Fuel cell and waste heat recovery integrated heat and power cogeneration system and heat and power cogeneration method

Abstract

The invention belongs to the technical field of fuel cell waste heat recovery, and relates to a fuel cell and waste heat recovery integrated cogeneration system which comprises a fuel cell, a heat storage device, a thermoacoustic generator, a heat exchanger, a cooling module and a control unit. The fuel cell is connected with an input port of the heat storage device through a pipeline, an output port of the heat storage device is connected with input ports of the thermo-acoustic generator, the heat exchanger and the cooling module through pipelines, and an output port of the thermo-acoustic generator is connected with an input port of the heat exchanger through a pipeline. An output port of the heat exchanger is connected with an input port of the cooling module; the control unit is used for controlling the operation states of the fuel cell, the heat storage device, the thermo-acoustic generator, the heat exchanger and the cooling module. The invention further relates to a combined heat and power supply method integrating the fuel cell and waste heat recovery. According to the invention, the fuel cell and the thermoacoustic engine are integrated, so that an efficient waste heat recovery and utilization system is constructed.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated utilization of fuel cells and cogeneration systems, and specifically relates to a cogeneration system integrating fuel cells and waste heat recovery, and also relates to a cogeneration method integrating fuel cells and waste heat recovery. Background Art

[0002] Solid oxide fuel cells (hereinafter referred to as fuel cells) are an efficient and environmentally friendly energy conversion device that has been widely used in distributed energy supply, combined heat and power (CHP) and other fields in recent years. During operation, fuel cells can directly convert the chemical energy of fuels such as hydrogen into electrical energy, while generating a large amount of waste heat. If this waste heat is not effectively recovered and utilized, it will be wasted, reducing the energy efficiency of the entire system. Therefore, in fuel cell combined heat and power systems, how to efficiently utilize these waste heat resources has become one of the key technical issues in current research and application. However, existing fuel cell combined heat and power systems have a variety of technical bottlenecks and practical problems in the utilization of waste heat.

[0003] At present, the waste heat utilization method of most fuel cell cogeneration systems is relatively simple, usually using simple heat exchange devices to use waste heat for heating or providing domestic hot water. This single thermal energy utilization method seriously limits the overall efficiency of the system. In particular, for the medium and high temperature waste heat generated by fuel cells, if it is only used for heating or hot water, there are often problems of low efficiency and excessive heat energy waste. In addition, the recovery efficiency of medium and low temperature waste heat is even lower, and it is difficult for existing technologies to achieve the step-by-step utilization of medium and low temperature waste heat, resulting in a considerable amount of potential available energy being lost in vain.

[0004] In addition, although there have been many studies on waste heat utilization technology in existing fuel cell systems, most methods are to add a variety of external equipment, such as heat exchangers, hot water boilers, etc., to the original system. These devices are often bulky, complex to install, and have a low degree of integration with the fuel cell system, which increases the structural complexity of the entire system and increases the difficulty of maintenance and management. The collaborative work between multiple devices is also not ideal, and efficient management and scheduling of thermal energy cannot be achieved. Over time, this complex system structure may also lead to increased failure rates and increased maintenance costs, limiting its widespread promotion and application.

[0005] In addition, the electrical energy and thermal energy output by the fuel cell system fluctuate with changes in workload. Under high load, the waste heat generated by the fuel cell is sufficient, but due to the limitations of existing technologies, it is impossible to flexibly and efficiently allocate thermal energy according to demand, resulting in a waste of thermal energy. Under low load, the waste heat is insufficient, and the existing waste heat utilization devices are also difficult to meet actual usage needs, which in turn affects the stability and economy of the entire cogeneration system. The existing system lacks effective thermal energy storage and peak-shaving capabilities, and cannot achieve balanced regulation of thermal power output under different load conditions.

[0006] With the development of fuel cell technology, the complexity of cogeneration systems is also increasing. Current fuel cell cogeneration systems often lack advanced control units for real-time monitoring and management, especially in terms of waste heat recovery and distribution, and lack the ability to intelligently adjust under various working conditions. This not only leads to low system efficiency, but also affects the life and overall performance of the fuel cell. Lack of intelligence makes the optimization of waste heat utilization and power output relatively passive, and it is impossible to flexibly dispatch according to real-time demand changes, making it difficult to achieve efficient operation of the system.

