A combined electricity and water supply system and method using fuel cells and photovoltaic power generation

Abstract

This invention provides a combined electricity and water supply system and method integrating fuel cells and photovoltaic power generation, belonging to the field of photovoltaic power generation technology. It includes: a fuel cell power generation system, a hydrogen production subsystem, a water production subsystem, and an organic Rankine cycle power generation system, each connected via pipelines and valves. The fuel cell power generation system is connected to the hydrogen production subsystem; the water production subsystem is connected to the fuel cell power generation system; and the organic Rankine cycle subsystem is connected to the fuel cell power generation system. This invention meets users' multiple energy needs for electricity, fresh water, and hydrogen storage while reducing energy losses during combined power supply, further improving the overall system efficiency, and replacing traditional fossil fuels with green, pollution-free clean energy to protect the ecological environment.

Description

Technical Field

[0001] This invention belongs to the field of new energy power generation technology, and in particular relates to a combined electricity and water supply system and method for fuel cells and photovoltaic power generation. Background Technology

[0002] Solar energy, as an inexhaustible and renewable energy source, boasts wide distribution, abundant energy, and zero pollution, making it a promising area for development. However, solar energy itself is unstable due to factors such as day-night cycles, geographical location, and variations in sunlight intensity. Converting this unstable solar energy into stable energy is crucial for its effective utilization. Research has found that using electricity generated by solar photovoltaic power for water electrolysis to produce and store hydrogen can effectively avoid equipment damage and energy waste caused by the instability of solar energy. Solid oxide fuel cells can directly utilize hydrogen as fuel for efficient power generation; if green hydrogen produced by solar power is used as a fuel source, zero CO2 emissions can be achieved during the energy utilization process.

[0003] In the power generation process of solid oxide fuel cells, there is a problem of incomplete fuel conversion, with some fuel (H2) remaining in the anode. Simultaneously, the exhaust gas temperature from the anode and cathode exceeds 600°C, and direct discharge would result in significant energy waste. Therefore, to achieve more efficient energy utilization and reduce environmental pollution from emissions, how to utilize the unreacted fuel in the battery for heat recovery in a cascade manner and achieve efficient energy utilization is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] This invention provides a combined electricity and water system integrating fuel cells and photovoltaic power generation. The system utilizes the residual heat from the flue gas after seawater preparation to drive a dual-pressure organic Rankine cycle to generate electricity. The entire system can simultaneously produce electricity, hydrogen, and oxygen, and has advantages such as high energy efficiency and zero CO2 emissions.

[0005] The system includes: a fuel cell power generation system, a hydrogen production subsystem, a water production subsystem, and an organic Rankine cycle power generation system;

[0006] The fuel cell power generation system is connected to the hydrogen production subsystem; the water production subsystem is connected to the fuel cell power generation system; the organic Rankine cycle power generation system is connected to the fuel cell power generation system.

[0007] The fuel cell power generation system uses proton exchange membrane to electrolyze water to produce hydrogen for power generation, which is then supplemented by combustion. The solid fuel cell uses hydrogen as fuel to carry out electrochemical reactions to generate electricity efficiently. The remaining fuel at the anode outlet of the solid oxide fuel cell and the exhaust gas discharged from the cathode outlet are burned and supplemented in the after-combustion chamber. The high-temperature gas at the outlet of the after-combustion chamber can drive the gas turbine to rotate and do work.

[0008] The hydrogen production subsystem is used to couple renewable resources—solar energy—to provide imported fuel for solid fuel cells;

[0009] The water production subsystem utilizes the high-grade waste heat from the exhaust of the fuel cell power generation system to prepare high-temperature steam. Part of the high-temperature steam is dissipated through pipelines to provide heat to users, while another part of the high-temperature steam is processed by a steam compressor to form high-temperature and high-pressure steam, and then the seawater is distilled multiple times in an evaporator to produce fresh water.

[0010] The organic Rankine cycle power generation system is used to recover and utilize the waste heat of the remaining low-to-medium grade flue gas. The circulating organic working fluid is heated by a preheater and then enters the turbine under two set pressure conditions to expand and generate electricity.

[0011] It should be further noted that the fuel cell power generation system includes: a solid oxide fuel cell, an afterburner, a gas turbine, an air compressor, a hydrogen compressor, a first preheater, a second preheater, and a heat recovery steam generator;

[0012] The power output terminal of the solid oxide fuel cell is connected to an inverter, which performs DC to AC conversion.

[0013] The outlet of the solid oxide fuel cell is connected to the inlet of the rear combustion chamber.

[0014] The gas turbine inlet is connected to the afterburner outlet; the air compressor and the hydrogen compressor are coaxially connected to the gas turbine.

[0015] Air is introduced into the air compressor inlet; hydrogen is introduced into the hydrogen compressor inlet; the first air inlet of the first preheater is connected to the air outlet of the gas turbine; the second air inlet of the first preheater is connected to the air outlet of the air compressor.

[0016] The first outlet of the first preheater is connected to the first inlet of the second preheater; the second outlet of the first preheater is connected to the cathode inlet of the solid oxide fuel cell; the outlet of the hydrogen compressor is connected to the second inlet of the second preheater; and the second outlet of the second preheater is connected to the first inlet of the heat recovery steam generator.

[0017] It should be further noted that a first pressure sensor and a first temperature sensor are installed on the connecting pipe between the gas turbine inlet and the afterburner outlet.

[0018] A second pressure sensor and a second temperature sensor are installed on the connecting pipe between the first air outlet of the first preheater and the first air inlet of the second preheater.

[0019] It should be further noted that the inverter is equipped with a current sensor and a voltage sensor on its input and output sides, respectively.

[0020] It should be further noted that the hydrogen production subsystem includes: photovoltaic modules, solar controller, rectifier, proton exchange membrane electrolyzer, activated carbon hydrogen storage tank, hydrogen valve, and oxygen storage tank;

[0021] The first outlet of the photovoltaic module is connected to the inlet of the solar controller; the first outlet of the solar controller is connected to the inlet of the inverter; the second outlet of the solar controller is connected to the inlet of the rectifier.

[0022] The outlet of the rectifier is connected to the first inlet of the proton exchange membrane electrolyzer; the second outlet of the water storage tank is connected to the second inlet of the proton exchange membrane electrolyzer; and the second outlet of the proton exchange membrane electrolyzer is connected to the inlet of the oxygen storage tank.

