Temperature control system and method for hydrogen fuel cell waste heat recovery and generated water utilization

Abstract

A temperature control system and method for recovering waste heat and utilizing generated water from a hydrogen fuel cell include a hydrogen fuel cell cascade waste heat recovery unit and a building heating unit, which exchange heat through a first temperature control unit; the first temperature control unit controls the flow direction of generated water and cooling water based on the cooling water outlet temperature and the municipal hot water supply temperature measured by a first temperature sensor and a second temperature sensor, thereby controlling the heating temperature; the hydrogen fuel cell cascade waste heat recovery unit includes a second temperature control unit and a third temperature control unit, which further adjusts the cooling temperature of the fuel cell stack by controlling the opening of a fifth electromagnetic three-way valve and the heater of a second water tank; the system simultaneously utilizes the heat of the generated water and cooling water of the hydrogen fuel cell, realizes cascade waste heat recovery, and thus reduces energy waste in the hydrogen fuel cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen energy utilization and thermal management, and relates to a temperature control system and method for recovering waste heat and utilizing generated water in a hydrogen fuel cell. Background Art

[0002] Hydrogen fuel cells (proton exchange membrane fuel cells) are a clean energy technology that directly generates electricity through the electrochemical reaction of hydrogen and oxygen. During operation, hydrogen fuel cells release significant heat. While appropriately increasing the operating temperature can enhance the electrochemical activity of hydrogen fuel cells, excessively high temperatures can cause dehydration and cracking of the proton exchange membrane, thereby affecting cell performance. Therefore, a precise thermal management system is crucial to maintaining efficient and stable battery operation.

[0003] During the power generation process, hydrogen fuel cells convert only a portion of their chemical energy into electricity, while the majority is dissipated as heat. While current cooling systems can maintain a stable stack temperature, they are inefficient in recovering this heat. This situation urgently needs to be addressed through optimized thermal management systems and the development of new waste heat recovery technologies to achieve truly efficient cogeneration and raise the system's overall energy efficiency to an ideal level of over 80%.

[0004] At present, existing methods include: Patent publication number CN116031436A discloses a household hydrogen fuel cell heat recovery system and method, which directly uses the stack cooling water with waste heat as the user's domestic hot water, and uses deionized user cold water as the cooling water inlet of the stack, avoiding heat loss caused by secondary heat exchange using a heat exchanger; and Chinese patent CN117832537A provides a waste heat recovery device for a fuel cell system, which uses a spray method to maintain the temperature difference between the hot end and the cold end of the semiconductor power generation, thereby reducing the overall heat dissipation energy consumption of the fuel cell system and maximizing the secondary utilization of the waste heat of the fuel cell system; in addition, utility model patent publication number CN220543961U discloses a waste heat recovery system based on hydrogen fuel cell cogeneration, which smoothly transfers the waste heat generated by the PEM fuel cell through the waste heat recovery system formed by coupling the cooling system and the waste heat recovery subsystem, thereby realizing the overall collection and redistribution of the waste heat.

[0005] In summary, although existing technologies have achieved waste heat recovery in hydrogen fuel cells, the following problems still exist:

[0006] ① Ignoring the effective use of water heat energy generated by hydrogen fuel cells, resulting in energy waste;

[0007] ② The use of cooling water for hydrogen fuel cells is limited to a single scenario, resulting in energy waste when high-temperature waste heat is directly used for low-temperature needs;

[0008] ③ The optimal cooling temperature range and cascade utilization of energy of hydrogen fuel cells are not fully considered, which limits the battery performance and service life. Summary of the Invention

[0009] In order to solve the deficiencies in the prior art, the present invention addresses the problems of waste of generated water and cooling water heat energy and uncontrollable cooling temperature of hydrogen fuel cells in existing hydrogen fuel cell waste heat recovery methods, and proposes a temperature control system and method for hydrogen fuel cell waste heat recovery and generated water utilization. The cascade recovery and utilization of cooling water waste heat not only improves the hydrogen fuel cell waste heat recovery rate and energy utilization rate, but also avoids the risk of damage caused by direct contact of cooling water to the human body; at the same time, the generated water of hydrogen fuel cells is converted into domestic hot water supply, which reduces the water cost of buildings compared with the traditional direct discharge mode; in addition, the heating temperature control method and the stack cooling temperature control method are adopted to respond to the control strategy in time with changes in external temperature, so that the heating temperature and the stack cooling temperature are always in the optimal temperature control range, ensuring precise temperature control.

