Fuel cell combined cooling heating and power supply system and operation method

Abstract

The invention discloses a fuel cell combined cooling heating and power supply system and an operation method. The fuel cell combined cooling heating and power system comprises a hydrogen production system; the fuel cell stack is connected with the user side power grid, the fuel cell stack is provided with a cooling heat dissipation loop, the hydrogen production system is connected with the fuel cell stack to convey hydrogen, and the cooling heat dissipation loop is connected with a branch in parallel; the absorption refrigerating unit comprises a heat absorption end and a refrigerating end, and the heat absorption end exchanges heat with the heat circulation loop; the heat storage water tank is provided with a circulating water flow channel connected with the refrigerating end; the branch is connected with the circulating water flow channel; the heat storage water tank exchanges heat with the cooling heat dissipation loop, supplies hot water to a user side water network and is provided with a heating unit; the heat pump unit comprises a heat supply / refrigeration end and a heat release end, the heat supply / refrigeration end is connected with the circulating water flow channel, the heat storage water tank is connected with the heat release end, and a heat supply / refrigeration loop is merged into a user side water network. The method can effectively solve the problem of coupling lag of the cooling and heating power load.

Description

Technical Field

[0001] This application relates to the field of building distributed energy and hydrogen energy utilization technology, and in particular to a fuel cell combined cooling, heating and power system and its operation method. Background Technology

[0002] With the continuous growth of global building energy consumption, the building sector has become one of the major sources of global energy consumption. Among these, heating, air conditioning, and hot water demand are the main sources of energy consumption. Currently, most building energy supply systems rely on external energy sources, but this dependence leads to low energy efficiency and poor system adjustability. Especially under extreme weather conditions, building energy demand fluctuates greatly, resulting in energy waste and unstable operation.

[0003] Proton exchange membrane fuel cells (PEMFCs) have become an important technology in building combined cooling, heating, and power (CCHP) systems due to their high efficiency and low emissions. However, existing PEMFC systems for buildings generally suffer from problems such as inaccurate energy management, poor coupling of cooling, heating, and power load fluctuations, and low system efficiency. Traditional energy management systems often rely on static scheduling strategies or single-time-scale control, which cannot cope with the diversity and time-varying nature of building energy demands, making it difficult for building CCHP systems to achieve precise load matching and energy efficiency optimization. Therefore, how to achieve precise matching of cooling, heating, and power in buildings and improve the overall energy efficiency of building energy systems has become a current technical challenge in the field of building energy management. Summary of the Invention

[0004] To address the aforementioned technical issues, this application provides a fuel cell combined cooling, heating and power system and its operation method, aiming to achieve efficient coupling of hydrogen energy, electrical energy, thermal energy and cold energy in building energy systems.

[0005] The present invention solves the above-mentioned technical problems mainly through the following technical solutions: A fuel cell combined cooling, heating and power system is provided, including a hydrogen production system; A fuel cell stack is connected to the user's power grid for power transmission. The fuel cell stack is equipped with a cooling and heat dissipation circuit. The hydrogen production system is connected to the fuel cell stack through a pipeline to transport hydrogen. The cooling and heat dissipation circuit has a branch in parallel. The cooling and heat dissipation circuit and the branch can be selectively turned on. An absorption chiller unit includes a heat absorption end and a cooling end. The heat absorption end is provided with a heat circulation loop, and the cooling end is provided with a cold circulation loop. The cooling and heat dissipation loop and the heat circulation loop are respectively connected to a first heat exchanger to achieve heat exchange between the two. A modular air handling unit, wherein the modular air handling unit is provided with a circulating water channel for heat exchange with air, the cold circulation loop is connected to the circulating water channel; and the branch line is connected to the circulating water channel; The hot water storage tank is equipped with a heat absorption circuit. The cooling and heat dissipation circuit and the heat absorption circuit are respectively connected to a second heat exchanger to achieve heat exchange between the two. The hot water storage tank is connected to the user's water network through pipelines to supply hot water. The hot water storage tank is equipped with a heating unit.

