Off-network zero-carbon energy supply and fresh water production cooperative system and method based on reversible solid oxide battery

Abstract

The invention discloses an off-network zero-carbon energy supply and fresh water production cooperation system and method based on a reversible solid oxide battery, and belongs to the field of power generation. Comprising a power integration module which comprises a wind turbine unit, a photovoltaic array, an energy storage battery and a direct current bus and is used for integrating renewable energy power generation and electric energy storage; the RSOC system module is electrically connected with the power integration module and has a bidirectional operation function of a solid oxide electrolytic cell SOEC mode and a solid oxide fuel cell SOFC mode; the fresh water production module is in thermal connection with the RSOC system module, comprises a direct contact membrane distillation seawater desalination device, and is used for carrying out seawater desalination by utilizing waste heat generated during running of the RSOC system module; a hydrogen storage tank; a water storage tank; and the intelligent controller is in communication connection with the electric power integration module and the RSOC system module, and is configured to control the mode switching of the RSOC system module according to the difference value between the wind-solar power generation power and the load demand power.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power generation, in particular, to an off-grid zero-carbon energy supply and fresh water production collaborative system and method based on reversible solid oxide cell. BACKGROUND

[0002] In off-grid environments, especially small islands lacking infrastructure, energy and fresh water supply have long relied on diesel generators and independent seawater desalination equipment. This mode not only results in high costs due to fuel transportation difficulties, but also is accompanied by high carbon emissions and noise pollution, making it difficult to meet the needs of sustainable development. With the popularity of renewable energy such as wind and light, off-grid systems are gradually transforming towards clean energy, but their volatility and intermittency pose higher requirements for energy storage technology: lithium batteries can short-term frequency modulation, but are limited by capacity attenuation and continuous power supply capability in extreme weather; while traditional hydrogen energy storage can achieve long-term energy storage, but due to equipment redundancy, energy efficiency loss, and the fragmentation of the fresh water production system, the overall economic efficiency of the system is insufficient. SUMMARY

[0003] The summary portion of the present application is used to introduce the concepts in a brief form, which will be described in detail in the specific embodiments section later. The summary portion of the present application is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0004] To solve the technical problems mentioned in the background section, some embodiments of the present application provide an off-grid zero-carbon energy supply and fresh water production collaborative system based on reversible solid oxide cell, comprising: a power integration module comprising a wind turbine unit, a photovoltaic array, an energy storage battery and a direct current bus, for integrating renewable energy generation and energy storage; an RSOC system module electrically connected to the power integration module, having a bidirectional operation function of solid oxide electrolysis cell SOEC mode and solid oxide fuel cell SOFC mode; a fresh water production module thermally connected to the RSOC system module, comprising a direct contact membrane distillation seawater desalination device, for seawater desalination using the waste heat generated during operation of the RSOC system module; a hydrogen storage tank connected to the RSOC system module, for storing hydrogen in SOEC mode and supplying hydrogen in SOFC mode; a water storage tank connected to the fresh water production module and the RSOC system module, for storing fresh water and supplying water for SOEC mode; an intelligent controller communicatively connected to the power integration module and the RSOC system module, configured to control the mode switching of the RSOC system module according to the difference between wind and light power generation and load demand power.

[0005] Further, the wind turbine generator and the photovoltaic array are connected to the DC bus through power converters; the energy storage battery is connected to the DC bus through a bidirectional DC-DC converter; the RSOC system module is connected to the DC bus through unidirectional DC-DC converters 108, 109.

[0006] Further, the RSOC system module comprises a RSOC stack, BOP equipment in SOEC mode and BOP equipment in SOFC mode; the BOP equipment in SOEC mode comprises preheating components for treating water and air, and a condenser and a compressor for treating hydrogen; the BOP equipment in SOFC mode comprises components for preheating air and hydrogen, and a catalytic combustor for treating reaction tail gas.