[0010] The present invention adopts the following technical solutions. On one hand, the present invention provides a temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization, including a hydrogen fuel cell waste heat cascade recovery unit and a building heating unit;

[0011] The hydrogen fuel cell waste heat cascade recovery unit utilizes cooling water and water generated by the hydrogen fuel cell, and controls the electromagnetic three-way valve group set on the pipeline based on the temperature control unit to perform cascade heat recovery, thereby realizing domestic hot water supply, domestic hot water replenishment, and municipal pipeline cold water recovery, and providing the required heat for the building heating unit.

[0012] Preferably, the hydrogen fuel cell waste heat cascade recovery unit includes a hydrogen fuel cell stack, a cascade heat exchanger and an electromagnetic three-way valve group; the cascade heat exchanger includes a first heat exchanger, a second heat exchanger and a third heat exchanger;

[0013] The cooling water of the fuel cell stack exchanges heat with tap water through the first heat exchanger to achieve domestic hot water supply;

[0014] After the generated water of the fuel cell stack passes through the first electromagnetic three-way valve, one path is mixed with the cooling water after heat exchange in the first heat exchanger and then flows into the second electromagnetic three-way valve, and the other path is used to provide domestic hot water supply;

[0015] The generated water and cooling water of the fuel cell stack are mixed and passed through the second electromagnetic three-way valve. One path is passed through the second heat exchanger for heat exchange with the hot water supply from the municipal pipeline. The other path is mixed with the hot water from the municipal pipeline after heat exchange and then passed through the third heat exchanger to provide heat for the building heating unit.

[0016] Preferably, after the hot water in the hydrogen fuel cell waste heat cascade recovery unit passes through the third heat exchanger and the third electromagnetic three-way valve, one path is recovered as cold water in the municipal pipeline network, and the other path is mixed with the hot water after passing through the second heat exchanger through the fourth electromagnetic three-way valve, and then flows into the stack cooling water inlet through the stack cooling water inlet pipe.

[0017] Preferably, a first temperature sensor is provided at the input end of the hot side of the second heat exchanger to obtain the cooling water outlet temperature; a second temperature sensor is provided at the input end of the cold side of the second heat exchanger to obtain the hot water supply temperature of the municipal pipe network;

[0018] The first temperature control unit compares the values ​​of the cooling water outlet temperature, the hot water supply temperature of the municipal pipeline network, and the temperature required for user heating, and controls the opening and closing of the first electromagnetic three-way valve, the second electromagnetic three-way valve, and the third electromagnetic three-way valve to realize domestic hot water replenishment and municipal pipeline cold water recovery, and provide the building heating unit with the heat required for user heating.

[0019] Preferably, the stack cooling water inlet pipeline includes a fifth electromagnetic three-way valve, a first water pump, a second water tank, a second water pump and a first deionizer;

[0020] The hot water after passing through the second heat exchanger is mixed through the fourth electromagnetic three-way valve, then mixed with the user's cold water supply through the fifth electromagnetic three-way valve, and then flows into the second water tank through the first water pump. The cooling water flowing out of the second water tank flows into the first deionizer through the second water pump to remove ionic impurities in the water. The cooling water after impurities are removed flows into the cooling water inlet of the fuel cell stack.

[0021] A heater is provided in the second water tank for heating the water flowing into the second water tank.

[0022] Preferably, the output end of the fifth electromagnetic three-way valve is provided with a third temperature sensor for obtaining the temperature of the outlet of the fifth electromagnetic three-way valve; the outlet of the second water tank is provided with a fourth temperature sensor for obtaining the temperature of the outlet of the second water tank;

[0023] The temperature at the outlet of the fifth electromagnetic three-way valve is compared with the cooling temperature of the cooling water through the second temperature control unit, and the temperature at the outlet of the second water tank is compared with the cooling temperature of the cooling water through the third temperature control unit; based on the two comparison results, the opening of the fifth electromagnetic three-way valve is jointly controlled to achieve fuel cell stack cooling.

[0024] Preferably, the building heating unit comprises a first gate valve, a second gate valve, a water distributor and a water collector;

[0025] The return water from heating users is collected through the water collector and flows into the third heat exchanger through the second gate valve for heat exchange; the hot water obtained after heat exchange is diverted to different heating users through the first gate valve and the water distributor to achieve heating.