[0023] The first outlet of the proton exchange membrane electrolyzer is connected to the inlet of the activated carbon hydrogen storage tank; the first outlet of the activated carbon hydrogen storage tank can provide hydrogen energy to the user.

[0024] The second outlet of the activated carbon hydrogen storage tank is connected to the inlet of the hydrogen valve; the outlet of the hydrogen valve is connected to the inlet of the hydrogen compressor.

[0025] It should be further noted that the water production subsystem includes: a heat recovery steam generator, a steam compressor, a first water pump, a first evaporator, a third preheater, a second evaporator, a fourth preheater, a third evaporator, a fifth preheater, a fourth evaporator, a sixth preheater, a fifth evaporator, a first condenser, a second water pump, a third water pump, a fourth water pump, and an inlet seawater valve.

[0026] The first air inlet of the heat recovery steam generator is connected to the first air outlet of the third preheater; the second air outlet of the heat recovery steam generator is connected to the first air inlet of the steam compressor.

[0027] The first air outlet of the fifth evaporator is connected to the second air inlet of the steam compressor;

[0028] The steam compressor's outlet is connected to the first air inlet of the first evaporator; the first water outlet of the first evaporator is connected to the water inlet of the first water pump.

[0029] The outlet of the first water pump is connected to the second inlet of the heat recovery steam generator; the second outlet of the third preheater is connected to the second inlet of the first evaporator.

[0030] The second air outlet of the first evaporator is connected to the first air inlet of the third preheater;

[0031] The third liquid outlet of the first evaporator is connected to the third liquid inlet of the second evaporator; the liquid outlet of the second evaporator is connected to the liquid inlet of the third evaporator; the liquid outlet of the third evaporator is connected to the liquid inlet of the fourth evaporator.

[0032] The liquid outlet of the fourth evaporator is connected to the liquid inlet of the fifth evaporator;

[0033] The first air outlet of the third preheater is connected to the first air inlet of the second evaporator;

[0034] The third outlet of the fifth evaporator is connected to the inlet of the third water pump; the outlet of the third water pump is used to discharge the recovered concentrated brine.

[0035] The outlet of the fourth water pump is connected to the first inlet of the first condenser.

[0036] The first liquid outlet of the first condenser is connected to the inlet seawater valve;

[0037] The second outlet of the first condenser discharges seawater; the third outlet of the first condenser is connected to the second water pump; the outlet of the second water pump is connected to a water storage tank; and the second outlet of the water storage tank is used to provide fresh water to users.

[0038] It should be further noted that the pipeline between the first air inlet of the heat recovery steam generator and the first air outlet of the third preheater, the pipeline between the second air outlet of the heat recovery steam generator and the first air inlet of the steam compressor, and the pipeline between the first air outlet of the fifth evaporator and the second air inlet of the steam compressor are respectively equipped with third pressure sensors.

[0039] The outlets of the first evaporator, second evaporator, third evaporator, fourth evaporator, fifth evaporator, and the liquid outlet of the first condenser are each equipped with a third temperature sensor.

[0040] It should be further noted that the organic Rankine cycle power generation system includes: an organic Rankine cycle preheater, a high-pressure pump, a high-pressure steam generator, a high-pressure turbine, a low-pressure steam generator, a mixing chamber, a low-pressure turbine, a second condenser, a low-pressure pump, and a water separator.

[0041] The first outlet of the organic Rankine cycle preheater is connected to the inlet of the high-pressure pump.

[0042] The outlet of the high-pressure pump is connected to the first inlet of the high-pressure steam generator;

[0043] The first outlet of the high-pressure steam generator is connected to the inlet of the high-pressure turbine.

[0044] The outlet of the high-pressure turbine is connected to the inlet of the mixing chamber;

[0045] The second liquid outlet of the organic Rankine cycle preheater is connected to the first liquid inlet of the low-pressure steam generator.

[0046] The first outlet of the low-pressure steam generator is connected to the second inlet of the mixing chamber;

[0047] The outlet of the mixing chamber is connected to the inlet of the low-pressure turbine;

[0048] The outlet of the low-pressure turbine is connected to the first inlet of the second condenser; circulating condensate is introduced into the second inlet of the second condenser.

[0049] The outlet of the second condenser is connected to the inlet of the low-pressure pump;

[0050] The outlet of the low-pressure pump is connected to the first inlet of the organic Rankine cycle preheater.

[0051] The second air inlet of the high-pressure steam generator is connected to the first air outlet of the heat recovery steam generator.

[0052] The second outlet of the high-pressure steam generator is connected to the second outlet of the low-pressure steam generator.

[0053] The second outlet of the low-pressure steam generator is connected to the second outlet of the organic Rankine cycle preheater.

[0054] The third air outlet of the organic Rankine cycle preheater is connected to the air inlet of the water separator.

[0055] The first outlet of the water separator is connected to the second inlet of the water storage tank;

[0056] The second outlet of the water separator discharges the gas into the atmosphere.

[0057] This application also provides a method for combined electricity, gas, and water supply using fuel cells and photovoltaic power generation, the method comprising:

[0058] Step 1: Preheat the compressed air and hydrogen, then use the hydrogen fuel to generate electricity through an electrochemical reaction, and use the remaining fuel to drive the gas turbine to expand and do work.

[0059] Step two: The photovoltaic modules generate electricity based on solar energy. The solar controller adjusts the photovoltaic modules to output maximum power, and the inverter and rectifier are used to regulate the voltage. Hydrogen and oxygen are produced by electrolyzing water through a proton exchange membrane and then stored.

[0060] Step 3: Use the medium-grade waste heat from the system exhaust to prepare saturated steam. Then, use part of the medium-grade waste heat to provide heat to users, and use the other part to obtain high-temperature and high-pressure steam through a steam compressor. Based on the feed seawater, after passing through multiple steam generators and condensers, it is distilled and desalinated into product water for supply to users.

