High-power fuel cell cogeneration energy storage system and working method thereof

Abstract

The invention relates to a high-power fuel cell heat and power cogeneration energy storage system and a working method thereof.The system comprises a high-power proton exchange membrane fuel cell power generation unit, a power supply energy storage unit and a heat and cold supply unit, and when the system serves as a power supply system, grid-connected output or off-grid output can be achieved; when used as a heat supply system, the heat preservation water tank is arranged to store heat and supply heat, so that a user can conveniently and efficiently obtain hot water in time according to heat use requirements; when serving as a cold supply system, cold water is provided for users in real time through the cold water pipeline; as an energy storage system, when the fuel cell operates normally, the electric energy generated by the fuel cell or the generator in the power supply and energy storage unit can charge the energy storage cell, and the energy storage cell can supply power to the user when the power is cut off for a short time or the user needs low load. According to the high-power fuel cell combined heat and power energy storage system, waste heat of all parts in the system is fully utilized, the energy utilization efficiency is improved, and'electricity, heat and cold 'combined supply can be carried out on users.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a high-power fuel cell combined heat and power storage system and a working method thereof. Background Art

[0002] The use of high-power hydrogen fuel cells can effectively peak the power grid and achieve low-carbon goals. However, the power generation efficiency of fuel cells is not high, about 40% to 60%, and most of the energy is released in the form of heat. This heat is actively removed through the cooling system, which causes energy waste. The existing technology uses thermal management methods to achieve efficient utilization of waste heat, thereby improving the energy utilization efficiency of cogeneration of fuel cell systems. During operation, high-power fuel cells have multiple low-temperature heat sources with uneven parameters and uncertain emission timing, which are difficult to use and require the development of new heat storage technologies. Traditional methods can usually only supply electricity to the outside and cannot meet users' complex cooling, heating, and electricity needs.

[0003] CN116344861A discloses a proton exchange membrane hydrogen fuel cell cogeneration system, which focuses on the residential cogeneration application of medium and low temperature fuel cells, and the waste heat is used for floor heating and heating water supply. However, the hot water temperature is relatively low, which limits the heating distance, so such systems often use distributed nearby consumption. At the same time, due to the limitation of user heat demand, there will be a problem of mismatch between heat and electricity demand, resulting in reduced system efficiency.

[0004] In addition, there are also some technical problems with existing fuel cell systems with cogeneration. In the research on existing fuel cell cogeneration systems, only the waste heat of PEMFC is recovered, and the utilization of other waste heat is not considered; and under different working conditions and demand times, the user's cooling and heating demands are very unbalanced, and the waste heat of the entire system is not fully utilized, resulting in a very low energy utilization efficiency of the cogeneration of the fuel cell system.

[0005] Therefore, it is urgent to design a high-power fuel cell cogeneration energy storage system and a working method thereof to solve the problems existing in the above-mentioned prior art. Summary of the invention

[0006] In view of this, the present invention provides a high-power fuel cell cogeneration energy storage system and its working method, the purpose of which is to make full use of the system waste heat, improve the energy utilization rate of the fuel cell system as a whole, and ensure timely and convenient cooling and heating for users under different working conditions and demand times.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A high-power fuel cell combined heat and power storage system, the high-power fuel cell combined heat and power storage system comprising: a high-power proton exchange membrane fuel cell power generation unit, a power supply energy storage unit and a heating and cooling unit;

[0009] The power supply and energy storage unit includes a first condenser, a first circulation pump, a first heat exchanger, an expander, a generator and an energy storage battery; the outlet of the first condenser is connected to the inlet of the first circulation pump, the outlet of the first circulation pump is connected to the inlet of the liquid working medium of the first heat exchanger, the outlet of the liquid working medium of the first heat exchanger is connected to the inlet of the expander, and the outlet of the expander is connected to the inlet of the first condenser; the expander is connected to the generator, and the generator supplies power to the energy storage battery;

