A regional multi-energy complementary system coupling reversible solid oxide battery technology with a closed CO2 network

Abstract

The present invention relates to the field of new energy, and discloses a regional multi-energy complementary zero-carbon energy supply system that couples reversible solid oxide cell technology with a closed CO2 network, including RSOC thermal-mass-electricity reversible conversion, a closed CO2 circulation network, renewable energy power, an external heat source, chemical energy storage, natural cold and heat sources, and end-use energy modules. In the present invention, the RSOC operates bidirectionally in the power generation and electrolysis modes, and couples with the chemical energy storage module to achieve regional multi-time-scale energy balance. Photovoltaic power generation supplies power to both the RSOC electrolysis and end users simultaneously. In the external heat source module, concentrating solar heat collection and industrial waste heat can be integrated with the RSOC module to reduce the electrolysis power consumption. The closed CO2 network uses pressurized low-temperature CO2 as the circulating working fluid for the regional heating and cooling network. It can fully utilize the waste heat of the RSOC and natural cold and heat resources on the source side; at the end, it greatly improves the heating and cooling capacity of the network through phase change heat transfer to achieve passive cooling of users, and at the same time couples with a water source heat pump to meet different-grade heating demands, with net zero carbon emissions throughout the process.

Description

Technical Field

[0001] The present invention relates to the field of new energy, and in particular to a regional multi-energy complementary system that couples reversible solid oxide battery technology with a closed CO2 network. Background Art

[0002] Driven by the strategic goals of "carbon neutrality and carbon peak", my country's installed capacity of renewable energy power generation has increased rapidly, reaching 1.45 billion kilowatts by the end of 2023, historically exceeding thermal power. Developing a regional energy supply system with renewable energy as the main body is an important path to building my country's clean, low-carbon, safe and efficient energy system.

[0003] Heating and cooling are the core of regional energy supply. After four technological innovations, the system energy efficiency has been continuously improved. Compared with traditional energy supply methods, the fifth-generation regional heating and cooling system (5GDHC) based on ultra-low temperature network (12-30°C) can make full use of low-grade waste heat resources. By integrating natural cold and heat sources and wind and solar resources and coupling water source heat pumps, it can further break through the current efficiency of combined cooling / heating / electricity (~80%). In addition, 5GDHC uses two pipelines to achieve simultaneous cooling and heating, which is suitable for efficient supply of cold / heating / electricity in various climate regions in my country. It has great potential for cost reduction and application promotion, and is expected to become a new way to solve the problem of local consumption of renewable energy and deep utilization of low-grade waste heat in the future.

[0004] However, the existing 5GDHC system uses water circulation to achieve heating and cooling. The temperature of the cold and heat sources, the heat exchange temperature difference, and the small temperature difference of the supply and return water (~10°C) limit the heat transmission capacity of the water network, and the energy consumption standards of the terminal buildings are extremely high. At the same time, the real-time energy supply of the system is affected by the large-scale integrated strong fluctuations and intermittent fluctuations of renewable energy. The long-term energy supply on the load side faces difficulties such as summer cooling peak loads, high heat-to-electricity ratios in winter, and cross-seasonal imbalances in cold and hot loads. It is difficult to achieve regional multi-time scale supply and demand balance through direct use of local energy resources, and cross-seasonal imbalances in cold and hot loads will cause serious problems such as ecological damage. Therefore, it is urgent to build a new regional multi-energy complementary zero-carbon emission and environmentally friendly energy supply system that can realize cross-seasonal storage and efficient utilization of renewable energy and break through the limitations of existing energy supply methods.

[0005] The existing Chinese patent document with publication number CN116885789A discloses a multi-energy complementary energy supply system based on regional wind, solar and storage combined heat and power generation. The multi-energy complementary system includes: an electric balance system, a heat balance system, and a cold balance system. The electric balance system includes a photovoltaic power generation system, a wind power generation system, a gas turbine, an energy storage device and a main grid; the heat balance system includes a gas boiler and a waste heat boiler; the cold balance system includes an electric refrigerator and an absorption refrigerator. However, the patent technology only explains the energy production and conversion equipment, and has the following disadvantages:

[0006] 1. This technology does not explain the system energy supply network;

[0007] 2. The energy storage equipment in this technology is mainly used for electricity storage, and fails to consider the storage of regional energy across seasons;

[0008] 3. The equipment used in this technology are all conventional energy supply equipment, and the system energy efficiency has room for further improvement.

[0009] The existing Chinese patent with publication number CN214841824 U discloses a regional cooling and heating system based on multi-energy complementarity, which includes cold and hot water sources, a heat pump unit that can work in cooling or heating mode, and a user heat exchanger group. The cold and hot water sources are connected to the heat pump unit through a water source side circulation pipeline, and the heat pump unit and the user heat exchanger group are connected through a user side circulation pipeline. It also includes a power supply system for supplying power to the heat pump unit. The cold and hot water sources include surface water sources and hot water sources from thermal power plants. The power supply system includes a municipal power system, a wind power generation system, and a photovoltaic power generation system.

[0010] This patented technology has the following disadvantages:

[0011] 1. The conventional water network is used for heating and cooling, which has the problems of large energy dissipation in the energy supply process and limited heating and cooling capacity. The water network is used for heating and cooling;

[0012] 2. The solar energy utilization method is single, and only photovoltaic arrays are configured;

[0013] 3. The cold and hot water sources of the system include surface water sources, but the water network has limited utilization of natural cold and hot sources;

[0014] 4. Including city electricity, it is impossible to achieve regional energy self-consistency;

[0015] 5. Multi-time scale energy storage equipment is not configured, and regional short-term and cross-seasonal energy balance cannot be achieved.

[0016] In 2010, Céline Weber published an article, Conventional and advanced CO2 based district energy systems, which first introduced a district energy system using CO2 as a working fluid. Two pipes filled with refrigerant were used to meet the requirements of heating, hot water and cooling. However, this technical solution only analyzed the technical and economic feasibility of the CO2 network and had the following disadvantages:

[0017] 1. This technology only considers the heat transfer with natural cold and heat sources, but does not consider the imbalance of cold and heat loads across seasons, nor the ecological threats caused by the difference in cold and heat loads;

[0018] 2. The technology does not clarify the source of electricity, and there are carbon emissions in the system energy supply process;

[0019] 3. This technology is not fully supplied by local energy resources and cannot achieve regional energy self-consistency.