[0026] Another aspect of the present invention provides a temperature control method for recovering waste heat and utilizing generated water from a hydrogen fuel cell, using a temperature control system for recovering waste heat and utilizing generated water from a hydrogen fuel cell, comprising:

[0027] The first temperature control unit obtains the cooling water outlet temperature in real time and municipal hot water supply temperature , combined with 、 and the temperature required for heating by the user , controlling the opening and closing of the first electromagnetic three-way valve, the second electromagnetic three-way valve and the third electromagnetic three-way valve by a heating temperature control method;

[0028] The second temperature control unit obtains the temperature of the outlet of the fifth electromagnetic three-way valve in real time The third temperature control unit obtains the actual temperature of the stack cooling water inlet in real time ; Combine 、 and the cooling temperature of the stack , the opening of the fifth electromagnetic three-way valve is controlled by the stack cooling temperature control method.

[0029] Preferably, according to and 、 , controls the opening and closing of the outlet of the first electromagnetic three-way valve at the cooling water outlet pipe, and determines whether the water flowing into the second electromagnetic three-way valve is cooling water;

[0030] when When the stack cooling water outlet flows directly into the second electromagnetic three-way valve;

[0031] when or When the stack is turned on, the generated water is combined with the cooling water outlet through the first electromagnetic three-way valve and then flows into the second electromagnetic three-way valve.

[0032] Preferably, the heating temperature control method is:

[0033] Compare 、 The value of controls the opening and closing of the outlets of the second and third electromagnetic three-way valves, determines whether to supply hot water to the municipal pipe network, and selects different heat exchangers for heat exchange;

[0034] when When the water flows out of the second electromagnetic three-way valve, it enters the third heat exchanger for heat exchange to supplement the heat required by the heating user. The water after heat exchange is used to cool the fuel cell stack.

[0035] when When the water flowing out of the second electromagnetic three-way valve enters the second heat exchanger to exchange heat with the hot water supplied by the municipal pipe network; the water after heat exchange enters the third heat exchanger to exchange heat, realizing the cold water recovery of the municipal pipe network and providing the heat required by heating users;

[0036] when When the water flowing out of the second electromagnetic three-way valve merges with the hot water supplied by the municipal pipe network, it enters the third heat exchanger for heat exchange to supplement the heat required by heating users. The water after heat exchange is used to cool the fuel cell stack.

[0037] Preferably, the stack cooling temperature control method includes:

[0038] Step 4.1, compare the temperature at the outlet of the fifth electromagnetic three-way valve and the cooling temperature of the stack ;when When the user's cold water supply is open, increase the opening of the fifth electromagnetic three-way valve inlet until When , no longer adjust the opening; when When the valve is opened, increase the opening of the fifth electromagnetic three-way valve inlet at the outlet of the fourth three-way valve until When , no longer adjust the opening;

[0039] Step 4.2: Compare the actual temperature of the stack cooling water inlet and the cooling temperature of the stack ;when When the user's cold water supply is open, increase the opening of the fifth electromagnetic three-way valve inlet until , return to step 4.1; when The heater heats until Stop heating.

[0040] Compared with the prior art, the beneficial effects of the present invention include at least:

[0041] (1) The hydrogen fuel cell waste heat cascade recovery unit of the present invention adopts a hierarchical strategy of "first-level domestic hot water supply and second-level building heating supply", and the building heating supply adopts different heat recovery methods according to the cooling water temperature and the municipal pipe network hot water temperature. It not only improves the hydrogen fuel cell waste heat recovery rate and energy utilization rate, but also can stably output high-temperature hot water to meet the domestic hot water supply and building heating needs in extremely cold areas and cold regions, reducing heat energy waste.

[0042] (2) The present invention recycles all the water generated by the hydrogen fuel cell and converts it into domestic hot water supply, and supplements the heat of the building heating unit through the first temperature control unit, thereby reducing the current heat waste of the water generated by the hydrogen fuel cell.

[0043] (3) The present invention adopts a heating temperature control method and a stack cooling temperature control method, which responds to the control strategy in a timely manner as the external temperature changes, so that the heating temperature and the stack cooling temperature are always within the optimal temperature control range, ensuring precise temperature control and solving the performance degradation and life reduction of hydrogen fuel cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the structure of the temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization provided by the present invention;

[0045] Figure 2 A flow chart of the user heating temperature control method provided by the present invention;

[0046] Figure 3 This is a flow chart of the stack cooling temperature control method provided by the present invention.

