A high-efficiency fuel cell cogeneration system based on multi-end recovery

Abstract

This invention belongs to the field of fuel cell cogeneration technology and discloses a high-efficiency fuel cell cogeneration system based on multi-terminal recovery. The system includes a fuel cell system, a multi-terminal waste heat recovery system, a kinetic energy recovery system, and a user domestic hot water and heating system. The fuel cell system is connected to the multi-terminal waste heat recovery system, the kinetic energy recovery system, and the user domestic hot water and heating system. A multi-terminal waste heat recovery and exhaust kinetic energy recovery loop is provided. The multi-terminal waste heat recovery simultaneously considers the air distribution side, the power conversion side, and the exhaust side, including fuel cell heat recovery, power converter heat recovery, air compressor heat recovery, compressed air heat recovery, and exhaust gas condensation phase change latent heat recovery, thereby effectively improving the overall energy efficiency of the fuel cell cogeneration system.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell cogeneration technology, and particularly relates to a high-efficiency fuel cell cogeneration system based on multi-end recovery. Background Technology

[0002] With the increasing carbon emissions and energy consumption of buildings year by year, the application and development of clean and efficient distributed energy systems are particularly important. Hydrogen energy has great application and development potential due to its high calorific value and clean, pollution-free nature. Fuel cells can effectively utilize hydrogen energy and have the advantages of high efficiency, no pollution, and high power density. Distributed energy systems with fuel cells as power supply devices are an important application direction to adapt to the future trend of cleaner and lower-carbon energy.

[0003] Improving the overall efficiency of energy systems is a key technology for the application and development of fuel cell cogeneration systems. Based on this, this invention considers both multi-terminal waste heat recovery and exhaust kinetic energy recovery, proposing a cogeneration system with high overall energy efficiency. This system is theoretically feasible, and constructing a distributed energy system using this multi-terminal recovery method has significant practical implications. This invention focuses on designing a fuel cell cogeneration system based on multi-terminal recovery to achieve effective recovery of waste heat and exhaust kinetic energy, thereby improving the overall efficiency of the cogeneration system. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a high-efficiency fuel cell combined heat and power system based on multi-end recovery.

[0005] This invention is implemented as follows: a high-efficiency fuel cell cogeneration system based on multi-end recovery includes:

[0006] Fuel cell systems, multi-terminal waste heat recovery systems, kinetic energy recovery systems, and domestic hot water and heating systems;

[0007] The fuel cell system is connected to a multi-terminal waste heat recovery system, the fuel cell system is connected to a kinetic energy recovery system, and the user's domestic hot water and heating system is connected to the multi-terminal waste heat recovery system.

[0008] Furthermore, the fuel cell system includes an air distribution path, a hydrogen distribution path, a multi-fuel cell, a DC / AC power conversion device, and an exhaust gas path.

[0009] The air distribution path is connected to the cathode inlet side of the multi-unit fuel cell and includes an air filter, an air compressor, and an intercooler;

[0010] The hydrogen transmission and distribution path includes a hydrogen storage tank, a hydrogen circulation pump and an anode water distributor. The hydrogen storage tank is connected to the anode inlet side of the multi-engine fuel cell, and the anode water distributor is connected to the anode outlet side of the multi-engine fuel cell.

[0011] The exhaust gas flow path is connected to the cathode outlet side of the multi-engine fuel cell.

[0012] Furthermore, the multi-terminal waste heat recovery system includes a waste heat recovery flow path and a heat dissipation flow path, which are switched by a three-way valve;

[0013] The waste heat recovery flow path includes a water pump, a three-way valve, a plate heat exchanger, and a hot water storage tank. The water pump, three-way valve, and plate heat exchanger are connected to the devices that need to be heat recovered, and the plate heat exchanger is connected to the hot water storage tank.

[0014] The heat dissipation flow path includes a water pump, a three-way valve, an auxiliary radiator, and an auxiliary water storage tank. The auxiliary radiator is connected to the device that needs to be cooled through the three-way valve, and the auxiliary water storage tank is connected to the device that needs to be cooled through the water pump to provide cooling water for auxiliary heat dissipation.

[0015] The kinetic energy recovery system includes a back pressure valve and an expander. The expander is connected to both the cathode outlet of the multi-fuel cell and the DC / AC power conversion device. The back pressure valve is connected to both the multi-fuel cell and the expander.

[0016] Furthermore, the user's domestic hot water and heating system mainly includes a hot water storage tank and a water pump; the hot water storage tank includes a hot water side and a cold water side, the cold water side is connected to the tap water supply side, a plate heat exchanger is connected to the hot water storage tank, and the hot water side of the hot water storage tank is connected to the user through the water pump.

[0017] Furthermore, this includes multi-terminal waste heat recovery and exhaust kinetic energy recovery.

[0018] Furthermore, the multi-terminal waste heat recovery system includes fuel cell waste heat recovery, power conversion device heat recovery, air compressor motor heat recovery, compressed air heat recovery, and exhaust waste heat recovery; according to the corresponding heat source grade, fuel cell waste heat recovery and compressed air heat recovery are set up as one waste heat recovery loop; air compressor motor heat recovery and power conversion device heat recovery are set up as one waste heat recovery loop; exhaust waste heat recovery is a condensation phase change heat recovery method, and a separate waste heat recovery loop is set up.

[0019] The tail exhaust waste heat recovery circuit includes a condensing phase change heat exchanger, which cools and condenses the tail exhaust into water to realize the recovery of latent heat of phase change and condensate. It is connected to the kinetic energy recovery system. One end of the heat exchanger is connected to the tail end of the expander, and the other end is connected to the cold water side of the hot water storage tank.

[0020] In the fuel cell waste heat recovery and compressed air heat recovery loops, the heat exchange fluid is the fuel cell coolant; in the air compressor motor heat recovery and power conversion device heat recovery loops, the heat exchange fluid is the motor coolant.

[0021] The cooling water flowing through the condenser phase changer in the circuit can be directly introduced into the cold water side of the hot water storage tank or heated through heat exchange before being introduced into the hot water side of the hot water storage tank.