[0020] The existing US patent with publication number US20100018668A1 proposes a valuable alternative to the existing regional energy system. In view of safety issues such as space occupation of regional energy supply pipelines and leakage of working fluids, a regional energy system using CO2 as working fluid is proposed to solve the above problems. However, the patent technology has the following problems:

[0021] 1. This technology covers traditional fossil energy conversion technology and cannot achieve zero carbon emissions;

[0022] 2. This technology does not take into account the imbalance of cold and heat loads across seasons and the ecological threats it causes;

[0023] 3. The system is not equipped with a multi-time scale energy storage device and cannot achieve regional energy self-consistent balance.

[0024] In 2018, Raluca Suciu published an article titled Energy integration of CO2 networks and power to gas for emerging energy autonomous cities in Europe, which evaluated the application potential of CO2 regional energy networks. By integrating CO2 regional heating networks, electricity to gas, cogeneration and long-term energy storage technologies, the local renewable resources can be used for heating and power generation to the maximum extent. This technical solution has the following disadvantages:

[0025] 1. This technology uses solar energy in a single way, with only photovoltaic arrays configured.

[0026] 2. This technology uses solid oxide technology as the electric gasification technology, but does not consider the impact of integrating external heat sources and expanding the thermal integration boundary on the system energy efficiency. Summary of the invention

[0027] In order to overcome or alleviate one or more of the above technical problems, the purpose of the present invention is to provide a regional multi-energy complementary system that couples reversible solid oxide battery technology with a closed CO2 network. By coupling RSOC heat-mass-electricity reversible conversion, closed CO2 circulation network multi-source-multi-sink energy transfer, heat pump low-grade thermal energy quality improvement and efficiency enhancement and other complex processes, the complementary utilization of various energy sources such as ambient low-temperature cold and heat sources, solar energy, methane, electricity and heat is achieved, overcoming the problems of cross-seasonal cold and heat load imbalance and system energy efficiency improvement of the regional energy supply system, and having the advantages of deep utilization of waste heat, passive cooling, compact structure, high energy efficiency and zero carbon emissions.

[0028] The present invention provides the following technical solutions:

[0029] A regional multi-energy complementary system that couples reversible solid oxide battery technology with a closed CO2 network, comprising a RSOC heat-mass-electricity reversible conversion module, a closed CO2 circulation network module, a renewable energy power module, an external heat source module, a chemical energy storage module, a natural cold and heat source module, and a terminal energy module:

[0030] The RSOC heat-mass-electricity reversible conversion module uses solid oxide electrolysis and fuel cells to perform heat-CH4-electricity reversible conversion, thereby achieving efficient conversion and storage of regional renewable energy and intra-day / inter-seasonal energy balance; the RSOC heat-mass-electricity reversible conversion module operates in two modes: solid oxide electrolysis cell and solid oxide fuel cell mode, i.e., SOEC and SOFC;

[0031] The closed CO2 circulation network module includes a gaseous main pipeline and a liquid main pipeline with similar temperature and pressure and different phases, and realizes heat transfer between the pipeline working medium and the source side / load side through the CO2 liquid / gas phase change;

[0032] The renewable energy power module includes photovoltaic power generation equipment, which provides renewable electricity for the electrolysis of the RSOC heat-mass-electricity reversible conversion module, the system power equipment and the terminal power load;

[0033] The external heat source module includes a concentrating heat collection device, a heat storage device and industrial waste heat. The concentrating heat collection device is used to collect solar energy to provide high-temperature heat, and the heat storage device is used to store renewable energy heat for a short time. The concentrating heat collection device and the industrial waste heat are integrated with the RSOC heat-mass-electricity reversible conversion module to reduce the power consumption of SOEC.

[0034] The chemical energy storage module includes a methane storage device for storing methane produced by SOEC and providing fuel for SOFC power generation;

[0035] The natural cold and heat source module includes rivers and lakes; in summer, when the internal heat of the closed CO2 circulation network module is excessive, heat exchange is performed with the natural cold source to achieve energy balance; in winter, when the internal heat of the closed CO2 circulation network module is insufficient, the waste heat of the natural heat source and the RSOC heat-mass-electricity reversible conversion module is used to supplement the heat of the regional multi-energy complementary system to achieve energy balance;

[0036] The terminal energy module meets the electric load demand through photovoltaic power generation and SOFC power generation, realizes passive cooling through heat exchange with the liquid CO2 in the closed CO2 circulation network module, realizes the refrigeration demand by coupling the refrigeration cycle unit with the closed CO2 circulation network module, and realizes the terminal hot water and heating heat load demand by coupling the water source heat pump with the closed CO2 circulation network module.

[0037] According to some embodiments, the RSOC heat-mass-electricity reversible conversion module is powered by the renewable energy power module and heat is provided by the external heat source module in the SOEC mode, and synthetic raw materials are provided through the water storage tank and the CO2 storage tank, and the synthetic methane enters the chemical energy storage module for storage, and the tail waste heat is transmitted to the closed CO2 cycle network module after generating electricity through the organic Rankine cycle;

[0038] In the SOFC mode, the methane provided by the chemical energy storage module is used to generate electricity to supply the terminal power load, and the generated water and CO2 flow to the water storage tank and the CO2 storage tank respectively. After being input into the external heat source module, they are successively transferred to the organic Rankine cycle and the closed CO2 circulation network module.

[0039] According to some embodiments, the external heat source module comprises a solar collector (1), industrial waste heat (2), a cold tank (3), a hot tank (4) and an external heat source heat exchanger (5); the solar collector (1) converts solar energy into thermal energy, and heats the low-temperature working fluid from the cold tank (3) with the industrial waste heat (2), and transports it to the hot tank (4), forming a flow cycle; the external heat source heat exchanger (5) is used to transfer heat to the RSOC heat-mass-electricity reversible conversion module to generate electricity or electrolysis;