[0007] Existing cogeneration systems also often lack appropriate energy storage units, especially for long-term storage of waste heat. The fuel cell system needs to consume the generated heat energy in real time, otherwise it will cause excess heat and cannot be effectively utilized. Most systems adopt an instant heating mode, which cannot achieve energy peak regulation or load regulation, and there is no effective energy storage mechanism when demand is low. This defect makes it impossible for the system to achieve balanced energy utilization when the heat demand is uneven, which in turn affects the overall efficiency of the system. The Chinese utility model patent with an application date of December 15, 2023 and an authorization announcement date of October 29, 2024, with an announcement number of CN221929339U, discloses a portable hydrogen fuel power source residual energy recovery system, which essentially converts the residual hydrogen energy of the portable hydrogen fuel power source into electrical energy and stores it in a battery for recovery in the form of electrical energy, but this method generally only recovers the generated high-temperature waste heat, and often cannot effectively recover the medium and low temperature waste heat, which can only be discharged by heat dissipation, and the energy recovery rate is low.

[0008] In summary, the existing fuel cell cogeneration system has many shortcomings in terms of waste heat utilization efficiency, system integration complexity, energy balance regulation and intelligent control. Summary of the invention

[0009] The first purpose of the present invention is to provide a combined heat and power system integrating a fuel cell and waste heat recovery, so as to solve the problems of low waste heat utilization efficiency, system integration complexity, poor energy balance regulation and insufficient intelligent control in the existing fuel cell combined heat and power system. Through a graded utilization method, it is ensured that waste heat resources at different temperatures are most effectively utilized, energy waste is avoided, and high efficiency and energy saving are achieved.

[0010] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a combined heat and power system integrating fuel cell and waste heat recovery, comprising a fuel cell, a heat storage device, a thermoacoustic generator, a heat exchanger, a cooler and a control unit; the fuel cell is connected to the heat storage device through a first pipeline and a second pipeline, the heat storage device is connected to the waste heat inlet on the heat exchanger through a third pipeline, the heat storage device is connected to the waste heat outlet on the heat exchanger through a fourth pipeline, the heat storage device is connected to the thermoacoustic generator through a fifth pipeline, the thermoacoustic generator is connected to the waste heat inlet of the heat exchanger through a sixth pipeline, the heat storage device is connected to the cooler through a seventh pipeline and an eighth pipeline, the cooler is connected with a second water supply pipe, a second water return pipe, a third water supply pipe and a third water return pipe, the second water supply pipe is connected to the first water return port on the heat exchanger, the first water return port is connected to the first water return pipe, the second water return pipe is connected to the first water supply port on the heat exchanger, and the first water supply port is connected to the first water supply pipe; the control unit is used to control the operating states of the fuel cell, the heat storage device, the thermoacoustic generator, the heat exchanger and the cooler respectively.

[0011] The technical solution of the present invention also has the following characteristics: The heat storage device comprises a metal shell and a heat storage medium located in the metal shell; the heat storage medium is silica sand or a phase change material.

[0012] A heat insulation layer is arranged on the inner side of the metal shell.

[0013] One-way valves are provided on the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, the seventh pipeline, the eighth pipeline, the first water supply pipe, the first water return pipe, the second water supply pipe, the second water return pipe, the third water supply pipe and the third water return pipe. The control unit controls the operating states of the heat storage device, the thermoacoustic generator, the heat exchanger and the cooler by adjusting the opening and closing of the one-way valves.

[0014] The heat conduction medium used for heat conduction in the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, the seventh pipeline and the eighth pipeline is air, carbon dioxide or water vapor.

[0015] The cooler comprises a shell, a fan arranged in the shell, and a heat dissipation fin installed at a driving end of the fan.

[0016] The thermoacoustic generator includes a box body and a hot-end heat exchanger, a cold-end heat exchanger, a phase modulator, a regenerator and a linear motor located inside the box body; the phase modulator is connected to the driving end of the linear motor, and the hot-end heat exchanger, the regenerator and the cold-end heat exchanger are connected in sequence and installed on the outside of the phase modulator.