[0022] This invention provides a high-efficiency fuel cell cogeneration method based on multi-end recovery, comprising:

[0023] Step 1: Power is supplied through a fuel cell system;

[0024] Step two: Recover waste heat through a multi-terminal waste heat recovery system;

[0025] Step 3: Recover kinetic energy through the kinetic energy recovery system;

[0026] Step four: Heat is supplied through the user's domestic hot water and heating system.

[0027] The present invention provides a computer device, characterized in that the computer device includes a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, the processor performs the steps of a high-efficiency fuel cell cogeneration method based on multi-end recovery.

[0028] The present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of a high-efficiency fuel cell cogeneration method based on multi-end recovery.

[0029] The present invention provides an information data processing terminal, characterized in that the information data processing terminal is used to realize the high-efficiency fuel cell cogeneration system based on multi-end recovery.

[0030] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0031] First, the detailed breakdown of the fuel cell cogeneration system proposed in this invention is as follows, in order to better understand its working principle and innovations:

[0032] 1. Efficiency issues of fuel cell combined heat and power systems:

[0033] Currently, small-scale (hundred-kilowatt level) fuel cell combined heat and power systems can achieve energy efficiency of over 90% due to their low auxiliary power consumption and direct DC current output.

[0034] For large-scale (megawatt-level) systems, the necessary auxiliary equipment and inverter processes reduce energy efficiency, typically to around 85%.

[0035] 2. The structure of the fuel cell cogeneration system of the present invention:

[0036] This invention improves the overall energy efficiency of the system by recovering waste heat from multiple sources, including but not limited to fuel cell heat recovery, power converter heat recovery, air compressor heat recovery, compressed air heat recovery, exhaust kinetic energy recovery, and exhaust gas condensation phase change latent heat recovery.

[0037] Especially for megawatt-level high-power fuel cell cogeneration systems, this comprehensive heat and kinetic energy recovery solution can significantly improve system efficiency, reaching or exceeding 90%.

[0038] 3. Innovations in the recovery of latent heat of phase change in exhaust gas:

[0039] Compared to existing technologies that mainly focus on sensible heat recovery, this invention innovatively introduces latent heat recovery from exhaust gases, which not only increases the magnitude of heat recovery but also expands the scope and efficiency of recovery.

[0040] The sensible heat of the exhaust gas and the latent heat released during its phase change are effectively recovered and utilized, enhancing the comprehensiveness of heat recovery.

[0041] 4. Comprehensive considerations for improving system efficiency:

[0042] By comprehensively recovering heat energy from fuel cells and their auxiliary equipment, and by making deep use of exhaust kinetic and thermal energy, this invention can effectively improve the energy efficiency of large-scale fuel cell combined heat and power systems.

[0043] This comprehensive and multi-faceted heat recovery and energy conversion strategy enables megawatt-level combined heat and power systems to overcome traditional efficiency bottlenecks and achieve high-efficiency operation.

[0044] This invention not only provides a novel solution for improving the efficiency of fuel cell cogeneration systems, but also offers important technical references for the design and optimization of large-scale fuel cell cogeneration systems in the future.

[0045] Second, the high-efficiency fuel cell cogeneration method based on multi-end recovery provided by this invention solves the following technical problems and achieves the following significant technological advancements:

[0046] 1. Technical problems to be solved:

[0047] Low energy utilization efficiency: In traditional energy systems, a large amount of heat energy is released into the environment without being effectively utilized, resulting in energy waste. This invention significantly improves energy utilization efficiency by comprehensively utilizing waste heat from multiple sources.

[0048] Severe environmental pollution: Traditional energy production and consumption processes generate large amounts of pollutants. This invention significantly reduces pollutant emissions by using a fuel cell system for power generation and waste heat recovery.

[0049] Unstable energy supply: Heating or power supply systems that rely on a single energy source often lack stability. This invention improves the stability of the system's energy supply by integrating multiple energy recovery and supply methods.

[0050] 2. Significant technological advancements achieved:

[0051] High-efficiency comprehensive energy utilization: This invention achieves high-efficiency energy conversion and utilization by integrating the high-efficiency electrical energy conversion of fuel cells and the multi-terminal waste heat utilization, which greatly improves the energy utilization rate.

[0052] Environmentally friendly: It reduces pollutant emissions during energy production and consumption, contributing to environmental protection and sustainable development.

[0053] Energy system optimization and integration: This invention achieves efficient integration and optimization of thermal energy, electrical energy and kinetic energy, thereby improving the energy flexibility and adaptability of the system.

[0054] Improved economic benefits: By improving energy efficiency, energy consumption and operating costs are reduced, which also reduces the economic burden of environmental pollution control.

[0055] This invention, by integrating and optimizing different energy recovery and utilization pathways, not only improves energy efficiency but also contributes to environmental protection and sustainable development, representing a significant advancement in the field of energy technology. Attached Figure Description

[0056] Figure 1 This is a structural diagram of a high-efficiency fuel cell cogeneration system based on multi-end recovery provided in an embodiment of the present invention.

[0057] Figure 2 This is a structural diagram of a high-efficiency fuel cell cogeneration system with multi-terminal recovery provided in this embodiment of the invention, which can change the utilization method of tail gas phase change heat recovery.

[0058] Figure 3 This is a flowchart of a high-efficiency fuel cell cogeneration method based on multi-end recovery provided in an embodiment of the present invention.

[0059] Figure 4 This is an energy flow diagram of the efficiency of the fuel cell cogeneration system provided in Application Example 1 of this invention.

[0060] Figure 5 This is an energy flow diagram of the efficiency of the fuel cell cogeneration system provided in Application Example 2 of this invention.

[0061] Figure 6 This is an energy flow diagram showing the efficiency of a conventional fuel cell combined heat and power system provided in an embodiment of the present invention.

[0062] Figure 7This is a schematic diagram of the system efficiency and power under different test conditions provided in the embodiments of the present invention.