[0047] Description of the drawings: a-hydrogen fuel cell waste heat cascade recovery unit, b-building heating unit, 1-fuel cell stack, 2-first heat exchanger, 3-filter, 4-first water tank, 5-first electromagnetic three-way valve, 6-second electromagnetic three-way valve, 7-first temperature sensor, 8-second heat exchanger, 9-third heat exchanger, 10-second temperature sensor, 11-electric gate valve, 12-third electromagnetic three-way valve, 13-fourth electromagnetic three-way valve, 14-fifth electromagnetic three-way valve, 15-third temperature sensor, 16-first water pump, 17-second water tank, 18-heater, 19-fourth temperature sensor, 20-second water pump, 21-electromagnetic flowmeter, 22-first deionizer, 23-second deionizer, 24-first gate valve, 25-second gate valve, 26-water distributor, 27-water collector. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] The present invention provides a temperature control system and method for recovering waste heat and utilizing generated water from hydrogen fuel cells. The cascaded recovery and utilization of cooling water waste heat not only improves the waste heat recovery rate and energy utilization rate of the hydrogen fuel cell, but also avoids the risk of damage caused by direct contact of hydrogen fuel cell cooling water with the human body; the generated water from the hydrogen fuel cell is converted into domestic hot water for replenishment, which reduces the cost of building water use compared to the traditional direct discharge mode; the heating temperature control method and the stack cooling temperature control method are adopted, and the system responds to the control strategy in time with changes in external temperature, so that the heating temperature and the stack cooling temperature are always within the optimal temperature control range, ensuring precise temperature control.

[0050] In order to better understand the technical solution of the present application, the above technical solution will be described in detail below in conjunction with the accompanying drawings in the specification and the specific implementation method.

[0051] Example 1

[0052] like Figure 1 As shown, this embodiment discloses a temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization, including a hydrogen fuel cell waste heat cascade recovery unit a and a building heating unit b.

[0053] Furthermore, the hydrogen fuel cell waste heat cascade recovery unit a uses cooling water and hydrogen fuel cell generated water, and based on the temperature control unit controls the electromagnetic three-way valve group installed on the pipeline to perform cascade heat recovery, thereby realizing domestic hot water supply, domestic hot water replenishment, and municipal pipeline cold water recovery, and providing the required heat for the building heating unit b.

[0054] Furthermore, the hydrogen fuel cell waste heat cascade recovery unit a includes a hydrogen fuel cell stack 1, a cascade heat exchanger and an electromagnetic three-way valve group; the cascade heat exchanger includes a first heat exchanger 2, a second heat exchanger 8 and a third heat exchanger 9;

[0055] The cooling water of the stack 1 exchanges heat with tap water through the first heat exchanger 2 to provide domestic hot water;

[0056] The generated water from the fuel cell stack 1 flows through the filter 3 into the first water tank 4. The generated water output from the first water tank 4 passes through the first electromagnetic three-way valve 5. One path is mixed with the cooling water after heat exchange in the first heat exchanger 2 and then flows into the second electromagnetic three-way valve 6. The other path is used to provide domestic hot water supply.

[0057] After the generated water and cooling water of the fuel cell stack 1 are mixed and pass through the second electromagnetic three-way valve 6, one path passes through the second heat exchanger 8 to exchange heat with the hot water supply of the municipal pipeline network, and the other path is mixed with the hot water of the municipal pipeline network after heat exchange and then passes through the third heat exchanger 9 to provide heat for the building heating unit b.

[0058] Furthermore, after the hot water in the hydrogen fuel cell waste heat cascade recovery unit a passes through the third heat exchanger 9 and the third electromagnetic three-way valve 12, one path is recovered as cold water in the municipal pipeline network, and the other path is mixed with the hot water after passing through the second heat exchanger 8 through the fourth electromagnetic three-way valve 13, and then flows into the cooling water inlet of the fuel cell stack 1 through the fuel cell stack cooling water inlet pipe.

[0059] Furthermore, a first temperature sensor 7 is provided at the input end of the hot side of the second heat exchanger 8 to obtain the outlet temperature of the cooling water; a second temperature sensor 10 is provided at the input end of the cold side of the second heat exchanger 8 to obtain the hot water supply temperature of the municipal pipe network;

[0060] The first temperature control unit compares the values ​​of the cooling water outlet temperature, the hot water supply temperature of the municipal pipeline network, and the temperature required for user heating, and controls the opening and closing of the first electromagnetic three-way valve 5, the second electromagnetic three-way valve 6 and the third electromagnetic three-way valve 12 to realize the supply of domestic hot water and the recovery of cold water from the municipal pipeline network, and provide the building heating unit b with the heat required for user heating.

[0061] In this embodiment, the following three optional implementation methods are provided to achieve cascade heat recovery; specifically, they include:

[0062] In the first embodiment, the water flowing out of the second electromagnetic three-way valve 6 directly enters the third heat exchanger 9 for heat exchange, providing the heat required for heating the building heating unit b. The heat-exchanged water passes through the third electromagnetic three-way valve 12 and is used to cool the fuel cell stack.