[0040] The RSOC heat-mass-electricity reversible conversion module comprises an RSOC unit and an ORC waste heat power generation unit, wherein the RSOC unit comprises a water pump (6), a water-side electric heater (7), a first compressor (8), a CO2-side electric heater (9), a fuel-side heat exchanger (10), a first valve (11), a reactor (12), a CH4 cooler (13), a steam-water separator (14), a purification device (15), a second compressor (16), a methane pipeline three-way valve (17), a methane storage tank (18), a fuel-side electric heater (19), a fuel cell (20), a combustion chamber (21), a second valve (22), and a third compressor (23). ), an air side heat exchanger (24) and an air side electric heater (25); on the RSOC fuel inlet side, the outlet of the water pump (6) is connected to the water side electric heater (7) and the external heat source heat exchanger (5) in sequence, the outlet of the first compressor (8) is connected to the CO2 side electric heater (9), the CO2 side electric heater (9) and the outlet of the external heat source heat exchanger (5) are mixed and then connected to the fuel side heat exchanger (10) and the fuel side electric heater (19) in sequence, and then connected to the fuel side inlet of the fuel cell stack (20); on the RSOC air side, the outlet of the third compressor (23) is connected to the air side heat exchanger (24), and then connected to the air side electric heater (25) in sequence. and the air side inlet of the stack (20); the fuel side outlet of the stack (20) is connected to the combustion chamber (21), and then connected to the fuel side heat exchanger (10), and the fuel side outlet of the stack can also be directly connected to the fuel side heat exchanger (10); the fuel side heat exchanger (10) is connected to the first valve (11) and the second valve (22); the first valve (11) is connected to the reactor (12), the CH4 cooler (13), the steam-water separator (14), the purification device (15), the second compressor (16), and the methane pipeline three-way valve (17) in sequence, and the second valve (22) is connected to the air side heat exchanger (24); the air side outlet of the stack (20) is connected to the fuel side outlet The ORC waste heat power generation unit comprises an ORC source side heat exchanger (26), a turbine (27), a generator (28), an ORC cold end heat exchanger (29) and a circulation pump (30). The outlet of the ORC source side heat exchanger (26) is connected to the turbine (27), the outlet of the turbine is connected to the ORC cold end heat exchanger (29), and the generator (28) is driven by the shaft to generate electricity. The outlet of the ORC cold end heat exchanger (29) is connected to the circulation pump (30), and then connected to the inlet of the ORC source side heat exchanger (26).

[0041] According to some embodiments, the renewable energy power module includes a photovoltaic array (59), which converts solar energy into electrical energy and inputs it into a power bus (54). The generator (28) and the SOFC electrical output (55) are connected to the power bus (54), and the power bus supplies electricity to SOEC power (56), auxiliary equipment power (57) and user loads (58).

[0042] According to some embodiments, in the closed CO2 circulation network module, the low-temperature liquid CO2 is vaporized into gaseous CO2 and flows into the gaseous CO2 main pipeline (53) after absorbing the waste heat of the RSOC heat-mass-electricity reversible conversion module on the source side, the heat of the natural heat source in the rivers and lakes, and the indoor heat on the load side; the gaseous CO2 releases heat to the natural cold source on the source side and provides heat to the terminal on the load side, and is liquefied into liquid CO2 and flows into the liquid CO2 main pipeline (52).

[0043] According to some embodiments, the closed CO2 circulation network module includes a liquid CO2 main pipeline (52) and a gaseous CO2 main pipeline (53), and the two pipelines are connected to the RSOC heat-mass-electricity reversible conversion module through an ORC cold end heat exchanger (29) on the source side, and heat is exchanged with the ambient natural cold and heat source module through a natural cold source cooler (32) and a natural heat source heater (36). The terminal cooling demand is met through a passive cooling heat exchanger (48) and a refrigeration cycle heat exchanger (50), and the terminal multi-heat demand is met through a closed heat pump user side heat exchanger (38), a closed heat pump CO2 network side heat exchanger (40) and an open heat pump user side heat exchanger (44).

[0044] According to some embodiments, when the natural cold and heat source module is operated in summer, the CO2 gas in the gaseous CO2 main pipeline (53) passes through the gaseous CO2 pipeline three-way valve (31), flows through the natural cold source cooler (32) to exchange heat with rivers and lakes, releases excess heat, and then is pressurized by the first booster pump (33) and injected into the liquid CO2 main pipeline (52) through the liquid CO2 pipeline three-way valve (34);

[0045] During winter operation, the liquid CO2 in the liquid CO2 main pipeline (52) flows through the throttle valve (35) via the liquid CO2 pipeline three-way valve (34), and after the liquid pressure drops, it enters the natural heat source heater (36), absorbs the heat from rivers, lakes and reservoirs, and is then gasified after being pressurized by the fourth compressor (37) and passed into the gaseous CO2 main pipeline (53).

[0046] According to some embodiments, in the terminal energy consumption module, the power demand is provided by the renewable energy power module, the terminal heat demand is supplied by the closed heat pump unit and the open heat pump unit connected to the closed CO2 circulation network module, and the terminal cooling demand is met by the passive cooling unit and the refrigeration circulation unit connected to the closed CO2 circulation network module;

[0047] The closed heat pump unit comprises a closed heat pump user-side heat exchanger (38), a closed heat pump throttle valve (39), a closed heat pump CO2 network-side heat exchanger (40), a second booster pump (41) and a closed heat pump compressor (42). The gaseous CO2 in the gaseous CO2 main pipeline (53) in the closed CO2 circulation network module flows into the closed heat pump CO2 network-side heat exchanger (40), releases heat to become liquid CO2, is pressurized by the second booster pump (41) and flows into the liquid CO2 main pipeline (52). The closed heat pump working fluid is heated by the closed heat pump CO2 network-side heat exchanger (40), is pressurized by the closed heat pump compressor (42), and then passes through the closed heat pump user-side heat exchanger (38) to provide heat to the terminal. At the same time, the working fluid is liquefied and then passes through the closed heat pump throttle valve. (39) decompression; the open heat pump unit comprises an open heat pump compressor (43), an open heat pump user-side heat exchanger (44), an open heat pump expander (45), an open heat pump throttle valve (46) and an open heat pump steam-water separator (47); the gaseous CO2 in the gaseous CO2 main pipeline (53) in the closed CO2 circulation network module flows into the open heat pump compressor (43) for pressurization, then flows into the open heat pump user-side heat exchanger (44) to release heat, expands through the open heat pump expander (45), then enters the open heat pump throttle valve (46) for decompression, performs gas-liquid separation in the open heat pump steam-water separator (47), the gaseous CO2 re-enters the open heat pump compressor (43) for pressurization, and the liquid CO2 enters the liquid CO2 main pipeline (52);

[0048] The passive cooling unit includes a passive cooling heat exchanger (48), and the liquid in the liquid CO2 main pipeline (52) undergoes a phase change after flowing through the passive cooling heat exchanger (48), and then flows into the gaseous CO2 main pipeline (53); the refrigeration cycle unit includes a refrigeration cycle throttle valve (49), a refrigeration cycle heat exchanger (50) and a refrigeration cycle compressor (51), and the liquid in the liquid CO2 main pipeline (52) first flows through the refrigeration cycle throttle valve (49) to reduce pressure, and then absorbs terminal heat through the refrigeration cycle heat exchanger (50), and then is pressurized by the refrigeration cycle compressor (51) and injected into the gaseous CO2 main pipeline (53).