[0063] In the diagram: 1. Plate heat exchanger one; 2. Auxiliary radiator one; 3. Three-way valve one; 4. Pump one; 5. Water storage tank; 6. Air filter; 7. Air compressor; 8. Intercooler; 9. Multi-unit fuel cell; 10. Hydrogen circulation pump; 11. Hydrogen storage tank; 12. Auxiliary liquid storage tank; 13. Auxiliary radiator two; 14. Back pressure valve; 15. Anode water distributor; 16. Pump two; 17. Three-way valve two; 18. Three-way valve three; 19. Valve one; 20. Expander; 21. DC / AC power conversion device; 22. User side; 23. Plate heat exchanger two; 24. Hot water storage tank; 25. Phase change heat exchanger; 26. Air; 27. Pump three. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0065] like Figure 1 As shown, this invention provides key components of a complex fuel cell combined heat and power system. These components are interconnected and work together to achieve efficient energy conversion and utilization.

[0066] Plate heat exchanger 1: It is usually connected to the heat output side of the multi-unit fuel cell 9 to recover the high-temperature heat energy generated by the fuel cell and transfer it to the hot water or heating cycle in the system.

[0067] Auxiliary radiator 12: Works in conjunction with plate heat exchanger 1 to dissipate excess heat and ensure system temperature balance.

[0068] Three-way valve 3 and pump 4: regulate and drive the flow of hot water or cooling fluid in the system to ensure that heat is distributed as needed.

[0069] Water storage tank 5: Stores water heated by plate heat exchanger 1 to provide hot water for users' heating systems.

[0070] Air filter 6 and air compressor 7: provide the clean air required by the fuel cell, and compress the air to meet the system requirements.

[0071] Intercooler 8: Used to cool the compressed air output from the air compressor, improving the efficiency of the fuel cell system.

[0072] Multi-engine fuel cell 9: This is the core of the system, converting hydrogen and oxygen into electrical and thermal energy.

[0073] Hydrogen circulation pump 10 and hydrogen storage tank 11: The hydrogen circulation pump is used to drive the flow of hydrogen in the system, and the hydrogen storage tank is used to store hydrogen.

[0074] Auxiliary liquid storage tank 12 and auxiliary radiator 2 13: provide storage and temperature regulation of cooling fluid for the system.

[0075] Back pressure valve 14 and anode water separator 15: ensure pressure balance and safety of hydrogen flow, while the anode water separator separates water from the gas discharged from the fuel cell.

[0076] Pump 2 16, Three-way valve 2 17, Three-way valve 3 18: These components work together to control and regulate the flow direction and velocity of different fluids in the system.

[0077] Valve 19: Used to control the fluid flow direction in a part of the system in response to changes in system demand.

[0078] Expander 20: can be used to recover and convert low-grade heat energy in the system for reuse.

[0079] DC / AC power conversion device 21: Converts the direct current generated by the fuel cell into alternating current for user use.

[0080] User side 22: refers to users who receive and use the electrical and thermal energy provided by the system.

[0081] Plate heat exchanger 23 and hot water storage tank 24: These two components work together to store and distribute the heat energy generated by the system.

[0082] Phase change heat exchanger 25: Utilizes the heat absorbed or released during the phase change of a substance to further improve the system's heat recovery efficiency.

[0083] Air 26, Pump 3 27: Air serves as the oxygen source for the fuel cell, and Pump 3 is used to propel air or other fluids through the system.

[0084] These components work together to ensure that the fuel cell combined heat and power system can operate efficiently and stably, achieving optimized energy utilization.

[0085] This invention provides a high-efficiency fuel cell combined heat and power system based on multi-terminal heat recovery, including a fuel cell system, a multi-terminal waste heat recovery system, a kinetic energy recovery system, and a user domestic hot water and heating system. The fuel cell system is connected to the multi-terminal waste heat recovery system, the fuel cell system is connected to the kinetic energy recovery system, and the user domestic hot water and heating system is connected to the multi-terminal waste heat recovery system.

[0086] The fuel cell system includes an air distribution path, a hydrogen distribution path, a multi-unit fuel cell, a power output path, and an exhaust gas path. In the air distribution path, air enters the air compressor 7 through an air filter 6. The air compressor 7, acting as the power unit for the air distribution path, distributes the air purified by the air filter 6 to the cathode inlet of the fuel cell. Because the compressed air temperature is high, an intercooler 8 is installed between the air compressor 7 and the fuel cell 9 to cool the compressed air entering the fuel cell cathode in order to ensure the cathode gas temperature is suitable for efficient fuel cell operation. In the hydrogen distribution path, a hydrogen circulation pump 10, acting as the power unit, distributes hydrogen from the hydrogen storage tank 11 to the anode inlet of the fuel cell. For the fuel cell anode outlet flow path, some of the water generated during fuel cell operation enters the anode circulation. Additionally, condensation due to cooling also produces some liquid water in the anode circulation gas. Therefore, the flow path consists of water and some unreacted hydrogen. To prevent anode flooding and reduce the workload of the hydrogen circulation pump, the gas-liquid mixture needs to be separated by the anode water separator 15. The separated hydrogen is then fed into the hydrogen distribution flow path to ensure high hydrogen utilization. For the fuel cell cathode outlet flow path, the flow path mainly consists of air and water generated during fuel cell operation. Similarly, the air is separated by a gas-liquid separator, and the separated air becomes the exhaust gas. The heat and kinetic energy of the high-temperature, high-pressure exhaust gas are recovered through the waste heat recovery system and the power recovery system. The separated high-temperature water is recovered through the waste heat recovery system. The current generated by the fuel cell operation is converted into electricity by the DC / AC power converter 19 in the power output flow path to meet the power demand of the user side 20.

[0087] Fuel cells, power conversion devices, air compressor motors, compressed air, and exhaust gases all have high temperatures and require cooling. It is also considered to recover this waste heat. The exhaust gases are recovered using a condensation phase change method. On the one hand, this cools these components or gases, ensuring the normal operation of the components, and on the other hand, it can effectively improve the energy utilization efficiency of the system.