[0063] In the second embodiment, the water flowing out of the second electromagnetic three-way valve 6 enters the second heat exchanger 8 for heat exchange with hot water supplied by the municipal pipe network; the heat-exchanged water enters the third heat exchanger 9 for heat exchange, providing the heat required for heating the user in the building heating unit b; the heat-exchanged water in the third heat exchanger 9 passes through the third electromagnetic three-way valve 12 to realize the recovery of cold water from the municipal pipe network;

[0064] In the third embodiment, the water flowing out of the second electromagnetic three-way valve 6 merges with the hot water supplied by the municipal pipe network, enters the third heat exchanger 9 for heat exchange, and provides the building heating unit b with the heat required for user heating; the water after heat exchange passes through the third electromagnetic three-way valve 12 and is used for cooling the fuel cell stack.

[0065] Furthermore, the cooling water inlet pipeline of the fuel cell stack 1 includes a fifth electromagnetic three-way valve 14, a first water pump 16, a second water tank 17, a second water pump 20, an electromagnetic flowmeter 21 and a first deionizer 22;

[0066] The hot water after passing through the second heat exchanger 8 is mixed through the fourth electromagnetic three-way valve 13, and then mixed with the user's cold water supply through the fifth electromagnetic three-way valve 14. It then flows into the second water tank 17 through the first water pump 16. The cooling water flowing out of the second water tank 17 flows into the first deionizer 22 through the second water pump 20 and the electromagnetic flowmeter 21 to remove ionic impurities in the water. The cooling water after impurities are removed flows into the cooling water inlet of the fuel cell stack 1.

[0067] A heater 18 is provided in the second water tank 17 for heating the water flowing into the second water tank.

[0068] Furthermore, a third temperature sensor 15 is provided at the output end of the fifth electromagnetic three-way valve 14 for obtaining the temperature of the outlet of the fifth electromagnetic three-way valve 14; a fourth temperature sensor 19 is provided at the outlet of the second water tank 17 for obtaining the temperature of the outlet of the second water tank 17;

[0069] The temperature at the outlet of the fifth electromagnetic three-way valve 14 is compared with the cooling temperature of the cooling water through the second temperature control unit, and the temperature at the outlet of the second water tank 17 is compared with the cooling temperature of the cooling water through the third temperature control unit; based on the two comparison results, the opening of the fifth electromagnetic three-way valve 14 is jointly controlled to achieve fuel cell stack cooling.

[0070] Furthermore, the building heating unit b includes a first gate valve 24, a second gate valve 25, a water distributor 26 and a water collector 27;

[0071] The return water from the heating users is collected by the water collector 27 and flows into the third heat exchanger 9 through the second gate valve 25 for heat exchange; the hot water obtained after heat exchange passes through the first gate valve 24 and the water distributor 26 and is diverted to different heating users to achieve heating.

[0072] Example 2

[0073] This embodiment discloses a temperature control method for recovering waste heat and utilizing generated water from a hydrogen fuel cell, including:

[0074] The first temperature control unit obtains the cooling water outlet temperature in real time through the first temperature sensor 7 and the second temperature sensor 10 and municipal hot water supply temperature , see Figure 1 ; Combine 、 and the temperature required for heating by the user , the opening and closing of the first electromagnetic three-way valve 5, the second electromagnetic three-way valve 6 and the third electromagnetic three-way valve 12 are controlled by the heating temperature control method.

[0075] Further, see Figure 1 and Figure 2 , heating temperature control methods include:

[0076] according to and 、 , controls the opening and closing of the outlet of the first electromagnetic three-way valve at the cooling water outlet pipe, and determines whether the water flowing into the second electromagnetic three-way valve is cooling water;

[0077] when When the outlet C of the first electromagnetic three-way valve 5 is closed, the cooling water outlet of the stack 1 flows directly into the second electromagnetic three-way valve 6;

[0078] when or When , the outlet C of the first electromagnetic three-way valve 5 is opened; the generated water of the fuel cell stack 1 merges with the cooling water outlet through the first electromagnetic three-way valve 5 and then flows into the second electromagnetic three-way valve 6.