[0061] Step four: The supercooled organic working fluid absorbs the waste heat from the exhaust gas in the organic Rankine cycle preheater and becomes a saturated liquid. Part of the saturated liquid enters the high-pressure pump to be pressurized into a high-pressure organic working fluid. The high-pressure organic working fluid then enters the high-pressure steam generator to form a high-pressure saturated steam organic working fluid. The organic working fluid expands in the high-pressure turbine to generate electricity. Part of the saturated liquid enters the low-pressure steam generator to form a low-pressure saturated steam organic working fluid. The steam after the high-pressure turbine has done work is mixed with the steam at the outlet of the low-pressure steam generator in the mixing chamber. The mixed working fluid enters the low-pressure turbine to expand and generate electricity.

[0062] Turbine exhaust steam enters the second condenser and condenses into a subcooled state. The organic working fluid enters the low-pressure pump for pressurization and then passes into the preheater. The flue gas discharged from the heat recovery steam generator enters the high-pressure steam generator for heat exchange and temperature reduction. The flue gas continues to enter the low-temperature steam generator for heat exchange with the organic working fluid. The flue gas recovers heat in the organic Rankine cycle preheater. The flue gas is separated by a water separator. The separated water enters the water storage tank for storage, and the remaining flue gas is discharged into the environment.

[0063] It should be further noted that step two also includes:

[0064] The seawater is first preheated in the first condenser, and then a preset amount of seawater is preheated to the boiling temperature in the preheater by a valve, but no phase change occurs.

[0065] Seawater enters the first evaporator and undergoes heat exchange to generate a large amount of secondary steam, which then enters the second evaporator. The hot steam exchanges heat with the seawater in the second evaporator and condenses into water, which is then collected in the storage tank. The remaining unevaporated seawater flows into the next stage evaporator and undergoes the same reaction.

[0066] The process continues until the concentrated brine in the fifth evaporator is discharged and recovered. Part of the hot steam enters the air compressor to mix with the hot steam for heating, while part of the water vapor releases heat in the first condenser to obtain the required product water, which is then stored in a water tank.

[0067] As can be seen from the above technical solutions, the present invention has the following advantages:

[0068] The combined cycle power system (CCHP) provided by this invention utilizes solar energy for photovoltaic power generation and storage, and produces and stores hydrogen and oxygen through proton exchange membrane electrolysis of water. Simultaneously, it can store and utilize the energy from the solid oxide fuel cell for electricity storage. Furthermore, it uses the residual fuel and waste heat from the battery electrode outlet exhaust to generate high-temperature gas via a heat recovery steam generator, which then exchanges heat with seawater for evaporation, providing fresh water, hydrogen, and electricity. The remaining waste heat from the flue gas continues to generate electricity in a dual-pressure organic Rankine cycle. This reduces the internal heat consumption of the CCHP system, improves the efficiency of fossil fuel utilization, and uses green hydrogen energy without CO2 generation.

[0069] This invention utilizes energy based on the principle of "temperature matching and tiered utilization" by coupling solid oxide fuel cells, photovoltaic power generation, water electrolysis for hydrogen production, dual-pressure organic Rankine cycle, and steam generator, thereby maximizing the utilization of heat. This energy system has high energy utilization efficiency.

[0070] This invention can simultaneously meet the user's demand for electricity, hydrogen, oxygen, and freshwater. Furthermore, the operating parameters and working mode of the combined power supply system can be adjusted according to changes in external conditions such as environmental changes and user needs. Utilizing solar energy to produce hydrogen can reduce the operating cost of hydrogen production through water electrolysis. Based on the full utilization of solar energy, this invention leverages the high energy efficiency of the combined power supply system and rationally allocates the ratio of electricity, hydrogen, and freshwater products, offering advantages such as flexible configuration and high energy efficiency. Attached Figure Description

[0071] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0072] Figure 1 This is a schematic diagram of a combined electricity and water supply system that integrates fuel cells and photovoltaic power generation. Detailed Implementation

[0073] The following describes in detail the combined electricity and water supply system for fuel cells and photovoltaic power generation involved in this application. Specific details, such as particular system structures and technologies, are set forth below for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0074] In the combined electricity and water supply system of fuel cells and photovoltaic power generation involved in this application, when used in this specification, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0075] In this application, "one or more" refers to one, two, or more than two, and "multiple" refers to two or more than two. In the description of this application, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B. The term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone.

[0076] To facilitate a clear description of the technical solutions of this application, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" do not necessarily imply that they are different.

[0077] The terms "one embodiment" or "some embodiments" used in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this application do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0078] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0079] Please see Figure 1 The diagram shown is a schematic of a combined electricity and water system integrating fuel cells and photovoltaic power generation in a specific embodiment.

[0080] The combined electricity and water system involving fuel cells and photovoltaic power generation in this embodiment is a "electricity-gas-water" CO2 zero-emission combined supply system that couples solid oxide fuel cells and photovoltaic power generation. It can flexibly meet users' multiple energy needs for electricity, fresh water and hydrogen storage, reduce energy utilization losses in the system process, further improve the overall utilization efficiency of the system, and use green and pollution-free clean energy to replace traditional fossil energy to protect the ecological environment.

[0081] Specifically, the combined electricity, water, and gas power supply system for fuel cells and photovoltaic power generation includes: a fuel cell power generation system, a hydrogen production subsystem, a water production subsystem, and an organic Rankine cycle power generation system. Each system in this embodiment is connected via pipelines and valves. The fuel cell power generation system is connected to the hydrogen production subsystem; the water production subsystem is connected to the fuel cell power generation system; and the organic Rankine cycle subsystem is connected to the fuel cell power generation system.

[0082] In this embodiment, the fuel cell power generation system uses proton exchange membrane to electrolyze water to produce hydrogen for power generation, which is then supplemented by combustion. The solid fuel cell uses hydrogen as fuel to carry out electrochemical reactions for efficient power generation. The remaining fuel at the anode outlet and the exhaust gas discharged from the cathode outlet of the solid oxide fuel cell are burned and supplemented in the afterburner. The high-temperature gas at the outlet of the afterburner can drive the gas turbine to rotate and do work.

[0083] The hydrogen production subsystem is used to couple renewable energy—solar energy—to provide imported fuel for solid-state fuel cells, reducing the power generation system's dependence on fossil fuels and emitting environmentally friendly gases to protect the environment. Utilizing solar energy for hydrogen production can reduce the operating costs of water electrolysis, and the absence of CO2 production during the process effectively avoids the greenhouse effect's environmental damage. It converts unstable solar energy into green and stable hydrogen energy, achieving efficient energy storage and utilization.