[0007] Further, in SOEC mode, the air electrode exhaust of the RSOC stack is guided to the fresh water production module to provide waste heat; in SOFC mode, the tail gas discharged by the catalytic combustor is guided to the fresh water production module to provide waste heat.

[0008] Further, the fresh water production module further comprises a water pump two, a heat exchanger one and a heat exchanger two; the water pump two is used to pressurize seawater and then pump it into the heat exchanger one and the heat exchanger two in sequence for heating, and the heated seawater enters the feed water side of the direct contact membrane distillation seawater desalination device.

[0009] Further, the high-temperature side heat source of the heat exchanger one is the air electrode exhaust in SOEC mode; the high-temperature side heat source of the heat exchanger two is the catalytic combustion tail gas in SOFC mode.

[0010] A method for operating the system, comprising the following steps: real-time monitoring of renewable energy power generation, load demand power and state of charge SOC of the energy storage battery; calculating the power difference ΔP = P_gen - P_load between power generation and load; controlling the energy storage battery to respond to the power difference ΔP; when ΔP is greater than a first set threshold, controlling the RSOC system module to switch to SOEC mode for electrolysis to produce hydrogen; when ΔP is less than a second set threshold, controlling the RSOC system module to switch to SOFC mode for power generation.

[0011] Further, the first set threshold is associated with the maximum charging power of the energy storage battery, and the second set threshold is associated with the maximum discharging power of the energy storage battery.

[0012] Further, the decision of mode switching further refers to the SOC state of the energy storage battery, and triggers SOEC mode when ΔP > ΔP_H and SOC is higher than an upper limit value, and triggers SOFC mode when ΔP < ΔP_L and SOC is lower than a lower limit value.

[0013] Further, the first set threshold and the second set threshold can be adaptively adjusted according to real-time weather prediction data and load demand trends.

[0014] The beneficial effects of the present application are: 1. Off-grid zero-carbon operation: Driven by renewable energy such as wind and solar energy, the entire system's energy supply and fresh water production process is completely independent of fossil fuels, achieving zero carbon emissions, especially suitable for ecologically sensitive off-grid scenarios such as islands.

[0015] 2. Highly stable and reliable source supply: A "wind-solar-hydrogen" multi-energy complementary system is built. Energy storage batteries are responsible for short-term and rapid power fluctuation smoothing; RSOC stores energy through hydrogen energy for long-term and large-scale "electricity-hydrogen-electricity" energy storage and conversion, fundamentally solving the core problem of large renewable energy fluctuations and unstable supply in off-grid scenarios.

[0016] 3. Efficient integration of hydrogen energy management: RSOC, as the core, has dual functions of "energy storage" electrolytic hydrogen production and "power generation" hydrogen utilization, realizing the integration of "storage-generation" of hydrogen energy, eliminating the need for independent electrolytic cells and fuel cells, and improving system integration, energy conversion efficiency and economy.

[0017] 4. Significantly reduce fresh water production costs: Innovatively use the low-grade waste heat of 150-250°C generated by the RSOC system in two modes as the heat source for the seawater desalination device. This process does not require additional consumption of high-grade electric energy, greatly reducing the energy consumption cost of fresh water production, and solving the problem of high cost of fresh water production in off-grid areas. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which form a part of this application, are used to provide further understanding of the application, and make the other features, purposes and advantages of the application more apparent. The schematic embodiment drawings of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation on the present application.

[0019] In addition, throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic, and the elements and elements are not necessarily drawn to scale.