[0010] The heating and cooling unit comprises an absorber, a second circulating pump, a second heat exchanger, a third heat exchanger, a high temperature generator, a low temperature generator and a pressure reducing valve; the refrigerant outlet of the absorber is connected to the inlet of the second circulating pump, the outlet of the second circulating pump is connected to the cold source inlet of the second heat exchanger, the cold source outlet of the second heat exchanger is connected to the cold source inlet of the third heat exchanger, the cold source outlet of the third heat exchanger is connected to the high temperature generator, the high temperature generator is connected to the heat source inlet of the third heat exchanger, the heat source outlet of the third heat exchanger is connected to the low temperature generator, the low temperature generator is connected to the heat source inlet of the second heat exchanger, the heat source outlet of the second heat exchanger is connected to the pressure reducing valve, and the pressure reducing valve is connected to the refrigerant inlet of the absorber; and the high temperature generator is connected to the low temperature generator;

[0011] The coolant of the fuel cell in the high-power proton exchange membrane fuel cell power generation unit flows out from the coolant outlet, first flows through the first heat exchanger of the power supply and energy storage unit, then flows through the high-temperature generator of the heating and cooling unit, and then flows back into the fuel cell through the coolant inlet of the fuel cell.

[0012] Furthermore, the heating and cooling unit also includes a second condenser, an expansion valve and an evaporator, the second condenser is connected downstream of the low-temperature generator, the expansion valve is connected downstream of the second condenser, the evaporator is connected downstream of the expansion valve, and the evaporator is connected to the absorber.

[0013] Furthermore, the high-power fuel cell cogeneration energy storage system also includes a heating circuit, and the hot water pipeline passes through the second condenser, the absorber and the first condenser in sequence and is connected to the insulated water tank.

[0014] Furthermore, the high-power fuel cell cogeneration energy storage system also includes a cooling circuit, and a cold water pipeline passes through an evaporator.

[0015] Furthermore, the electric energy generated by the fuel cell is provided to the user after passing through an AC / DC converter or is used to power an energy storage battery; when the user needs it, the electric energy stored in the energy storage battery is provided to the user after passing through an AC / DC converter.

[0016] Furthermore, the refrigerant in the heating and cooling unit is a mixed liquid of ammonia or a water / lithium bromide solution.

[0017] Furthermore, the liquid working medium in the power supply and energy storage unit adopts a working medium with a low boiling point characteristic.

[0018] The present invention also provides a working method based on the above-mentioned high-power fuel cell combined heat and power storage system, and the working method is specifically as follows:

[0019] After the fuel cell is started, the liquid working medium in the first condenser enters the first heat exchanger under the action of the first circulation pump, and exchanges heat with the high-temperature coolant of the fuel cell through the first heat exchanger. The liquid working medium is heated and evaporated to form a high-pressure steam working medium. The high-pressure steam working medium enters the expander to push the expander to do work. The expander outputs mechanical work to the outside, and the generator connected to the expander starts to generate electricity. The electric energy generated by the generator enters the energy storage battery to form a backup energy source. The high-pressure steam working medium is converted into a low-pressure steam working medium after passing through the expander. The low-pressure steam working medium enters the first condenser and is condensed into a liquid working medium, which continues to circulate under the action of the first circulation pump.

[0020] The low-temperature liquid refrigerant in the absorber, under the action of the second circulation pump, passes through the second heat exchanger and the third heat exchanger in sequence to reach the high-temperature generator. In the high-temperature generator, the low-temperature liquid refrigerant exchanges heat with the high-temperature coolant of the fuel cell, and the water in the low-temperature liquid refrigerant evaporates to form a primary flow water vapor. The evaporated concentrated liquid refrigerant enters the third heat exchanger again to exchange heat with the low-temperature liquid refrigerant, so that the low-temperature liquid refrigerant recovers the waste heat of the concentrated liquid refrigerant; then the concentrated liquid refrigerant enters the low-temperature generator, and at the same time, the primary flow water vapor formed by evaporation in the high-temperature generator enters the low-temperature generator as a heat source, and further exchanges heat with the concentrated liquid refrigerant in the low-temperature generator, so that the water in the concentrated liquid refrigerant further evaporates to form a secondary flow water vapor. The concentrated liquid refrigerant after the secondary evaporation enters the second heat exchanger again, and further exchanges heat with the low-temperature liquid refrigerant to recover more heat; then the concentrated liquid refrigerant flows back to the absorber after passing through the pressure reducing valve.