[0084] The water production subsystem described in this embodiment utilizes the high-grade waste heat from the exhaust of the power generation system to prepare high-temperature steam. A portion of the high-temperature steam is dissipated through pipes to provide a certain amount of heat to the user, while another portion of the high-temperature steam is processed by the steam compressor to form high-temperature and high-pressure steam, and then undergoes multiple distillations of seawater in the evaporator to produce fresh water.

[0085] The dual-pressure organic Rankine cycle system is used to recover and utilize the waste heat of the remaining low-to-medium grade flue gas. The circulating organic working fluid is heated by the preheater and then enters the turbine under two set pressure conditions to expand and generate electricity.

[0086] In this embodiment, the organic Rankine cycle system is a primary approach to low-temperature waste heat recovery power generation. The system is characterized by simple equipment and clean energy. It can utilize various waste heat sources, low-temperature heat sources, and renewable energy sources such as solar energy to generate electricity. Compared to a conventional organic Rankine cycle, the dual-pressure organic Rankine cycle system offers higher energy efficiency and better thermal performance. Since the exhaust gas retains its low-to-medium temperature waste heat after seawater desalination, its coupling with the dual-pressure organic Rankine cycle further achieves energy conservation and high efficiency, and also reduces dependence on traditional fossil fuels.

[0087] In one embodiment of the present invention, a possible implementation will be described below in a non-limiting manner.

[0088] Specifically, the fuel cell power generation system 100 includes a solid oxide fuel cell 101, an afterburner 102, a gas turbine 103, an air compressor 104, a hydrogen compressor 105, a first preheater 106, and a second preheater 107.

[0089] In some embodiments, the solid oxide fuel cell 101 performs DC-AC current conversion via the inverter 203. The outlet of the solid oxide fuel cell 101 is connected to the inlet of the afterburner 102; the inlet of the gas turbine 103 is connected to the outlet of the afterburner 102; the air compressor 104 and the hydrogen compressor 105 are coaxially connected to the gas turbine 103; air is introduced into the inlet of the air compressor 104; and hydrogen is introduced into the inlet of the hydrogen compressor 105.

[0090] The first air inlet of the first preheater 106 is connected to the air outlet of the gas turbine 103; the second air inlet of the first preheater 106 is connected to the air outlet of the air compressor 104; the first air outlet of the first preheater 106 is connected to the first air inlet of the second preheater 107; the second air outlet of the first preheater 106 is connected to the cathode air inlet of the solid oxide fuel cell 101; the air outlet of the hydrogen compressor 105 is connected to the second air inlet of the second preheater 107; and the second air outlet of the second preheater 107 is connected to the first air inlet of the heat recovery steam generator 301.

[0091] In some embodiments, the solid oxide fuel cell in the fuel cell power generation system is an advanced power generation device that utilizes an electrochemical reaction. Its operating temperature is generally 600 ℃ to 1000 ℃, and it can use hydrogen energy as fuel, with a power generation efficiency exceeding 60%.

[0092] In this implementation, the exhaust gas from the electrode of the solid oxide fuel cell still contains unreacted fuel and high-grade waste heat. By integrating it with other forms of power systems, such as gas turbines and steam turbines, the overall energy utilization efficiency can be increased to 70% or more.

[0093] In some embodiments, the hydrogen production subsystem 200 includes: a photovoltaic module 201, a solar controller 202, an inverter 203, a rectifier 204, a proton exchange membrane electrolyzer 205, an activated carbon hydrogen storage tank 206, a hydrogen valve 207, and an oxygen storage tank 208.

[0094] The first outlet of the photovoltaic module 201 is connected to the inlet of the solar controller 202; the first outlet of the solar controller 202 is connected to the inlet of the inverter 203; the second outlet of the solar controller 202 is connected to the inlet of the rectifier 204; the outlet of the rectifier 204 is connected to the first inlet of the proton exchange membrane electrolyzer 205; and the second outlet of the water storage tank 315 is connected to the second inlet of the proton exchange membrane electrolyzer 205. The second outlet of the proton exchange membrane electrolyzer 205 is connected to the inlet of the oxygen storage tank 208; the first outlet of the proton exchange membrane electrolyzer 205 is connected to the inlet of the activated carbon hydrogen storage tank 206; the first outlet of the activated carbon hydrogen storage tank 206 can provide hydrogen energy to users; the second outlet of the activated carbon hydrogen storage tank 206 is connected to the inlet of the hydrogen valve 207; the outlet of the hydrogen valve 207 is connected to the inlet of the hydrogen compressor 105.

[0095] In this embodiment, the hydrogen production subsystem generates electricity initially through photovoltaic modules by absorbing solar energy. A solar controller continuously monitors changes in the current and voltage of the photovoltaic array before outputting maximum power, adjusting the inverter and rectifier accordingly. The proton exchange membrane electrolyzes water using a stable current obtained from the rectifier to produce hydrogen. The hydrogen is stored in an activated carbon hydrogen storage tank, and oxygen is stored in an oxygen storage tank. This hydrogen production subsystem can utilize unstable sunlight to convert into stable hydrogen, ensuring a continuous and stable operating environment for the subsequent power generation system. The entire system uses sustainable solar energy and green hydrogen energy for power, increasing energy availability while reducing dependence on fossil fuels. Zero CO2 emissions mitigate the environmental damage caused by industry and enhance the system's environmental friendliness.

[0096] In some specific embodiments, the water production subsystem 300 includes: a heat recovery steam generator 301, a steam compressor 302, a first water pump 303, a first evaporator 304, a third preheater 305, a second evaporator 306, a fourth preheater 307, a third evaporator 308, a fifth preheater 309, a fourth evaporator 310, a sixth preheater 311, a fifth evaporator 312, a first condenser 313, a second water pump 314, a third water pump 316, a water storage tank 315, a fourth water pump 317, and an inlet seawater valve 318.