[0006] Furthermore, the cooling and heat dissipation circuit is equipped with a first buffer water tank and a first liquid circulation pump.

[0007] Furthermore, control valves are provided upstream and downstream of the branch.

[0008] Furthermore, the thermal circulation loop is equipped with a second buffer water tank and a second liquid circulation pump.

[0009] Furthermore, it also includes a renewable power system, which is connected to the user's power grid for power transmission and to the hydrogen production system for power transmission.

[0010] Furthermore, the renewable power system includes a solar power system and a power battery pack, which, after being connected to the grid, transmit power to the user-end power grid and the hydrogen production system, respectively.

[0011] Furthermore, the renewable power system also includes a power battery pack. After the solar power system and the power battery pack are connected to the grid, they respectively transmit power to the power battery pack and the hydrogen production system, and then transmit power to the user-end power grid through the power battery pack. The fuel cell stack is connected in parallel with the power battery pack.

[0012] Furthermore, the hydrogen production system includes a water electrolysis hydrogen production device and a hydrogen storage tank. The water electrolysis hydrogen production device supplies and stores hydrogen to the hydrogen storage tank through pipelines. The water electrolysis hydrogen production device also supplies oxygen to the fuel cell stack through pipelines. The hydrogen storage tank supplies hydrogen to the fuel cell stack through pipelines.

[0013] Furthermore, the fuel cell stack is a proton exchange membrane fuel cell stack.

[0014] A method for operating a fuel cell combined cooling, heating and power system is also provided, including: Summer operation and winter operation; The summer operation is as follows: the fuel cell stack transmits power to the user's grid, and part of the power is stored in the power battery pack. A portion of the heat generated by the operation of the fuel cell stack is transferred to the absorption chiller, which drives it to generate cooling capacity, reducing the circulating water temperature of the combined air handling unit to achieve cooling. At the same time, part of the power is used to drive the combined air handling unit and the heat pump unit to further cool down and meet peak cooling load demand. During this process, the heat generated by the operation of the heat pump unit is recovered and stored in the hot water storage tank for domestic hot water use. If the hot water storage tank is insufficient or a peak in hot water demand occurs, the heating unit of the storage tank is activated to heat the water and achieve continuous hot water supply. The winter operation is as follows: the heat from the fuel cell stack is transferred to the circulating water of the absorption chiller unit through the branch circuit to achieve heating. The upper limit of the heat pump outlet water temperature is controlled below the set temperature. The return water temperature T1 of the combined air handling unit is monitored in real time. When T1 is greater than the set temperature, the heat distribution is optimized by reducing the output of the heat pump unit or adjusting the flow ratio of the first heat exchanger and the second heat exchanger. If the heat load is still not met, the flow rate of the first heat exchanger is increased or the output of the heat pump unit is increased. Domestic hot water is provided by the combined hot water storage tank and the heat pump. When the heat pump unit is insufficient, the heating unit of the storage tank is activated to maintain a stable outlet water temperature.

[0015] The beneficial effects of the fuel cell combined cooling, heating and power system and operating method of the present invention are: This system couples renewable energy electrolysis for hydrogen production, hydrogen storage, and fuel cell power generation, forming a highly efficient, low-carbon, and intelligent building energy supply system. The system combines multi-energy complementarity, thermo-electric synergy, and adaptive control, effectively improving the overall energy utilization rate of buildings and the operational stability of the energy system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a fuel cell combined cooling, heating and power system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of another embodiment of the fuel cell combined cooling, heating and power system provided in this invention. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0019] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0023] For details, please refer to Figure 1 This application provides a fuel cell combined cooling, heating and power system, which mainly includes a hydrogen production system 1, a fuel cell stack 2 and a dual-channel cooling and heating supply unit; wherein, the dual-channel cooling and heating supply unit includes an absorption chiller unit 3, a combined air handling unit 4, a hot water storage tank 5 and a heat pump unit 6.