[0017] The second purpose of the present invention is to provide a combined heat and power method integrating fuel cells and waste heat recovery, so as to solve the problems of low waste heat utilization efficiency, system integration complexity, poor energy balance regulation and insufficient intelligent control in the existing fuel cell combined heat and power system. Through the graded utilization method, it is ensured that waste heat resources at different temperatures are used most effectively, energy waste is avoided, and high efficiency and energy saving are achieved.

[0018] In order to achieve the above object, the present invention adopts a technical solution: a combined heat and power method integrating a fuel cell and waste heat recovery, which is implemented by step 1, step 2 or step 3 for different heat temperatures, including: Step 1, first close all the one-way valves, then the control unit controls the fuel cell to start, and then opens the one-way valves on the first pipeline and the second pipeline. When the heat temperature that the heat storage device can output is above 200°C, open the one-way valves on the fourth pipeline, the fifth pipeline, the sixth pipeline and the first water supply pipe; If the hot water temperature output from the first water return pipe is less than 60°C, open the one-way valve on the first water return pipe; If the temperature of the hot water output from the first water return pipe is greater than 60°C, open the one-way valves on the second water supply pipe, the second water return pipe, the third water supply pipe and the third water return pipe; Step 2, first close all the one-way valves, then the control unit controls the fuel cell to start, and then opens the one-way valves on the first pipeline and the second pipeline. When the heat temperature that the heat storage device can output is not greater than 200°C and not less than 100°C, open the one-way valves on the third pipeline, the fourth pipeline and the first water supply pipe; If the hot water temperature output from the first water return pipe is less than 60°C, open the one-way valve on the first water return pipe; If the temperature of the hot water output from the first water return pipe is greater than 60°C, open the one-way valves on the second water supply pipe, the second water return pipe, the third water supply pipe and the third water return pipe; Step 3, first close all the one-way valves, then the control unit controls the fuel cell to start, and then opens the one-way valves on the first pipeline and the second pipeline. When the heat temperature that the heat storage device can output is lower than 100°C and not less than 60°C, open the one-way valves on the seventh pipeline, the eighth pipeline, the third water supply pipe and the third return pipe.

[0019] The beneficial effects of the present invention are as follows: the combined heat and power system integrating the fuel cell and waste heat recovery of the present invention constructs an efficient waste heat recovery and utilization system by integrating the fuel cell and the thermoacoustic engine. First, the present invention utilizes the waste heat generated by the fuel cell, and through a multi-stage waste heat utilization system, flexibly applies this part of the waste heat to the needs of domestic hot water supply, building heating, etc., thereby realizing efficient recovery and distribution of waste heat. Secondly, the integrated thermoacoustic engine can further recover high-temperature waste heat and convert it into sound energy to drive power generation or other mechanical equipment, thereby improving the overall energy efficiency of the system. Finally, the system monitors the operating status of the fuel cell in real time through the control unit, rationally allocates thermoelectric output and storage, optimizes the combined heat and power efficiency of the system, and realizes the maximization and flexibility of energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a combined heat and power system integrating a fuel cell and waste heat recovery according to the present invention; Figure 2 It is a schematic diagram of a combined heat and power system integrating a fuel cell and waste heat recovery according to the present invention; Figure 3 yes Figure 1 Schematic diagram of the thermoacoustic generator.

[0021] In the figure: 1. fuel cell, 2. first pipeline, 3. second pipeline, 4. heat storage device, 5. fifth pipeline, 6. thermoacoustic generator, 601. box, 602. linear generator, 603. phase modulator, 604. regenerator, 605. hot end heat exchanger, 606. cold end heat exchanger, 7. sixth pipeline, 8. third pipeline, 9. fourth pipeline, 10. heat exchanger, 11. first water supply pipe, 12. second water supply pipe, 13. first water return pipe, 14. one-way valve, 15. third water supply pipe, 16. third water return pipe, 17. fan, 18. cooler, 19. seventh pipeline, 20. eighth pipeline, 21. second water return pipe. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] Example 1 like Figure 1 As shown, a combined heat and power system integrating a fuel cell and waste heat recovery of the present invention comprises a fuel cell 1, a heat storage device 4, a thermoacoustic generator 6, a heat exchanger 10, a cooler 18 and a control unit.