[0020] In the drawings: Figure 1 is a whole schematic diagram according to an embodiment of the present application; Figure 2 is a structural schematic diagram of a part of the embodiment, mainly showing Figure 1 a specific flowchart of Reference numerals

[0021] 100, power integration module; 101. Wind turbine; 102. Photovoltaic array; 103. Energy storage battery; 104. DC bus; 105. AC-DC rectifier; 106. Boost DC-DC converter; 107. Bidirectional DC-DC converter; 108. First unidirectional DC-DC converter; 109. Second unidirectional DC-DC converter; 110. DC-AC inverter; 200. RSOC system module; 210. RSOC fuel cell stack; 221. Water pump one; 222. Water evaporator; 23. Steam electric heater; 224. Fan two; 225. Air preheater two; 226. Air electric heater; 227. Condenser; 228. Compressor; 231. Fan one; 232. Air preheater one; 233. Pressure regulator; 234. Flow controller; 235. Fuel preheater; 236. Catalytic combustor; 300. Freshwater production module; 311. Water pump two; 312. Heat exchanger one; 313. Heat exchanger two; 314. Water pump three; 320. Direct contact membrane distillation seawater desalination unit; 400. Hydrogen storage tank; 500. Water storage tank; 600. Intelligent controller. Detailed Implementation

[0022] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0023] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0024] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0025] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0026] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] Reference Figures 1-2 , This application provides an off-grid zero-carbon energy supply and freshwater production co-production system and method based on reversible solid oxide batteries, which is applicable to off-grid scenarios such as islands. Through multi-energy complementarity of wind, solar, storage and hydrogen and cascade utilization of waste heat, it realizes zero-carbon co-production of energy and freshwater, and solves the problems of unstable energy supply, high freshwater production cost and carbon emissions in off-grid scenarios.

[0028] To make the inventive objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0029] This embodiment provides an off-grid zero-carbon energy supply and freshwater production synergy system based on reversible solid oxide batteries. Please refer to [link to relevant documentation]. Figure 1 The system includes a power integration module, an RSOC system module, a freshwater production module, a hydrogen storage tank, a water storage tank, and an intelligent controller.

[0030] The power integration module 100 is responsible for converting fluctuating renewable energy into stable electrical energy and distributing it to loads or other modules.

[0031] RSOC system module 200, as the core of the system's energy and material conversion, has bidirectional operation capability. RSOC system module 200 has the function of switching between solid oxide fuel cell (SOFC) power generation mode and solid oxide electrolyzer (SOEC) hydrogen production mode.

[0032] The freshwater production module 300 utilizes the low-grade waste heat generated by the RSOC system as the main energy source to produce freshwater.

[0033] Hydrogen storage tank 400 and water storage tank 500 serve as storage units for hydrogen energy and fresh water, respectively, constituting the system's material buffer and circulation hub. Hydrogen storage tank 400 stores hydrogen produced by the RSOC system in SOEC mode, and the stored hydrogen is used to supply the fuel required by the RSOC system in SOFC mode. Water storage tank 500 stores fresh water produced by the fresh water production system module, mainly to meet the island's fresh water needs, and partly to meet the RSOC system's water supply needs in SOEC mode.

[0034] The intelligent controller 600 acts as the system's brain, coordinating the collaborative operation of various modules through data acquisition and algorithmic decision-making. It monitors the output and load data of the power integration module to adjust the charging and discharging of the energy storage battery and switch the operating modes of the RSOC system modules based on this data.

[0035] The components of each module are as follows: The power integration module 100 includes a wind turbine 101, a photovoltaic array 102, an energy storage battery 103, a DC bus 104, an AC-DC rectifier 105, a boost DC-DC converter 106, a bidirectional DC-DC converter 107, a first unidirectional DC-DC converter 108 and a second unidirectional DC-DC converter 109, and a DC-AC inverter 110.

[0036] RSOC system module 200 includes RSOC fuel cell stack 210, BOP equipment in SOEC mode: pump 221, evaporator 222, steam heater 223, fan 224, air preheater 225, air heater 226, condenser 227, compressor 228, and BOP equipment in SOFC mode: fan 231, air preheater 232, pressure reducer 233, flow controller 234, fuel preheater 235, catalytic combustor 236; freshwater production system module 300 includes pump 311, heat exchanger 312, heat exchanger 313, pump 314, and direct contact membrane distillation seawater desalination unit 320.

