Combined Heat and Power Generation System Integrating Fuel Cell and Waste Heat Recovery and Combined Heat and Power Generation Method

Abstract

The present invention belongs to the technical field of fuel cell waste heat recovery, and relates to a combined heat and power supply system integrating a fuel cell and waste heat recovery, including 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 to the input port of the heat storage device through a pipeline, and the output port of the heat storage device is respectively connected to the input ports of the thermoacoustic generator, the heat exchanger and the cooling module through pipelines, the output port of the thermoacoustic generator is connected to the input port of the heat exchanger through a pipeline, and the output port of the heat exchanger is connected to the input port of the cooling module; 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 cooling module respectively. The present invention also relates to a combined heat and power supply method integrating a fuel cell and waste heat recovery. The present invention constructs an efficient waste heat recovery and utilization system by integrating a fuel cell and a thermoacoustic engine.

Description

Technical Field

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

[0002] Solid oxide fuel cells (hereinafter simply referred to as fuel cells), as an efficient and environmentally friendly energy conversion device, have been widely used in recent years in the fields of distributed energy supply, combined heat and power supply, etc. During the operation of a fuel cell, the chemical energy of fuels such as hydrogen can be directly converted into electrical energy, and at the same time, a large amount of waste heat is generated. This waste heat, if not effectively recovered and utilized, will be wasted, reducing the energy utilization efficiency of the entire system. Therefore, in a fuel cell combined heat and power system, how to efficiently utilize these waste heat resources has become one of the key technical issues in current research and applications. However, there are various technical bottlenecks and practical problems in the waste heat utilization of existing fuel cell combined heat and power systems.

[0003] Currently, the waste heat utilization methods of most fuel cell combined heat and power systems are relatively single, usually using the waste heat for heating or providing domestic hot water through a simple heat exchange device. This single thermal energy utilization method severely limits the overall efficiency of the system. Especially for the medium-high temperature waste heat generated by fuel cells, if it is only used for heating or hot water production, there are often problems of low efficiency and excessive waste of thermal energy. In addition, the recovery efficiency of medium-low temperature waste heat is even lower, and it is difficult for existing technologies to achieve stepped utilization of medium-low temperature waste heat, resulting in the loss of a considerable part of potentially available energy.

[0004] In addition, in existing fuel cell systems, although there have been many studies on waste heat utilization technologies, most methods add various external devices, such as heat exchangers, hot water boilers, etc., on the basis of the original system. These devices are often bulky, complex to install, and have a low integration degree with the fuel cell system, resulting in an increase in the structural complexity of the entire system and an increase in the difficulty of maintenance and management. The coordinated operation between various 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 an increase in the failure rate and maintenance cost, limiting its wide promotion and application.

[0005] In addition, the electrical and thermal energy output by the fuel cell system fluctuates with the change of the working load. At high loads, the fuel cell generates sufficient surplus heat energy. However, due to the limitations of existing technologies, it is impossible to flexibly and efficiently allocate the thermal energy according to demand, resulting in waste of thermal energy. At low loads, the surplus heat is insufficient, and the existing waste heat utilization devices are also difficult to meet the actual usage requirements, thus affecting the stability and economy of the entire combined heat and power system. The existing system lacks effective thermal energy storage and peak shaving capabilities and cannot achieve balanced regulation of the combined heat and power output under different load conditions.

[0006] With the development of fuel cell technology, the complexity of the combined heat and power system is also increasing. The current fuel cell combined heat and power systems often lack advanced control units for real-time monitoring and management. Especially in terms of waste heat recovery and distribution, they lack the intelligent regulation ability under various working conditions. This not only leads to low system efficiency but also affects the lifespan and overall performance of the fuel cell. The lack of intelligence makes the optimization of waste heat utilization and power output relatively passive. It cannot be flexibly scheduled according to real-time demand changes and is difficult to achieve the efficient operation of the system.