[0088] This implementation case considers the air compressor and power conversion device operating at rated power. At this time, the casing temperature of the motor is between 60°C and 80°C when operating under rated load. In order to recover this part of the waste heat, a waste heat recovery circuit is set up for the air compressor and power conversion device.

[0089] The multi-terminal waste heat recovery system includes waste heat recovery from fuel cells, heat recovery from power conversion devices, heat recovery from air compressor motors, heat recovery from compressed air, and waste heat recovery from exhaust. Based on the grade of the corresponding heat sources, the waste heat recovery from fuel cells and compressed air is configured into a single waste heat recovery loop (loop one), with the fuel cell coolant serving as the heat exchange fluid (loop two). The heat recovery from air compressor motors and power conversion devices is configured into a single waste heat recovery loop (loop two), with the motor coolant serving as the heat exchange fluid (loop one). Exhaust waste heat recovery utilizes a condensation phase change heat recovery method, and is configured as a separate waste heat recovery loop (loop three), with water serving as the heat exchange fluid.

[0090] For the fuel cell waste heat recovery and compressed air heat recovery loops, the high-temperature water after gas-liquid separation at the outlet of intercooler 8 and the outlet of fuel cell 9 is pumped to three-way valve 3 via pump 4. The switching of three-way valve 3 is determined by the load of the hot water storage tank 22, deciding whether the high-temperature water enters the heat recovery loop or the heat dissipation loop. When the hot water storage tank 22 is not at its rated load, the hot fluid enters the plate heat exchanger 1 to exchange heat with the cold end heat exchange fluid of the hot water storage tank 22, achieving heat recovery. When the hot water storage tank 22 reaches its rated load, the hot fluid is connected to the auxiliary radiator 2 via three-way valve 3 for heat dissipation. The cooling water in plate heat exchanger 1 after heat is removed by the hot water storage tank 22, or the cooling water after heat dissipation by the auxiliary radiator 2, then enters intercooler 8 and fuel cell 9 to cool the compressed air and fuel cell 9 respectively. The cooling water temperature is determined by the flow rate of the heat exchange fluid between plate heat exchanger 1 and hot water storage tank 22, and the flow rate setting is determined by the operating temperature of fuel cell 9 and the load of hot water storage tank 22. When the operating temperature of fuel cell 9 increases or the hot water storage tank 22 reaches its rated load, the flow rate of water in the circuit is further controlled by controlling the distribution of cooling water in the waste heat utilization circuit by the water storage tank 5, so as to ensure the efficient and stable operation of the fuel cell system.

[0091] For the heat recovery loop of the air compressor motor and the power conversion device, pump 2 16 serves as the power unit for the waste heat recovery loop. High-temperature water from the outlet of the water-cooled pipeline between the air compressor motor 7 and the DC / AC power conversion device 19 is fed into three-way valve 2 17. The switching of three-way valve 2 17 is determined by the load condition of the hot water storage tank 22, deciding whether the high-temperature water enters the heat recovery loop or the heat dissipation loop. When the hot water storage tank 22 is below its rated load, the hot fluid enters the plate heat exchanger 2 21 to exchange heat with the cold end heat exchange fluid of the hot water storage tank 22, achieving heat recovery. When the hot water storage tank 22 reaches its rated load, the hot fluid connects to the auxiliary radiator 2 13 through three-way valve 2 17 for heat dissipation. The cooling water from the cold water side of the hot water storage tank 22 or the cooling water after being cooled by the auxiliary radiator 2 13 then enters the air compressor motor 7 and the DC / AC power conversion device 19 through pump 2 16, cooling the air compressor motor 7 and the DC / AC power conversion device 19 respectively.

[0092] For the kinetic energy recovery system, the high-temperature, high-pressure exhaust gas obtained from the gas-liquid separator at the cathode outlet of fuel cell 9 enters back pressure valve 14. Back pressure valve 14 is simultaneously connected to fuel cell 9 and expander 19. When the exhaust gas pressure of the fuel cell system is higher than the set pressure of back pressure valve 14, the fuel cell exhaust gas flow path connects to expander 18. The high-pressure exhaust gas recovers kinetic energy through expander 18, and the kinetic energy of the exhaust gas is converted into electrical energy, which is then fed into DC / AC power conversion device 19 to output electrical energy to the user side. For the exhaust gas waste heat recovery flow path, the atmospheric pressure, high-temperature exhaust gas passing through expander 19 is fed into phase change heat exchanger 23, where it undergoes condensation and phase change heat exchange with the cooling water supplied from the cold water side of hot water storage tank 22, and is discharged as atmospheric pressure, ambient temperature air 24. Since the temperature reached by the condensation phase change heat recovered from the cooling water supplied to the cold water side of the hot water storage tank 22 is relatively low, it is directly fed into the cold water side of the hot water storage tank 22 for recovery. The water on the cold water side of the hot water storage tank 22 provides heat exchange between plate heat exchanger 1 and plate heat exchanger 21 in the corresponding waste heat recovery loop.

[0093] The user's domestic hot water and heating system mainly includes a hot water storage tank 22 and a pump 25. The hot water storage tank includes a hot water side and a cold water side. The cold water side is connected to the tap water supply side. A plate heat exchanger is connected to the hot water storage tank. The hot water side of the hot water storage tank is connected to the user through a water pump.

[0094] Example 2

[0095] like Figure 2 As shown, the present invention provides a high-efficiency fuel cell cogeneration system with multi-terminal waste heat recovery, which can change the utilization method of exhaust gas phase change heat recovery. It includes a fuel cell system, a multi-terminal waste heat recovery system, a kinetic energy recovery system, and a user's domestic hot water and heating system.

[0096] The multi-terminal waste heat recovery system includes waste heat recovery from fuel cells, heat recovery from power conversion devices, heat recovery from air compressor motors, heat recovery from compressed air, and waste heat recovery from exhaust.