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1. The present invention provides a regional multi-energy complementary system that couples reversible solid oxide battery technology with a closed CO2 network, which adopts the idea of ​​regional zero-carbon energy supply. Breaking through the traditional decarbonization strategy of "electrification" and "zero-carbon energy", by coupling reversible solid oxide battery technology with a closed CO2 circulation network system, the closed network internal state change cycle avoids environmental carbon emissions; in the RSOC efficient conversion process, carbon elements realize the CO2-CH4-CO2 cycle, and the whole process achieves system net zero emissions, expanding new ways of CO2 utilization.

[0051] 2. The present invention adopts a regional self-consistent energy supply mode. By utilizing the characteristics of CO2 that are compatible with the temperature of natural cold and heat sources, and utilizing its phase change latent heat, the network's heating and cooling capacity can be greatly improved; at the same time, the circulating network operates at ambient temperature, with low heat dissipation loss, which can enhance the utilization of waste heat; the terminal is coupled with a water source heat pump to achieve thermal energy quality improvement, further improve system energy efficiency, and meet users' diversified energy needs; coupled with RSOC to solve the problem of efficient storage of regional renewable energy on multiple time scales and cross-seasonal heat and cold load imbalance.

[0052] 3. The present invention adopts regional multi-energy complementary technology. By coupling solar thermal / waste heat and closed CO2 circulation network, the thermal energy utilization boundary of RSOC unit is expanded to improve the unit energy efficiency; multiple energy sources of different grades such as natural low-temperature cold and heat sources, solar energy, methane, electricity and heat are coupled and complemented to improve the energy supply efficiency and stability of the system; at the same time, RSOC mode switching and chemical energy storage units are coupled to achieve efficient conversion and storage of renewable energy and intra-day / inter-seasonal energy balance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A structural block diagram of a regional multi-energy complementary system that couples reversible solid oxide battery technology with a closed CO2 network provided in an embodiment of the present invention.

[0054] Figure 2 A schematic diagram of the structure of a regional multi-energy complementary system for coupling reversible solid oxide battery technology and a closed CO2 network provided in an embodiment of the present invention.

[0055] Figure 3 This is a SOEC mode operation diagram provided by an embodiment of the present invention.

[0056] Figure 4 This is a SOFC mode operation diagram provided by an embodiment of the present invention.

[0057] Figure 5 A flowchart of the external cold source participating in energy balance provided in an embodiment of the present invention.

[0058] Figure 6 A flowchart of the process of using an ambient heat source to heat a system according to an embodiment of the present invention.

[0059] In the figure:

[0060] 1- Solar concentrator; 2- Industrial waste heat; 3- Cold tank; 4- Hot tank; 5- External heat source heat exchanger; 6- Water pump; 7- Water side electric heater; 8- First compressor; 9- CO2 side electric heater; 10- Fuel side heat exchanger; 11- First valve; 12- Reactor; 13- CH4 cooler; 14- Steam-water separator; 15- Purification device; 16- Second compressor; 17- Methane pipeline three-way valve; 18- Methane Storage tank; 19-fuel side electric heater; 20-fuel stack; 21-combustion chamber; 22-second valve; 23-third compressor; 24-air side heat exchanger; 25-air side electric heater; 26-ORC source side heat exchanger; 27-turbine; 28-generator; 29-ORC cold end heat exchanger; 30-circulation pump; 31-gas CO2 pipeline three-way valve; 32-natural cold source cooler; 33-first booster pump; 34- Three-way valve of liquid CO2 pipeline; 35-throttle valve; 36-natural heat source heater; 37-fourth compressor; 38-closed heat pump user-side heat exchanger; 39-closed heat pump throttle valve; 40-closed heat pump CO2 network-side heat exchanger; 41-second booster pump; 42-closed heat pump compressor; 43-open heat pump compressor; 44-open heat pump user-side heat exchanger; 45-open heat pump expander; 46-open heat pump throttle valve; 47-open heat pump steam-water separator; 48-passive cooling heat exchanger; 49-refrigeration cycle throttle valve; 50-refrigeration cycle heat exchanger; 51-refrigeration cycle compressor; 52-liquid CO2 main pipeline; 53-gaseous CO2 main pipeline; 54-power bus; 55-SOFC power output; 56-SOEC power consumption; 57-auxiliary equipment power consumption; 58-user load; 59-photovoltaic array; 60-natural gas pipeline. DETAILED DESCRIPTION

[0061] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0062] The present invention will be further described below in conjunction with the accompanying drawings.

[0063] Example 1

[0064] See also Figure 1 In the figure, the solid line in the connecting line indicates the SOEC power generation mode, and the dotted line indicates the SOFC power generation mode. This embodiment proposes a regional multi-energy complementary system that couples reversible solid oxide battery technology and a closed CO2 network, hereinafter referred to as the system, which includes the following modules:

[0065] Renewable energy power module, external heat source module, RSOC heat-mass-electricity reversible conversion module, chemical energy storage module, closed CO2 cycle network module, natural cold and heat source module and terminal energy module. Through the complementarity between photovoltaic, solar thermal, industrial waste heat and natural cold and heat sources, the efficient, stable and self-consistent supply of terminal cold-heat-electricity multi-loads is achieved.

[0066] More specifically, see Figure 2 , the renewable energy power module consists of a power bus 54, a SOFC power output 55, a SOEC power consumption 56, an auxiliary equipment power consumption 57, a user load 58 and a photovoltaic array 59. The photovoltaic array 59 converts solar energy into electrical energy and then inputs it into the power bus 54. After the SOFC power output 55 outputs electricity to the power bus 54, the power bus supplies electricity to the SOEC power consumption 56, the auxiliary equipment power consumption 57 and the user load 58. SOEC and SOFC cannot operate at the same time. In the renewable energy power module, the solar photovoltaic array 59 converts light energy into electrical energy and transmits it to the power bus 54. The SOFC power output 55 is connected to the power bus 54; at the same time, the power bus 54 can directly provide power to the end-user load 58, and can also be used to drive the RSOC thermal-mass-electricity reversible module in the SOEC electrolysis mode to consume electrical equipment to meet the power consumption of the auxiliary equipment power consumption 57.