[0024] The hydrogen production system 1 mainly produces hydrogen and oxygen, and delivers the hydrogen to the fuel cell stack 2, enabling the fuel cell stack 2 to generate electricity through a reaction.

[0025] The fuel cell stack 2 has a coolant flow channel inside, and a cooling and heat dissipation circuit is connected between the inlet and outlet of the coolant flow channel to cool and absorb the heat generated by the operation of the fuel cell stack 2. The fuel cell stack 2 also serves as a power source, connecting to the user's power grid and transmitting power to the user's power grid to supply the power demand of user A. In this embodiment, the user can be a building, and the user's power grid can be an internal or external power grid of the building.

[0026] The cooling and heat dissipation loop connected to the fuel cell stack 2 exchanges heat with the absorption chiller unit 3, providing the heat required for the operation of the absorption chiller unit 3. The absorption chiller unit 3 then converts the absorbed heat into cooling capacity, which is then delivered to the combined air handling unit 4 for cooling. The absorption chiller unit 3 is a prior art device; in this embodiment, a lithium bromide absorption chiller unit is specifically used, with a cooling capacity of 13.5 kW, a coefficient of performance (COP) of 0.45, a required hot water inlet / outlet temperature range of 70 / 60℃, and a minimum start-up temperature of 65℃. This absorption chiller unit 3 (lithium bromide absorption chiller unit) mainly consists of a generator, condenser, evaporator, absorber, heat exchanger, and circulating pump. The generator (i.e., the heat absorption end of the absorption chiller unit 3) has a first heat absorption channel. A heat circulation loop is connected between the inlet and outlet of this first channel. This heat circulation loop exchanges heat with the cooling and heat dissipation loop connected to the fuel cell stack 2 via the first heat exchanger 9. The evaporator (i.e., the cooling end of the absorption chiller unit 3) is equipped with a second flow channel. A cold circulation loop is connected between the inlet and outlet of this second flow channel. The coolant loops of the absorber and condenser are both connected in series to the cooling tower to form a heat-driven loop. The combined air handling unit 4 is equipped with a circulating water flow channel for heat exchange with the air. The inlet and outlet of this circulating water flow channel are connected in series to the cold circulation loop.

[0027] A branch is connected in parallel to the cooling and heat dissipation circuit. The inlet and outlet of the circulating water channel are connected in series on the branch. During operation, the branch and the section of pipe connected in parallel with the cooling and heat dissipation circuit are selected to keep the pipeline unobstructed. That is, when the cooling and heat dissipation circuit and the section of pipe connected in parallel with the branch are distributing flowing fluid, the branch is disconnected from the non-flowing fluid. Conversely, when the branch is distributing flowing fluid, the section of pipe connected in parallel with the cooling and heat dissipation circuit is disconnected from the non-flowing fluid.

[0028] The combined air handling unit 4 is mainly used for a circulating water channel for heat exchange with air. During use, indoor air enters the unit and exchanges heat with the medium flowing through the circulating water channel, thus cooling or heating the indoor air. A cold circulation loop is connected to this circulating water channel; branch lines are also connected to it. The combined air handling unit 4 is a prior art device, containing an internal air duct. A fan, filter, and heat exchange components are installed between the upstream and downstream ends of the air duct. The heat exchange components exchange heat with the air entering through the air duct, and the aforementioned circulating water channel is located inside the heat exchange components.

[0029] The hot water storage tank 5 is equipped with a first circulation port, a second circulation port, and a hot water outlet. Two independent heat absorption circuits are connected between the first and second circulation ports. The cooling and heat dissipation circuit exchanges heat with one of the heat absorption circuits through a second heat exchanger 10, thereby heating the water in the hot water storage tank 5. The hot water storage tank 5 has a hot water outlet, which is connected to the user's water network through a pipeline to supply hot water to the user's water network. Furthermore, the hot water storage tank 5 is equipped with a self-heating unit to quickly heat water to meet the supply demand when the hot water supply is insufficient. More specifically, the hot water storage tank 5 has a capacity of 100L, excellent heat preservation performance (temperature drop of 2–4℃ in 24 hours), a rated pressure of 5 kg / cm², a maximum working pressure of 7 kg / cm², a design temperature of 70℃, and the heating unit uses a conventional electric heating device (such as an electric heating element) to achieve hot water temperature compensation.