[0097] In this embodiment, the first air inlet of the heat recovery steam generator 301 is connected to the first air outlet of the third preheater 305; the second air outlet of the heat recovery steam generator 301 is connected to the first air inlet of the steam compressor 302; the first air outlet of the fifth evaporator 312 is connected to the second air inlet of the steam compressor 302; the air outlet of the steam compressor 302 is connected to the first air inlet of the first evaporator 304; the first water outlet of the first evaporator 304 is connected to the water inlet of the first water pump 303; and the water outlet of the first water pump 303 is connected to the second water inlet of the heat recovery steam generator 301.

[0098] The second air outlet of the third preheater 305 is connected to the second air inlet of the first evaporator 304; the second air outlet of the first evaporator 304 is connected to the first air inlet of the third preheater 305; the third liquid outlet of the first evaporator 304 is connected to the third liquid inlet of the second evaporator 306; and the first air outlet of the third preheater 305 is connected to the first air inlet of the second evaporator 306.

[0099] The inlet and outlet flow of the second evaporator 306, the third evaporator 308, the fourth evaporator 310, and the fifth evaporator 312 is the same as that of the first evaporator 304; the third outlet of the fifth evaporator 312 is connected to the inlet of the third water pump 316; the outlet of the third water pump 316 discharges recovered concentrated brine; the outlet of the fourth water pump 317 is connected to the first inlet of the first condenser 313; the first outlet of the first condenser 313 is connected to the seawater inlet valve 318; and the second outlet of the first condenser 313 discharges seawater.

[0100] The third outlet of the first condenser 313 is connected to the second water pump 314; the outlet of the second water pump 314 is connected to the water storage tank 315; the second outlet of the water storage tank 315 provides fresh water supply to the user.

[0101] The water production system described in this embodiment recovers high-grade waste heat from the exhaust gas of the power generation system in the heat recovery steam generator to produce steam at a certain pressure and temperature. After compressing the steam with a steam compressor, the steam is used to exchange heat with seawater in an evaporator to produce fresh water.

[0102] Specifically, seawater can be preheated in a condenser and then preheated again in a preheater to increase the heat exchange area and improve freshwater production.

[0103] In this embodiment, steam from the medium-pressure section of the steam generator can be extracted for district heating, and domestic hot water can be prepared using the low-to-medium grade energy after heat exchange in the steam generator.

[0104] In some embodiments, the organic Rankine cycle power generation system 400 includes: an organic Rankine cycle preheater 401, a high-pressure pump 402, a high-pressure steam generator 403, a high-pressure turbine 404, a low-pressure steam generator 405, a mixing chamber 406, a low-pressure turbine 407, a second condenser 408, a low-pressure pump 409, and a water separator 410.

[0105] In this embodiment, the first liquid outlet of the organic Rankine cycle preheater 401 is connected to the liquid inlet of the high-pressure pump 402; the liquid outlet of the high-pressure pump 402 is connected to the first liquid inlet of the high-pressure steam generator 403; the first air outlet of the high-pressure steam generator 403 is connected to the air inlet of the high-pressure turbine 404; the air outlet of the high-pressure turbine 404 is connected to the air inlet of the mixing chamber 406; the second liquid outlet of the organic Rankine cycle preheater 401 is connected to the first liquid inlet of the low-pressure steam generator 405; the first air outlet of the low-pressure steam generator 405 is connected to the second air inlet of the mixing chamber 406; and the air outlet of the mixing chamber 406 is connected to the air inlet of the low-pressure turbine 407.

[0106] The air outlet of the low-pressure turbine 407 is connected to the first air inlet of the second condenser 408; circulating condensate is introduced into the second water inlet of the second condenser 408; the liquid outlet of the second condenser 408 is connected to the liquid inlet of the low-pressure pump 409; and the liquid outlet of the low-pressure pump 409 is connected to the first liquid inlet of the organic Rankine cycle preheater 401.

[0107] The second air inlet of the high-pressure steam generator 403 is connected to the first air outlet of the heat recovery steam generator 301; the second air outlet of the high-pressure steam generator 403 is connected to the second outlet of the low-pressure steam generator 405; the second air outlet of the low-pressure steam generator 405 is connected to the second air outlet of the organic Rankine cycle preheater 401; the third air outlet of the organic Rankine cycle preheater 401 is connected to the air inlet of the water separator 410; the first water outlet of the water separator 410 is connected to the second water inlet of the water storage tank 315; and the second air outlet of the water separator 410 discharges the gas into the atmosphere.

[0108] In this embodiment, when the fuel cell power generation system exhausts, it generates medium- and low-grade waste heat. The organic steam under the two pressure conditions can be used to drive the high-pressure turbine and the low-pressure turbine to do work.

[0109] According to embodiments of this application, a combined electricity, water, and gas power system integrating fuel cells and photovoltaic power generation incorporates components such as a solid oxide fuel cell, an afterburner, a gas turbine, an air compressor, a hydrogen compressor, a preheater, and a heat recovery steam generator, constructing a highly efficient and multifunctional energy conversion and utilization system. Electricity is generated directly through electrochemical reactions in the solid oxide fuel cell, and the afterburner and gas turbine further recover unreacted fuel energy, improving the overall system's energy conversion efficiency.

[0110] The system is equipped with a heat recovery steam generator, which can recover the waste heat from the exhaust gas of the gas turbine and the preheating of hydrogen to produce steam or hot water, realizing the cascade utilization of energy and improving the overall energy utilization rate of the system.

[0111] The first and second preheaters in this embodiment preheat the air and hydrogen entering the solid oxide fuel cell, respectively, increasing the reaction temperature and thus improving the fuel cell's power generation efficiency and stability. The system uses hydrogen as fuel, and the combustion product is mainly water, reducing environmental pollutant emissions. Furthermore, hydrogen, as a renewable energy source, contributes to sustainable energy development.

[0112] The following are embodiments of the combined electricity and water supply method for fuel cells and photovoltaic power generation provided in this disclosure. This method belongs to the same inventive concept as the combined electricity and water supply system for fuel cells and photovoltaic power generation in the above embodiments. For details not described in detail in the embodiments of the combined electricity and water supply method for fuel cells and photovoltaic power generation, please refer to the embodiments of the combined electricity and water supply system for fuel cells and photovoltaic power generation described above.

[0113] Step 1: In the fuel cell power generation system, air and hydrogen are compressed and preheated. The solid oxide fuel cell uses hydrogen fuel to generate electricity through an electrochemical reaction. The remaining fuel is burned in the afterburner and then drives the gas turbine to expand and do work.