[0097] For tailpipe phase change waste heat recovery, to improve the overall system efficiency, the temperature of the cold water in the phase change latent heat exchanger must be kept low to release more latent heat. Since the cooling water entering the phase change heat exchanger from the hot water storage tank has absorbed the sensible and latent heat of the tailpipe exhaust gas, its temperature is lower than that of the hot water storage tank. If it directly enters the hot water storage tank, it will lower the temperature of the hot water there, reducing system efficiency. Therefore, the water at the outlet of the phase change heat exchanger needs to be utilized in a cascade manner before being introduced into the hot water storage tank. Based on the power of the air compressor and the motor of the power conversion device, this implementation case can switch between two cascade waste heat recovery schemes: Scheme 1 and Scheme 2.

[0098] Based on the grade of the corresponding heat source, the waste heat recovery from the fuel cell and the compressed air heat recovery are configured into a single waste heat recovery loop (loop one), with the fuel cell coolant serving as the heat exchange fluid in loop two. The heat recovery from the air compressor motor and the power conversion device is configured into a single waste heat recovery loop (loop two), with the motor coolant serving as the heat exchange fluid in loop one. The plate heat exchangers in both loop one and loop two are connected to a loop three that connects to a hot water storage tank. Water is the heat exchange fluid in loop three.

[0099] For loop three, the switching between cascade waste heat recovery scheme one and cascade waste heat recovery scheme two is controlled by three-way valve three 18 and valve one 19: when three-way valve three 18 connects plate heat exchanger two 23 and hot water storage tank 24, the flow path between plate heat exchanger two 23 and plate heat exchanger one 1 is closed, and valve one 19 is opened, which is cascade waste heat recovery scheme one; when three-way valve three 18 connects plate heat exchanger two 23 and plate heat exchanger one 1, the flow path between plate heat exchanger two 23 and hot water storage tank 24 is closed, and valve one 19 is closed, which is cascade waste heat recovery scheme two.

[0100] For the first stage of waste heat recovery scheme, when the air compressor and the motor of the power conversion device are operating at rated power: the cooling water at the outlet of the hot water storage tank 24 first recovers the sensible heat and latent heat of the exhaust gas through the phase change heat exchanger 25, then recovers the waste heat of the air compressor 7 and the motor of the power conversion device 21, and finally enters the hot water storage tank 24. The cooling water on the cold water side of the hot water storage tank 24 recovers the waste heat of the exhaust gas through the phase change heat exchanger 25. The cooling water, which absorbs the sensible and latent heat of the exhaust gas, has a lower temperature than the hot water storage tank. At this time, the motor operating temperature is high. The water at the outlet of the phase change heat exchanger 25 is then fed into the plate heat exchanger 23 in the second waste heat recovery loop. On the other side of the plate heat exchanger 23 is the motor coolant, which has recovered the waste heat generated by the rated power operation of the air compressor 7 motor and the DC / AC power conversion device 21 motor. After the water at the outlet of the phase change heat exchanger 25 recovers the waste heat of the air compressor 7 motor and the DC / AC power conversion device 21 motor through the plate heat exchanger 23, the temperature can reach the hot water temperature of the hot water storage tank. Finally, it enters the hot water storage tank through the three-way valve 3 18.

[0101] For waste heat recovery from the fuel cell and compressed air heat recovery, the high-temperature water after gas-liquid separation at the outlet of the intercooler 8 and the outlet of the fuel cell 9 is pumped to the three-way valve 3 via pump 4. The switching of the three-way valve 3 is determined by the load of the hot water storage tank 24, deciding whether the high-temperature water enters the heat recovery circuit or the heat dissipation circuit. When the hot water storage tank 24 is not at its rated load, the hot fluid enters the plate heat exchanger 1 to exchange heat with the cold end heat exchange fluid of the hot water storage tank 24, achieving heat recovery. When the hot water storage tank 24 reaches its rated load, the hot fluid is connected to the auxiliary radiator 2 via the three-way valve 3 for heat dissipation. The cooling water in the plate heat exchanger 1 after heat is removed by the hot water storage tank 24, or the cooling water after heat dissipation by the auxiliary radiator 2, then enters the intercooler 8 and the fuel cell 9 to cool the compressed air and the fuel cell 9, respectively. The cooling water temperature is determined by the flow rate of the heat exchange fluid between the plate heat exchanger 1 and the hot water storage tank 24, and the flow rate setting is determined by the operating temperature of the fuel cell 9 and the load of the hot water storage tank 24. When the operating temperature of fuel cell 9 increases or the hot water storage tank 24 reaches its rated load, the flow rate of water in the circuit is further controlled by controlling the distribution of cooling water in the waste heat utilization circuit by the water storage tank 5, so as to ensure the efficient and stable operation of the fuel cell system.

[0102] For the second stage of waste heat recovery scheme, when the air compressor and power conversion device motors are operating at low power: Since the heat generated by the motors of air compressor 7 and power conversion device 21 is much lower than the working heat of compressed air and fuel cell 9 during low-power operation, even if the cooling water at the outlet of the hot water storage tank 24 simultaneously recovers the sensible heat and latent heat of the exhaust gas, as well as the waste heat from the motors of air compressor 7 and power conversion device 21, the water temperature is still lower than the hot water temperature in the hot water storage tank 24. Directly introducing the water into the hot water storage tank 24 will lead to a decrease in the overall system efficiency. Therefore, to ensure system efficiency, scheme two sets up exhaust waste heat recovery, air compressor and power conversion device motor heat recovery, and compressed air and fuel cell waste heat recovery as a staged waste heat recovery loop based on grade. That is, the cooling water at the outlet of the hot water storage tank 24 first recovers the sensible heat and latent heat of the exhaust gas, then recovers the waste heat from the air compressor and power conversion device motor, then recovers the waste heat from the fuel cell and compressed air, and finally introduces it into the hot water storage tank 24. The cooling water on the cold water side of the hot water storage tank 24 recovers waste heat from the exhaust gas through the phase change heat exchanger 25. The water from the outlet of the phase change heat exchanger 25 is then fed into the plate heat exchanger 23 in the second waste heat recovery loop. On the other side of the plate heat exchanger 23 is the motor coolant that has recovered waste heat generated by the low-power operation of the air compressor 7 motor and the DC / AC power conversion device 21 motor. The water from the outlet of the phase change heat exchanger 25 recovers waste heat from the air compressor 7 motor and the DC / AC power conversion device 21 motor through the plate heat exchanger 23. After the waste heat is removed, the temperature is still lower than the hot water temperature in the hot water storage tank. At this time, it enters the plate heat exchanger 1 in the waste heat recovery loop 1 through the three-way valve 318. On the other side of the plate heat exchanger 1, there is fuel cell coolant that has recovered the waste heat generated by the operation of fuel cell 9 and compressed air through fuel cell 9 and intercooler 8. The water at the outlet of plate heat exchanger 23 recovers the waste heat of fuel cell and compressed air through plate heat exchanger 1, and the temperature reaches the hot water temperature of the hot water storage tank. Then it is introduced into the hot water storage tank 24.

