Household fuel cell cogeneration system and operation method thereof

Abstract

The invention belongs to the field of fuel cell heat supply systems, and particularly relates to a household fuel cell heat and power cogeneration system, which comprises a fuel cell stack, an electrical control module, and an air supply module, a hydrogen supply module, a stack temperature control module and a heat recovery and storage module which are connected with the electrical control module, the air supply module and the hydrogen supply module are used for receiving the control instruction and providing a heat production reactant for the fuel cell stack; the electric pile temperature control module is used for circularly cooling the fuel cell electric pile to enable the temperature of the fuel cell electric pile to reach a preset range, and receiving a control instruction of the electrical control module and heating a condensing agent to circularly heat the fuel cell electric pile to realize quick start when the fuel cell electric pile is in cold start; the heat recovery and storage module is connected with the electric pile temperature control module and used for absorbing heat in the electric pile temperature control module and storing the heat in the household electric water heater; the efficiency and the starting speed of the household fuel cell cogeneration system are remarkably improved, and the cost, the size and the installation space of the system are greatly reduced.

Description

Technical Field

[0001] The invention belongs to the field of fuel cell heating systems, in particular to a household fuel cell heat and power cogeneration system and an operation method thereof. Background Art

[0002] Proton exchange membrane fuel cell (PEMFC) generates electricity and heat by catalyzing the electrochemical reaction of hydrogen and oxygen. It is not limited by the Carnot cycle and is a highly efficient energy conversion device. Due to its low operating temperature, wide efficient operating range, easy start and stop, etc., it has attracted widespread attention in the fields of backup power supply, mobile power supply and household power station, and has been commercialized in Japan, South Korea and other countries, with a comprehensive power generation efficiency of more than 80%. Compared with traditional power generation and other new energy power generation, it has irreplaceable advantages in compactness and efficiency, and is one of the important means to reduce carbon emissions.

[0003] However, due to the high cost of household fuel cell cogeneration systems, existing products lack economic efficiency, which is very unfavorable for the promotion of household fuel cell cogeneration systems. On the other hand, the high housing prices have made consumers put forward higher requirements for the compactness of the product, and the size of the product setting space has also become one of the sensitive factors in the market when purchasing the product. At the same time, with the rapid development of the economy, people's pace of life has generally accelerated, which has also prompted people to have a faster demand for the start-up speed of the product. In patent CN110676482B, the problem of long battery start-up time is solved by directly storing the heat generated by the combustion raw materials or the unused raw materials in the fuel cell unit and transmitting it to the battery unit to quickly heat it up. However, the use of the combustion chamber increases the complexity of system control, safety requirements and difficulty of water, electricity and gas management. In patent CN216308059U, a buffer water tank is introduced and the cooling water is auxiliary heated by a solar collector to solve the cold start problem, but it is worth noting that the change in solar energy intensity is positively correlated with the temperature in most cases. The start-up time is long in winter, and auxiliary heating continues. At this time, the solar energy intensity is also relatively weak, and the two cannot show good coupling. In patent CN114156502A, a heat storage tank with a heat exchange coil is used to recover and store the heat generated by the fuel cell stack. On the one hand, the heat exchange efficiency of the heat exchange coil decreases as the temperature of the heat storage tank rises, and the heat of the stack cannot be recovered when the water tank is fully loaded, resulting in the system being unable to operate. On the other hand, the use of the water tank greatly increases the system volume and cannot achieve rapid startup of the system. Summary of the invention

[0004] The purpose of the present invention is to provide a household fuel cell cogeneration system and its operation method, which will develop a proton exchange membrane fuel cell cogeneration system based on the existing household electric water heater, thereby reducing the cost and volume of the system. At the same time, an electric heating channel is built into the stack temperature control module to reduce the amount of cooling water required for heating and the heat loss of pipeline transportation during rapid startup, thereby achieving rapid heating and temperature rise of the stack. This overcomes the defects of the above-mentioned fuel cell method.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a household fuel cell cogeneration system, including: a fuel cell stack, an electrical control module, and an air supply module, a hydrogen supply module, a stack temperature control module, and a heat recovery storage module connected to the electrical control module;

[0006] The air supply module is connected to the fuel cell stack and is used to receive control instructions from the electrical control module and provide air to the fuel cell stack;

[0007] The hydrogen supply module is connected to the fuel cell stack and is used to receive control instructions from the electrical control module and cyclically provide hydrogen fuel to the fuel cell stack;

[0008] The fuel cell stack is used to generate heat after receiving hydrogen fuel and air for reaction, and transmit the heat to the heat recovery storage module through the stack temperature control module; at the same time, the stack temperature control module controls its own temperature;

[0009] The stack temperature control module is connected to the fuel cell stack and is used to circulate and cool the fuel cell stack so that its temperature reaches a preset range. When the fuel cell stack is cold started, it receives a control instruction from the electrical control module and heats the condensing agent to circulate and heat the fuel cell stack, thereby achieving a quick start.

[0010] The heat recovery storage modules are respectively connected to the stack temperature control modules, and are used to absorb the heat in the stack temperature control modules and store it in the household electric water heater;

[0011] The electrical control module is used to send control instructions to the air supply module, the hydrogen supply module, the fuel cell temperature control module, and the heat recovery storage module to control the opening or closing of the air supply module, the hydrogen supply module, the fuel cell temperature control module, and the heat recovery storage module.