[0079] Furthermore, comparison 、 The numerical value of controls the opening and closing of the outlets of the second electromagnetic three-way valve 6 and the third electromagnetic three-way valve 7, determines whether to supply hot water to the municipal pipe network, and selects different heat exchangers for heat exchange;

[0080] when At this time, outlet C of the second electromagnetic three-way valve 6 is closed and outlet B is opened; the electric gate valve 11 is closed; outlet C of the third electromagnetic three-way valve 12 is opened and outlet B is closed; inlet C of the fourth electromagnetic three-way valve 13 is opened and inlet B is closed; the water flowing out of the second electromagnetic three-way valve 6 enters the third heat exchanger 9 for heat exchange, replenishing the heat required by the heating user, and the heat-exchanged water is used to cool the fuel cell stack;

[0081] when At this time, outlet C of the second electromagnetic three-way valve 6 is opened and outlet B is closed, the electric gate valve 11 is opened, outlet C of the third electromagnetic three-way valve 12 is closed and outlet B is opened, and inlet C of the fourth electromagnetic three-way valve 13 is closed and inlet B is opened; the water flowing out of the second electromagnetic three-way valve 6 enters the second heat exchanger 8 to exchange heat with hot water supplied by the municipal pipe network; the water after heat exchange enters the third heat exchanger 9 for heat exchange, realizing the cold water recovery of the municipal pipe network and providing the heat required by heating users;

[0082] when At this time, outlet C of the second electromagnetic three-way valve 6 is closed and outlet B is opened, the electric gate valve 11 is opened, outlet C of the third electromagnetic three-way valve 12 is opened and outlet B is closed, and inlet C of the fourth electromagnetic three-way valve 13 is opened and inlet B is closed; the water flowing out of the second electromagnetic three-way valve 6 is combined with the hot water supplied by the municipal pipeline network, and then enters the third heat exchanger 9 for heat exchange to supplement the heat required by heating users. The water after heat exchange is used to cool the fuel cell stack.

[0083] Furthermore, the second temperature control unit obtains the temperature of the outlet of the fifth electromagnetic three-way valve 14 in real time through the third temperature sensor 15. , see Figure 1 The third temperature control unit obtains the temperature of the outlet of the second water tank 17, that is, the actual temperature of the stack cooling water inlet, in real time through the fourth temperature sensor 19. ; Combine 、 and the cooling temperature of stack 1 , the opening of the fifth electromagnetic three-way valve 14 is controlled by the stack cooling temperature control method.

[0084] Further, see Figure 3 The stack cooling temperature control method of step 4 includes the following steps:

[0085] Step 4.1, compare the temperature at the outlet of the fifth electromagnetic three-way valve 14 and the cooling temperature of the stack ;when When the user's cold water supply is increased, the opening of the fifth electromagnetic three-way valve 14 inlet is increased to increase the user's cold water volume until When , no longer adjust the opening; when When the opening of the fifth electromagnetic three-way valve 14 at the outlet of the fourth three-way valve 13 is increased, the amount of water after the cooling water heat exchange is increased until When , no longer adjust the opening;

[0086] Step 4.2: Compare the actual temperature of the stack cooling water inlet and the cooling temperature of the stack ;when When the user's cold water supply is opened, increase the opening of the fifth electromagnetic three-way valve 14 inlet until , return to step 4.1; when When the heater 18 is heated, Stop heating.

[0087] Furthermore, the valve opening control process of the electromagnetic three-way valve includes:

[0088] Obtain the inlet temperature and inlet flow of the two inlets of the electromagnetic three-way valve and the valve opening of the inlet of the valve to be regulated ; Construct the valve flow-opening relationship function, the specific formula is:

[0089] ;

[0090] Where, Indicates valve flow rate in m³ / h; Indicates the flow coefficient when the valve is at its maximum opening, which is calibrated by the valve factory test; Indicates valve opening Flow coefficient when Indicates the pressure difference before and after the valve, in bar; Indicates the index weight coefficient, which is calibrated by the valve factory test;

[0091] Combined with the law of conservation of heat, the flow rate ratio of the valve inlet to be regulated before and after regulation is calculated. The specific formula is expressed as:

[0092] ;

[0093] ;

[0094] ;

[0095] Where, and Respectively represent the inlet flow of the two inlets of the electromagnetic three-way valve; Indicates outlet temperature; and Respectively represent the inlet temperatures of the two inlets of the electromagnetic three-way valve; Indicates the inlet flow rate of the valve to be regulated after the opening is regulated; Indicates the target temperature. In this embodiment ; Indicates the flow rate ratio of the valve inlet to be regulated before and after regulation;

[0096] According to the valve flow-opening relationship function and the flow ratio of the inlet of the valve to be regulated before and after regulation, the valve opening of the inlet of the valve to be regulated after regulation is calculated. The specific formula is:

[0097] ;

[0098] Where, Indicates the valve opening at the inlet of the valve to be regulated after regulation; Represents the logarithmic function.