[0037] Reference Figure 2 This section introduces the composition, connection methods, and specific functions of each module in the system: The specific structure and electrical connections of the power integration module are as follows: The output of the wind turbine 101 is connected to the AC-DC rectifier 105, which converts the generated alternating current into stable direct current.

[0038] The output of the photovoltaic array 102 is connected to the boost DC-DC converter 106, which boosts the variable voltage DC power generated by the photovoltaic panel to a voltage level that matches the DC bus 104.

[0039] The energy storage battery 103, for example, is a lithium-ion battery pack connected to the DC bus 104 via a bidirectional DC-DC converter 107. The converter 107 has bidirectional energy flow capability, capable of both charging the battery and releasing battery energy to the bus.

[0040] In RSOC system module 200, the RSOC stack 210 is connected to the DC bus via two unidirectional DC-DC converters. These two unidirectional DC-DC converters are a first unidirectional DC-DC converter and a second unidirectional DC-DC converter. Specifically, the first unidirectional DC-DC converter 108, in SOEC mode, steps down and regulates the power from the DC bus before supplying it to the RSOC stack 210 for electrolysis; the second unidirectional DC-DC converter 109, in SOFC mode, steps up the low-voltage DC power generated by the RSOC stack 210 before feeding it back to the DC bus 104.

[0041] A DC-AC inverter 110 is connected to the end of the DC bus 104 to convert the DC power on the DC bus into industrial frequency AC power such as 220V / 50Hz, so as to power the AC loads of the island such as lighting, communication equipment, household appliances, etc., as well as the AC auxiliary equipment of each module in the system such as water pumps and fans.

[0042] RSOC system module 200 is the core of realizing bidirectional energy conversion. RSOC system module 200 includes RSOC stack 210 and two balancing devices (BOPs) are configured around the stack.

[0043] The RSOC system operates in two modes: SOEC electrolysis hydrogen production mode and SOFC power generation mode.

[0044] When wind and solar power output is excessive, the intelligent controller's built-in dynamic threshold algorithm triggers SOEC mode: When the power output from wind and solar power is insufficient, the system switches to SOFC mode: The process for producing hydrogen via SOEC electrolysis is as follows: When the system experiences a surplus of wind and solar power generation, the intelligent controller 600 triggers SOEC mode. Water pump 221 starts and draws deionized water from water storage tank 500.

[0045] Liquid water first enters the water evaporator 222, where it is heated by the high-temperature exhaust gas from the fuel electrode of the RSOC stack and completely vaporized into atmospheric pressure water vapor.

[0046] The generated steam then enters the steam electric heater 223, where it is further heated to a high temperature of 750°C through precise resistance heating to meet the inlet temperature requirements of the RSOC stack 210 fuel electrode.

[0047] High-temperature water vapor enters the fuel electrode of RSOC stack 210 and undergoes an electrochemical reaction under the drive of direct current provided by a unidirectional DC-DC converter 108 to generate hydrogen gas.

[0048] The exhaust gas from the fuel electrode mainly consists of unreacted water vapor and generated hydrogen gas. After exiting the fuel cell stack, the gas returns to the shell side of the water evaporator 222 to preheat the incoming liquid water as a heat source, while being cooled itself.

[0049] The cooled gas-liquid mixture enters condenser 227, where water vapor is condensed into liquid water. The separated high-purity hydrogen is pressurized to 3.0 MPa by compressor 228 and then transported to hydrogen storage tank 400 for storage. The condensate produced in condenser 227 is recycled to water storage tank 500, realizing the recycling of water resources within the system.

[0050] Air-to-oxygen side process: Fan 224 starts up, pressurizing the ambient air by about 0.2 MPa.

[0051] The pressurized air first enters the air preheater 225, where it exchanges heat with the high-temperature exhaust gas from the air electrode of the RSOC fuel cell stack and is preheated.

[0052] The preheated air then enters the air electric heater 226 and is precisely heated to 600°C by resistance heating to meet the air inlet temperature requirements of the fuel cell stack.