[0012] The stack temperature control module includes: a heating pipeline, a circulation pipeline, a circulating water pump arranged on the circulation pipeline, a liquid / liquid heat exchanger, a condensing agent passage, a three-way valve A, a three-way valve B and an electric heater;

[0013] The condensing agent passage is arranged in the fuel cell stack and is used to remove the heat generated when the fuel cell stack is working;

[0014] The heating pipeline is arranged in parallel with the circulation pipeline, and an electric heater is wound around the outside of the heating pipeline, and the first and last ends of the heating pipeline are respectively connected to the second inlet of the three-way valve A and the second outlet of the three-way valve B;

[0015] The first outlet of the three-way valve A is connected to the first inlet of the three-way valve A via a circulating water pump, a condensing agent passage, the three-way valve B, the first inlet of the liquid / liquid heat exchanger, and the first outlet of the liquid / liquid heat exchanger;

[0016] One of the outlets of the three-way valve B is normally closed and connected to the heating pipeline. When the fuel cell stack is quickly cold started, the electrical control module controls the outlet of the three-way valve B to be opened and communicated with the inlet of the three-way valve B, and the condensing agent is led out through the second outlet of the three-way valve B to the heating pipeline for heating and temperature increase, thereby heating the fuel cell stack to achieve rapid start-up;

[0017] The circulating water pump, three-way valve A, three-way valve B and electric heater are all connected to the electrical control module.

[0018] An air-cooled radiator is provided on the pipeline between the first inlet of the three-way valve A and the first outlet of the liquid / liquid heat exchanger;

[0019] The air-cooled radiator is connected to the electrical control module and is used to receive control instructions from the electrical control module to turn it on or off; when the liquid / liquid heat exchanger is not working, the heat generated by the fuel cell stack is discharged through air cooling to control the condensing agent entering the condensing agent passage in the fuel cell stack to meet a preset temperature range.

[0020] The heat recovery storage module includes: a tap water pump, a liquid / liquid heat exchanger tap water passage, and a check valve arranged on the tap water pipeline;

[0021] The tap water passage of the liquid / liquid heat exchanger is arranged in the liquid / liquid heat exchanger and is arranged opposite to the circulation pipeline of the stack temperature control module arranged in the liquid / liquid heat exchanger, so as to absorb the heat of the condensing agent in the circulation pipeline through the heat exchange method of the liquid / liquid heat exchanger;

[0022] The tap water pump is connected to the electrical control module and is used to receive a control instruction from the electrical control module to turn it on or off;

[0023] The inlet of the tap water pump is connected to the hot water outlet of the electric water heater at the user's location to extract the tap water stored in the electric water heater; the outlet of the tap water pump is connected to the second inlet of the liquid / liquid heat exchanger to recover the heat generated by the fuel cell stack carried by the circulation pipeline in the liquid / liquid heat exchanger;

[0024] The outlet of the tap water passage of the liquid / liquid heat exchanger is connected to the upper water inlet of the electric water heater through the second outlet of the liquid / liquid heat exchanger, and the recovered heat is stored in the electric water heater;

[0025] The check valve is arranged at any position of the tap water pipeline to ensure that the tap water in the tap water pipeline flows in a single direction.

[0026] The fuel cell stack is a PEMFC battery stack;

[0027] The fuel cell stack is connected to a DC / AC grid-connected inverter for converting the direct current output by the fuel cell stack into alternating current with the same voltage and frequency as the grid power. The converted alternating current is then output to power the user's household appliances or a household fuel cell cogeneration system.

[0028] The air supply module is an air compressor or an air pump;

[0029] The output end of the air supply module is connected to the air inlet of the fuel cell stack.

[0030] The hydrogen supply module comprises: a gas supply pipeline, an exhaust pipeline, a hydrogen circulation pump and an exhaust valve;

[0031] The gas supply pipeline is connected to the hydrogen inlet of the fuel cell stack; a gas supply branch is provided on the gas supply pipeline, and the gas supply branch is connected to the output end of the hydrogen circulation pump;

[0032] The exhaust pipeline is connected to the hydrogen outlet of the fuel cell stack; an exhaust branch is provided on the exhaust pipeline, and the exhaust branch is connected to the input end of the hydrogen circulation pump;

[0033] When the fuel cell stack reacts, the unreacted hydrogen is discharged to the exhaust branch, and the hydrogen circulation pump extracts the unreacted hydrogen and inputs it into the gas supply pipeline through the gas supply branch; when the fuel cell stack reaction is completed, the reacted gas is discharged to the exhaust branch and discharged to the atmosphere through the exhaust valve arranged on the exhaust branch;

[0034] The hydrogen circulation pump and the exhaust valve are both connected to the electrical control module.