[0103] For waste heat recovery and compressed air heat recovery of fuel cells, the high-temperature water after gas-liquid separation at the outlet of intercooler 8 and the outlet of fuel cell 9 is transported to three-way valve 3 by pump 4. The switching of three-way valve 3 is determined by the load of hot water storage tank 24, which determines whether the high-temperature water enters the heat recovery circuit or the heat dissipation circuit. When the hot water storage tank 24 does not reach its rated load, the hot fluid enters the plate heat exchanger 1 and exchanges heat with the cold end heat exchange fluid of the hot water storage tank 24. On the one hand, this realizes the recovery of heat between the fuel cell and the compressed air. On the other hand, since the cold end heat exchange fluid of the plate heat exchanger 1 is warm water that has absorbed the waste heat from the exhaust, the air compressor 7 motor, and the DC / AC power conversion device 21, it can better ensure that the hot end outlet temperature of the plate heat exchanger 1 is not too low, thus preventing the outlet water temperature after heat recovery from being lower than the operating temperature of the fuel cell 9, ensuring the efficient operation of the fuel cell 9. When the hot water storage tank 24 reaches its rated load, the hot fluid is connected to the auxiliary radiator 2 through a three-way valve for heat dissipation. At this time, the waste heat from the exhaust, the air compressor 7 motor, and the DC / AC power conversion device 21 is dissipated through the auxiliary radiator 13 in the waste heat recovery loop 2. The cold water side of the hot water storage tank 24 is connected to the tap water side. Cooling water from plate heat exchanger 1, after heat is removed by hot water storage tank 24 or after cooling through auxiliary radiator 2, enters intercooler 8 and fuel cell 9 to cool compressed air and fuel cell 9 respectively. The cooling water temperature is determined by the flow rate of the heat exchange fluid between plate heat exchanger 1 and hot water storage tank 24, and the flow rate is set by the operating temperature of fuel cell 9 and the load on hot water storage tank 24. When the operating temperature of fuel cell 9 increases or hot water storage tank 24 reaches its rated load, the flow rate of water in the loop is further controlled by controlling the distribution of cooling water in waste heat utilization loop by water storage tank 5, ensuring efficient and stable operation of the fuel cell system.

[0104] When switching between the two cascade waste heat recovery schemes in this implementation case, the fuel cell system, kinetic energy recovery system, and user domestic hot water and heating system remain unchanged.

[0105] The fuel cell system includes an air distribution path, a hydrogen distribution path, a multi-unit fuel cell, a power output path, and an exhaust gas path. In the air distribution path, air enters the air compressor 7 through the air filter 6. The air compressor 7, as the power unit for the air distribution path, distributes the air purified by the air filter 6 to the cathode inlet of the fuel cell. Because the compressed air temperature is high, an intercooler 8 is installed between the air compressor 7 and the fuel cell 9 to cool the compressed air entering the fuel cell cathode in order to ensure the cathode gas temperature is suitable for efficient fuel cell operation. In the hydrogen distribution path, the hydrogen circulation pump 10, as the power unit for the hydrogen distribution path, distributes hydrogen from the hydrogen storage tank 11 to the anode inlet of the fuel cell. For the fuel cell anode outlet flow path, some of the water generated during fuel cell operation enters the anode circulation. Additionally, condensation due to cooling also produces some liquid water in the anode circulation gas. Therefore, the flow path consists of water and some unreacted hydrogen. To prevent anode flooding and reduce the workload of the hydrogen circulation pump, the gas-liquid mixture needs to be separated by the anode water separator 15. The separated hydrogen is then fed into the hydrogen distribution flow path to ensure high hydrogen utilization. For the fuel cell cathode outlet flow path, the flow path mainly consists of air and water generated during fuel cell operation. Similarly, the air is separated by a gas-liquid separator, and the separated air becomes the exhaust gas. The heat and kinetic energy of the high-temperature, high-pressure exhaust gas are recovered through the waste heat recovery system and the power recovery system. The separated high-temperature water is recovered through the waste heat recovery system. The current generated by the fuel cell operation is converted into electricity by the DC / AC power converter 21 in the power output flow path to meet the power demand of the user side 22.

[0106] For the kinetic energy recovery system, the high-temperature, high-pressure exhaust gas obtained from the gas-liquid separator at the cathode outlet of fuel cell 9 enters the back pressure valve 14. The back pressure valve 14 is simultaneously connected to both fuel cell 9 and expander 20. When the exhaust gas pressure of the fuel cell system is higher than the set pressure of the back pressure valve 14, the fuel cell exhaust gas flow path connects to expander 20. The high-pressure exhaust gas recovers kinetic energy through expander 20, and the kinetic energy of the exhaust gas is converted into electrical energy, which is then fed into DC / AC power conversion device 21 to output electrical energy to the user side. For the exhaust gas waste heat recovery flow path, the atmospheric pressure, high-temperature exhaust gas passing through expander 20 enters phase change heat exchanger 25, where it undergoes condensation and phase change heat exchange with the cooling water supplied from the cold water side of hot water storage tank 24, and is discharged as atmospheric pressure, ambient temperature air 26.