[0099] In this embodiment, when hour, Indicates the outlet temperature, the inlet C of the fifth electromagnetic three-way valve 14 is the inlet of the valve to be regulated; when hour, Indicates the outlet temperature, the inlet B of the fifth electromagnetic three-way valve 14 is the inlet of the valve to be regulated; when hour, Indicates the outlet temperature, and the inlet C of the fifth electromagnetic three-way valve 14 is the inlet of the valve to be regulated.

[0100] Compared with the prior art, the beneficial effects of the present invention include at least:

[0101] (1) The hydrogen fuel cell waste heat cascade recovery unit of the present invention adopts a hierarchical strategy of "first-level domestic hot water supply and second-level building heating supply", and the building heating supply adopts different heat recovery methods according to the cooling water temperature and the municipal pipe network hot water temperature. It not only improves the hydrogen fuel cell waste heat recovery rate and energy utilization rate, but also can stably output high-temperature hot water to meet the domestic hot water supply and building heating needs in extremely cold areas and cold regions, reducing heat energy waste.

[0102] (2) The present invention recycles all the water generated by the hydrogen fuel cell and converts it into domestic hot water supply, and supplements the heat of the building heating unit through the first temperature control unit, thereby reducing the current heat waste of the water generated by the hydrogen fuel cell.

[0103] (3) The present invention adopts a heating temperature control method and a stack cooling temperature control method, which responds to the control strategy in a timely manner as the external temperature changes, so that the heating temperature and the stack cooling temperature are always within the optimal temperature control range, ensuring precise temperature control and solving the performance degradation and life reduction of hydrogen fuel cells.

[0104] The present disclosure may be a system, method and / or computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization, including a hydrogen fuel cell waste heat cascade recovery unit and a building heating unit, characterized by: The hydrogen fuel cell waste heat cascade recovery unit utilizes cooling water and hydrogen fuel cell generated water, and based on the temperature control unit controls the electromagnetic three-way valve group set on the pipeline to perform cascade heat recovery, thereby realizing domestic hot water supply, domestic hot water replenishment, and municipal pipe network cold water recovery, and providing the required heat for the building heating unit; The hydrogen fuel cell waste heat cascade recovery unit includes a hydrogen fuel cell stack, a cascade heat exchanger and an electromagnetic three-way valve group; the cascade heat exchanger includes a first heat exchanger, a second heat exchanger and a third heat exchanger; The cooling water of the fuel cell stack exchanges heat with tap water through the first heat exchanger to achieve domestic hot water supply; After the generated water of the fuel cell stack passes through the first electromagnetic three-way valve, one path is mixed with the cooling water after heat exchange in the first heat exchanger and then flows into the second electromagnetic three-way valve, and the other path is used to provide domestic hot water supply; After the generated water and cooling water of the fuel cell stack are mixed and pass through the second electromagnetic three-way valve, one path is passed through the second heat exchanger to exchange heat with the hot water supply of the municipal pipeline network, and the other path is mixed with the hot water of the municipal pipeline network after heat exchange and then passes through the third heat exchanger to provide heat for the building heating unit.

2. The temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization according to claim 1 is characterized in that: After passing through the third heat exchanger and the third electromagnetic three-way valve, the hot water in the hydrogen fuel cell waste heat cascade recovery unit is recovered as cold water in the municipal pipeline network in one way, and the other way is mixed with the hot water after passing through the second heat exchanger through the fourth electromagnetic three-way valve, and then flows into the stack cooling water inlet through the stack cooling water inlet pipe.

3. The temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization according to claim 2 is characterized in that: The input end of the hot side of the second heat exchanger is provided with a first temperature sensor to obtain the cooling water outlet temperature; the input end of the cold side of the second heat exchanger is provided with a second temperature sensor to obtain the hot water supply temperature of the municipal pipe network; The first temperature control unit compares the values ​​of the cooling water outlet temperature, the hot water supply temperature of the municipal pipeline network, and the temperature required for user heating, and controls the opening and closing of the first electromagnetic three-way valve, the second electromagnetic three-way valve, and the third electromagnetic three-way valve to realize domestic hot water replenishment and municipal pipeline cold water recovery, and provide the building heating unit with the heat required for user heating.

4. The temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization according to claim 2 is characterized in that: The stack cooling water inlet pipeline includes a fifth electromagnetic three-way valve, a first water pump, a second water tank, a second water pump and a first deionizer; The hot water after passing through the second heat exchanger is mixed through the fourth electromagnetic three-way valve, then mixed with the user's cold water supply through the fifth electromagnetic three-way valve, and then flows into the second water tank through the first water pump. The cooling water flowing out of the second water tank flows into the first deionizer through the second water pump to remove ionic impurities in the water. The cooling water after impurities are removed flows into the cooling water inlet of the fuel cell stack. A heater is provided in the second water tank for heating the water flowing into the second water tank.