[0035] A method for operating a household fuel cell cogeneration system comprises the following steps:

[0036] 1) Determine whether to set the working mode and the temperature threshold of the electric water heater;

[0037] If setting is required, the working mode and temperature threshold Tmax are set through the electrical control module; if setting is not required, the electrical control module defaults to working mode A;

[0038] 2) The electrical control module controls the second outlet of the three-way valve B connected to the heating pipeline to open, and starts the circulating water pump and the electric heater at the same time; after the electric heater heats the condensing agent to 75°C, the electrical control module controls the air pump and the hydrogen circulating pump to open, and turns off the electric heater, and the fuel cell stack generates electricity;

[0039] The electrical control module controls the outlet of the three-way valve A to open, and the fuel cell stack discharges the generated heat to the liquid / liquid heat exchanger through the internal condenser passage while generating electricity;

[0040] 3) The electrical control module determines whether the water temperature in the current electric water heater tank is greater than the temperature threshold; if it is greater than the temperature threshold, directly execute step 8); otherwise, if it is less than or equal to the temperature threshold, determine the current working mode;

[0041] If the current working mode is working mode A, execute step 4); if the current working mode is working mode B, execute step 5); if the current working mode is working mode C, execute step 6);

[0042] 4) The electrical control module controls the water pump to start, and the water in the electric water heater is transported to the liquid / liquid heat exchanger to recover the heat generated by the battery stack. The water temperature in the water tank of the electric water heater gradually rises, and step 7 is executed;

[0043] 5) The electrical control module controls the water pump to start, and delivers the water in the electric water heater to the liquid / liquid heat exchanger. At the same time, the electric water heater is turned on to heat the water in the electric water heater synchronously, so that the hot water can be quickly heated, and step 7 is executed;

[0044] 6) The electrical control module controls the air pump and the hydrogen circulation pump to shut down, the fuel cell stack stops generating electricity, the electrical control module turns on the electric water heater to heat the water, the water temperature in the water tank of the electric water heater gradually rises, and step 8 is executed;

[0045] 7) When the user uses hot water and the water temperature in the electric water heater remains below Tmax, the electrical control module controls the fuel cell stack to continue generating electricity and recovers the heat and stores it in the electric water heater;

[0046] When the water temperature in the electric water heater is still higher than Tmax, the heat generated at this time cannot be completely recovered and stored in the electric water heater. The air-cooled radiator is turned on to send the heat into the atmosphere in an air-cooled manner.

[0047] 8) The electrical control module controls the system to shut down, and sequentially shuts down the hydrogen circulation pump, air pump, air-cooled radiator, electric heater, circulating water pump, tap water pump and electric water heater.

[0048] The present invention has the following beneficial effects and advantages:

[0049] 1. The present invention can significantly improve the efficiency and startup speed of a household fuel cell cogeneration system, and greatly reduce the cost, size and installation space of the system.

[0050] 2. The present invention has a built-in electric heating channel in the temperature control module of the fuel cell stack, which reduces the amount of cooling water required for heating and the heat loss of pipeline transportation during rapid startup, thereby achieving rapid heating and temperature rise of the fuel cell stack.

[0051] 3. The present invention realizes efficient heat recovery by connecting the electric heater, the air-cooled radiator and the liquid / liquid heat exchanger in parallel / series, dissipates heat when heat recovery fails, and rapidly heats up the battery stack during rapid startup.

[0052] 4. The present invention adopts 4 working modes to achieve more efficient heating efficiency for the environment that requires heating, and can prevent the problem of not being able to recover the heat of the battery stack and not being able to achieve quick start when the electric water heater tank is fully loaded with heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a principle block diagram of a specific example of an embodiment of the present invention;

[0054] Among them, 10 is a hydrogen circulation pump, 11 is an exhaust valve, 20 is a fuel cell stack, 21 is an electric heater, 22 is a three-way valve B, 23 is an air-cooled radiator, 24 is a three-way valve A, 25 is a circulating water pump, 30 is an air supply module, 40 is a liquid / liquid heat exchanger, 41 is a check valve, 42 is a tap water pump, 50 is a DC / AC grid-connected inverter, and 60 is an electric water heater;

[0055] Figure 2 It is a flow chart of a control method of a fuel cell cogeneration system and a household electric water heater in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0057] like Figure 1 As shown, it is a principle block diagram of an embodiment of the present invention, taking a conventional fuel cell cogeneration system as an embodiment. Compared with the prior art, a heat storage tank or a multi-stage heat storage tank is used in the system, which increases the system cost and greatly increases the volume of the system. The design adopts an electric water heater 60 based on popular household use, which reduces the manufacturing cost of the system and greatly reduces the volume of the system; during cold start, the self-heating of the fuel cell stack during low-load operation is used for heating, and the condensing agent heats up slowly, and the system startup speed is as long as more than 30 minutes. The design increases the condensing agent electric heating channel, forces the condensing agent to be diverted to the electric heater 21 through the three-way valve B22, and uses the electric heater 21 to quickly heat the condensing agent.

[0058] Specifically, the present invention provides a household fuel cell cogeneration system, comprising: a fuel cell stack 20, an electrical control module, and an air supply module 30 connected to the electrical control module, a hydrogen supply module, a stack temperature control module, and a heat recovery storage module;

[0059] (1) Air supply module

[0060] The air supply module is connected to the fuel cell stack 20 and is used to receive control instructions from the electrical control module and provide air to the fuel cell stack 20;

[0061] The air supply module 30 is an air compressor or an air pump;

[0062] An output end of the air supply module 30 is connected to an air inlet of the fuel cell stack 20 .