[0030] The heat pump unit 6 includes a heating / cooling end and a heat dissipation end. The heat dissipation end has an internal heat dissipation channel, the inlet and outlet of which are connected in series to another heat absorption circuit. The heating / cooling end of the heat pump unit 6 also has an internal heating / cooling channel, the inlet and outlet of which are connected to a heating / cooling circuit. The inlet and outlet of a circulating water channel are connected in series to this heating / cooling circuit. The heat pump unit 6 delivers heat or cooling energy to the combined air handling unit 4 through the heating / cooling end and the heating / cooling circuit, thereby heating or cooling the air passing through the combined air handling unit 4.

[0031] During the cooling season, the heat pump unit 6, together with the excess waste heat generated by the fuel cell stack 2, is stored in the hot water storage tank 5 to meet the user's hot water needs. If the hot water demand is insufficient, the heating unit built into the hot water storage tank 5 will heat the water to meet the user's hot water needs. The heat / cold energy provided by the dual-channel heating and cooling supply unit meets the user's heating / cooling needs through the combined air handling unit 4.

[0032] It should be noted that the first heat exchanger 9 and the second heat exchanger 10 are equipped with valves that regulate the flow rate of the cooling and heat dissipation circuit through their internal medium channels.

[0033] In some examples, heat pump unit 6 uses a suitable model of heat pump unit with a heating capacity of 27 kW, a cooling capacity of 25 kW, a cooling EER of 2.74, and a heating COP of 3.0. When heat pump unit 6 is running, it can recover the condensation heat under cooling conditions to the hot water storage tank 5 for domestic hot water supply.

[0034] In some examples, the first heat exchanger 9 is provided with a first medium channel and a second medium channel that exchange heat with each other. The inlet and outlet of the first medium channel are connected in series in a cooling and heat dissipation circuit, and the inlet and outlet of the second medium channel are connected in series in a heat circulation circuit.

[0035] In some examples, the second heat exchanger 10 is provided with a third medium channel and a fourth medium channel for mutual heat exchange. The inlet and outlet of the third medium channel are connected in series in the cooling and heat dissipation circuit, and the inlet and outlet of the fourth medium channel are connected in series in one of the heat absorption circuits of the aforementioned hot water storage tank 5.

[0036] In some examples, a first buffer water tank 21 and a first liquid circulation pump 22 are connected in series in the cooling and heat dissipation circuit. Specifically, the downstream pipe section of the cooling and heat dissipation circuit is connected in series with the first buffer water tank 21 and the first liquid circulation pump 22. The first buffer water tank 21 stores the coolant medium after heat exchange to meet the water demand for supplying coolant to the fuel cell stack 2. The fuel cell stack 2 operates under variable power conditions, and the first liquid circulation pump 22 regulates the flow rate of coolant entering the fuel cell stack 2 to ensure stable battery temperature. The first buffer water tank 21 is equipped with a liquid level sensor, a temperature sensor, and a tap water inlet to monitor the water level and temperature and automatically replenish water when the liquid level is lower than a set threshold to ensure stable operation of the system's thermal circulation.

[0037] In some examples, control valves 23 are installed upstream and downstream of the branch, respectively. These control valves 23 enable the switching between heating and cooling modes by opening the heat cycle and cold cycle loops of the absorption chiller under seasonal changes. Specifically, the two control valves 23 open when the system switches from cooling mode to heating mode, thereby switching the heat / cold energy flow.

[0038] In some embodiments, valves should also be installed upstream and downstream of a section of pipe in parallel with the cooling heat dissipation circuit and the branch. By controlling the valves, the "two-choice" control of the section of pipe in parallel with the cooling heat dissipation circuit and the branch can be realized.