[0067] The external heat source module includes a heat storage device for intraday heat storage. The cross-seasonal energy balance is mainly achieved through the chemical energy storage module, and heat storage is mainly used for short-term energy storage. Specifically, the external heat source module consists of a concentrating and collecting device 1, industrial waste heat 2, a cold tank 3, a hot tank 4 and an external heat source heat exchanger 5. The concentrating and collecting device 1 converts solar energy into thermal energy, and heats the low-temperature working fluid from the cold tank 3 with the industrial waste heat 2, and transports it to the hot tank 4 to form a flow cycle; the external heat source heat exchanger 6 is used to transfer heat to the RSOC heat-mass-electricity reversible conversion module, and supply the RSOC heat-mass-electricity reversible conversion module for power generation or electrolysis, thereby improving the overall energy efficiency of the system.

[0068] The RSOC heat-mass-electricity reversible conversion module operates in two modes: solid oxide electrolyzer (SOEC) and solid oxide fuel cell (SOFC). It includes an RSOC unit and an ORC waste heat power generation unit. The RSOC unit consists of a water pump 6, a water-side electric heater 7, a first compressor 8, a CO2-side electric heater 9, a fuel-side heat exchanger 10, a first valve 11, a reactor 12, a CH4 cooler 13, a steam-water separator 14, a purification device 15, a second compressor 16, a methane pipeline three-way valve 17, a fuel-side electric heater 19, a fuel cell 20, a combustion chamber 21, a second valve 22, a third compressor 23, an air-side heat exchanger 24 and an air-side electric heater 25. On the RSOC fuel inlet side, the outlet of the water pump 6 is connected to the water-side electric heater 7, and then passes through the external heat source heat exchanger 5 in sequence. The outlet of the first compressor 8 is connected to the CO2-side electric heater 9, and the CO2-side electric heater 9 exchanges heat with the external heat source. The outlet of the compressor 5 is mixed and connected to the fuel side heat exchanger 10 and the fuel side electric heater 19 in sequence, and then connected to the fuel side inlet of the fuel stack 20; on the RSOC air side, the outlet of the third compressor 23 is connected to the air side heat exchanger 24, and then connected to the air side electric heater 25 and the air side inlet of the fuel stack 20 in sequence; the fuel side outlet of the fuel stack 22 is connected to the combustion chamber 21, and then connected to the fuel side heat exchanger 10, and the fuel side outlet of the fuel stack can also be directly connected to the fuel side heat exchanger 10; the fuel side heat exchanger 10 is connected to the first valve 11 and the second valve 22; the first valve 11 is connected to the reactor 12, the CH4 cooler 13, the steam-water separator 14, the purification device 15, the second compressor 16, and the methane pipeline three-way valve 17 in sequence, and the second valve is connected to the air side heat exchanger 24; the air side outlet of the fuel stack 20 is connected to the combustion chamber 21, and then connected to the air side heat exchanger 24, and the air side outlet of the fuel stack can also be directly connected to the air side heat exchanger 24. The ORC waste heat power generation unit consists of an ORC source side heat exchanger 26, a turbine 27, a generator 28, an ORC cold end heat exchanger 29, and a circulating pump 30. The outlet of the ORC source side heat exchanger 26 is connected to the turbine 27, the outlet of the turbine is connected to the ORC cold end heat exchanger 29, and the generator 28 is driven by the shaft to generate electricity. The outlet of the ORC cold end heat exchanger 29 is connected to the circulating pump 30, and then connected to the inlet of the ORC source side heat exchanger 26.

[0069] The RSOC heat-mass-electricity reversible conversion module can operate in SOEC electrolysis to produce methane and SOFC power generation modes respectively:

[0070] In SOEC power-to-methane mode, the system operation process is detailed in Figure 3On the fuel side, water is pressurized by the booster pump 6 and then input into the system, preheated by the water side electric heater 7, and then absorbed by the external heat source heat exchanger 5 from the hot fluid of the hot tank 3, and then further heated by the fuel side heat exchanger 10 and the fuel side electric heater 19 in turn, and after reaching the stack inlet temperature requirement, it is passed into the stack 20 fuel electrode; CO2 is pressurized by the compressor 8 and then input into the system, preheated by the CO2 side electric heater 9, and then further heated by the fuel side heat exchanger 10 and the fuel side electric heater 19 in turn, and after reaching the stack inlet temperature requirement, it is passed into the stack 20 fuel electrode; air is pressurized by the compressor 23 and then passed through the air side heat exchanger 24 and the air side electric heater 2 5 is heated to reach the working temperature of the stack inlet, and then the air electrode of the stack 20 is introduced; in the SOEC mode, the valve 11 is opened and the valve 22 is closed, and the gas at the outlet of the fuel electrode of the stack is introduced into the fuel side heat exchanger 10 for cooling, and then enters the reactor 12 through the valve 11 for further reaction, and the obtained mixed gas enters the CH4 cooler 13 and then enters the steam-water separator 14, and the separated water re-enters the water pump 6 for recycling, and the separated gas enters the purification device 15 and is purified to obtain high-purity methane, and then is pressurized by the compressor 16 and passed through the methane pipeline three-way valve 17 to the methane storage tank 18 for storage; the gas at the outlet of the air electrode of the stack passes through the air side heat exchanger 24 and then enters the ORC waste heat power generation unit.

[0071] In SOFC power generation mode, the system operation process is detailed in Figure 4 The methane stored in the methane storage tank 18 enters the natural gas pipeline 60 after passing through the methane pipeline three-way valve 17, absorbs the heat energy from the hot fluid of the hot tank 3 through the external heat source heat exchanger 5, and then passes through the fuel side heat exchanger 10 and the fuel side electric heater 19 for further heating in turn. After reaching the stack inlet temperature requirement, it is passed into the stack 20 fuel electrode; the air is pressurized by the compressor 23, and then passes through the air side heat exchanger 24 and the air side electric heater 25 in turn to heat up to the stack inlet working temperature, and then passes into the stack 20 air electrode; in the SOFC mode, the valve 11 is closed and the valve 22 is opened, and the outlet gases of the fuel electrode and the air electrode of the stack 20 are passed into the combustion chamber 21, and the excess air introduced into the air side reacts with the excess fuel in the fuel side to burn, and the combustion chamber outlet gas is split into two streams, which enter the fuel side heat exchanger 10 and the air side heat exchanger 24 respectively, and then the two gases are mixed and passed into the ORC waste heat power generation unit.