[0063] (II) Hydrogen supply module

[0064] The hydrogen supply module is connected to the fuel cell stack 20 and is used to receive control instructions from the electrical control module and circulate hydrogen fuel to the fuel cell stack 20;

[0065] The hydrogen supply module includes: a gas supply pipeline, an exhaust pipeline, a hydrogen circulation pump 10 and an exhaust valve 11;

[0066] The gas supply pipeline is connected to the hydrogen inlet of the fuel cell stack 20; a gas supply branch is provided on the gas supply pipeline, and the gas supply branch is connected to the output end of the hydrogen circulation pump 10;

[0067] The exhaust pipeline is connected to the hydrogen outlet of the fuel cell stack 20; an exhaust branch is provided on the exhaust pipeline, and the exhaust branch is connected to the input end of the hydrogen circulation pump 10;

[0068] When the fuel cell stack 20 reacts, the incompletely reacted hydrogen is discharged to the exhaust branch, and the hydrogen circulation pump 10 extracts the incompletely reacted hydrogen and inputs it into the gas supply pipeline through the gas supply branch; when the fuel cell stack 20 reacts, the reacted gas is discharged to the exhaust branch, and discharged into the atmosphere through the exhaust valve 11 arranged on the exhaust branch;

[0069] The hydrogen circulation pump 10 and the exhaust valve 11 are both connected to the electrical control module.

[0070] (III) Fuel cell stack

[0071] The fuel cell stack 20 is used to generate heat after receiving hydrogen fuel and air for reaction, and transmit it to the heat recovery storage module through the stack temperature control module; at the same time, the temperature of the stack itself is controlled by the stack temperature control module;

[0072] The fuel cell stack 20 is a proton exchange membrane fuel cell stack;

[0073] The fuel cell stack 20 is connected to a DC / AC grid-connected inverter 50 for converting the direct current output by the fuel cell stack 20 into alternating current with the same voltage and frequency as the grid power. After the conversion, part of the alternating current is used to power system components, and part of it is used to power household appliances.

[0074] (IV) Stack temperature control module

[0075] The stack temperature control module is connected to the fuel cell stack 20 and is used to circulate and cool the fuel cell stack 20 so that its temperature reaches a preset range. When the fuel cell stack 20 is cold started, it receives a control instruction from the electrical control module and heats the condensing agent to circulate and heat the fuel cell stack 20, thereby achieving a quick start.

[0076] like Figure 1 The lower part shown in the figure, wherein the stack temperature control module includes: a heating pipeline, a circulation pipeline, a circulation water pump 25 arranged on the circulation pipeline, a liquid / liquid heat exchanger 40, a condensing agent passage, a three-way valve A24, a three-way valve B22 and an electric heater 21;

[0077] The condensing agent passage is provided in the fuel cell stack 20 to remove the heat generated when the fuel cell stack 20 is working;

[0078] The heating pipeline is arranged in parallel with the circulation pipeline, and an electric heater 21 is wound around the outside of the heating pipeline, and the first and last ends of the heating pipeline are respectively connected to the second inlet of the three-way valve A24 and the second outlet of the three-way valve B22;

[0079] The first outlet of the three-way valve A24 is connected to the first inlet of the three-way valve A24 via the circulating water pump 25, the condensing agent passage, the three-way valve B22, the first inlet of the liquid / liquid heat exchanger 40, and the first outlet of the liquid / liquid heat exchanger 40;

[0080] One of the outlets of the three-way valve B22 is normally closed and connected to the heating pipeline. When the fuel cell stack 20 is quickly cold started, the electrical control module controls the outlet of the three-way valve B22 to be opened and communicated with the inlet of the three-way valve B22, and the condensing agent is led out through the second outlet of the three-way valve B22 to the heating pipeline for heating and temperature increase, thereby heating the fuel cell stack 20 to achieve rapid start-up;

[0081] The circulating water pump 25, the three-way valve A24, the three-way valve B22 and the electric heater 21 are all connected to the electrical control module.

[0082] The circulating water pump 25 should be installed before the cooling water inlet of the fuel cell stack to reduce the power consumption of the pump required for cooling water circulation.

[0083] An air-cooled radiator 23 is provided on the pipeline between the first inlet of the three-way valve A24 and the first outlet of the liquid / liquid heat exchanger 40;

[0084] The air-cooled radiator 23 is connected to the electrical control module and is used to receive control instructions from the electrical control module to turn it on or off; when the liquid / liquid heat exchanger 40 is not working, the heat generated by the fuel cell stack 20 is discharged through air cooling to control the condensing agent entering the condensing agent passage in the fuel cell stack 20 to meet the preset temperature range.

[0085] Furthermore, in other embodiments, the stack temperature control module uses an electric heater 21, an air-cooled radiator 23, and a liquid / liquid heat exchanger 40 in parallel to achieve efficient heat recovery, heat dissipation when heat recovery fails, and rapid temperature rise of the stack during rapid startup.

[0086] Furthermore, the inlet and outlet of the electric heater 21 should be as close as possible to the inlet and outlet of the fuel cell stack to reduce the heat dissipation of the pipeline and the amount of circulating water required for heating during rapid startup, so as to improve the heating speed and efficiency of the fuel cell stack.