[0053] When hot air enters the air electrode of RSOC stack 210, the reaction that occurs is: O²⁻→1 / 2O₂+2e⁻, releasing oxygen.

[0054] The high-temperature, oxygen-rich air discharged from the air outlet, at approximately 700-800°C, first flows through the tube side of the air preheater 225, preheating the incoming air and then reducing its own temperature to 150-250°C. Subsequently, this exhaust gas, which still retains residual heat value, is guided to the heat exchanger 312 in the freshwater production module 300, serving as a heat source for heating the seawater.

[0055] Process in SOFC power generation mode: When the system's wind and solar power generation is insufficient, the intelligent controller 600 triggers SOFC mode.

[0056] Fuel electrode hydrogen side process: The high-pressure hydrogen in the hydrogen storage tank 400 is first reduced to a working pressure of approximately 0.15 MPa by the pressure reducer 233.

[0057] The depressurized hydrogen gas is precisely controlled by the flow controller 234 (such as a mass flow controller) and enters the fuel preheater 235.

[0058] In the fuel preheater 235, hydrogen is heated to 750°C by the high-temperature exhaust gas from the catalytic burner and then enters the fuel pole of the RSOC stack 210.

[0059] Air-to-oxygen side process: Fan 1231 starts up, pressurizing the ambient air by about 0.15 MPa.

[0060] The pressurized air enters the air preheater 232, where it is heated to 600°C by the high-temperature exhaust gas from the catalytic burner, and then enters the air electrode of the RSOC stack 210.

[0061] Electrochemical reactions and exhaust gas treatment: Preheated hydrogen and air undergo electrochemical reactions inside the RSOC fuel cell stack 210: H₂ + O²⁻ → H₂O + 2e⁻ and 1 / 2O₂ + 2e⁻ → O²⁻, generating direct current (DC). This DC current is boosted by a unidirectional DC-DC converter 109 and then fed into the DC bus 104 to supplement the system's power.

[0062] The unreacted residual hydrogen and oxygen discharged from the fuel electrode and air electrode enter the catalytic combustor 236 together. Under the action of the catalyst, they undergo flameless combustion, instantly raising the exhaust gas temperature to approximately 900°C.

[0063] This high-temperature exhaust gas serves as a high-quality heat source, first flowing through the fuel preheater 235 to heat the incoming hydrogen; then flowing through the air preheater 232 to heat the incoming air.

[0064] After two stages of heat exchange, the exhaust gas temperature drops to 150-250℃ and is guided to heat exchanger 313 in the freshwater production module 300, serving as another heat source for heating the seawater. Water vapor in the exhaust gas partially condenses in heat exchanger 313, and the resulting condensate is collected and directed to the water storage tank 500. Example 2

[0065] Example 2 provides a method for operating the system based on Example 1, the method including the following steps: Real-time monitoring of renewable energy generation capacity, load demand, and state of charge (SOC) of energy storage batteries; Calculate the power difference between power generation and load, ΔP = P_gen - P_load; Control the power difference ΔP in the energy storage battery response; When ΔP is greater than the first set threshold, the RSOC system module is controlled to switch to SOEC mode for electrolytic hydrogen production. When ΔP is less than the second set threshold, the RSOC system module is controlled to switch to SOFC mode for power generation.

[0066] Specifically, the first set threshold is associated with the maximum charging power of the energy storage battery, and the second set threshold is associated with the maximum discharging power of the energy storage battery.

[0067] Specifically, the decision to switch modes further refers to the SOC state of the energy storage battery. When ΔP > ΔP_H and the SOC is higher than an upper limit, SOEC mode is triggered. When ΔP < ΔP_L and the SOC is lower than a lower limit, SOFC mode is triggered.

[0068] Specifically, the first and second set thresholds can be adaptively adjusted based on real-time weather forecast data and load demand trends.

