second heat exchanger 204 are sequentially connected to form a first circulation loop, and the solar collector 201 can be selectively connected to the first circulation loop; another heat exchange chamber of the second heat exchanger 204 is connected to another heat exchange chamber of the second heater 1132.

[0078] Further, the solar thermal module 2 further includes: a second pump body 205 and a third pump body 206; the second pump body 205 is arranged between the solar collector 201 and the working fluid storage tank 203, and the third pump body 206 is arranged between the heat storage tank 202 and the working fluid storage tank 203.

[0079] Further, the solar thermal module 2 further includes: a plurality of valve bodies, and the valve bodies can be valve bodies well known in the art, such as solenoid valves.

[0080] In some embodiments, the plurality of valve bodies include a second valve body 207, a third valve body 208, a fourth valve body 209, a fifth valve body 210, a sixth valve body 211, and a seventh valve body 212.

[0081] Among them, the solar thermal module 2 includes a heat storage process and a heat release process.

[0082] Heat storage process: When there is sufficient sunlight, the second valve body 207, the third valve body 208, the fourth valve body 209 and the seventh valve body 212 are all opened, the fifth valve body 210 and the sixth valve body 211 are all closed, the heat storage tank 202, the working fluid storage tank 203 are connected to the solar collector 201, one heat exchange chamber of the second heat exchanger 204 is connected to the solar collector 201, and one heat exchange chamber of the second heat exchanger 204 is connected in parallel with the heat storage tank 202 and the working fluid storage tank 203.

[0083] Part of the third cycle working fluid is driven by the second pump body 205 into the heat storage tank 202 to store heat. At the same time, another part of the third cycle working fluid passes through one heat exchange chamber of the second heat exchanger 204 to provide a heat source for heating the low-temperature water from the second heater 1132 and making it into high-temperature water through the second heater 1132, forming a third heat exchange loop.

[0084] Among them, the types of the heat exchange working fluid in one heat exchange chamber of the second heat exchanger 204 and the heat exchange working fluid in its other heat exchange chamber can be the same or different.

[0085] For example, the heat exchange working fluid in one heat exchange chamber of the second heat exchanger 204 can be water and water vapor, and the heat exchange working fluid in the other heat exchange chamber can be other heat exchange working fluids such as heat-conducting oil to achieve water-oil heat exchange.

[0086] In some embodiments, the heat storage tank 202 can store heat by heating the pebbles therein through sensible heat exchange.

[0087] Heat release process: When there is insufficient sunlight, the second valve body 207, the third valve body 208 and the seventh valve body 212 are all closed, the fourth valve body 209, the fifth valve body 210 and the sixth valve body 211 are all opened, and the heat storage tank 202, the working fluid storage tank 203 and the second heat exchanger 204 are connected in sequence.

[0088] The third cycle working fluid stored in the working fluid storage tank 203 is driven by the third pump body 206 into the heat storage tank 202 to absorb the stored heat. The third cycle working fluid with an increased temperature then passes through one heat exchange chamber of the second heat exchanger 204 to repeat the heat storage process and heat the incoming water.

[0089] In some embodiments, the heat storage tank 202 can be a device for storing heat energy well-known in the art. For example, a packed bed type high-temperature heat storage device can be used.

[0090] In some embodiments, the heat storage tank 202 includes necessary heat preservation measures to extend the heat storage duration.

[0091] Further, a circulation pump is also provided in the second heat exchange circuit formed by sequentially connecting another heat exchange chamber of the second cooler 1122, the first cold storage liquid tank 109, another heat exchange chamber of the first heater 1131, and the second cold storage liquid tank 110 to accelerate the flow rate of the second circulating working medium and improve the heat exchange efficiency.

[0092] The present invention provides a liquid carbon dioxide energy storage system for island reefs. On the one hand, by organically combining offshore new energy (new energy power generation system, solar thermal module 2) and the energy storage module 1, the problem of heat supply can be solved by recovering the compression heat at the same time. The solar thermal system provides heating for the expansion process to achieve multi-energy complementarity of light - heat - electricity - storage, meeting the scenario requirements of small - scale power generation, electricity storage, power consumption, and heat supply, and solving the long - standing problems of power shortage, instability, and energy optimization on island reefs; on the other hand, using the carbon dioxide energy storage of liquid carbon dioxide has advantages such as high energy storage density, small floor area, and stable operation compared with compressed air energy storage. Moreover, the energy storage system can independently regulate various working conditions of energy storage, energy release, heat storage, and heat release according to natural conditions and power consumption requirements. Combining heat supply and solar thermal heat supply can eliminate the need for heat storage equipment, and the whole system is relatively simple; on the third hand, it can operate in an off - grid and isolated island mode to ensure load power supply and energy consumption requirements.