[0072] In the ORC waste heat power generation unit, the tail waste heat from the RSOC unit is absorbed by the ORC source side heat exchanger 26. The organic working fluid inside the ORC system evaporates in the ORC source side heat exchanger 26 and then enters the turbine 27 to expand and do work, driving the generator 28 to generate electricity, which is transmitted to the power bus 54. The organic working fluid after expansion and work enters the ORC cold end heat exchanger 29 for condensation and liquefaction, and then is pressurized by the circulation pump 30. At the same time, the liquid CO2 in the system liquid CO2 main pipeline 52 is vaporized after absorbing the waste heat of the heat exchanger 29, and then injected into the gaseous CO2 main pipeline 53.

[0073] The chemical energy storage module, including the methane storage tank 18, achieves self-consistency of energy at multiple time scales within the region by coupling the RSOC heat-mass-electricity reversible conversion module and the chemical energy storage module, solving the problem of imbalanced supply and demand of cold and heat loads across seasons in the system. When the RSOC heat-mass-electricity reversible conversion module operates in the SOEC mode, it is used to store the produced methane; when the RSOC heat-mass-electricity reversible conversion module operates in the SOFC mode, it also provides fuel for SOFC power generation.

[0074] This embodiment uses a closed CO2 circulation network module (~15°C, ~50bar) with a temperature close to the ambient temperature for heating and cooling, achieving low energy dissipation between the heating and cooling network and the natural environment. A low-temperature closed CO2 circulation network is used for heating and cooling, recycling the waste heat of the RSOC heat-mass-electricity conversion module, making full use of low-cost natural cold and heat sources, and realizing terminal passive cooling, and using the recovered indoor heat for the terminal heat load demand within the region; heat transfer is achieved by replacing the traditional hot water sensible heat with the CO2 phase change latent heat, greatly reducing the pipe network diameter and low space occupancy.

[0075] Specifically, the closed CO2 circulation network module includes two pipelines with similar temperature and pressure and different phases, namely, the liquid CO2 main pipeline 52 and the gaseous CO2 main pipeline 53. The two pipelines are connected to the RSOC heat-mass-electricity reversible conversion module through the ORC cold end heat exchanger 29 on the source side, and heat is exchanged with the environment natural cold and heat source module through the natural cold source cooler 32 and the natural heat source heater 36. The terminal cooling demand is met through the passive cooling heat exchanger 48 and the refrigeration cycle heat exchanger 50, and the terminal multi-heat demand is met through the closed heat pump user side heat exchanger 38, the closed heat pump CO2 network side heat exchanger 40, and the open heat pump user side heat exchanger 44.

[0076] This embodiment expands the thermal integration boundary of the RSOC heat-mass-electricity reversible conversion module by coupling an external heat source module, an RSOC heat-mass-electricity reversible conversion module, and a closed CO2 circulation network module, and improves the energy efficiency of the RSOC heat-mass-electricity reversible conversion module by integrating an external heat source and deep waste heat utilization.

[0077] By coupling the RSOC heat-mass-electricity reversible change module, chemical energy storage module, water storage tank and CO2 storage tank, the RSOC heat-mass-electricity reversible conversion module switches between SOEC mode and SOFC mode, the system carbon element realizes the CO2-CH4-CO2 cycle, and the system achieves net zero emissions throughout the entire process.

[0078] The natural cold and heat source module is composed of a circulation pump 30, a gaseous CO2 pipeline three-way valve 31, a natural cold source cooler 32, a first booster pump 33, a liquid CO2 pipeline three-way valve 34, a throttle valve 35, a natural heat source heater 36, and a fourth compressor 37. The energy interaction mechanism between the natural cold and heat source module and the closed CO2 circulation network module is different in summer and winter:

[0079] During summer operation, the system has too much heat inside and requires an external cooling source to participate in energy balance. For details on the working process principle, see Figure 5 The gaseous CO2 in the gaseous CO2 main pipeline 53 passes through the gaseous CO2 pipeline three-way valve 31, flows through the natural cold source cooler 32 to exchange heat with rivers, lakes and reservoirs, releasing excess heat, and then is pressurized by the first booster pump 33 and injected into the liquid CO2 main pipeline 52 through the liquid CO2 pipeline three-way valve 34.

[0080] When the system is running in winter, the internal heat is insufficient and the ambient heat source can be used to heat the system. For details on the working process principle, see Figure 6 The liquid CO2 in the liquid CO2 main pipeline 52 flows through the throttle valve 35 through the liquid CO2 pipeline three-way valve 34, and enters the natural heat source heater 36 after the liquid pressure drops, and then vaporizes after absorbing the heat of rivers, lakes and reservoirs, and is pressurized by the fourth compressor 37 and then passed into the gaseous CO2 main pipeline 53.

[0081] In the terminal energy consumption module, it is mainly divided into electricity, heating and cooling demands. The electricity demand is provided by the renewable electricity energy module, the terminal heat demand is supplied by the closed heat pump unit and the open heat pump unit connected to the closed CO2 circulation network module, and the terminal cooling demand is met by the passive cooling unit and the refrigeration circulation unit connected to the closed CO2 circulation network module.

[0082] The closed heat pump unit is composed of a closed heat pump user-side heat exchanger 38, a closed heat pump throttle valve 39, a closed heat pump CO2 network-side heat exchanger 40, a second booster pump 41, and a closed heat pump compressor 42. The gaseous CO2 in the gaseous CO2 main pipeline 53 in the closed CO2 circulation network flows into the closed heat pump CO2 network-side heat exchanger 40, releases heat to become liquid CO2, and is pressurized by the second booster pump 41 before flowing into the liquid CO2 main pipeline. After the closed heat pump working fluid is heated by the closed heat pump CO2 network-side heat exchanger 40, it is pressurized by the closed heat pump compressor 42, and then passes through the closed heat pump user-side heat exchanger 38 to provide heat to the terminal, while the working fluid is liquefied, and then is depressurized by the closed heat pump throttle valve 39.

[0083] The open heat pump unit is composed of an open heat pump compressor 43, an open heat pump user-side heat exchanger 44, an open heat pump expander 45, an open heat pump throttle valve 46, and an open heat pump steam-water separator 47. The gaseous CO2 in the gaseous CO2 main pipeline 53 in the closed CO2 circulation network module flows into the open heat pump compressor 43 for pressurization, then flows into the open heat pump user-side heat exchanger 44 for heat release, expands through the open heat pump expander 45, then enters the open heat pump throttle valve 46 for decompression, and performs gas-liquid separation in the open heat pump steam-water separator 47, and the gaseous CO2 re-enters the open heat pump compressor 43 for pressurization, and the liquid CO2 enters the liquid CO2 main pipeline.