[0069] Or: First threshold ΔP H Set to 85% of the maximum charging power of energy storage, SOEC mode is triggered when wind and solar power output exceeds load demand and SOC > 90%; the second threshold ΔP L Set to 75% of the maximum energy storage discharge power, SOFC mode is triggered when wind and solar power are insufficient and SOC < 20%.

[0070] This system achieves integrated hydrogen energy storage and generation through RSOC dual-mode switching, coupling wind, solar, and hydrogen storage multi-energy complementarity and waste heat cascade utilization to solve the problems of energy fluctuations and high energy consumption in off-grid scenarios and freshwater production. The direct contact membrane distillation unit operates at a temperature of 50~80℃ and utilizes low-grade waste heat. The equipment is compact and suitable for decentralized water supply on islands. The intelligent dynamic threshold algorithm achieves high-efficiency operation, zero carbon emissions, and freshwater self-sufficiency through wind and solar forecasting and adaptive optimization of load demand mode switching, and has high reliability and scenario adaptability.

[0071] A proposed operation method for an off-grid zero-carbon energy supply and freshwater production collaborative system based on reversible solid oxide batteries is used to guide the control of the system. All load fluctuations are preferentially responded to by the energy storage battery, and the RSOC system only intervenes when the energy storage's charging and discharging reaches its limits. The intelligent controller collects real-time data on the power generation Pgen of the wind turbines and photovoltaic arrays in the power integration module, the state of charge (SOC) of the energy storage battery, and the load demand Pload, generating a dynamic difference ΔP = Pgen - Pload. The intelligent controller 600 employs a dynamic threshold algorithm for optimized operation: the first threshold ΔPH is set to 85% of the maximum charging power of the energy storage; when wind and solar power output exceeds load demand and SOC > 90%, SOEC mode is triggered. The second threshold ΔPL is set to 75% of the maximum discharging power of the energy storage; when wind and solar power are insufficient and SOC < 20%, SOFC mode is triggered. The thresholds are dynamically adjusted based on 48-hour weather forecasts: if continuous rain is predicted, ΔPH is lowered by 10% to allow for advance hydrogen production and storage; if a load surge is predicted, ΔPL is raised by 15% to reserve discharge margin.

[0072] Specifically, when forecasts indicate continuous rain, decreased wind speed, or insufficient sunlight, the system determines that renewable energy generation capacity will decline. The intelligent controller accordingly lowers the value of ΔP_H (e.g., by approximately 10%) to trigger the RSOC system to enter SOEC mode for hydrogen electrolysis in advance, thus pre-storing hydrogen energy and providing energy security for subsequent periods of low power generation. Conversely, when forecasts indicate a significant increase in future load demand (e.g., increased cooling load due to high temperatures or special power consumption events), the system determines that load-side power demand will increase. The intelligent controller then raises the value of ΔP_L (e.g., by approximately 15%), delaying the RSOC system's entry into SOFC mode to retain more hydrogen storage and battery capacity to cope with peak loads.

[0073] When both power generation and load are stable and no significant trend is predicted, the threshold remains at its default setting to achieve optimal switching control of the system under dynamic energy supply and demand balance. Through this adaptive threshold adjustment strategy, the RSOC system can proactively optimize its operating status based on external meteorological conditions and energy consumption trends, achieving efficient energy management and stable power supply for wind-solar-hydrogen storage systems in off-grid scenarios.

[0074] This system achieves integrated hydrogen energy storage and generation through RSOC dual-mode switching, coupling wind, solar, and hydrogen storage multi-energy complementarity and waste heat cascade utilization to solve the problems of energy fluctuations and high energy consumption in off-grid scenarios and freshwater production. The direct contact membrane distillation unit operates at a temperature of 50~80℃ and utilizes low-grade waste heat. The equipment is compact and suitable for decentralized water supply on islands. The intelligent dynamic threshold algorithm achieves high-efficiency operation, zero carbon emissions, and freshwater self-sufficiency through wind and solar forecasting and adaptive optimization of load demand mode switching, and has high reliability and scenario adaptability.