[0039] In some examples, a second buffer water tank 31 and a second liquid circulation pump 32 are connected in series in the thermal circulation loop. At least two second buffer water tanks 31 are provided, distributed upstream and downstream of the thermal circulation loop. The second liquid circulation pump 32 is located downstream of the thermal circulation loop. The two second buffer water tanks 31 can smooth out heat fluctuations and achieve stable operation of the cooling end. The fluid circulation temperature within the cooling end is regulated by the second liquid circulation pump 32 by controlling the flow rate. The second buffer water tank 31 is equipped with a level sensor, a temperature sensor, and a tap water inlet to monitor the water level and temperature and automatically replenish water when the level falls below a set threshold, ensuring stable thermal circulation operation of the system.

[0040] In this embodiment, the fuel cell stack 2 adopts a compatible proton exchange membrane fuel cell stack, which is equipped with an air supply fan, a hydrogen flow control valve, and a coolant temperature sensor. Hydrogen and oxygen produced by the hydrogen production system 1 enter the fuel cell stack 2 and undergo a chemical reaction to provide electrical energy. The generated electrical energy is then connected to the user's power grid via a DC / AC inverter a on the transmission line to meet the user's energy needs.

[0041] In some examples, the hydrogen production system 1 includes a water electrolysis hydrogen production device 11 and a hydrogen storage tank 12. The water electrolysis hydrogen production device 11 is a proton exchange membrane electrolyzer, which operates after being connected to a power source. The anode and cathode of the water electrolysis hydrogen production device 11 are respectively equipped with a gas-liquid separator and a gas drying and purification device to obtain high-purity hydrogen with a purity greater than 99.999%. The hydrogen produced by electrolysis enters the hydrogen storage tank 12 through pipelines. The hydrogen storage tank 12 is a high-pressure composite material hydrogen storage tank with a rated pressure of 35MPa to 70MPa. It is equipped with a hydrogen temperature sensor, a pressure sensor, a pressure relief valve, and an electromagnetic safety valve for real-time monitoring of the hydrogen storage status and automatic pressure relief under abnormal operating conditions.

[0042] In some examples, see Figure 2 The power supply for the water electrolysis hydrogen production equipment 11 is provided by a renewable power system. At the same time, the renewable power system can also be connected to the user's power grid for direct power supply.

[0043] In some examples, the renewable power system includes a solar power system 71 and a wind power system 72. After being connected to the grid, the solar power system 71 and the wind power system 72 supply power to the user's power grid and the hydrogen production system 1, respectively. Specifically, the solar power system 71 uses a conventional photovoltaic array, and the wind power system 72 uses a wind turbine array. The electricity generated by both is converted into constant voltage and constant current DC power by an AC / DC rectifier b and a DC / DC regulator c, providing a stable power supply for the water electrolysis hydrogen production equipment 11. The renewable power system also includes a power battery pack 73. The electricity generated by the solar power system 71 and the wind power system 72 is partially supplied to the water electrolysis hydrogen production equipment 11 and partially stored in the power battery pack 73. At the same time, the electricity generated by the fuel cell stack 2 is partially supplied to the user's power grid and partially stored in the power battery pack 73. The power battery pack 73 then supplies power to the user's power grid and other electrical equipment in the entire fuel cell combined cooling, heating and power system.

[0044] It should be further explained that the power battery pack 73 is equipped with voltage, temperature, and state of charge (SOC) detection modules, which are used to collect real-time operating parameters of the power battery and upload the data to the energy management module. This enables coordinated control of the output power of the fuel cell stack 2 and the charging and discharging process of the power battery pack 73, ensuring dynamic energy balance of the system under different load conditions. Furthermore, the electrical energy generated by the fuel cell stack 2 is connected in parallel with the power battery pack 73 via a DC / DC regulator c (here, parallel connection refers to electrical parallel connection) to achieve dynamic power sharing and bidirectional energy flow between the fuel cell stack 2 and the power battery pack 73.