[0024] The fuel cell 1 is connected to the heat storage device 4 via the first pipeline 2 as an input pipeline, and the fuel cell 1 is connected to the heat storage device 4 via the second pipeline 3 as an output pipeline. The waste heat in the fuel cell 1 is input into the heat storage device 4 through the first pipeline 2 through the heat transfer medium for heat exchange, and then the heat transfer medium that has exchanged heat is re-input into the fuel cell 1 through the second pipeline 3 to extract heat again, so as to complete the heat exchange of the next cycle.

[0025] The side of the heat storage device 4 is provided with multiple waste heat inlets and multiple waste heat outlets, the side of the heat exchanger 10 is provided with a waste heat inlet and a waste heat outlet, one end of the third pipeline 8 is connected to the waste heat inlet on the heat exchanger 10, and the other end is connected to a waste heat outlet on the heat storage device 4; one end of the fourth pipeline 9 is connected to the waste heat outlet on the heat exchanger 10, and the other end is connected to a waste heat inlet on the heat storage device 4.

[0026] A waste heat outlet on the heat storage device 4 is connected to the thermoacoustic generator 6 through the fifth pipeline 5, the thermoacoustic generator 6 is connected to the waste heat inlet of the heat exchanger 10 through the sixth pipeline 7, a waste heat outlet on the heat storage device 4 is connected to the waste heat inlet on the cooler 18 through the seventh pipeline 19, and a corresponding waste heat inlet on the heat storage device 4 is connected to the waste heat outlet on the cooler 18 through the eighth pipeline 20. The cooler 18 is provided with a second water supply port, a second water return port, a third water supply port and a third water return port, the second water supply port is connected to the second water supply pipe 12, the second water return port is connected to the second water return pipe 21, the third water supply port is connected to the third water supply pipe 15, and the third return water port is connected to the third water return pipe 16.

[0027] The heat exchanger 10 is provided with a first water supply port and a first water return port, the second water supply pipe 12 is connected to the first water return port on the heat exchanger 10, the first water return port is connected to the first water return pipe 13, the second water return pipe 21 is connected to the first water supply port on the heat exchanger 10, and the first water supply port is connected to the first water supply pipe 11.

[0028] The heat exchanger 10 is mainly used to recover the medium-temperature waste heat (100°C-200°C) generated by the fuel cell 1. The heat in the heat storage device 4 enters the heat exchanger 10 through the third pipeline 8, and returns to the heat storage device 4 through the fourth pipeline 9 after heat exchange. Cold water is introduced from the first water supply pipe 11 into the heat exchanger 10 to complete the heat exchange, and then discharged from the first return pipe 13 in the form of hot water to meet the needs of domestic hot water and heating. The first water supply pipe 11 adopts a spiral coil design to increase the water flow path length inside the heat exchanger 10, increase the heat exchange area, and improve the absorption efficiency of thermal energy.

[0029] The first pipeline 2 , the second pipeline 3 , the third pipeline 8 , the fourth pipeline 9 , the fifth pipeline 5 , the sixth pipeline 7 , the seventh pipeline 19 and the eighth pipeline 20 are filled with heat transfer medium.

[0030] The first pipeline 2, the second pipeline 3, the third pipeline 8, the fourth pipeline 9, the fifth pipeline 5, the sixth pipeline 7, the seventh pipeline 19, the eighth pipeline 20, the first water supply pipe 11, the first water return pipe 13, the second water supply pipe 12, the second water return pipe 21, the third water supply pipe 15 and the third water return pipe 16 are all provided with a one-way valve 14. The control unit controls the operating state of the heat storage device 4, the thermoacoustic generator 6, the heat exchanger 10 and the cooler 18 by adjusting the opening and closing of the one-way valve 14. The control unit directly controls the operating state of the fuel cell 1.

[0031] Combination Figure 2 When working, the control unit controls the fuel cell 1 to work, and the waste heat generated in the fuel cell 1 flows into the heat storage device 4 through the first pipeline 2. After the heat exchange is completed in the heat storage device 4, it flows back to the fuel cell 1 through the second pipeline 3 to obtain heat again, so as to be transferred to the heat storage device 4 for heat exchange again, and the heat exchange and heat collection are circulated in sequence. The control unit will divide the heat stored in the heat storage device 4 into high-temperature waste heat, medium-temperature waste heat and low-temperature waste heat according to the temperature of the heat stored in the heat storage device 4. The temperature of high-temperature waste heat refers to above 200℃, the temperature of medium-temperature waste heat is between 100℃ and 200℃, and the temperature of low-temperature waste heat is between 60℃ and 100℃.