[0114] The specific process of step one in this embodiment is as follows: after the hydrogen fuel is compressed and preheated, it is reformed in the anode of the solid oxide fuel cell and undergoes an electrochemical reaction with oxygen in the air entering the cathode of the battery. The generated DC current can be converted into AC current by the inverter and provided to the user.

[0115] In this embodiment, the solid oxide fuel cell still has some unreacted combustible gas at the anode outlet, which can be mixed and burned with the battery cathode exhaust in the afterburner (where fuel can be injected for supplemental combustion) to provide high-temperature gas for the gas turbine to expand and generate electricity.

[0116] When the gas turbine is operating, it can drive a coaxial air compressor and a hydrogen compressor to compress hydrogen and air, respectively. The first preheater and the second preheater preheat the air and hydrogen, respectively.

[0117] Step two: In the hydrogen production subsystem, photovoltaic modules use solar energy to generate electricity, and the solar controller adjusts the photovoltaic modules to output maximum power; the inverter and rectifier are used to adjust the appropriate voltage; and proton exchange membranes electrolyze water to produce hydrogen and oxygen for storage.

[0118] The specific process of step two in this embodiment is as follows: According to the irradiation pattern of sunlight, the photovoltaic module regulates the power generation, and the solar controller tracks the maximum power point of the photovoltaic module by controlling the photovoltaic module; the output voltage is converted into AC power by the inverter to supply the user, and converted into suitable DC power by the rectifier to supply the hydrogen production process.

[0119] Hydrogen and oxygen are produced in a proton exchange membrane electrolyzer and stored in activated carbon hydrogen storage tanks and oxygen storage tanks; hydrogen is controlled to enter the electron generation system through a hydrogen valve.

[0120] Step 3: The water treatment subsystem uses the waste heat from the flue gas of the power generation system to prepare saturated steam. Part of the waste heat is used to provide heat to the user, and the other part is used to obtain high-temperature and high-pressure steam through a steam compressor. The feed seawater is distilled and desalinated into product water after passing through multiple steam generators and condensers and supplied to the user.

[0121] The specific process of step three in this embodiment is as follows: The seawater is first preheated in the first condenser, and then a certain amount of seawater is preheated to the boiling temperature but without phase change by controlling a valve in the preheater. The seawater enters the first evaporator and generates a large amount of secondary steam, which enters the second evaporator. The hot steam exchanges heat with the seawater in the second evaporator and condenses into water, which is then recovered into the water storage tank. The remaining unevaporated seawater flows into the next stage evaporator to undergo the same reaction.

[0122] The evaporation principle in the multi-stage evaporator is the same as that in the first evaporator; the concentrated brine in the fifth evaporator is discharged and recovered, while part of the hot steam enters the air compressor to mix and heat with the hot steam, and part of the water vapor releases heat in the first condenser to obtain the required product water, which is then stored in a water tank to provide fresh water resources for users.

[0123] Step four: The subcooled organic working fluid absorbs exhaust heat in the organic Rankine cycle preheater and becomes saturated liquid. Part of the saturated liquid enters the high-pressure pump to be pressurized into high-pressure organic working fluid. The organic working fluid then enters the high-pressure steam generator to form high-pressure saturated steam organic working fluid. The organic working fluid expands in the high-pressure turbine to generate electricity. Part of the saturated liquid enters the low-pressure steam generator to form low-pressure saturated steam organic working fluid. The steam after the high-pressure turbine has done work is mixed with the steam at the outlet of the low-pressure steam generator in the mixing chamber. The mixed working fluid enters the low-pressure turbine to expand and generate electricity. The turbine exhaust steam enters the second condenser to be condensed into a subcooled state.

[0124] The organic working fluid is pressurized in the low-pressure pump and then fed into the preheater. The flue gas discharged from the heat recovery steam generator enters the high-pressure steam generator to exchange heat and reduce its temperature. The flue gas continues to enter the low-temperature steam generator to exchange heat with the organic working fluid. The flue gas recovers heat in the organic Rankine cycle preheater. The flue gas is separated by a water separator. The separated water is stored in a water tank, and the remaining flue gas is discharged into the environment.

[0125] In summary, the combined electricity and water supply method for fuel cells and photovoltaic power generation involved in this application is based on the energy utilization principle of "temperature matching and cascade utilization". It can simultaneously produce electricity, hydrogen, oxygen and fresh water by reasonably coupling the fuel cell power generation system, hydrogen production subsystem, water production subsystem and dual-pressure organic Rankine cycle subsystem, which can meet the user's load demand for electricity, hydrogen, oxygen and fresh water.

[0126] In the solid oxide fuel cell power generation process, the upper end provides a continuous and stable hydrogen energy as fuel through solar photovoltaic power generation and proton exchange membrane electrolysis of water. The utilization of renewable and green energy can reduce dependence on traditional fossil fuels and reduce pollutant emissions. The lower end uses a steam generator to carry out a multi-effect distillation seawater desalination process, which solves the problem of freshwater shortage through the rational utilization of seawater resources. After seawater desalination, the medium and low temperature flue gas, which still has a certain quality, is used to generate electricity through an organic Rankine cycle, which promotes energy recovery and utilization and reduces losses.

[0127] Solid oxide fuel cells can use hydrogen as fuel to generate electricity efficiently with zero CO2 emissions. The waste heat from medium and low temperatures can be used to produce fresh water and generate electricity through organic Rankine cycle. This method utilizes the residual fuel and high-temperature waste heat from the battery exhaust in a cascade manner, resulting in high energy efficiency, reduced carbon emissions, and the ability to meet various energy needs of users.