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

[0008] In summary, the existing fuel cell combined heat and power systems have many deficiencies in terms of waste heat utilization efficiency, system integration complexity, energy balance regulation, and intelligent control. Summary of the Invention

[0009] The first object of the present invention is to provide a combined heat and power system integrating a fuel cell and waste heat recovery, which solves the problems of low waste heat utilization efficiency, system integration complexity, poor energy balance regulation, and insufficient intelligent control existing in the existing fuel cell combined heat and power systems. Through a hierarchical utilization method, it ensures that waste heat resources at different temperatures are most effectively utilized, avoids energy waste, and achieves high efficiency and energy conservation.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows: A combined heat and power supply system integrating a fuel cell and waste heat recovery, including 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, and 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 with a 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 with a 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:

[0012] The heat storage device includes a metal shell and a heat storage medium located inside the metal shell; the heat storage medium is silica sand or a phase change material.

[0013] An insulating layer is provided on the inner side of the metal shell.

[0014] 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.

[0015] 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.

[0016] The cooler includes a housing, a fan provided inside the housing, and heat dissipation fins installed at the driving end of the fan.

[0017] 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 sequentially connected and installed outside the phase modulator.

[0018] The second object of the present invention is to provide a combined heat and power supply method integrating a fuel cell and waste heat recovery, which solves the problems of low waste heat utilization efficiency, high system integration complexity, poor energy balance regulation, and insufficient intelligent control existing in the existing combined heat and power supply system of fuel cells. Through a hierarchical utilization method, waste heat resources at different temperatures are ensured to be utilized most effectively, energy waste is avoided, and high-efficiency energy conservation is achieved.

[0019] To achieve the above object, the technical solution adopted by the present invention is: a combined heat and power supply method integrating a fuel cell and waste heat recovery, which is implemented by adopting Step 1 or Step 2 or Step 3 according to different heat temperatures, and includes:

[0020] Step 1: First, close all check valves, then the control unit controls the fuel cell to start, and then open the check 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 check valves on the fourth pipeline, the fifth pipeline, the sixth pipeline, and the first water supply pipe;

[0021] If the hot water temperature output by the first return water pipe is less than 60 °C, open the check valve on the first return water pipe;

[0022] If the hot water temperature output by the first return water pipe is greater than 60 °C, open the check valves on the second water supply pipe, the second return water pipe, the third water supply pipe, and the third return water pipe;

[0023] Step 2: First, close all check valves, then the control unit controls the fuel cell to start, and then open the check 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 check valves on the third pipeline, the fourth pipeline, and the first water supply pipe;

[0024] If the hot water temperature output by the first return water pipe is less than 60 °C, open the check valve on the first return water pipe;

[0025] If the hot water temperature output by the first return water pipe is greater than 60 °C, open the check valves on the second water supply pipe, the second return water pipe, the third water supply pipe, and the third return water pipe;

[0026] Step 3: First, close all check valves, then the control unit controls the fuel cell to start, and then open the check 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 check valves on the seventh pipeline, the eighth pipeline, the third water supply pipe, and the third return water pipe.

[0027] The beneficial effects of the present invention are as follows: The combined heat and power supply system integrating the fuel cell and waste heat recovery of the present invention constructs an efficient waste heat recovery and utilization system by integrating a fuel cell and a thermoacoustic engine. First, the present invention utilizes the waste heat generated by the fuel cell. Through a multi-stage waste heat utilization system, this part of waste heat is flexibly applied to the needs such as domestic hot water supply and building heating, realizing the efficient recovery and distribution of waste heat. Second, 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, 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 the thermoelectric output and storage, optimizes the combined heat and power supply efficiency of the system, and realizes the maximization and flexibility of energy utilization. Brief Description of the Drawings

[0028] Figure 1 is a schematic structural diagram of a combined heat and power supply system integrating a fuel cell and waste heat recovery of the present invention;

[0029] Figure 2 is a schematic principle diagram of a combined heat and power supply system integrating a fuel cell and waste heat recovery of the present invention;