[0032] According to the different classifications of high-temperature waste heat, medium-temperature waste heat and low-temperature waste heat, the control unit will control the combined heat and power system integrating a fuel cell and waste heat recovery of the present invention to work in the following three situations: (1) For high-temperature waste heat, the one-way valve 14 is closed first during operation, and then the control unit controls the fuel cell 1 to start, and then opens the one-way valves 14 on the first pipeline 2 and the second pipeline 3. When the heat temperature that the heat storage device 4 can output is above 200°C, the one-way valves 14 on the fourth pipeline 9, the fifth pipeline 5, the sixth pipeline 7 and the first water supply pipe 11 are opened; If the temperature of the hot water outputted from the first water return pipe 13 is less than 60°C, the one-way valve 14 on the first water return pipe 13 is opened, and the hot water can be directly outputted to the outside through the second water return pipe 13, providing a heat source for the heating system and the hot water system, which is widely used in building heating and domestic hot water; If the temperature of the hot water output by the first return pipe 13 is greater than 60°C, the one-way valve 14 on the second water supply pipe 12, the second return pipe 21, the third water supply pipe 15 and the third return pipe 16 is opened, and the hot water is sent to the cooler 18 through the second water supply pipe 12 to exchange heat with the water sent by the third water supply pipe 15 and then sent back to the first water supply pipe 11 through the second return pipe 21. The hot water heated in the third water supply pipe 15 is sent out through the third return pipe 16 to be used for building heating or to provide domestic hot water to meet daily household or commercial needs.

[0033] (2) For medium-temperature waste heat, first close all the one-way valves 14, then the control unit controls the fuel cell 1 to start, and then opens the one-way valves 14 on the first pipeline 2 and the second pipeline 3. When the heat temperature that the heat storage device 4 can output is not greater than 200°C and not less than 100°C, open the one-way valves 14 on the third pipeline 8, the fourth pipeline 9 and the first water supply pipe 11; If the temperature of the hot water outputted from the first water return pipe 13 is less than 60°C, the one-way valve 14 on the first water return pipe 13 is opened, and the hot water can be directly outputted to the outside through the second water return pipe 13, providing a heat source for the heating system and the hot water system, which is widely used in building heating and domestic hot water; If the temperature of the hot water output by the first return pipe 13 is greater than 60°C, the one-way valve 14 on the second water supply pipe 12, the second return pipe 21, the third water supply pipe 15 and the third return pipe 16 is opened, and the hot water is sent to the cooler 18 through the second water supply pipe 12 to exchange heat with the water sent by the third water supply pipe 15 and then sent back to the first water supply pipe 11 through the second return pipe 21. The hot water heated in the third water supply pipe 15 is sent out through the third return pipe 16 for building heating or providing domestic hot water to meet daily household or commercial needs.

[0034] (3) For low-temperature waste heat, all the one-way valves 14 are closed first, and then the control unit controls the fuel cell 1 to start, and then the one-way valves 14 on the first pipeline 2 and the second pipeline 3 are opened. When the temperature of the heat that can be output by the heat storage device 4 is lower than 100°C and not less than 60°C, the one-way valves 14 on the seventh pipeline 19, the eighth pipeline 20, the third water supply pipe 15 and the third water return pipe 16 are opened. The heat of the heat transfer medium in the seventh pipeline 19 and the eighth pipeline 20 is exchanged with the water in the third water supply pipe 15 and the third water return pipe 16, and then discharged through the third water return pipe 16 for building heating or providing domestic hot water to meet daily household or commercial needs.

[0035] This graded utilization method ensures that waste heat resources at different temperatures are used most effectively, avoids energy waste, and achieves efficient energy saving of the system.

[0036] Example 2 like Figure 1 As shown, different from Example 1, in Example 2 of the present invention, a combined heat and power system integrating a fuel cell and waste heat recovery, the heat storage device 4 includes a metal shell and a heat storage medium located in the metal shell, and the heat storage medium is silica sand or phase change material.

[0037] When the heat-conducting medium in the first pipeline 2 , the second pipeline 3 , the third pipeline 8 , and the fourth pipeline 9 flows through the metal shell of the heat storage device 4 through the pipelines, it can quickly exchange heat with the heat storage medium in the metal shell.