[0087] Optionally, the air-cooled radiator 23 and the liquid / liquid heat exchanger 40 can be connected in series, and the hot water from the fuel cell stack 20 flows through the liquid / liquid heat exchanger 40 and then flows through the air-cooled radiator 23. In the heat recovery state, the air-cooled radiator does not work, and the heat generated by the stack is recovered and reused through the liquid / liquid heat exchanger. When the heat storage is fully loaded, the cooling water discharges heat to the atmosphere through the air-cooled radiator to maintain the temperature of the stack stable.

[0088] (V) Heat recovery storage module

[0089] The heat recovery storage modules are respectively connected to the stack temperature control modules and are used to absorb the heat in the stack temperature control modules and store it in the household electric water heater;

[0090] like Figure 1 In the lower right part shown, the heat recovery storage module includes: a tap water pump 42 provided on the tap water pipeline, a liquid / liquid heat exchanger tap water passage, and a check valve 41;

[0091] The tap water passage of the liquid / liquid heat exchanger is arranged in the liquid / liquid heat exchanger 40, and is arranged opposite to the circulation pipeline of the stack temperature control module arranged in the liquid / liquid heat exchanger 40, so as to absorb the heat of the condensing agent in the circulation pipeline through the heat exchange method of the liquid / liquid heat exchanger 40;

[0092] The tap water pump 42 is connected to the electrical control module and is used to receive a control instruction from the electrical control module to turn it on or off;

[0093] The inlet of the tap water pump 42 is connected to the hot water outlet of the electric water heater 60 at the user's location to extract the tap water stored in the electric water heater 60; the outlet of the tap water pump 42 is connected to the second inlet of the liquid / liquid heat exchanger 40 to recover the heat generated by the fuel cell stack 20 carried by the circulation pipeline in the liquid / liquid heat exchanger;

[0094] The outlet of the tap water passage of the liquid / liquid heat exchanger is connected to the upper water inlet of the electric water heater 60 through the second outlet of the liquid / liquid heat exchanger 40, and the recovered heat is stored in the electric water heater 60;

[0095] The check valve 42 is arranged at any position of the tap water pipeline to ensure that the tap water in the tap water pipeline flows in a single direction. (six)

[0097] An electrical control module, used to send control instructions to the air supply module 30, the hydrogen supply module, the stack temperature control module, and the heat recovery storage module to control the opening or closing of the air supply module 30, the hydrogen supply module, the stack temperature control module, and the heat recovery storage module;

[0098] In this embodiment, the electrical control module may be a PLC control system.

[0099] like Figure 2 As shown, a flow chart of a control method of a fuel cell cogeneration system and a household electric water heater in an embodiment of the present invention, an operation method of a household fuel cell cogeneration system in the present invention is characterized by comprising the following steps:

[0100] 1) Determine whether to set the working mode and the temperature threshold of the electric water heater;

[0101] If setting is required, the working mode and temperature threshold Tmax are set through the electrical control module; if setting is not required, the electrical control module defaults to working mode A;

[0102] 2) The electrical control module controls the three-way valve B22 to open the second outlet connected to the heating pipeline, and starts the circulating water pump 25 and the electric heater 21 at the same time; after the electric heater 21 heats the condensing agent to 75° C., the electrical control module controls the air pump and the hydrogen circulating pump 10 to open, and turns off the electric heater 21, and the fuel cell stack 20 generates electricity;

[0103] The electrical control module controls the outlet of the three-way valve A24 to open, and the fuel cell stack 20 discharges the generated heat to the liquid / liquid heat exchanger 40 through the internal condensing agent passage while generating electricity;

[0104] 3) The electrical control module determines whether the water temperature in the water tank of the electric water heater 60 is greater than the temperature threshold; if it is greater than the temperature threshold, directly execute step 5); otherwise, if it is less than or equal to the temperature threshold, determine the current working mode, and after executing the current working mode, execute the next step.

[0105] 4) When the user uses hot water and the water temperature in the electric water heater 60 remains below Tmax, the electrical control module controls the fuel cell stack 20 to continue to generate electricity and recovers the heat and stores it in the electric water heater 60;

[0106] When the water temperature in the electric water heater 60 is still higher than Tmax, the heat generated at this time cannot be completely recovered and stored in the electric water heater 60, and the air-cooled radiator 23 is turned on to send the heat into the atmosphere in an air-cooled manner;

[0107] 5) The electrical control module controls the system to shut down, and sequentially shuts down the hydrogen circulation pump 10, the air pump 30, the air-cooled radiator 23, the electric heater 21, the circulating water pump 25, the tap water pump 42 and the electric water heater 60.

[0108] In the operating method of the household fuel cell cogeneration system, there are four working modes, namely working mode A, working mode B, working mode C, and working mode D;

[0109] Among them, working mode A is the fuel cell heating mode alone;

[0110] Working mode B is a mode in which the fuel cell stack and the electric water heater 60 are heated together;

[0111] Working mode C is the electric water heater single heating mode;

[0112] Working mode D is the full load cooling mode.