[0084] The passive cooling unit is realized by the passive cooling heat exchanger 48. The liquid in the liquid CO2 main pipeline undergoes a phase change after flowing through the passive cooling heat exchanger 48, and then flows into the gaseous CO2 main pipeline 53. The refrigeration cycle unit is composed of a refrigeration cycle throttle valve 49, a refrigeration cycle heat exchanger 50, and a refrigeration cycle compressor 51. The liquid in the liquid CO2 main pipeline first flows through the refrigeration cycle throttle valve 49 to reduce pressure, then absorbs terminal heat through the refrigeration cycle heat exchanger 50, and then is pressurized by the refrigeration cycle compressor 51 and injected into the gaseous CO2 main pipeline 53.

[0085] This embodiment provides a system that covers complex processes such as RSOC heat-mass-electricity reversible conversion, closed CO2 cycle network multi-source-multi-sink energy transfer, and heat pump low-grade thermal energy quality and efficiency improvement, involving multiple energy sources such as ambient low-temperature cold and heat sources, solar energy, methane, electricity and heat, and overcomes the problems of cross-seasonal cold and heat load imbalance and system energy efficiency improvement in regional energy supply systems. It has the advantages of deep utilization of waste heat, passive cooling, compact structure, high energy efficiency and zero carbon emissions. It realizes efficient, stable and clean supply of high-energy and low-consumption regional energy, and obtains a new regional energy supply model with carbon power and material conversion cycle as the core.

[0086] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A regional multi-energy complementary system coupling reversible solid oxide battery technology with a closed CO2 network, characterized in that: It includes RSOC heat-mass-electricity reversible conversion module, closed CO2 cycle network module, renewable energy power module, external heat source module, chemical energy storage module, natural cold and heat source module and terminal energy module: The RSOC heat-mass-electricity reversible conversion module uses solid oxide electrolysis and fuel cells to perform heat-CH4-electricity reversible conversion, thereby achieving efficient conversion and storage of regional renewable energy and intra-day / inter-seasonal energy balance; the RSOC heat-mass-electricity reversible conversion module operates in two modes: solid oxide electrolysis cell and solid oxide fuel cell mode, i.e., SOEC and SOFC; The closed CO2 circulation network module includes a gaseous main pipeline and a liquid main pipeline with similar temperature and pressure and different phases, and realizes heat transfer between the pipeline working medium and the source side / load side through the CO2 liquid / gas phase change; The renewable energy power module includes photovoltaic power generation equipment, which provides renewable electricity for the electrolysis of the RSOC heat-mass-electricity reversible conversion module, the system power equipment and the terminal power load; The external heat source module includes a concentrating heat collection device, a heat storage device and industrial waste heat. The concentrating heat collection device is used to collect solar energy to provide high-temperature heat, and the heat storage device is used to store renewable energy heat for a short time. The concentrating heat collection device and the industrial waste heat are integrated with the RSOC heat-mass-electricity reversible conversion module to reduce the power consumption of SOEC. The chemical energy storage module includes a methane storage device for storing methane produced by SOEC and providing fuel for SOFC power generation; The natural cold and heat source module includes rivers and lakes; in summer, when the internal heat of the closed CO2 circulation network module is excessive, heat exchange is performed with the natural cold source to achieve energy balance; in winter, when the internal heat of the closed CO2 circulation network module is insufficient, the waste heat of the natural heat source and the RSOC heat-mass-electricity reversible conversion module is used to supplement the heat of the regional multi-energy complementary system to achieve energy balance; The terminal energy module meets the electric load demand through photovoltaic power generation and SOFC power generation, realizes passive cooling through heat exchange with the liquid CO2 in the closed CO2 circulation network module, realizes the refrigeration demand by coupling the refrigeration cycle unit with the closed CO2 circulation network module, and realizes the terminal hot water and heating heat load demand by coupling the water source heat pump with the closed CO2 circulation network module.

2. The regional multi-energy complementary system according to claim 1, wherein the system is characterized in that: In the SOEC mode, the RSOC heat-mass-electricity reversible conversion module is powered by the renewable energy power module, the external heat source module provides heat, and the water storage tank and the CO2 storage tank provide synthetic raw materials. The synthetic methane enters the chemical energy storage module for storage, and the tail waste heat is transmitted to the closed CO2 circulation network module after generating electricity through the organic Rankine cycle. In the SOFC mode, the methane provided by the chemical energy storage module is used to generate electricity to supply the terminal power load, and the generated water and CO2 flow to the water storage tank and the CO2 storage tank respectively. After being input into the external heat source module, they are successively transferred to the organic Rankine cycle and the closed CO2 circulation network module.

3. The regional multi-energy complementary system according to claim 2, wherein the system is characterized in that: The external heat source module comprises a solar collector (1), industrial waste heat (2), a cold tank (3), a hot tank (4) and an external heat source heat exchanger (5); the solar collector (1) converts solar energy into thermal energy, and heats the low-temperature working fluid from the cold tank (3) with the industrial waste heat (2), and transports the heat to the hot tank (4), thereby forming a flow cycle; the external heat source heat exchanger (5) is used to transfer heat to the RSOC heat-mass-electricity reversible conversion module to generate electricity or electrolysis; The RSOC heat-mass-electricity reversible conversion module comprises an RSOC unit and an ORC waste heat power generation unit, wherein the RSOC unit comprises a water pump (6), a water-side electric heater (7), a first compressor (8), a CO2-side electric heater (9), a fuel-side heat exchanger (10), a first valve (11), a reactor (12), a CH4 cooler (13), a steam-water separator (14), a purification device (15), a second compressor (16), a methane pipeline three-way valve (17), a methane storage tank (18), a fuel-side electric heater (19), a fuel cell (20), a combustion chamber (21), a second valve (22), and a third compressor (23). ), an air side heat exchanger (24) and an air side electric heater (25); on the RSOC fuel inlet side, the outlet of the water pump (6) is connected to the water side electric heater (7) and the external heat source heat exchanger (5) in sequence, the outlet of the first compressor (8) is connected to the CO2 side electric heater (9), the CO2 side electric heater (9) and the outlet of the external heat source heat exchanger (5) are mixed and then connected to the fuel side heat exchanger (10) and the fuel side electric heater (19) in sequence, and then connected to the fuel side inlet of the fuel cell stack (20); on the RSOC air side, the outlet of the third compressor (23) is connected to the air side heat exchanger (24), and then connected to the air side electric heater (25) in sequence. and the air side inlet of the stack (20); the fuel side outlet of the stack (20) is connected to the combustion chamber (21), and then connected to the fuel side heat exchanger (10), and the fuel side outlet of the stack can also be directly connected to the fuel side heat exchanger (10); the fuel side heat exchanger (10) is connected to the first valve (11) and the second valve (22); the first valve (11) is connected to the reactor (12), the CH4 cooler (13), the steam-water separator (14), the purification device (15), the second compressor (16), and the methane pipeline three-way valve (17) in sequence, and the second valve (22) is connected to the air side heat exchanger (24); the air side outlet of the stack (20) is connected to the fuel side outlet The ORC waste heat power generation unit comprises an ORC source side heat exchanger (26), a turbine (27), a generator (28), an ORC cold end heat exchanger (29) and a circulation pump (30). The outlet of the ORC source side heat exchanger (26) is connected to the turbine (27), the outlet of the turbine is connected to the ORC cold end heat exchanger (29), and the generator (28) is driven by the shaft to generate electricity. The outlet of the ORC cold end heat exchanger (29) is connected to the circulation pump (30), and then connected to the inlet of the ORC source side heat exchanger (26).