[0038] An insulating layer is arranged on the inner side of the metal shell, which can ensure better thermal insulation effect of the heat storage medium in the metal shell and avoid excessive heat loss.

[0039] Example 3 like Figure 1 As shown, different from Example 2, in a combined heat and power system integrating a fuel cell and waste heat recovery of the present invention in Example 3, the heat transfer medium used for heat conduction in the first pipeline 2, the second pipeline 3, the third pipeline 8, the fourth pipeline 9, the fifth pipeline 5, the sixth pipeline 7, the seventh pipeline 19 and the eighth pipeline 20 is air, carbon dioxide or water vapor.

[0040] By using air, carbon dioxide or water vapor as the heat transfer medium, heat exchange can be completed efficiently at a low cost.

[0041] Example 4 like Figure 1 As shown, different from Example 3, in Example 4 of the present invention, a combined heat and power system integrating a fuel cell and waste heat recovery, the cooler 18 includes a shell, a fan 17 disposed in the shell, and heat dissipation fins installed at the fan drive end.

[0042] There are multiple fans 17 evenly distributed in various places of the outer shell. When the hot water in the second water supply pipe 12 and the second return pipe 21 is cooled by air cooling by the fan 17 and the cold water heat exchange in the third water supply pipe 15 and the third return pipe 16, hot water of suitable temperature can be output from the third return pipe 16 to supply daily needs.

[0043] Example 5 like Figure 3 As shown, different from Example 4, in Example 5 of the present invention, a combined heat and power system integrating a fuel cell and waste heat recovery, the thermoacoustic generator 6 comprises a box 601 and a hot end heat exchanger 605, a cold end heat exchanger 606, a phase modulator 603, a regenerator 604 and a linear generator 602 in the box 601. The phase modulator 603 is connected to the driving end of the generator 602, and the hot end heat exchanger 605, the regenerator 604 and the cold end heat exchanger 606 are connected in sequence and installed outside the phase modulator 603.

[0044] Thermoacoustic generator 6 is an energy conversion device based on thermoacoustic effect, which can convert thermal energy into sound energy and further drive generators or other mechanical equipment through sound waves. The device is particularly suitable for the recovery of medium and high temperature waste heat. Its working principle is to form sound wave vibration at high temperature, thereby further converting waste heat into mechanical energy or electrical energy. Through the thermoacoustic engine 6, the high-temperature waste heat generated by the fuel cell 1 is reused, which not only improves the overall energy utilization rate of the system, but also provides additional power output.

[0045] Thermoacoustic generator 6 is a device that realizes the conversion of thermal energy into electrical energy based on the thermoacoustic effect. Its core consists of two parts: a thermoacoustic engine and a linear motor. Helium or a nitrogen-argon mixture is usually used as a high-pressure working medium inside the system. Among them, the thermoacoustic engine breaks through the structural limitations of traditional internal combustion engines. It does not require mechanical components such as combustion chambers and valves. Instead, it forms a temperature gradient through the high-temperature and low-temperature heat exchangers arranged along the resonance tube to stimulate the working gas to produce self-sustaining acoustic oscillations. Driven by the fluctuation of acoustic pressure, the gas forms an alternating flow, periodically undergoes a compression-expansion thermal process, and exchanges sensible heat and latent heat with the heat exchanger, thereby converting the external heat source energy into high-intensity acoustic energy; the linear motor adopts a contactless magnetoelectric coupling design, and maintains a gas lubrication gap of 20-50 microns between its mover and stator. It not only forms a dynamic sealing layer through the viscous shear effect, but also uses the penetration characteristics of the magnetic field to realize the direct conversion of mechanical vibration energy and electrical energy. This non-contact transmission mechanism effectively eliminates the friction loss of traditional piston rings, giving the system a theoretical infinite cycle life. When the whole machine is running, the acoustic oscillation frequency of the thermoacoustic resonance cavity is precisely matched with the electromagnetic response frequency of the linear motor, forming a resonance enhancement effect of energy transfer and significantly improving the energy conversion efficiency.

[0046] Compared with traditional heat engines, this system has the advantages of streamlined structure (90% reduction in moving parts), efficiency breakthrough (theoretical Carnot efficiency reaches 40%-50%), maintenance-free operation (lifespan exceeds 100,000 hours) and high heat source adaptability (wide temperature range of 200-800℃). At the same time, the fully closed helium cycle achieves zero pollution emissions, which is particularly suitable for industrial waste heat recovery and aerospace energy systems.