[0113] Among them, regarding working mode A, working mode B, and working mode C, the following steps are performed respectively:

[0114] If the current working mode is working mode A, the electrical control module controls the water pump 42 to start, and the water in the electric water heater 60 is transported to the liquid / liquid heat exchanger 40 to recover the heat generated by the battery stack 20, and the water temperature in the water tank of the electric water heater 60 gradually rises; execute the above general step 4);

[0115] If the current working mode is working mode B, the electrical control module controls the water pump 42 to start, and the water in the electric water heater 60 is transported to the liquid / liquid heat exchanger 40, and the electric water heater 60 is turned on to heat the water in the electric water heater 60 synchronously, so as to achieve rapid heating of hot water; execute the above general step 4);

[0116] If the current working mode is working mode C, the electrical control module controls the air pump and the hydrogen circulation pump (10) to be turned off, the fuel cell stack stops generating electricity, the electrical control module turns on the electric water heater (60) to heat the water, the water temperature in the water tank of the electric water heater (60) gradually rises, and the above general step 5) is executed;

[0117] Four embodiments are listed below. For each different working mode, the working principle of the present invention is as follows:

[0118] Example 1

[0119] Specifically, after the system is started, the system defaults to mode A, and the maximum temperature Tmax. of the electric water heater 60 is 70°C by default. Open outlet No. 2 of the three-way valve 22, start the circulating water pump 25 and the electric heater 21, and after the condensed water is heated to 75°C, start the air pump 30 and the hydrogen circulating pump 10 and turn off the electric heater 21. At the same time, open outlet No. 1 of the three-way valve 11, and the system generates electricity while discharging the generated heat through the liquid / liquid heat exchanger 40. At this time, turn on the tap water pump 42 to pump the water in the electric water heater 60 to the liquid / liquid heat exchanger to recover the heat generated by the proton exchange membrane fuel cell stack 20. As the system runs, the water temperature in the water tank gradually rises. When the user uses hot water, the hot water flows out from the hot water outlet of the electric water heater, and under the action of the pipeline pressure, the water is automatically replenished from the tap water inlet, and the water temperature in the water tank drops. When the water temperature in the electric water heater 60 is kept below Tmax., the system continues to generate electricity for the user and recovers the heat and stores it in the electric water heater 60. When the water temperature in the electric water heater 60 is higher than Tmax., the system continues to generate electricity. At this time, the heat generated cannot be completely recovered and stored in the electric water heater 60. The air-cooled radiator is turned on to discharge the heat into the atmosphere. When the system is shut down, the hydrogen circulation pump 10, the air pump 30, the air-cooled radiator 23, the electric heater 21, the circulating water pump 25, the tap water pump 42 and the electric water heater 60 are shut down in sequence, and the system power is turned off.

[0120] Example 2

[0121] Specifically, after the system is started, the system working mode is set to mode B, and the maximum temperature Tmax. of the electric water heater 60 is set to 60°C. Open the outlet No. 2 of the three-way valve 22, start the circulating water pump 25 and the electric heater 21, and after the condensed water is heated to 75°C, start the air pump 30 and the hydrogen circulating pump 10 and turn off the electric heater 21. At the same time, open the outlet No. 1 of the three-way valve 11, and the system generates electricity while discharging the generated heat through the liquid / liquid heat exchanger 40. At this time, turn on the tap water pump 42 to pump the water in the electric water heater 60 to the liquid / liquid heat exchanger to recover the heat generated by the proton exchange membrane fuel cell stack 20. At the same time, turn on the electric water heater 60 to heat the water in the water heater synchronously, so as to achieve rapid heating of hot water. As the system runs, the water temperature in the water tank gradually rises. When the user uses hot water, hot water flows out from the hot water outlet of the electric water heater. Under the action of the pipeline pressure, water is automatically replenished from the tap water inlet, and the water temperature in the water tank drops. When the water temperature in the electric water heater 60 is kept below Tmax., the system continues to generate electricity for the user and recovers the heat and stores it in the electric water heater 60. When the water temperature in the electric water heater 60 is higher than Tmax., the system continues to generate electricity. At this time, the heat generated cannot be completely recovered and stored in the electric water heater 60. The air-cooled radiator is turned on to discharge the heat into the atmosphere. When the system is shut down, the hydrogen circulation pump 10, the air pump 30, the air-cooled radiator 23, the electric heater 21, the circulating water pump 25, the tap water pump 42 and the electric water heater 60 are shut down in sequence, and the system power is turned off.

[0122] Example 3

[0123] Specifically, after the system is started, the system operating mode is set to mode C, and the maximum temperature Tmax. of the electric water heater 60 is set to 60°C. At this time, the power generation system does not work, and the electric water heater 60 is turned on to heat the water in the water heater. As the system runs, the water temperature in the water tank gradually rises. When the user uses hot water, hot water flows out from the hot water outlet of the electric water heater. Under the action of the pipeline pressure, water is automatically replenished from the tap water inlet, and the water temperature in the water tank drops. When the water temperature in the electric water heater 60 is kept below Tmax., the system continues to generate electricity for the user and recovers and stores the heat in the electric water heater 60. When the water temperature in the electric water heater 60 is higher than Tmax., the system continues to generate electricity. At this time, the heat generated cannot be completely recovered and stored in the electric water heater 60. The system operating mode automatically switches to mode 3, and the air-cooled radiator is turned on to discharge the heat into the atmosphere. When the system is shut down, the hydrogen circulation pump 10, the air pump 30, the air cooling radiator 23, the electric heater 21, the circulation water pump 25, the tap water pump 42 and the electric water heater 60 are shut down in sequence, and the system power is turned off.