5. The temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization according to claim 4 is characterized in that: The output end of the fifth electromagnetic three-way valve is provided with a third temperature sensor for obtaining the temperature of the outlet of the fifth electromagnetic three-way valve; the outlet of the second water tank is provided with a fourth temperature sensor for obtaining the temperature of the outlet of the second water tank; The temperature at the outlet of the fifth electromagnetic three-way valve is compared with the cooling temperature of the cooling water through the second temperature control unit, and the temperature at the outlet of the second water tank is compared with the cooling temperature of the cooling water through the third temperature control unit; based on the two comparison results, the opening of the fifth electromagnetic three-way valve is jointly controlled to achieve fuel cell stack cooling.

6. The temperature control system for hydrogen fuel cell waste heat recovery and generated water utilization according to claim 1 is characterized in that: The building heating unit includes a first gate valve, a second gate valve, a water distributor and a water collector; The return water from heating users is collected through the water collector and flows into the third heat exchanger through the second gate valve for heat exchange; the hot water obtained after heat exchange is diverted to different heating users through the first gate valve and the water distributor to achieve heating.

7. A temperature control method for recovering waste heat from a hydrogen fuel cell and utilizing generated water, using the temperature control system for recovering waste heat from a hydrogen fuel cell and utilizing generated water according to claim 4, characterized in that: include: The first temperature control unit obtains the cooling water outlet temperature of the hot side input end of the second heat exchanger in real time and municipal hot water supply temperature , combined with 、 and the temperature required for heating by the user , controlling the opening and closing of the first electromagnetic three-way valve, the second electromagnetic three-way valve and the third electromagnetic three-way valve by a heating temperature control method; The second temperature control unit obtains the temperature of the outlet of the fifth electromagnetic three-way valve in real time The third temperature control unit obtains the actual temperature of the stack cooling water inlet in real time ; Combine 、 and the cooling temperature of the stack , the opening of the fifth electromagnetic three-way valve is controlled by the stack cooling temperature control method.

8. The temperature control method for recovering waste heat and utilizing generated water from a hydrogen fuel cell according to claim 7, characterized in that: The heating temperature control method comprises: according to and 、 , controls the opening and closing of the outlet of the first electromagnetic three-way valve at the cooling water outlet pipe, and determines whether the water flowing into the second electromagnetic three-way valve is cooling water; when When the stack cooling water outlet flows directly into the second electromagnetic three-way valve; when or When the stack is turned on, the generated water is combined with the cooling water outlet through the first electromagnetic three-way valve and then flows into the second electromagnetic three-way valve.

9. The temperature control method for hydrogen fuel cell waste heat recovery and generated water utilization according to claim 8, characterized in that: Compare 、 The value of controls the opening and closing of the outlets of the second and third electromagnetic three-way valves, determines whether to supply hot water to the municipal pipe network, and selects different heat exchangers for heat exchange; when When the water flows out of the second electromagnetic three-way valve, it enters the third heat exchanger for heat exchange to supplement the heat required by the heating user. The water after heat exchange is used to cool the fuel cell stack. when When the water flowing out of the second electromagnetic three-way valve enters the second heat exchanger to exchange heat with the hot water supplied by the municipal pipe network; the water after heat exchange enters the third heat exchanger to recycle the cold water of the municipal pipe network and provide the heat required by heating users; when When the water flowing out of the second electromagnetic three-way valve merges with the hot water supplied by the municipal pipe network, it enters the third heat exchanger for heat exchange to supplement the heat required by heating users. The water after heat exchange is used to cool the fuel cell stack.

10. The temperature control method for recovering waste heat and utilizing generated water from a hydrogen fuel cell according to claim 7, characterized in that: The stack cooling temperature control method includes: Step 4.1, compare the temperature at the outlet of the fifth electromagnetic three-way valve and the cooling temperature of the stack ;when When the user's cold water supply is open, increase the opening of the fifth electromagnetic three-way valve inlet until When , no longer adjust the opening; when When the valve is opened, increase the opening of the fifth electromagnetic three-way valve inlet at the outlet of the fourth electromagnetic three-way valve until When , no longer adjust the opening; Step 4.2: Compare the actual temperature of the stack cooling water inlet and the cooling temperature of the stack ;when When the user's cold water supply is open, increase the opening of the fifth electromagnetic three-way valve inlet until , return to step 4.1; when The heater heats until Stop heating.

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