[0047] The hot end heat exchanger 605 is connected to the fifth pipeline 5, and the cold end heat exchanger 606 is connected to the sixth pipeline 7. When working, the regenerator 604 absorbs heat and transfers it to the phase modulator 603 to convert it into power for the linear motor 602, thereby generating electrical output.

[0048] Example 6 like Figure 1 As shown, a combined heat and power method of the present invention integrating a fuel cell and waste heat recovery includes the control of the following three situations: (1) When working, the one-way valve 14 is closed first, and then the control unit controls the fuel cell 1 to start, and then opens the one-way valves 14 on the first pipeline 2 and the second pipeline 3. When the heat temperature that the heat storage device 4 can output is above 200°C, the one-way valves 14 on the fourth pipeline 9, the fifth pipeline 5, the sixth pipeline 7 and the first water supply pipe 11 are opened; If the temperature of the hot water outputted from the first water return pipe 13 is less than 60°C, the one-way valve 14 on the first water return pipe 13 is opened, and the hot water can be directly outputted to the outside through the second water return pipe 13, providing a heat source for the heating system and the hot water system, which is widely used in building heating and domestic hot water; If the temperature of the hot water output by the first return pipe 13 is greater than 60°C, the one-way valve 14 on the second water supply pipe 12, the second return pipe 21, the third water supply pipe 15 and the third return pipe 16 is opened, and the hot water is sent to the cooler 18 through the second water supply pipe 12 to exchange heat with the water sent by the third water supply pipe 15 and then sent back to the first water supply pipe 11 through the second return pipe 21. The hot water heated in the third water supply pipe 15 is sent out through the third return pipe 16 to be used for building heating or to provide domestic hot water to meet daily household or commercial needs.

[0049] (2) First, all the one-way valves 14 are closed, and then the control unit controls the fuel cell 1 to start, and then the one-way valves 14 on the first pipeline 2 and the second pipeline 3 are opened. When the temperature of the heat that can be output by the heat storage device 4 is not greater than 200°C and not less than 100°C, the one-way valves 14 on the third pipeline 8, the fourth pipeline 9 and the first water supply pipe 11 are opened; If the temperature of the hot water outputted from the first water return pipe 13 is less than 60°C, the one-way valve 14 on the first water return pipe 13 is opened, and the hot water can be directly outputted to the outside through the second water return pipe 13, providing a heat source for the heating system and the hot water system, which is widely used in building heating and domestic hot water; If the temperature of the hot water output by the first return pipe 13 is greater than 60°C, the one-way valve 14 on the second water supply pipe 12, the second return pipe 21, the third water supply pipe 15 and the third return pipe 16 is opened, and the hot water is sent to the cooler 18 through the second water supply pipe 12 to exchange heat with the water sent by the third water supply pipe 15 and then sent back to the first water supply pipe 11 through the second return pipe 21. The hot water heated in the third water supply pipe 15 is sent out through the third return pipe 16 for building heating or providing domestic hot water to meet daily household or commercial needs.

[0050] (3) All the one-way valves 14 are closed first, and then the control unit controls the fuel cell 1 to start, and then the one-way valves 14 on the first pipeline 2 and the second pipeline 3 are opened. When the temperature of the heat that can be output by the heat storage device 4 is lower than 100°C and not less than 60°C, the one-way valves 14 on the seventh pipeline 19, the eighth pipeline 20, the third water supply pipe 15 and the third water return pipe 16 are opened. The heat of the heat transfer medium in the seventh pipeline 19 and the eighth pipeline 20 is exchanged with the water in the third water supply pipe 15 and the third water return pipe 16, and then discharged through the third water return pipe 16 for building heating or providing domestic hot water to meet daily household or commercial needs.