[0030] Figure 3 is Figure 1 the schematic principle diagram of the thermoacoustic generator in

[0031] In the figure: 1. Fuel cell, 2. First pipeline, 3. Second pipeline, 4. Heat storage device, 5. Fifth pipeline, 6. Thermoacoustic generator, 601. Box body, 602. Linear generator, 603. Phase shifter, 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. Check 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 Embodiments

[0032] The technical solutions of the present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0033] Embodiment 1

[0034] As Figure 1 shown, a combined heat and power supply system integrating a fuel cell and waste heat recovery of the present invention includes a fuel cell 1, a heat storage device 4, a thermoacoustic generator 6, a heat exchanger 10, a cooler 18 and a control unit.

[0035] The fuel cell 1 is connected to the heat storage device 4 through the first pipeline 2 as an input pipeline, and the fuel cell 1 is connected to the heat storage device 4 through 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 by a heat-conducting medium for heat exchange, and then the heat-conducting medium after heat exchange is re-input into the fuel cell 1 through the second pipeline 3 to extract heat again, so as to complete the heat exchange in the next cycle.

[0036] A plurality of waste heat inlets and a plurality of waste heat outlets are provided on the side of the heat storage device 4. One waste heat inlet and one waste heat outlet are provided on the side of the heat exchanger 10. 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 one 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 one waste heat inlet on the heat storage device 4.

[0037] One 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, one 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 one 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 water return port is connected to the third water return pipe 16.

[0038] 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. The first water supply port is connected to the first water supply pipe 11.

[0039] 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, and after heat exchange, it returns to the heat storage device 4 through the fourth pipeline. Cold water is introduced into the heat exchanger 10 through the first water supply pipe 11 to complete heat exchange, and then discharged in the form of hot water through the first water return pipe 13 to meet the needs of domestic hot water and heating. The first water supply pipe 11 adopts a spiral coil design to increase the length of the water flow path inside the heat exchanger 10, increase the heat exchange area, and improve the heat absorption efficiency.

[0040] 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 a heat-conducting medium.

[0041] One-way valves 14 are provided on 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. The control unit controls the operating states 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 valves 14, and directly controls the operating state of the fuel cell.

[0042] Combined with Figure 2 , during operation, the control unit controls the fuel cell 1 to work. The waste heat generated in the fuel cell 1 flows into the heat storage device 4 through the first pipeline 2. After heat exchange in the heat storage device, it flows back to the fuel cell 1 through the second pipeline 3 to extract heat again, so as to be transferred to the heat storage device 4 again for heat exchange, and heat exchange and heat extraction are cycled in this way. The control unit will classify 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 its temperature. Among them, the temperature of high-temperature waste heat refers to above 200 °C, medium-temperature waste heat is between 100 °C and 200 °C, and low-temperature waste heat is between 60 °C and 100 °C.

[0043] According to the different classifications of high-temperature waste heat, medium-temperature waste heat and low-temperature waste heat, the control unit will control a combined heat and power supply system integrating a fuel cell and waste heat recovery of the present invention to work in the following three situations:

[0044] (1) For high-temperature waste heat, first close the one-way valve 14 during operation, then the control unit controls the fuel cell 1 to start, and then open the one-way valves 14 on the first pipeline 2 and the second pipeline 3. When the temperature of the heat that the heat storage device 4 can output is above 200 °C, open 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;

[0045] If the temperature of the hot water output from the first water return pipe 13 is less than 60 °C, open the one-way valve 14 on the first water return pipe 13, and the hot water can be directly output through the second water return pipe 13 to provide heat sources for the heating system and the hot water system, and is widely used in building heating and domestic hot water;

[0046] If the temperature of the hot water output from the first water return pipe 13 is greater than 60 °C, open the one-way valves 14 on 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. The hot water is sent into the cooler 18 through the second water supply pipe 12 to exchange heat and cool down with the water sent by the third water supply pipe 15, and then is sent back to the first water supply pipe 11 through the second water return pipe 21. The hot water with increased temperature in the third water supply pipe 15 is then sent out through the third water return pipe 16 for building heating or providing domestic hot water to meet daily household or commercial needs.