[0075] The above description is merely a selection of preferred embodiments of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with technical features having similar functions disclosed in the embodiments of this disclosure.

Claims

1. A collaborative system for off-grid zero-carbon energy supply and freshwater production based on reversible solid oxide batteries, characterized in that, include: The power integration module, including wind turbines, photovoltaic arrays, energy storage batteries, and DC buses, is used to integrate renewable energy generation and energy storage. The RSOC system module is electrically connected to the power integration module and has bidirectional operation function in both solid oxide electrolyzer (SOEC) mode and solid oxide fuel cell (SOFC) mode. The freshwater production module is thermally connected to the RSOC system module and includes a direct contact membrane distillation seawater desalination device for using the waste heat generated during the operation of the RSOC system module to desalinate seawater. A hydrogen storage tank, connected to the RSOC system module, is used to store hydrogen in SOEC mode and supply hydrogen in SOFC mode; A water storage tank, connected to the freshwater production module and the RSOC system module, is used to store freshwater and supply water for SOEC mode; The intelligent controller, which is communicatively connected to the power integration module and the RSOC system module, is configured to control the mode switching of the RSOC system module based on the difference between the wind and solar power generation and the load demand power.

2. The system according to claim 1, characterized in that, The wind turbine and photovoltaic array are connected to the DC bus via a power converter; the energy storage battery is connected to the DC bus via a bidirectional DC-DC converter; and the RSOC system module is connected to the DC bus via a unidirectional DC-DC converter (108, 109).

3. The system according to claim 2, characterized in that, The RSOC system module includes an RSOC fuel cell stack, a BOP device in SOEC mode, and a BOP device in SOFC mode. The BOP equipment in the SOEC mode includes a preheating component for treating water and air, and a condenser and compressor for treating hydrogen. The BOP equipment in the SOFC mode includes components for preheating air and hydrogen, and a catalytic combustor for treating the reaction exhaust gas.

4. The system according to claim 3, characterized in that, In SOEC mode, the exhaust gas from the air electrode of the RSOC stack is directed to the freshwater production module to provide waste heat; in SOFC mode, the exhaust gas from the catalytic burner is directed to the freshwater production module to provide waste heat.

5. The system according to claim 1, characterized in that, The freshwater production module also includes a second water pump, a first heat exchanger, and a second heat exchanger. The second water pump is used to pressurize seawater and pump it sequentially into the first and second heat exchangers for heating. The heated seawater then enters the feed water side of the direct contact membrane distillation seawater desalination device.

6. The system according to claim 5, characterized in that, The high-temperature heat source of heat exchanger one is the air exhaust gas in SOEC mode; the high-temperature heat source of heat exchanger two is the catalytic combustion exhaust gas in SOFC mode.

7. A method for operating the system according to any one of claims 1-6, characterized in that, Includes the following steps: Real-time monitoring of renewable energy generation capacity, load demand, and state of charge (SOC) of energy storage batteries; Calculate the power difference between power generation and load, ΔP = P_gen - P_load; Control the power difference ΔP in the energy storage battery response; When ΔP is greater than the first set threshold, the RSOC system module is controlled to switch to SOEC mode for electrolytic hydrogen production. When ΔP is less than the second set threshold, the RSOC system module is controlled to switch to SOFC mode for power generation.

8. The method according to claim 7, characterized in that, The first set threshold is associated with the maximum charging power of the energy storage battery, and the second set threshold is associated with the maximum discharging power of the energy storage battery.

9. The method according to claim 8, characterized in that, The decision to switch modes further refers to the SOC state of the energy storage battery. When ΔP > ΔP_H and the SOC is higher than an upper limit, SOEC mode is triggered. When ΔP < ΔP_L and the SOC is lower than a lower limit, SOFC mode is triggered.

10. The method according to claim 7, characterized in that, The first and second set thresholds can be adaptively adjusted based on real-time weather forecast data and load demand trends.

Images