Claims

1. A combined heat and power system integrating a fuel cell and waste heat recovery, characterized in that: It includes a fuel cell, a heat storage device, a thermoacoustic generator, a heat exchanger, a cooler and a control unit; the fuel cell is connected to the heat storage device through a first pipeline and a second pipeline, the heat storage device is connected to the waste heat inlet on the heat exchanger through a third pipeline, the heat storage device is connected to the waste heat outlet on the heat exchanger through a fourth pipeline, the heat storage device is connected to the thermoacoustic generator through a fifth pipeline, the thermoacoustic generator is connected to the waste heat inlet of the heat exchanger through a sixth pipeline, the heat storage device is connected to the cooler through a seventh pipeline and an eighth pipeline, the cooler is connected with a second water supply pipe, a second water return pipe, a third water supply pipe and a third water return pipe, the second water supply pipe is connected to the first water return port on the heat exchanger, the first water return port is connected to the first water return pipe, the second water return pipe is connected to the first water supply port on the heat exchanger, and the first water supply port is connected to the first water supply pipe; the control unit controls the operating states of the fuel cell, the heat storage device, the thermoacoustic generator, the heat exchanger and the cooler respectively.

2. The combined heat and power system integrating fuel cell and waste heat recovery according to claim 1, characterized in that: The heat storage device comprises a metal shell and a heat storage medium located in the metal shell; the heat storage medium is silica sand or a phase change material.

3. The combined heat and power system integrating fuel cell and waste heat recovery according to claim 2 is characterized in that: A heat insulation layer is arranged on the inner side of the metal shell.

4. The combined heat and power system integrating fuel cell and waste heat recovery according to claim 3 is characterized in that: The first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, the seventh pipeline, the eighth pipeline, the first water supply pipe, the first water return pipe, the second water supply pipe, the second water return pipe, the third water supply pipe and the third water return pipe are all provided with a one-way valve, and the control unit controls the operating status of the heat storage device, the thermoacoustic generator, the heat exchanger and the cooler by adjusting the opening and closing of the one-way valve.

5. The combined heat and power system integrating fuel cell and waste heat recovery according to claim 1, characterized in that: The heat conduction medium used by the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, the seventh pipeline and the eighth pipeline for heat conduction is air, carbon dioxide or water vapor.

6. The combined heat and power system integrating fuel cell and waste heat recovery according to claim 1, characterized in that: The cooler comprises a shell, a fan arranged in the shell and heat dissipation fins installed at the driving end of the fan.

7. The combined heat and power system integrating fuel cell and waste heat recovery according to claim 6, characterized in that: The thermoacoustic generator includes a box body and a hot-end heat exchanger, a cold-end heat exchanger, a phase modulator, a regenerator and a linear motor located inside the box body; the phase modulator is connected to the driving end of the linear motor, and the hot-end heat exchanger, the regenerator and the cold-end heat exchanger are connected in sequence and installed outside the phase modulator.

8. A combined heat and power method integrating fuel cells and waste heat recovery, using the combined heat and power system integrating fuel cells and waste heat recovery according to claim 7, characterized in that: According to different heat temperatures, step 1, step 2 or step 3 is adopted for implementation, including: Step 1, first close all the one-way valves, then the control unit controls the fuel cell to start, and then opens the one-way valves on the first pipeline and the second pipeline. When the heat temperature that the heat storage device can output is above 200°C, open the one-way valves on the fourth pipeline, the fifth pipeline, the sixth pipeline and the first water supply pipe; If the hot water temperature output from the first water return pipe is less than 60°C, open the one-way valve on the first water return pipe; If the temperature of the hot water output from the first water return pipe is greater than 60°C, open the one-way valves on the second water supply pipe, the second water return pipe, the third water supply pipe and the third water return pipe; Step 2, first close all the one-way valves, then the control unit controls the fuel cell to start, and then opens the one-way valves on the first pipeline and the second pipeline. When the heat temperature that the heat storage device can output is not greater than 200°C and not less than 100°C, open the one-way valves on the third pipeline, the fourth pipeline and the first water supply pipe; If the hot water temperature output from the first water return pipe is less than 60°C, open the one-way valve on the first water return pipe; If the temperature of the hot water output from the first water return pipe is greater than 60°C, open the one-way valves on the second water supply pipe, the second water return pipe, the third water supply pipe and the third water return pipe; Step 3, first close all the one-way valves, then the control unit controls the fuel cell to start, and then opens the one-way valves on the first pipeline and the second pipeline. When the heat temperature that the heat storage device can output is lower than 100°C and not less than 60°C, open the one-way valves on the seventh pipeline, the eighth pipeline, the third water supply pipe and the third return pipe.

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