[0047] (2) For medium-temperature waste heat, first close all check valves 14. Then, the control unit controls the fuel cell 1 to start. Next, open the check 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 check valves 14 on the third pipeline 8, the fourth pipeline 9, and the first water supply pipe 11.

[0048] If the hot water temperature output by the first return pipe 13 is less than 60 °C, open the check valve 14 on the first return pipe 13. The hot water can directly output hot water through the second return pipe 13 to provide heat sources for the heating system and the hot water system, and is widely used in building heating and domestic hot water.

[0049] If the hot water temperature output by the first return pipe 13 is greater than 60 °C, open the check valves 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. The hot water is sent into 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 is sent back to the first water supply pipe 11 through the second return pipe 21. The hot water with increased temperature in the third water supply pipe 15 is then sent out through the third return pipe 16 for building heating or providing domestic hot water to meet the daily household or commercial needs.

[0050] (3) For low-temperature waste heat, first close all check valves 14. Then, the control unit controls the fuel cell 1 to start. Next, open the check 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 lower than 100 °C and not less than 60 °C, open the check valves 14 on the seventh pipeline 19, the eighth pipeline 20, the third water supply pipe 15, and the third return pipe 16. After the heat of the heat-conducting medium in the seventh pipeline 19 and the eighth pipeline 20 exchanges heat with the water in the third water supply pipe 15 and the third return pipe 16, it is discharged through the third return pipe 16 for building heating or providing domestic hot water to meet the daily household or commercial needs.

[0051] This hierarchical utilization method ensures that waste heat resources at different temperatures are utilized most effectively, avoids energy waste, and realizes the high-efficiency energy conservation of the system.

[0052] Embodiment 2

[0053] As Figure 1 shown, different from Embodiment 1, in a combined heat and power supply system integrating a fuel cell and waste heat recovery of the present invention in Embodiment 2, the heat storage device 4 includes a metal shell and a heat storage medium located inside the metal shell. The heat storage medium is silica sand or a phase change material.

[0054] 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 through the pipelines, it can quickly exchange heat with the heat storage medium in the metal shell.

[0055] 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.

[0056] Example 3

[0057] 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.

[0058] By using air, carbon dioxide or water vapor as the heat transfer medium, heat exchange can be completed efficiently at a low cost.

[0059] Example 4

[0060] 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.

[0061] 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.

[0062] Example 5

[0063] 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.

[0064] The thermoacoustic generator 6 is an energy conversion device based on the thermoacoustic effect, which can convert thermal energy into acoustic energy and further drive a generator or other mechanical equipment through sound waves. This device is particularly suitable for the recovery of medium and high-temperature waste heat. Its working principle is to form acoustic wave vibrations at high temperatures, thereby further converting waste heat into mechanical energy or electrical energy. Through the thermoacoustic engine, the high-temperature waste heat generated by the fuel cell is reused, which not only improves the overall energy utilization rate of the system but also provides additional power output.

[0065] The thermoacoustic generator is a device that realizes the conversion of thermal energy into electrical energy based on the thermoacoustic effect. Its core consists of two major parts: a thermoacoustic engine and a linear motor. Helium or a helium-argon mixture is usually used as the high-pressure working medium inside the system. Among them, the thermoacoustic engine breaks through the structural limitations of traditional internal combustion engines and does not require mechanical components such as combustion chambers and valves. Instead, it forms a temperature gradient through heat exchangers at the high-temperature end and low-temperature end arranged along the resonance tube, stimulating the working gas to generate self-sustaining acoustic oscillations. The gas forms an alternating flow under the drive of acoustic pressure fluctuations, periodically undergoes compression-expansion thermodynamic processes, and at the same time exchanges sensible heat and latent heat with the heat exchanger, thereby converting the energy of the external heat source into high-intensity acoustic energy; the linear motor adopts a non-contact magnetoelectric coupling design, and there is a gas lubrication gap of 20-50 microns between its mover and stator. This not only forms a dynamic sealing layer through the viscous shear effect but also realizes the direct conversion of mechanical vibration energy and electrical energy by using the magnetic field penetration characteristic. This non-contact transmission mechanism effectively eliminates the frictional losses of traditional piston rings, giving the system a theoretically infinite cycle life. When the whole machine operates, the acoustic oscillation frequency of the thermoacoustic resonator 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.