[0045] In this embodiment, the fuel cell combined cooling, heating, and power system is equipped with a control system. This control system is connected to the electrical components of the entire fuel cell combined cooling, heating, and power system to achieve automated and intelligent control. This control system belongs to the existing conventional intelligent control system and mainly includes a data acquisition module, a predictive control module, and an execution control module. The data acquisition module acquires the output of the solar power system 71 and the wind power system 72, the pressure in the hydrogen storage tank 12, the temperature of the fuel cell stack 2, the current of the electrolyzer, and the building's heating and cooling load data in real time. The predictive control module is based on a multi-timescale distributed prediction algorithm to achieve energy flow distribution and power coordination at the second-level timescale on the electric side and the minute-level timescale on the heating and cooling sides. The execution control module outputs control signals to the liquid circulation pump, control valve 23 (electrically controlled valve), electrolyzer, and inverter to achieve multi-energy complementarity and dynamic optimization of building cooling, heating, and electricity. Overall, it has the characteristics of high efficiency, low carbon, and intelligent regulation and can be widely used in integrated energy systems for residential and public buildings.

[0046] The entire fuel cell combined cooling, heating and power system operates mainly in two modes: summer operation and winter operation, as detailed below: 1) Summer Operation Mode In summer, the system primarily uses fuel cell stack 2 as its main energy supply unit. After startup, fuel cell stack 2 supplies power to the user's grid, with any remaining electricity stored in the power battery pack 73. The heat generated by fuel cell stack 2 is transferred to absorption chiller 3 via the first heat exchanger 9, driving it to generate cooling capacity and lower the circulating water temperature of combined air handling unit 4, thus achieving indoor cooling. Simultaneously, some electricity is used to drive heat pump unit 6 for further cooling to meet peak cooling load demands. During this process, waste heat generated by heat pump unit 6 is recovered and stored in hot water storage tank 5 for domestic hot water use. If heat storage is insufficient or a peak in hot water demand occurs, the system automatically activates the built-in heating unit in hot water storage tank 5 to supplement heating, ensuring a continuous hot water supply.

[0047] More specifically, during summer operation, the control system employs a hierarchical predictive control strategy for energy scheduling and load matching. The upper-level control module first uses historical load data to intelligently predict user-end energy consumption, obtaining predicted curves for the next day's electricity load, cooling load, and hot water load. Combining the operating models of the fuel cell stack 2, the water electrolysis hydrogen production equipment 11, the power battery pack 73, the absorption chiller unit 3, and the heat pump unit 6, and comprehensively considering equipment output constraints and the total system operating cost, a multi-objective optimization model is established to achieve globally optimal scheduling of the integrated energy system. The lower-level execution control module operates on a time-step basis. T operates in cycles, acquiring real-time user power demand and determining power supply and demand balance based on the output power of the power battery pack 73 and fuel cell stack 2. When the system power supply is detected to be lower than the load demand, the power generation power of the fuel cell stack 2 is adjusted. After the power supply and demand are matched, it is further determined whether the cooling load meets the requirements. If it is insufficient, the cooling output of the absorption chiller unit 3 is adjusted first. If the output of the absorption chiller unit 3 is limited, the heat pump unit 6 is started to supplement the cooling output of the combined air handling unit 4. Then, it is determined whether the hot water load meets the demand. If it is insufficient, the circulation flow of the second heat exchanger 10 is adjusted to improve the waste heat utilization efficiency. If it is still insufficient, the heating unit built into the hot water storage tank 5 is started for auxiliary heating, thereby realizing the dynamic coordination of multi-energy flow among the fuel cell stack 2, absorption chiller unit 3, heat pump unit 6 and hot water storage tank 5, ensuring the stable supply of building cooling, heating and electricity loads and the optimal energy efficiency of the system.