[0128] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A combined electricity and water supply system integrating fuel cells and photovoltaic power generation, characterized in that, include: The fuel cell power generation system (100), the hydrogen production subsystem (200), the water production subsystem (300), and the organic Rankine cycle power generation system (400). The fuel cell power generation system (100) is connected to the hydrogen production subsystem (200); the water production subsystem (300) is connected to the fuel cell power generation system (100); the organic Rankine cycle power generation system (400) is connected to the fuel cell power generation system (100); The fuel cell power generation system (100) uses a proton exchange membrane to electrolyze water to produce hydrogen for power generation and then supplements combustion. The solid fuel cell uses hydrogen as fuel to carry out electrochemical reaction for efficient power generation. The remaining fuel at the anode outlet of the solid oxide fuel cell and the exhaust gas discharged from the cathode outlet are burned and supplemented in the after-combustion chamber. The high-temperature gas at the outlet of the after-combustion chamber drives the gas turbine to rotate and do work. The hydrogen production subsystem (200) is used to couple renewable resources—solar energy—to provide imported fuel for solid fuel cells; The water production subsystem (300) uses the high-grade waste heat from the exhaust of the fuel cell power generation system (100) to prepare high-temperature steam. Part of the high-temperature steam is dissipated through the pipeline to provide heat to the user, and another part of the high-temperature steam is formed into high-temperature and high-pressure steam by the steam compressor and then undergoes multiple distillations of seawater in the evaporator to prepare fresh water. The organic Rankine cycle power generation system (400) is used to recover and utilize the residual low-grade flue gas heat. The circulating organic working fluid is heated by the preheater and then enters the turbine to expand and generate electricity under two set pressure conditions. The water production subsystem (300) includes: a heat recovery steam generator (301), a steam compressor (302), a first water pump (303), a first evaporator (304), a third preheater (305), a second evaporator (306), a fourth preheater (307), a third evaporator (308), a fifth preheater (309), a fourth evaporator (310), a sixth preheater (311), a fifth evaporator (312), a first condenser (313), a second water pump (314), a third water pump (316), a fourth water pump (317), and an inlet seawater valve (318). The first air inlet of the heat recovery steam generator (301) is connected to the first air outlet of the third preheater (305); the second air outlet of the heat recovery steam generator (301) is connected to the first air inlet of the steam compressor (302). The first outlet of the fifth evaporator (312) is connected to the second inlet of the steam compressor (302); The outlet of the steam compressor (302) is connected to the first air inlet of the first evaporator (304); the first water outlet of the first evaporator (304) is connected to the water inlet of the first water pump (303). The outlet of the first water pump (303) is connected to the second inlet of the heat recovery steam generator (301); the second outlet of the third preheater (305) is connected to the second inlet of the first evaporator (304). The second air outlet of the first evaporator (304) is connected to the first air inlet of the third preheater (305); The third liquid outlet of the first evaporator (304) is connected to the third liquid inlet of the second evaporator (306); the liquid outlet of the second evaporator (306) is connected to the liquid inlet of the third evaporator (308); and the liquid outlet of the third evaporator (308) is connected to the liquid inlet of the fourth evaporator (310). The liquid outlet of the fourth evaporator (310) is connected to the liquid inlet of the fifth evaporator (312); The first air outlet of the third preheater (305) is connected to the first air inlet of the second evaporator (306); The third outlet of the fifth evaporator (312) is connected to the inlet of the third water pump (316); the outlet of the third water pump (316) is used to discharge the recovered concentrated brine. The outlet of the fourth water pump (317) is connected to the first inlet of the first condenser (313); The first liquid outlet of the first condenser (313) is connected to the inlet seawater valve (318); The second outlet of the first condenser (313) discharges seawater; the third outlet of the first condenser (313) is connected to the second water pump (314); the outlet of the second water pump (314) is connected to the water storage tank (315); the second outlet of the water storage tank (315) is used to provide fresh water supply to users.

2. The combined electricity and water supply system for fuel cells and photovoltaic power generation according to claim 1, characterized in that, The fuel cell power generation system (100) includes: a solid oxide fuel cell (101), an afterburner (102), a gas turbine (103), an air compressor (104), a hydrogen compressor (105), a first preheater (106), a second preheater (107), and a heat recovery steam generator (301). The power output terminal of the solid oxide fuel cell (101) is connected to an inverter (203), which realizes DC to AC conversion; The outlet of the solid oxide fuel cell (101) is connected to the inlet of the rear combustion chamber (102); The gas turbine (103) has its air inlet connected to the exhaust outlet of the afterburner (102); the air compressor (104) and the hydrogen compressor (105) are coaxially connected to the gas turbine (103); Air is introduced into the air inlet of the air compressor (104); hydrogen is introduced into the air inlet of the hydrogen compressor (105); the first air inlet of the first preheater (106) is connected to the air outlet of the gas turbine (103); the second air inlet of the first preheater (106) is connected to the air outlet of the air compressor (104). The first outlet of the first preheater (106) is connected to the first inlet of the second preheater (107); the second outlet of the first preheater (106) is connected to the cathode inlet of the solid oxide fuel cell (101); the outlet of the hydrogen compressor is connected to the second inlet of the second preheater (107); and the second outlet of the second preheater (107) is connected to the first inlet of the heat recovery steam generator (301).

3. The combined electricity and water supply system for fuel cells and photovoltaic power generation according to claim 2, characterized in that, A first pressure sensor and a first temperature sensor are installed on the connecting pipeline between the air inlet of the gas turbine (103) and the air outlet of the afterburner (102). A second pressure sensor and a second temperature sensor are installed on the connecting pipeline between the first air outlet of the first preheater (106) and the first air inlet of the second preheater (107).

4. The combined electricity and water supply system for fuel cells and photovoltaic power generation according to claim 2, characterized in that, The inverter (203) is equipped with a current sensor and a voltage sensor on its input and output sides, respectively.

5. The combined electricity and water supply system for fuel cells and photovoltaic power generation according to claim 1, characterized in that, The hydrogen production subsystem (200) includes: a photovoltaic module (201), a solar controller (202), a rectifier (204), a proton exchange membrane electrolyzer (205), an activated carbon hydrogen storage tank (206), a hydrogen valve (207), and an oxygen storage tank (208). The first outlet of the photovoltaic module (201) is connected to the inlet of the solar controller (202); the first outlet of the solar controller (202) is connected to the inlet of the inverter (203); the second outlet of the solar controller (202) is connected to the inlet of the rectifier (204); The outlet of the rectifier (204) is connected to the first inlet of the proton exchange membrane electrolyzer (205); the second outlet of the water storage tank (315) is connected to the second inlet of the proton exchange membrane electrolyzer (205); and the second outlet of the proton exchange membrane electrolyzer (205) is connected to the inlet of the oxygen storage tank (208). The first outlet of the proton exchange membrane electrolyzer (205) is connected to the inlet of the activated carbon hydrogen storage tank (206); the first outlet of the activated carbon hydrogen storage tank (206) can provide hydrogen energy to the user. The second outlet of the activated carbon hydrogen storage tank (206) is connected to the inlet of the hydrogen valve (207); the outlet of the hydrogen valve (207) is connected to the inlet of the hydrogen compressor (105).