[0021] Furthermore, the working method also includes:

[0022] The primary flow water vapor and the secondary flow water vapor leave the low-temperature generator and enter the second condenser for condensation. The liquid water formed after condensation passes through the expansion valve to form low-temperature liquid water. The low-temperature liquid water enters the evaporator. In the evaporator, the low-temperature liquid water absorbs heat and becomes liquid water at room temperature. Then the liquid water at room temperature enters the absorber and mixes with the concentrated liquid refrigerant flowing back into the absorber.

[0023] Furthermore, the working method also includes:

[0024] The water in the hot water pipe exchanges heat with the primary flow water vapor and the secondary flow water vapor in the second condenser and absorbs heat; then it enters the absorber and exchanges heat with the liquid refrigerant, and the water in the hot water pipe further absorbs heat and heats up; next, the water in the hot water pipe enters the first condenser and exchanges heat with the low-pressure steam working medium, and the water in the hot water pipe further absorbs heat and heats up; finally, the water in the hot water pipe flows into the insulated water tank, providing hot water to users at any time when they need it;

[0025] The water in the cold water pipe exchanges heat with low-temperature liquid water in the evaporator. The low-temperature liquid water absorbs heat and becomes liquid water at room temperature. The water in the cold water pipe releases heat and its temperature decreases, providing cold water to users at any time when they need it.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The high-power fuel cell combined heat and power storage system of the present invention can be connected to the grid or off-grid when used as a power supply system; when used as a heating system, it can store heat and provide heat by setting up an insulated water tank, so that users can obtain hot water in a timely and efficient manner according to their heating needs; when used as a cooling system, it can provide cold water to users in real time through cold water pipes; as an energy storage system, when the fuel cell is operating normally, the electric energy generated by the fuel cell or the generator in the power supply storage unit can charge the energy storage battery, and when there is a short power outage or low load demand from the user, the energy storage battery can supply power to the user. In short, the high-power fuel cell combined heat and power storage system makes full use of the waste heat of each part of the system, improves energy utilization efficiency, and can provide users with "electricity, heat, and cooling" trigeneration.

[0028] (2) When a high-power fuel cell combined heat and power storage system is used in a grid-connected scenario, during the valley electricity price stage, or during the period of overflow of electricity generated by the fuel cell, the electricity generated by the fuel cell can be stored in the form of electricity in excess of the user's needs through the energy storage battery; and during the peak electricity price stage, or when the user's electricity demand is too high, the stored electricity can be released through the energy storage battery to meet the user's electricity consumption or reduce the energy usage fee, thereby reducing the user's peak-valley difference and improving the stability and reliability of user use.

[0029] (3) The power supply and energy storage unit and the heating and cooling unit are coupled with the coolant external circulation of the fuel cell through the first heat exchanger and the high-temperature generator, respectively, to effectively utilize the waste heat generated by the fuel cell. At the same time, by setting up a heating circuit and a cooling circuit, the energy utilization efficiency is further improved. In the cold water circuit, the low-temperature liquid water absorbs the heat of the water in the cold water pipe in the evaporator, providing the required cooling effect for the user's building or other household facilities; in the hot water circuit, the water in the hot water pipe flows through the second condenser, the absorber and the first condenser in turn, absorbs the heat therein, heats the water in the hot water pipe, and then flows into the insulated water tank for standby use, providing hot water for the user at any time.

[0030] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The schematic diagram of the structure of the high-power fuel cell cogeneration energy storage system according to the embodiment of the present invention is shown.

[0033] In the figure: 1. fuel cell; 2. high temperature generator; 3. low temperature generator; 4. second condenser; 5. first heat exchanger; 6. generator; 7. expander; 8. first condenser; 9. first circulation pump; 10. third heat exchanger; 11. second heat exchanger; 12. second circulation pump; 13. pressure reducing valve; 14. absorber; 15. expansion valve; 16. evaporator; 17. energy storage battery; 18. thermal insulation water tank; 19. AC / DC converter. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The embodiment of the present invention proposes a high-power fuel cell combined heat and power storage system, as shown in the attached Figure 1 As shown, the high-power fuel cell cogeneration energy storage system includes: a high-power proton exchange membrane fuel cell power generation unit, a power supply energy storage unit and a heating and cooling unit;

[0036] The power of the fuel cell of the high-power proton exchange membrane fuel cell power generation unit generally exceeds 250KW.