[0124] Example 4

[0125] Specifically, after the system is started, the system working mode is set to mode D, and the maximum temperature Tmax. of the electric water heater 60 is set to 60°C. Open outlet No. 2 of the three-way valve 22, start the circulating water pump 25 and the electric heater 21, and after the condensed water is heated to 75°C, start the air pump 30 and the hydrogen circulating pump 10 and turn off the electric heater 21, and at the same time open outlet No. 1 of the three-way valve 11, and at the same time turn on the air-cooled radiator 23 to discharge the generated heat into the atmosphere. When the system is shut down, turn off the hydrogen circulating pump 10, the air pump 30, the air-cooled radiator 23, the electric heater 21, the circulating water pump 25, the tap water pump 42 and the electric water heater 60 in sequence, and turn off the system power supply.

[0126] The above description is only an embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A household fuel cell cogeneration system, characterized in that: include: A fuel cell stack (20), an electrical control module, an air supply module (30) connected to the electrical control module, a hydrogen supply module, a stack temperature control module, and a heat recovery storage module; The air supply module is connected to the fuel cell stack (20) and is used to receive control instructions from the electrical control module and provide air to the fuel cell stack (20); The hydrogen supply module is connected to the fuel cell stack (20) and is used to receive control instructions from the electrical control module and circulate hydrogen fuel to the fuel cell stack (20); The fuel cell stack (20) is used to generate heat after receiving hydrogen fuel and air for reaction, and transmit the heat to the heat recovery storage module through the stack temperature control module; at the same time, the stack temperature control module controls the temperature of the stack itself; The stack temperature control module is connected to the fuel cell stack (20) and is used to circulate and cool the fuel cell stack (20) so that its temperature reaches a preset range, and when the fuel cell stack (20) is cold started, receives a control instruction from the electrical control module to heat the condensing agent to circulate and heat the fuel cell stack (20), thereby achieving rapid start-up; The heat recovery storage modules are respectively connected to the stack temperature control modules, and are used to absorb the heat in the stack temperature control modules and store it in the household electric water heater; The electrical control module is used to send control instructions to the air supply module (30), the hydrogen supply module, the stack temperature control module, and the heat recovery storage module to control the opening or closing of the air supply module (30), the hydrogen supply module, the stack temperature control module, and the heat recovery storage module.

2. A household fuel cell cogeneration system according to claim 1, characterized in that: The stack temperature control module comprises: a heating pipeline, a circulation pipeline, a circulation water pump (25) arranged on the circulation pipeline, a liquid / liquid heat exchanger (40), a condensing agent passage, a three-way valve A (24), a three-way valve B (22) and an electric heater (21); The condensing agent passage is arranged in the fuel cell stack (20) and is used to remove heat generated when the fuel cell stack (20) is in operation; The heating pipeline is arranged in parallel with the circulation pipeline, and an electric heater (21) is wound around the outside of the heating pipeline, and the first and second ends of the heating pipeline are respectively connected to the second inlet of the three-way valve A (24) and the second outlet of the three-way valve B (22); The first outlet of the three-way valve A (24) is connected to the first inlet of the three-way valve A (24) via the circulating water pump (25), the condensing agent passage, the three-way valve B (22), the first inlet of the liquid / liquid heat exchanger (40), and the first outlet of the liquid / liquid heat exchanger (40); One of the outlets of the three-way valve B (22) is normally closed and connected to the heating pipeline. When the fuel cell stack (20) is quickly cold started, the electrical control module controls the outlet of the three-way valve B (22) to be open and communicated with the inlet of the three-way valve B (22), and the condensing agent is guided into the heating pipeline through the second outlet of the three-way valve B (22) to be heated and heated, thereby heating the fuel cell stack (20) to achieve rapid start-up; The circulating water pump (25), the three-way valve A (24), the three-way valve B (22) and the electric heater (21) are all connected to the electrical control module.

3. A household fuel cell cogeneration system according to claim 2, characterized in that: An air-cooling radiator (23) is provided on the pipeline between the first inlet of the three-way valve A (24) and the first outlet of the liquid / liquid heat exchanger (40); The air-cooled radiator (23) is connected to the electrical control module and is used to receive a control instruction from the electrical control module to turn it on or off; when the liquid / liquid heat exchanger (40) is not working, the heat generated by the fuel cell stack (20) is discharged through air-cooled heat dissipation to control the condensing agent entering the condensing agent passage in the fuel cell stack (20) to meet a preset temperature range.

4. A household fuel cell cogeneration system according to claim 1, characterized in that: The heat recovery storage module comprises: a tap water pump (42) arranged on the tap water pipeline, a liquid / liquid heat exchanger tap water passage, and a check valve (41); The liquid / liquid heat exchanger tap water passage is arranged in the liquid / liquid heat exchanger (40), and is arranged opposite to the circulation pipeline of the stack temperature control module arranged in the liquid / liquid heat exchanger (40), so as to absorb the heat of the condensing agent in the circulation pipeline through the heat exchange method of the liquid / liquid heat exchanger (40); The tap water pump (42) is connected to the electrical control module and is used to receive a control instruction from the electrical control module to turn it on or off; The inlet of the tap water pump (42) is connected to the hot water outlet of the electric water heater (60) at the user's location so as to extract the tap water stored in the electric water heater (60); the outlet of the tap water pump (42) is connected to the second inlet of the liquid / liquid heat exchanger (40) so as to recover the heat generated by the fuel cell stack (20) carried by the circulation pipeline in the liquid / liquid heat exchanger; The outlet of the tap water passage of the liquid / liquid heat exchanger is connected to the upper water inlet of the electric water heater (60) via the second outlet of the liquid / liquid heat exchanger (40), and the recovered heat is stored in the electric water heater (60); The check valve (42) is arranged at any position of the tap water pipeline to ensure that the tap water in the tap water pipeline flows in a single direction.