[0066] Compared with traditional heat engines, this system has the advantages of a simple structure (reducing 90% of the moving parts), breakthrough efficiency (the theoretical Carnot efficiency reaches 40%-50%), maintenance-free operation (life exceeding 100,000 hours), and high heat source adaptability (a wide temperature range of 200-800°C). At the same time, the fully enclosed helium cycle achieves zero pollution emissions, making it particularly suitable for industrial waste heat recovery and aerospace energy systems.

[0067] 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. During operation, the regenerator 604 absorbs heat and transfers it to the phase modulator 603 to be converted into the power of the linear motor 602, generating electrical output.

[0068] Embodiment 6

[0069] As Figure 1 shown, a combined heat and power supply method integrating a fuel cell and waste heat recovery of the present invention includes the control of the following three situations:

[0070] (1) When working, first close the one-way valve 14, then the control unit controls the fuel cell 1 to start, and then open the one-way valves 14 on the first pipeline 2 and the second pipeline 3. When the temperature of the heat that the heat storage device 4 can output is above 200°C, then open 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;

[0071] If the temperature of the hot water output by the first return pipe 13 is less than 60°C, then open the one-way valve 14 on the first return pipe 13, and the hot water can be directly output through the first return pipe 13 to provide heat sources for the heating system and the hot water system, and is widely used in building heating and domestic hot water;

[0072] If the temperature of the hot water output by the first return pipe 13 is greater than 60°C, then open the one-way valves 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. The hot water is sent into the cooler 18 through the second water supply pipe 12 to exchange heat and cool down with the water sent by the third water supply pipe 15, and then is sent back to the first water supply pipe 11 through the second return pipe 21. The hot water with increased temperature 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 the daily household or commercial needs.

[0073] (2) First close all the one-way valves 14, then the control unit controls the fuel cell 1 to start, and then open the one-way valves 14 on the first pipeline 2 and the second pipeline 3. When the temperature of the heat that the heat storage device 4 can output is not greater than 200°C and not less than 100°C, then open the one-way valves 14 on the third pipeline 8, the fourth pipeline 9 and the first water supply pipe 11;

[0074] If the temperature of the hot water output by the first return pipe 13 is less than 60°C, then open the one-way valve 14 on the first return pipe 13, and the hot water can be directly output through the first return pipe 13 to provide heat sources for the heating system and the hot water system, and is widely used in building heating and domestic hot water;

[0075] If the temperature of the hot water output by the first return pipe 13 is greater than 60°C, then open the one-way valves 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. The hot water is sent into the cooler 18 through the second water supply pipe 12 to exchange heat and cool down with the water sent by the third water supply pipe 15, and then is sent back to the first water supply pipe 11 through the second return pipe 21. The hot water with increased temperature 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 the daily household or commercial needs.

[0076] (3) First, close all the one-way valves 14. Then, the control unit controls the fuel cell 1 to start. Next, open the one-way valves 14 on the first pipeline 2 and the second pipeline 3. When the temperature of the heat that the heat storage device 4 can output is lower than 100 °C and not less than 60 °C, open 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. After the heat of the heat transfer medium in the seventh pipeline 19 and the eighth pipeline 20 exchanges heat with the water in the third water supply pipe 15 and the third water return pipe 16, it is discharged through the third water return pipe 16 for building heating or providing domestic hot water to meet the daily household or commercial needs.

Claims

1. A combined heat and power system integrating fuel cells 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 cell and waste heat recovery, using the combined heat and power system integrating fuel cell 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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