[0037] The power supply and energy storage unit includes a first condenser 8, a first circulation pump 9, a first heat exchanger 5, an expander 7, a generator 6 and an energy storage battery 17; the outlet of the first condenser 8 is connected to the inlet of the first circulation pump 9, the outlet of the first circulation pump 9 is connected to the inlet of the liquid working medium of the first heat exchanger 5, the outlet of the liquid working medium of the first heat exchanger 5 is connected to the inlet of the expander 7, and the outlet of the expander 7 is connected to the inlet of the first condenser 8; the expander 7 is connected to the generator 6, and the generator 6 supplies power to the energy storage battery 17;

[0038] The heating and cooling unit includes an absorber 14, a second circulating pump 12, a second heat exchanger 11, a third heat exchanger 10, a high temperature generator 2, a low temperature generator 3 and a pressure reducing valve 13; the refrigerant outlet of the absorber 14 is connected to the inlet of the second circulating pump 12, the outlet of the second circulating pump 12 is connected to the cold source inlet of the second heat exchanger 11, the cold source outlet of the second heat exchanger 11 is connected to the cold source inlet of the third heat exchanger 10, the cold source outlet of the third heat exchanger 10 is connected to the high temperature generator 2, the high temperature generator 2 is connected to the heat source inlet of the third heat exchanger 10, the heat source outlet of the third heat exchanger 10 is connected to the low temperature generator 3, the low temperature generator 3 is connected to the heat source inlet of the second heat exchanger 11, the heat source outlet of the second heat exchanger 11 is connected to the pressure reducing valve 13, and the pressure reducing valve 13 is connected to the refrigerant inlet of the absorber 14; and the high temperature generator 2 is connected to the low temperature generator 3.

[0039] The coolant of the fuel cell 1 in the high-power proton exchange membrane fuel cell power generation unit flows out from the coolant outlet, first flows through the first heat exchanger 5 of the power supply and energy storage unit, then flows through the high-temperature generator 2 of the heating and cooling unit, and then flows back into the fuel cell 1 through the coolant inlet of the fuel cell 1.

[0040] The liquid working medium in the first condenser 8 enters the first heat exchanger 5 under the action of the first circulation pump 9, and exchanges heat with the high-temperature coolant of the fuel cell 1 through the first heat exchanger 5. The liquid working medium is heated and evaporated, thereby generating a higher vapor pressure. The high-pressure steam working medium enters the expander 7, pushing the expander 7 to do work. The expander 7 outputs mechanical work to the outside, and the generator 6 connected to the expander 7 starts to generate electricity. The electric energy generated by the generator 6 enters the energy storage battery 17 to form a backup energy source, thereby improving the stability and reliability of user use. The high-pressure steam working medium is converted into a low-pressure steam working medium after passing through the expander 7. The low-pressure steam working medium enters the first condenser 8, condenses into a liquid working medium, and continues to circulate under the action of the first circulation pump 9.

[0041] The liquid working medium in the power supply and energy storage unit adopts a working medium with a low boiling point characteristic.

[0042] The low-temperature liquid refrigerant in the absorber 14, under the action of the second circulation pump 12, passes through the second heat exchanger 11 and the third heat exchanger 10 in sequence to reach the high-temperature generator 2. In the high-temperature generator 2, the low-temperature liquid refrigerant exchanges heat with the high-temperature coolant of the fuel cell 1, and the water in the low-temperature liquid refrigerant evaporates to form a primary flow water vapor. The evaporated concentrated liquid refrigerant enters the third heat exchanger 10 again to exchange heat with the low-temperature liquid refrigerant, so that the low-temperature liquid refrigerant recovers the waste heat of the concentrated liquid refrigerant; then the concentrated liquid refrigerant enters the low-temperature generator 3, and at the same time, the primary flow water vapor formed by evaporation in the high-temperature generator 2 enters the low-temperature generator 3 as a heat source, and further exchanges heat with the concentrated liquid refrigerant in the low-temperature generator 3, so that the water in the concentrated liquid refrigerant further evaporates to form a secondary flow water vapor. The concentrated liquid refrigerant after the secondary evaporation enters the second heat exchanger 11 again, and further exchanges heat with the low-temperature liquid refrigerant to recover more heat; then the concentrated liquid refrigerant flows back to the absorber 14 after passing through the pressure reducing valve 13.