[0093] The liquid carbon dioxide micro - grid system for island reefs provided by the present invention will be described below. The liquid carbon dioxide micro - grid system for island reefs described below includes the liquid carbon dioxide storage system for island reefs described above.

[0094] As Figure 1 shown, the liquid carbon dioxide micro - grid system for island reefs provided by the present invention includes: a new energy power generation system, an electricity consumption system, and the liquid carbon dioxide energy storage system for island reefs as described in any one of the above; the new energy power generation system is electrically connected to the compression device 103, and the electricity consumption system is electrically connected to the energy release device 107.

[0095] Among them, the seawater introduction system is communicated with another heat exchange chamber of the first cooling device and is used to be communicated with the user heat supply system for heating users.

[0096] The present invention provides a liquid carbon dioxide microgrid system for island reefs. On the one hand, by organically combining offshore new energy (new energy power generation system, solar thermal module 2) and energy storage module 1, it can also solve the heating problem by recovering compression heat, provide heating quantity for the expansion process through the solar thermal system, realize the multi-energy complementarity of light-thermal-electricity-storage, meet the scenario requirements of small-scale power generation, electricity storage, electricity consumption and heating, and solve the long-term problems of insufficient, unstable power supply and energy optimization on island reefs; on the other hand, using the carbon dioxide energy storage of liquid carbon dioxide, compared with compressed air energy storage, it has the advantages of high energy storage density, small floor area, stable operation, etc. Moreover, the energy storage system can independently control various working conditions such as energy storage, energy release, heat storage and heat release according to natural conditions and electricity demand. Combining heating and solar thermal heating can eliminate the need for heat storage equipment, and the whole system is relatively simple; on the third hand, it can operate in an off-grid island mode to ensure the power supply and energy demand of the load.

[0097] The following combines Figure 1 , and takes a specific embodiment to illustrate the liquid carbon dioxide energy storage system for island reefs and the liquid carbon dioxide microgrid system for island reefs provided by the present invention.

[0098] Working principle of energy storage module 1:

[0099] Energy storage and heating process: The liquid carbon dioxide in the first liquid carbon dioxide storage tank 101 is cooled and gasified through the throttling effect of the first valve body 111, and then stores the cold quantity through the cold storage heat exchanger and further increases the temperature. Subsequently, the carbon dioxide gas enters the first-stage compressor, the first-stage first cooler 1121, the second-stage compressor and the second-stage first cooler 1121 in sequence. The compressor consumes the excess electric energy generated by the wind power generation and photovoltaic power generation systems to realize compressed energy storage. In this process, the carbon dioxide is compressed into a high-temperature and high-pressure supercritical state, and at the same time, the compression heat is discharged through the two-stage first cooler 1121. Here, the low-temperature seawater or desalinated seawater by-products introduced into the system are used as the cooling medium, and enter the second-stage first cooler 1121 and the first-stage first cooler 1121 in sequence to absorb heat, and the high-temperature water obtained can supply heat to heat users. The high-pressure normal-temperature carbon dioxide coming out of the second-stage first cooler 1121 is cooled by the low-temperature working medium coming out of the first cold storage liquid tank 109 through the second cooler 1122, and then enters the expansion device 104 to cool down and liquefy, and finally the liquid carbon dioxide is stored in the second liquid carbon dioxide storage tank 105.