[0048] 2) Winter Operation Mode In winter, the absorption chiller unit 3 is shut down. The heat generated by the fuel cell stack 2 is exchanged through the first heat exchanger 9 and then used to heat the circulating water of the combined air handling unit 4 via a branch line for building heating. Part of the heating demand is met by heat exchange between the heating / cooling end of the heat pump unit 6 and the circulating water channel. The upper limit of the outlet water temperature of the heat pump unit 6 is controlled below a set temperature (this set temperature is reasonably set according to actual usage requirements; no specific value is limited here, and any set value suitable for actual application is acceptable) to prevent damage to the compressor from excessively high return water temperature. The control system monitors the return water temperature T1 of the air handling unit in real time. When T1 exceeds the set value, heat distribution is optimized by reducing the output of the heat pump unit 6 or adjusting the flow rate ratio of the cooling circuit entering the first heat exchanger 9 and the second heat exchanger 10. If the heat load is still not met, the flow rate of the cooling circuit entering the first heat exchanger 9 or the output of the heat pump unit 6 is increased first. Domestic hot water is provided by the hot water storage tank 5 and the heat pump unit 6. When the heat pump unit 6 is insufficient, the heating unit of the hot water storage tank 5 is automatically activated to maintain a stable outlet water temperature.

[0049] More specifically, during winter operation, the system adopts a hierarchical predictive control strategy for energy scheduling and load matching. The upper-level control module first performs intelligent prediction of user-end energy consumption based on historical load data, obtaining the predicted curves of the next day's power load, heat load, and hot water load. Combining the operating models of the fuel cell stack 2, the water electrolysis hydrogen production equipment 11, the power battery pack 73, the absorption chiller unit 3, and the heat pump unit 6, and comprehensively considering the equipment output constraints and the total system operating cost, a multi-objective optimization model is established to achieve the global optimal scheduling of the integrated energy system. The lower-level execution control module first determines whether the current power supply meets the user's load demand. If insufficient power is detected, the output power of the fuel cell stack 2 is adjusted to compensate for the power shortage. Once the power supply and demand are balanced, the system enters the heat-side load judgment stage. The control module monitors the user-side heat load Q and the return water temperature T1 of the combined air handling unit 4 in real time. When T1 > 47℃ (this temperature can be defined as the corresponding water temperature of the fuel cell at a safe operating temperature), the system prioritizes reducing the output of the heat pump unit 6 or adjusting the circulation flow rate of the first heat exchanger 9, while appropriately increasing the output of the second heat exchanger 10. The system adjusts the circulation flow rate to prevent overheating and optimize heat distribution. It then determines whether the heat load Q is adequate. If insufficient, it prioritizes adjusting the circulation flow rate of the first heat exchanger 9 to improve heating efficiency. If the heat load is still insufficient, it increases the output of the heat pump unit 6 to compensate for the heat load difference. Finally, the control system detects whether the domestic hot water load meets the demand. If the hot water load is insufficient, it adjusts the flow rate of the second heat exchanger 10 to enhance waste heat recovery. If the demand is still not met, it automatically starts the heating unit built into the hot water storage tank 5 to provide auxiliary heating, achieving a stable supply of electricity, heat, and domestic hot water, and efficient energy utilization.

[0050] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0051] The above provides a detailed description of a fuel cell combined cooling, heating and power system and its operation method provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A fuel cell combined cooling, heating and power system, characterized in that, include: Hydrogen production system; A fuel cell stack is connected to the user's power grid for power transmission. The fuel cell stack is equipped with a cooling and heat dissipation circuit. The hydrogen production system is connected to the fuel cell stack through a pipeline to transport hydrogen. The cooling and heat dissipation circuit has a branch in parallel. The cooling and heat dissipation circuit and the branch can be selectively turned on. An absorption chiller unit includes a heat absorption end and a cooling end. The heat absorption end is provided with a heat circulation loop, and the cooling end is provided with a cold circulation loop. The cooling and heat dissipation loop and the heat circulation loop are respectively connected to a first heat exchanger to achieve heat exchange between the two. A modular air handling unit, wherein the modular air handling unit is provided with a circulating water channel for heat exchange with air, the cold circulation loop is connected to the circulating water channel; and the branch line is connected to the circulating water channel; A hot water storage tank is provided with a heat absorption circuit. The cooling and heat dissipation circuit and the heat absorption circuit are respectively connected to a second heat exchanger to achieve heat exchange between the two. The hot water storage tank is connected to the user's water network through pipelines to supply hot water. The hot water storage tank is provided with a heating unit. A heat pump unit includes a heating / cooling end and a heat dissipation end. The heating / cooling end is provided with a heating / cooling circuit, which is connected to the circulating water channel. The heat absorption circuit is connected to the heat dissipation end, and the heating / cooling circuit is connected to the user's water network.