4. The regional multi-energy complementary system according to claim 3, wherein: The renewable energy power module includes a photovoltaic array (59), which converts solar energy into electrical energy and then inputs it into a power bus (54). The generator (28) and the SOFC electrical output (55) are connected to the power bus (54), and the power bus supplies electricity to SOEC power (56), auxiliary equipment power (57) and user loads (58).

5. The regional multi-energy complementary system according to claim 4, wherein: In the closed CO2 circulation network module, the low-temperature liquid CO2 vaporizes into gaseous CO2 and flows into the gaseous CO2 main pipeline (53) after absorbing the waste heat of the RSOC heat-mass-electricity reversible conversion module on the source side, the heat of the natural heat source in the rivers and lakes, and the indoor heat on the load side; the gaseous CO2 releases heat to the natural cold source on the source side and provides heat to the terminal on the load side, and then liquefies into liquid CO2 and flows into the liquid CO2 main pipeline (52).

6. The regional multi-energy complementary system according to claim 5, characterized in that: The closed CO2 circulation network module comprises a liquid CO2 main pipeline (52) and a gaseous CO2 main pipeline (53). The two pipelines are connected to the RSOC heat-mass-electricity reversible conversion module through an ORC cold end heat exchanger (29) on the source side, and heat is exchanged with the ambient natural cold and heat source module through a natural cold source cooler (32) and a natural heat source heater (36). The terminal cooling demand is met through a passive cooling heat exchanger (48) and a refrigeration cycle heat exchanger (50), and the terminal multi-heat demand is met through a closed heat pump user side heat exchanger (38), a closed heat pump CO2 network side heat exchanger (40) and an open heat pump user side heat exchanger (44).

7. The regional multi-energy complementary system according to claim 6, characterized in that: When the natural cold and heat source module is operated in summer, the CO2 gas in the gaseous CO2 main pipeline (53) passes through the gaseous CO2 pipeline three-way valve (31), flows through the natural cold source cooler (32) to exchange heat with rivers and lakes, releases excess heat, and then is pressurized by the first booster pump (33) and injected into the liquid CO2 main pipeline (52) through the liquid CO2 pipeline three-way valve (34); During winter operation, the liquid CO2 in the liquid CO2 main pipeline (52) flows through the throttle valve (35) via the liquid CO2 pipeline three-way valve (34), and after the liquid pressure drops, it enters the natural heat source heater (36), absorbs the heat from rivers, lakes and reservoirs, and is then gasified after being pressurized by the fourth compressor (37) and passed into the gaseous CO2 main pipeline (53).

8. The regional multi-energy complementary system according to claim 5, characterized in that: In the terminal energy consumption module, the power demand is provided by the renewable energy power module, the terminal heat demand is supplied by the closed heat pump unit and the open heat pump unit connected to the closed CO2 circulation network module, and the terminal cooling demand is met by the passive cooling unit and the refrigeration circulation unit connected to the closed CO2 circulation network module; The closed heat pump unit comprises a closed heat pump user-side heat exchanger (38), a closed heat pump throttle valve (39), a closed heat pump CO2 network-side heat exchanger (40), a second booster pump (41) and a closed heat pump compressor (42). The gaseous CO2 in the gaseous CO2 main pipeline (53) in the closed CO2 circulation network module flows into the closed heat pump CO2 network-side heat exchanger (40), releases heat to become liquid CO2, is pressurized by the second booster pump (41) and flows into the liquid CO2 main pipeline (52). The closed heat pump working fluid is heated by the closed heat pump CO2 network-side heat exchanger (40), is pressurized by the closed heat pump compressor (42), and then passes through the closed heat pump user-side heat exchanger (38) to provide heat to the terminal. At the same time, the working fluid is liquefied and then passes through the closed heat pump throttle valve. (39) decompression; the open heat pump unit comprises an open heat pump compressor (43), an open heat pump user-side heat exchanger (44), an open heat pump expander (45), an open heat pump throttle valve (46) and an open heat pump steam-water separator (47); the gaseous CO2 in the gaseous CO2 main pipeline (53) in the closed CO2 circulation network module flows into the open heat pump compressor (43) for pressurization, then flows into the open heat pump user-side heat exchanger (44) to release heat, expands through the open heat pump expander (45), then enters the open heat pump throttle valve (46) for decompression, performs gas-liquid separation in the open heat pump steam-water separator (47), the gaseous CO2 re-enters the open heat pump compressor (43) for pressurization, and the liquid CO2 enters the liquid CO2 main pipeline (52); The passive cooling unit includes a passive cooling heat exchanger (48), and the liquid in the liquid CO2 main pipeline (52) undergoes a phase change after flowing through the passive cooling heat exchanger (48), and then flows into the gaseous CO2 main pipeline (53); the refrigeration cycle unit includes a refrigeration cycle throttle valve (49), a refrigeration cycle heat exchanger (50) and a refrigeration cycle compressor (51), and the liquid in the liquid CO2 main pipeline (52) first flows through the refrigeration cycle throttle valve (49) to reduce pressure, and then absorbs terminal heat through the refrigeration cycle heat exchanger (50), and then is pressurized by the refrigeration cycle compressor (51) and injected into the gaseous CO2 main pipeline (53).

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