[0043] The refrigerant in the heating and cooling unit is a mixed liquid of ammonia or a water / lithium bromide solution.

[0044] The heating and cooling unit also includes a second condenser 4, an expansion valve 15 and an evaporator 16, the second condenser 4 is connected downstream of the low-temperature generator 3, the expansion valve 15 is connected downstream of the second condenser 4, the evaporator 16 is connected downstream of the expansion valve 15, and the evaporator 16 is connected to the absorber 14.

[0045] The primary flow water vapor and the secondary flow water vapor leave the low-temperature generator 3 and enter the second condenser 4 for condensation. The liquid water formed after condensation passes through the expansion valve 15 to form low-temperature liquid water. The low-temperature liquid water enters the evaporator 16. In the evaporator 16, the low-temperature liquid water absorbs heat and becomes liquid water at room temperature. Then, the liquid water at room temperature enters the absorber 14 and mixes with the concentrated liquid refrigerant flowing back into the absorber 14.

[0046] The electric energy generated by the fuel cell 1 is provided to the user after passing through the AC / DC converter 19 or is used to supply power to the energy storage battery 17 ; when the user needs it, the electric energy stored in the energy storage battery 17 is provided to the user after passing through the AC / DC converter 19 .

[0047] The high-power fuel cell cogeneration energy storage system also includes a heating circuit. The hot water pipeline passes through the second condenser 4, the absorber 14 and the first condenser 8 in sequence and is connected to the insulated water tank 18. The insulated water tank 18 is used to provide hot water to users.

[0048] The water in the hot water pipe exchanges heat with the primary flow water vapor and the secondary flow water vapor in the second condenser 4, and absorbs heat; then it enters the absorber 14, exchanges heat with the liquid refrigerant, the liquid refrigerant releases heat and becomes a low-temperature liquid refrigerant, and the water in the hot water pipe further absorbs heat and heats up; next, the water in the hot water pipe enters the first condenser 8, exchanges heat with the low-pressure steam working medium, the low-pressure steam working medium releases heat and condenses into a liquid working medium, and the water in the hot water pipe further absorbs heat and heats up; finally, the water in the hot water pipe flows into the insulated water tank 18, and provides hot water to the user at any time when the user needs it.

[0049] The high-power fuel cell cogeneration energy storage system also includes a cooling circuit, and the cold water pipeline passes through the evaporator 16;

[0050] The water in the cold water pipe exchanges heat with the low-temperature liquid water in the evaporator 16, and the low-temperature liquid water absorbs heat and becomes liquid water at room temperature; the water in the cold water pipe releases heat and its temperature decreases, providing cold water to users at any time when users need it.

[0051] The power supply and energy storage unit and the heating and cooling unit are coupled with the coolant external circulation of the fuel cell through the first heat exchanger and the high-temperature generator, respectively, to effectively utilize the waste heat generated by the fuel cell. At the same time, by setting up a heating circuit and a cooling circuit, the energy utilization efficiency is further improved. In the cold water circuit, the low-temperature liquid water absorbs the heat of the water in the cold water pipe in the evaporator, providing the required cooling effect for the user's buildings or other household facilities; in the hot water circuit, the water in the hot water pipe flows through the second condenser, the absorber and the first condenser in turn, absorbs the heat therein, heats the water in the hot water pipe, and then flows into the insulated water tank for standby use, providing hot water for users at any time.

[0052] The present invention also provides a working method based on the above-mentioned high-power fuel cell combined heat and power storage system, and the working method is specifically as follows:

[0053] After the fuel cell 1 is started, the liquid working medium in the first condenser 8 enters the first heat exchanger 5 under the action of the first circulation pump 9, and exchanges heat with the high-temperature coolant of the fuel cell 1 through the first heat exchanger 5. The liquid working medium is heated and evaporated to form a high-pressure steam working medium. The high-pressure steam working medium enters the expander 7 to drive the expander 7 to do work. The expander 7 outputs mechanical work to the outside, and the generator 6 connected to the expander 7 starts to generate electricity. The electric energy generated by the generator 6 enters the energy storage battery 17 to form a backup energy source. The high-pressure steam working medium is converted into a low-pressure steam working medium after passing through the expander 7. The low-pressure steam working medium enters the first condenser 8, condenses into a liquid working medium, and continues to circulate under the action of the first circulation pump 9;