[0107] The user's domestic hot water and heating system mainly includes a hot water storage tank 24 and a pump 27. The hot water storage tank includes a hot water side and a cold water side. The cold water side is connected to the tap water supply side. A plate heat exchanger is connected to the hot water storage tank. The hot water side of the hot water storage tank is connected to the user through a water pump.

[0108] The working principle of the kinetic energy recovery section:

[0109] 1. During operation of fuel cell 9, high-temperature and high-pressure exhaust gas is generated at the cathode outlet. This gas first passes through a gas-liquid separator to remove liquid components, ensuring that the gas entering subsequent systems is pure.

[0110] 2. The separated gas enters the back pressure valve 14. The function of the back pressure valve 14 is to control the gas pressure. When the pressure of the fuel cell exhaust gas is higher than the set value of the back pressure valve 14, the back pressure valve 14 will open, allowing the gas to flow to the expander 20.

[0111] 3. Expander 20 is a device that converts the pressure energy of a gas into mechanical energy. When high-pressure exhaust gas passes through expander 20, its kinetic energy is converted into mechanical energy, and at the same time, the gas pressure decreases and the temperature drops accordingly.

[0112] 4. The mechanical energy generated by the expander 20 is further converted into electrical energy. Through the connected DC / AC power conversion device 21, the electrical energy is converted into a form suitable for user use and output to the user side.

[0113] Working principle of the exhaust gas waste heat recovery section:

[0114] 1. The exhaust gas from the expander 20, although at a lower pressure, is still at a high temperature. This gas enters the phase change heat exchanger 25.

[0115] 2. The phase change heat exchanger 25 is a highly efficient heat exchange device that uses the heat from the exhaust gas to heat the cold water in the hot water storage tank 24. During this process, the temperature of the exhaust gas gradually decreases, while the temperature of the cold water gradually increases.

[0116] 3. Finally, the exhaust gas is cooled to room temperature air 26 and discharged from the system. The heated cold water becomes hot water and is stored on the hot water side of the hot water storage tank 24.

[0117] Finally, regarding the working principle of the user's domestic hot water and heating system:

[0118] 1. The hot water storage tank 24 is divided into a hot water side and a cold water side. The cold water side is connected to the tap water supply side. When hot water is needed, tap water enters the hot water storage tank through the cold water side.

[0119] 2. The plate heat exchanger is located between the hot water storage tank and the hot water supply system. It can transfer the heat of the hot water in the storage tank to the cold water on the user side, thereby providing hot water to the user.

[0120] 3. When a user needs hot water, the water pump will start and transport the hot water from the hot water side of the storage tank to the user through pipes to meet the user's hot water needs.

[0121] Based on the working principle described above, the system not only realizes the kinetic energy recovery and waste heat recovery of fuel cell exhaust, improving energy utilization efficiency, but also provides users with hot water and heating services, realizing diversified energy utilization.

[0122] like Figure 3 As shown, a high-efficiency fuel cell cogeneration method based on multi-end recovery includes:

[0123] S101 is powered by a fuel cell system;

[0124] S102 recovers waste heat through a multi-terminal waste heat recovery system;

[0125] S103 recovers kinetic energy through a kinetic energy recovery system;

[0126] S104 provides heating through the user's domestic hot water and heating system.

[0127] The high-efficiency fuel cell combined heat and power (CHP) method based on multi-end recovery is a comprehensive energy utilization approach. Its main purpose is to maximize energy efficiency and reduce energy waste. The detailed working principle of this method is as follows:

[0128] Power supply via fuel cell system (S101): A fuel cell is a device that directly converts chemical energy into electrical energy. It operates without combustion, resulting in high efficiency and low pollution. In this stage, the fuel cell system provides the primary power supply for building lighting, equipment operation, etc.

[0129] Waste heat is recovered through a multi-terminal waste heat recovery system (S102): During the operation of a fuel cell, a large amount of heat energy is generated. In addition, industrial production, power equipment, etc., also generate a large amount of waste heat. A multi-terminal waste heat recovery system refers to collecting waste heat from these different sources and converting it into usable heat energy through heat exchangers and other equipment for heating, hot water supply, or even driving absorption chillers to provide cooling capacity.

[0130] Kinetic energy is recovered through a kinetic energy recovery system (S103): Kinetic energy recovery here usually refers to collecting and converting mechanical energy in a specific system, such as recovering kinetic energy during elevator, subway braking, or car braking. This recovered energy can be converted into electrical energy and stored for other uses.

[0131] Heating through the user's domestic hot water and heating system (S104): The heat energy collected above can be directly applied to the user's life through the hot water system and heating system, such as providing heating and hot water for residences, offices or industrial facilities, thereby reducing dependence on and consumption of external energy.

[0132] Overall, this system achieves efficient energy recycling, which can significantly reduce energy consumption and operating costs, as well as reduce environmental pollution, making it a green and efficient energy solution.

[0133] The multi-terminal heat and power (CHP) system proposed in this invention significantly improves the overall energy utilization rate by comprehensively utilizing heat recovery from the fuel cell, power converter, air compressor, compressed air, exhaust kinetic energy, and latent heat recovery from exhaust gas condensation phase change. The core advantage of this system lies in its ability to efficiently convert consumed fuel gas heat into electrical and thermal energy while minimizing energy loss.

[0134] In Application Example 1, when the consumed gas heat is 90kW, the system can generate 48.303kW of electricity from the fuel cell and an additional 1.2kW of electricity through exhaust kinetic energy recovery. Furthermore, the system further recovers heat energy through multiple recovery loops, including heat generated by the fuel cell, heat generated by the air compressor, heat generated by the power converter, and heat recovered from the condensation phase change of the fuel cell cathode exhaust. After comprehensive calculation, the efficiency of this combined heat and power system reaches 91.32%, which is 6.29% higher than that of traditional fuel cell combined heat and power systems.