2. The fuel cell combined cooling, heating and power system according to claim 1, characterized in that: The cooling and heat dissipation circuit is equipped with a first buffer water tank and a first liquid circulation pump.

3. A fuel cell combined cooling, heating and power system according to claim 1, characterized in that: The upstream and downstream of the branch are respectively equipped with control valves.

4. A fuel cell combined cooling, heating and power system according to claim 1, characterized in that: The thermal circulation loop is equipped with a second buffer water tank and a second liquid circulation pump.

5. A fuel cell combined cooling, heating and power system according to claim 1, characterized in that: It also includes a renewable power system, which is connected to the user's power grid for power transmission and to the hydrogen production system for power transmission.

6. A fuel cell combined cooling, heating and power system according to claim 5, characterized in that: The renewable power system includes a solar power system and a power battery pack. After being connected to the grid, the solar power system and the power battery pack transmit power to the user-end power grid and the hydrogen production system, respectively.

7. A fuel cell combined cooling, heating and power system according to claim 6, characterized in that: The renewable power system also includes a power battery pack. After the solar power system and the power battery pack are connected to the grid, they respectively transmit power to the power battery pack and the hydrogen production system. Then, the power battery pack is connected to the user-end power grid for power transmission. The fuel cell stack is connected in parallel with the power battery pack.

8. A fuel cell combined cooling, heating and power system according to claim 1, characterized in that: The hydrogen production system includes a water electrolysis hydrogen production device and a hydrogen storage tank. The water electrolysis hydrogen production device supplies and stores hydrogen to the hydrogen storage tank through pipelines. The water electrolysis hydrogen production device also supplies oxygen to the fuel cell stack through pipelines. The hydrogen storage tank supplies hydrogen to the fuel cell stack through pipelines.

9. A fuel cell combined cooling, heating and power system according to any one of claims 1 to 8, characterized in that: The fuel cell stack is a proton exchange membrane fuel cell stack.

10. A method for operating a fuel cell combined cooling, heating and power system, characterized in that, include: Summer operation and winter operation; The summer operation is as follows: the fuel cell stack transmits power to the user's grid, and part of the power is stored in the power battery pack. A portion of the heat generated by the operation of the fuel cell stack is transferred to the absorption chiller, which drives it to generate cooling capacity, reducing the circulating water temperature of the combined air handling unit to achieve cooling. At the same time, part of the power is used to supply the combined air handling unit and the heat pump unit to further cool down and meet peak cooling load demand. During this process, the heat generated by the heat pump unit is recovered and stored in the hot water storage tank for domestic hot water use. If the hot water storage tank is insufficient or a peak in hot water demand occurs, the heating unit of the storage tank is activated to heat the water and achieve continuous hot water supply. The winter operation is as follows: the heat from the fuel cell stack is transferred to the circulating water of the absorption chiller unit through the branch circuit to achieve heating. The upper limit of the heat pump outlet water temperature is controlled below the set temperature. The return water temperature T1 of the combined air handling unit is monitored in real time. When T1 is greater than the set temperature, the heat distribution is optimized by reducing the output of the heat pump unit or adjusting the flow ratio of the first heat exchanger and the second heat exchanger. If the heat load is still not met, the flow rate of the first heat exchanger is increased or the output of the heat pump unit is increased. Domestic hot water is provided by the combined hot water storage tank and the heat pump. When the heat pump unit is insufficient, the heating unit of the storage tank is activated to maintain a stable outlet water temperature.

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