5. A household fuel cell cogeneration system according to claim 1, characterized in that: The fuel cell stack (20) is a proton exchange membrane fuel cell stack; The fuel cell stack (20) is connected to a DC / AC grid-connected inverter (50) for converting the direct current output by the fuel cell stack (20) into alternating current with the same voltage and frequency as the grid power, and outputting the converted alternating current to power user household appliances or a household fuel cell cogeneration system.

6. A household fuel cell cogeneration system according to claim 1, characterized in that: The air supply module (30) is an air compressor or an air pump; The output end of the air supply module (30) is connected to the air inlet of the fuel cell stack (20).

7. A household fuel cell cogeneration system according to claim 1, characterized in that: The hydrogen supply module comprises: a gas supply pipeline, an exhaust pipeline, a hydrogen circulation pump (10) and an exhaust valve (11); The gas supply pipeline is connected to the hydrogen inlet of the fuel cell stack (20); a gas supply branch is provided on the gas supply pipeline, and the gas supply branch is connected to the output end of the hydrogen circulation pump (10); The exhaust pipeline is connected to the hydrogen outlet of the fuel cell stack (20); an exhaust branch is provided on the exhaust pipeline, and the exhaust branch is connected to the input end of the hydrogen circulation pump (10); When the fuel cell stack (20) reacts, the incompletely reacted hydrogen is discharged to the exhaust branch, and the hydrogen circulation pump (10) extracts the incompletely reacted hydrogen and inputs it into the gas supply pipeline through the gas supply branch; when the fuel cell stack (20) reacts, the reacted gas is discharged to the exhaust branch, and discharged into the atmosphere through the exhaust valve (11) arranged on the exhaust branch; The hydrogen circulation pump (10) and the exhaust valve (11) are both connected to the electrical control module.

8. The method for operating a household fuel cell cogeneration system according to claim 1, characterized in that: The following steps are involved: 1) Determine whether to set the working mode and the temperature threshold of the electric water heater; If setting is required, the working mode and temperature threshold Tmax are set through the electrical control module; if setting is not required, the electrical control module defaults to working mode A; 2) the electrical control module controls the three-way valve B (22) to open the second outlet connected to the heating pipeline, and simultaneously starts the circulating water pump (25) and the electric heater (21); after the electric heater (21) heats the condensing agent to 75° C., the electrical control module controls the air pump and the hydrogen circulating pump (10) to open, and turns off the electric heater (21), and the fuel cell stack (20) generates electricity; The electrical control module controls the outlet of the three-way valve A (24) to open, and the fuel cell stack (20) discharges the generated heat into the liquid / liquid heat exchanger (40) through the condensing agent passage inside the fuel cell stack (20) while generating electricity; 3) The electrical control module determines whether the water temperature in the water tank of the electric water heater (60) is greater than a temperature threshold; if it is greater than the temperature threshold, directly executing step 8); otherwise, if it is less than or equal to the temperature threshold, determining the current working mode; If the current working mode is working mode A, execute step 4); if the current working mode is working mode B, execute step 5); if the current working mode is working mode C, execute step 6); 4) The electrical control module controls the water pump (42) to start, and the water in the electric water heater (60) is transported to the liquid / liquid heat exchanger (40), and the heat generated by the battery stack (20) is recovered. The water temperature in the water tank of the electric water heater (60) gradually rises, and step 7) is executed; 5) The electrical control module controls the water pump (42) to start, and delivers the water in the electric water heater (60) to the liquid / liquid heat exchanger (40). At the same time, the electric water heater (60) is turned on to heat the water in the electric water heater (60) synchronously, so that the hot water can be quickly heated, and step 7) is executed; 6) The electrical control module controls the air pump and the hydrogen circulation pump (10) to be turned off, the fuel cell stack stops generating electricity, the electrical control module turns on the electric water heater (60) to heat the water, the water temperature in the water tank of the electric water heater (60) gradually rises, and step 8) is executed; 7) When the user uses hot water and the water temperature in the electric water heater (60) is kept below Tmax, the electrical control module controls the fuel cell stack (20) to continuously generate electricity and recovers heat to be stored in the electric water heater (60); When the water temperature in the electric water heater (60) is still higher than Tmax, the heat generated at this time cannot be completely recovered and stored in the electric water heater (60), and the air-cooled radiator (23) is turned on to send the heat into the atmosphere in an air-cooled manner; 8) The electrical control module controls the system to shut down, and sequentially shuts down the hydrogen circulation pump (10), the air pump (30), the air cooling radiator (23), the electric heater (21), the circulating water pump (25), the tap water pump (42) and the electric water heater (60).

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