[0135] In Application Example 2, when the consumed gas heat increased to 130kW, the system's power generation also increased to 69.771kW, while the power generated by exhaust kinetic energy recovery also increased to 1.95kW. Similarly, the system efficiently recovered heat energy through multiple recovery loops. Ultimately, the efficiency of this combined heat and power system reached 91.69%, which is 6.66% higher than that of traditional fuel cell combined heat and power systems.

[0136] pass Figure 4 The specific test data shown clearly demonstrates that the high-efficiency fuel cell cogeneration system based on the multi-end recovery of this invention has extremely high energy utilization efficiency, exceeding 90% overall energy efficiency. This not only helps reduce energy consumption and environmental pollution but also provides businesses and individuals with a more economical and efficient energy utilization solution.

[0137] The high-efficiency fuel cell cogeneration system based on multi-end recovery uses a condensation phase change latent heat exchanger, which is a high-efficiency heat exchange device, including but not limited to finned tube type, plate fin type and other structural forms, for exhaust waste heat recovery.

[0138] In summary, this invention significantly improves the overall energy utilization rate of fuel cell cogeneration systems by comprehensively utilizing multiple recycling methods, making an important contribution to the development of the energy utilization field.

[0139] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-efficiency fuel cell combined heat and power system based on multi-end recovery, characterized in that, include: Fuel cell systems, multi-terminal waste heat recovery systems, kinetic energy recovery systems, and domestic hot water and heating systems; The fuel cell system is connected to the multi-terminal waste heat recovery system, the fuel cell system is connected to the kinetic energy recovery system, and the user's domestic hot water and heating system is connected to the multi-terminal waste heat recovery system. The multi-terminal waste heat recovery system includes a waste heat recovery flow path and a heat dissipation flow path, which are switched by a three-way valve; The waste heat recovery flow path includes a water pump, a three-way valve, a plate heat exchanger, and a hot water storage tank. The water pump, three-way valve, and plate heat exchanger are connected to the devices that need to be heat recovered, and the plate heat exchanger is connected to the hot water storage tank. The heat dissipation flow path includes a water pump, a three-way valve, an auxiliary radiator, and an auxiliary water storage tank. The auxiliary radiator is connected to the device that needs to be cooled through the three-way valve, and the auxiliary water storage tank is connected to the device that needs to be cooled through the water pump to provide cooling water for auxiliary heat dissipation. The kinetic energy recovery system includes a back pressure valve and an expander. The expander is connected to both the cathode outlet of the multi-fuel cell and the DC / AC power conversion device. The back pressure valve is connected to both the multi-fuel cell and the expander. The multi-terminal waste heat recovery system includes fuel cell waste heat recovery, power conversion device heat recovery, air compressor motor heat recovery, compressed air heat recovery, and exhaust waste heat recovery. Based on the corresponding heat source grade, fuel cell waste heat recovery and compressed air heat recovery are configured into one waste heat recovery loop; air compressor motor heat recovery and power conversion device heat recovery are configured into one waste heat recovery loop; exhaust waste heat recovery uses a condensation phase change heat recovery method and is configured into a separate waste heat recovery loop. The tail exhaust waste heat recovery circuit includes a condensing phase change heat exchanger, which cools and condenses the tail exhaust into water to realize the recovery of latent heat of phase change and condensate. It is connected to the kinetic energy recovery system. One end of the heat exchanger is connected to the tail end of the expander, and the other end is connected to the cold water side of the hot water storage tank. The heat exchange fluid in the fuel cell waste heat recovery and compressed air heat recovery circuit is the fuel cell coolant, and the heat exchange fluid in the air compressor motor heat recovery and power conversion device heat recovery circuit is the motor coolant. The cooling water flowing through the condenser phase changer in the circuit can be directly introduced into the cold water side of the hot water storage tank or heated through heat exchange before being introduced into the hot water side of the hot water storage tank.

2. The high-efficiency fuel cell cogeneration system based on multi-end recovery according to claim 1, characterized in that, The fuel cell system includes an air distribution path, a hydrogen distribution path, a multi-fuel cell, a DC / AC power conversion device, and an exhaust gas path. The air distribution path is connected to the cathode inlet side of the multi-unit fuel cell and includes an air filter, an air compressor, and an intercooler; The hydrogen transmission and distribution path includes a hydrogen storage tank, a hydrogen circulation pump and an anode water distributor. The hydrogen storage tank is connected to the anode inlet side of the multi-engine fuel cell, and the anode water distributor is connected to the anode outlet side of the multi-engine fuel cell. The exhaust gas flow path is connected to the cathode outlet side of the multi-engine fuel cell.

3. The high-efficiency fuel cell cogeneration system based on multi-end recovery according to claim 1, characterized in that, The user's domestic hot water and heating system mainly includes a hot water storage tank and a water pump; the hot water storage tank includes a hot water side and a cold water side, the cold water side is connected to the tap water supply side, a plate heat exchanger is connected to the hot water storage tank, and the hot water side of the hot water storage tank is connected to the user through the water pump.

4. The high-efficiency fuel cell cogeneration system based on multi-end recovery according to claim 1, characterized in that, This includes multi-terminal waste heat recovery and exhaust kinetic energy recovery.

5. The high-efficiency fuel cell cogeneration system based on multi-end recovery according to claim 1, characterized in that, The condensing phase change latent heat exchanger used for tail exhaust waste heat recovery is a highly efficient heat exchange device, including finned tube and plate-fin structures.

6. A method for implementing a high-efficiency fuel cell cogeneration system based on multi-end recovery as described in any one of claims 1-5, characterized in that, The high-efficiency fuel cell cogeneration method based on multi-end recovery includes: Step 1: Power is supplied through a fuel cell system; Step two: Recover waste heat through a multi-terminal waste heat recovery system; Step 3: Recover kinetic energy through the kinetic energy recovery system; Step four: Heat is supplied through the user's domestic hot water and heating system.

7. A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the efficient combined heat and power method based on multi-terminal recovery as described in claim 6.

8. An information data processing terminal, characterized in that, The information data processing terminal is used to implement the high-efficiency fuel cell cogeneration system based on multi-end recovery as described in any one of claims 1-5.

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