[0100] Energy release power generation process: The liquid carbon dioxide stored in the second liquid carbon dioxide storage tank 105 increases in pressure through a cryogenic liquid pump, and at the same time, its temperature slightly rises. Then it enters the first heater 1131 to transfer the low-temperature cold energy to the medium-temperature cold energy storage working medium coming out of the second cold energy storage liquid tank 110. Subsequently, the temperature of the carbon dioxide rises significantly. Then it enters the first-stage second heater 1132, the first-stage energy release device 107, the second-stage second heater 1132, and the second-stage energy release device 107 in sequence. The carbon dioxide is heated and vaporized to drive the two-stage expanders to do work and generate electricity, realizing expansion energy release. During this process, the carbon dioxide is heated to a certain temperature by the high-temperature water from the solar thermal unit through the second heater 1132 at the inlet of each stage of the expander, which helps to improve the expansion work. The carbon dioxide coming out of the second-stage energy release device 107 is then cooled to room temperature through the heat dissipation device 108, and then enters the first heat exchanger 102 to be liquefied by the stored cold energy, and finally enters the first liquid carbon dioxide storage tank 101 for storage.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A liquid carbon dioxide energy storage system for island reefs, characterized in that, Comprising: An energy storage module and a solar thermal module; The energy storage module includes: a first liquid carbon dioxide storage tank, a first heat exchanger, a compression device, a cooling device, an expansion device, a second liquid carbon dioxide storage tank, a heating device, an energy release device, and a heat dissipation device; the cooling device includes a first cooler and a second cooler; the heating device includes a first heater and a second heater; The outlet of the first liquid carbon dioxide storage tank, one heat exchange chamber of the first heat exchanger, the compression device, one heat exchange chamber of the first cooler, one heat exchange chamber of the second cooler, the expansion device, the second liquid carbon dioxide storage tank, one heat exchange chamber of the first heater, one heat exchange chamber of the second heater, the energy release device, the heat dissipation device, the other heat exchange chamber of the first heat exchanger, and the inlet of the first liquid carbon dioxide storage tank are sequentially connected to form a first heat exchange loop; The other heat exchange chamber of the second cooler is connected to the other heat exchange chamber of the first heater; The compression device is used to be electrically connected to a new energy power generation system to store the electric energy of the new energy power generation system; The energy release device is used to be electrically connected to an electricity consumption system to supply power to the electricity consumption system; The solar thermal module is connected to the other heat exchange chamber of the second heater to provide heat energy for the heating device.

2. The liquid carbon dioxide energy storage system for island reefs according to claim 1, characterized in that, A plurality of the compression devices and the first coolers are provided, the number of the compression devices is the same as the number of the first coolers, and the compression devices and the first coolers are sequentially and alternately connected.

3. The liquid carbon dioxide energy storage system for island reefs according to claim 1, characterized in that, A plurality of the energy release devices and the second heaters are provided, the number of the energy release devices is the same as the number of the second heaters, and the energy release devices and the second heaters are sequentially and alternately connected.

4. The liquid carbon dioxide energy storage system for island reefs according to claim 1, characterized in that, The energy storage module further includes: a first pump body, and the first pump body is arranged between the second liquid carbon dioxide storage tank and the first heater.

5. The liquid carbon dioxide energy storage system for island reefs according to claim 1, characterized in that, The solar thermal module includes a solar collector, a heat storage tank, a working medium storage tank, and a second heat exchanger; The heat storage tank, the working medium storage tank, and one heat exchange chamber of the second heat exchanger are sequentially connected to form a first circulation loop, and the solar collector can be selectively connected to the first circulation loop; The other heat exchange chamber of the second heat exchanger is connected to the other heat exchange chamber of the second heater.

6. The liquid carbon dioxide energy storage system for island reefs according to claim 5, characterized in that, The solar thermal module further includes: a second pump body and a third pump body; The second pump body is arranged between the solar collector and the working medium storage tank, and the third pump body is arranged between the heat storage tank and the working medium storage tank.

7. The liquid carbon dioxide energy storage system for island reefs according to any one of claims 1 to 6, characterized in that, The energy storage module further includes: a first cold storage liquid tank and a second cold storage liquid tank; The other heat exchange chamber of the second cooler, the first cold storage liquid tank, the other heat exchange chamber of the first heater, and the second cold storage liquid tank are sequentially connected to form a second heat exchange loop.

8. The liquid carbon dioxide energy storage system for island reefs according to any one of claims 1 to 6, characterized in that, One end of the other heat exchange chamber of the first cooler is used to be connected to a seawater introduction system, and the other end is used to be connected to a user heating system.

9. The liquid carbon dioxide energy storage system for island reefs according to any one of claims 1 to 6, characterized in that, The first circulating working medium in the first heat exchange loop is carbon dioxide.

10. A liquid carbon dioxide microgrid system for island reefs, characterized in that, Including a new energy power generation system, an electricity consumption system, and the liquid carbon dioxide energy storage system for island reefs according to any one of claims 1 to 9; The new energy power generation system is electrically connected to the compression device, and the power consumption system is electrically connected to the energy release device.

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