6. The combined electricity and water supply system for fuel cells and photovoltaic power generation according to claim 1, characterized in that, The pipeline between the first air inlet of the heat recovery steam generator (301) and the first air outlet of the third preheater (305), the pipeline between the second air outlet of the heat recovery steam generator (301) and the first air inlet of the steam compressor (302), and the pipeline between the first air outlet of the fifth evaporator (312) and the second air inlet of the steam compressor (302) are respectively equipped with third pressure sensors; The outlets of the first evaporator (304), the second evaporator (306), the third evaporator (308), the fourth evaporator (310), the fifth evaporator (312), and the liquid outlet of the first condenser (313) are each equipped with a third temperature sensor.

7. The combined electricity and water supply system for fuel cells and photovoltaic power generation according to claim 2, characterized in that, The organic Rankine cycle power generation system (400) includes: an organic Rankine cycle preheater (401), a high-pressure pump (402), a high-pressure steam generator (403), a high-pressure turbine (404), a low-pressure steam generator (405), a mixing chamber (406), a low-pressure turbine (407), a second condenser (408), a low-pressure pump (409), and a water separator (410). The first outlet of the organic Rankine cycle preheater (401) is connected to the inlet of the high-pressure pump (402); The outlet of the high-pressure pump (402) is connected to the first inlet of the high-pressure steam generator (403); The first outlet of the high-pressure steam generator (403) is connected to the inlet of the high-pressure turbine (404); The outlet of the high-pressure turbine (404) is connected to the inlet of the mixing chamber (406); The second outlet of the organic Rankine cycle preheater (401) is connected to the first inlet of the low-pressure steam generator (405). The first outlet of the low-pressure steam generator (405) is connected to the second inlet of the mixing chamber (406); The outlet of the mixing chamber (406) is connected to the inlet of the low-pressure turbine (407); The outlet of the low-pressure turbine (407) is connected to the first inlet of the second condenser (408); circulating condensate is introduced into the second inlet of the second condenser (408); The outlet of the second condenser (408) is connected to the inlet of the low-pressure pump (409); The outlet of the low-pressure pump (409) is connected to the first inlet of the organic Rankine cycle preheater (401); The second air inlet of the high-pressure steam generator (403) is connected to the first air outlet of the heat recovery steam generator (301); The second outlet of the high-pressure steam generator (403) is connected to the second outlet of the low-pressure steam generator (405); The second outlet of the low-pressure steam generator (405) is connected to the second outlet of the organic Rankine cycle preheater (401); The third outlet of the organic Rankine cycle preheater (401) is connected to the inlet of the water separator (410). The first outlet of the water separator (410) is connected to the second inlet of the water storage tank (315); The second outlet of the water separator (410) discharges the gas into the atmosphere.

8. A method for combined electricity, water, and fuel cell power generation with photovoltaic power generation, characterized in that, The method is implemented based on the combined electricity and water supply system of fuel cell and photovoltaic power generation as described in any one of claims 1 to 7; The methods include: Step 1: Preheat the compressed air and hydrogen, then use the hydrogen fuel to generate electricity through an electrochemical reaction, and use the remaining fuel to drive the gas turbine to expand and do work. Step two: The photovoltaic modules generate electricity based on solar energy. The solar controller adjusts the photovoltaic modules to output maximum power, and the inverter and rectifier are used to regulate the voltage. Hydrogen and oxygen are produced by electrolyzing water through a proton exchange membrane and then stored. Step 3: Use the medium-grade waste heat from the system exhaust to prepare saturated steam. Then, use part of the medium-grade waste heat to provide heat to users, and use the other part to obtain high-temperature and high-pressure steam through a steam compressor. Based on the feed seawater, after passing through multiple steam generators and condensers, it is distilled and desalinated into product water for supply to users. Step four: The supercooled organic working fluid absorbs the waste heat from the exhaust gas in the organic Rankine cycle preheater and becomes a saturated liquid. Part of the saturated liquid enters the high-pressure pump to be pressurized into a high-pressure organic working fluid. The high-pressure organic working fluid then enters the high-pressure steam generator to form a high-pressure saturated steam organic working fluid. The organic working fluid expands in the high-pressure turbine to generate electricity. Part of the saturated liquid enters the low-pressure steam generator to form a low-pressure saturated steam organic working fluid. The steam after the high-pressure turbine has done work is mixed with the steam at the outlet of the low-pressure steam generator in the mixing chamber. The mixed working fluid enters the low-pressure turbine to expand and generate electricity. Turbine exhaust steam enters the second condenser and condenses into a subcooled state. The organic working fluid enters the low-pressure pump for pressurization and then passes into the preheater. The flue gas discharged from the heat recovery steam generator enters the high-pressure steam generator for heat exchange and temperature reduction. The flue gas continues to enter the low-temperature steam generator for heat exchange with the organic working fluid. The flue gas recovers heat in the organic Rankine cycle preheater. The flue gas is separated by a water separator. The separated water enters the water storage tank for storage, and the remaining flue gas is discharged into the environment.

9. The combined electricity and water supply method for fuel cells and photovoltaic power generation according to claim 8, characterized in that, Step two also includes: The seawater is first preheated in the first condenser, and then a preset amount of seawater is preheated to the boiling temperature in the preheater by a valve, but no phase change occurs. Seawater enters the first evaporator and undergoes heat exchange to generate a large amount of secondary steam, which then enters the second evaporator. The hot steam exchanges heat with the seawater in the second evaporator and condenses into water, which is then collected in the storage tank. The remaining unevaporated seawater flows into the next stage evaporator and undergoes the same reaction. The process continues until the concentrated brine in the fifth evaporator is discharged and recovered. Part of the hot steam enters the air compressor to mix with the hot steam for heating, while part of the water vapor releases heat in the first condenser to obtain the required product water, which is then stored in a water tank.

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