[0054] The low-temperature liquid refrigerant in the absorber 14, under the action of the second circulating pump 12, passes through the second heat exchanger 11 and the third heat exchanger 10 in sequence to reach the high-temperature generator 2. In the high-temperature generator 2, the low-temperature liquid refrigerant exchanges heat with the high-temperature coolant of the fuel cell 1, and the water in the low-temperature liquid refrigerant evaporates to form a primary flow water vapor. The evaporated concentrated liquid refrigerant enters the third heat exchanger 10 again to exchange heat with the low-temperature liquid refrigerant, so that the low-temperature liquid refrigerant recovers the waste heat of the concentrated liquid refrigerant; then the concentrated liquid refrigerant enters the low-temperature generator 3, and at the same time, the primary flow water vapor formed by evaporation in the high-temperature generator 2 enters the low-temperature generator 3 as a heat source, and further exchanges heat with the concentrated liquid refrigerant in the low-temperature generator 3, so that the water in the concentrated liquid refrigerant further evaporates to form a secondary flow water vapor. The concentrated liquid refrigerant after the secondary evaporation enters the second heat exchanger 11 again, and further exchanges heat with the low-temperature liquid refrigerant to recover more heat; then the concentrated liquid refrigerant flows back to the absorber 14 after passing through the pressure reducing valve 13;

[0055] The primary flow water vapor and the secondary flow water vapor leave the low temperature generator 3 and enter the second condenser 4 for condensation. The liquid water formed after condensation passes through the expansion valve 15 to form low temperature liquid water. The low temperature liquid water enters the evaporator 16. In the evaporator 16, the low temperature liquid water absorbs heat and becomes room temperature liquid water. Then, the room temperature liquid water enters the absorber 14 and mixes with the concentrated liquid refrigerant flowing back into the absorber 14.

[0056] The electric energy generated by the fuel cell 1 is provided to the user through the AC / DC converter 19 or is used to supply power to the energy storage battery 17; when the user needs it, the electric energy stored in the energy storage battery 17 is provided to the user through the AC / DC converter 19;

[0057] The water in the hot water pipe exchanges heat with the primary flow water vapor and the secondary flow water vapor in the second condenser 4, absorbing heat; then enters the absorber 14, exchanges heat with the liquid refrigerant, and the water in the hot water pipe further absorbs heat to increase its temperature; next, the water in the hot water pipe enters the first condenser 8, exchanges heat with the low-pressure steam working medium, and the water in the hot water pipe further absorbs heat to increase its temperature; finally, the water in the hot water pipe flows into the insulated water tank 18, and provides hot water to the user at any time when the user needs it;

[0058] The water in the cold water pipe exchanges heat with the low-temperature liquid water in the evaporator 16, and the low-temperature liquid water absorbs heat and becomes liquid water at room temperature; the water in the cold water pipe releases heat and its temperature decreases, providing cold water to users at any time when users need it.

[0059] The high-power fuel cell combined heat and power storage system of the present invention can be connected to the grid or off-grid when used as a power supply system; when used as a heating system, it can store heat and provide heat by setting up an insulated water tank, so that users can obtain hot water in a timely and efficient manner according to their heat needs; when used as a cooling system, it can provide cold water to users in real time through cold water pipes; as an energy storage system, when the fuel cell is operating normally, the electric energy generated by the fuel cell or the generator in the power supply storage unit can charge the energy storage battery, and the energy storage battery can supply power to the user during a short power outage or when the user has a low load demand. In short, the high-power fuel cell combined heat and power storage system makes full use of the waste heat of each part of the system, improves energy utilization efficiency, and can provide users with "electricity, heat, and cooling" trigeneration.

[0060] When a high-power fuel cell cogeneration energy storage system is used in a grid-connected scenario, during the valley electricity price stage, or during the period of overflow of electricity generated by the fuel cell, the electricity generated by the fuel cell can be stored in the form of electricity in excess of the user's needs through the energy storage battery; and during the peak electricity price stage, or when the user's electricity demand is too high, the stored electricity can be released through the energy storage battery to meet the user's electricity consumption or reduce energy usage fees, thereby reducing the user's peak-valley difference and improving the stability and reliability of user use.

[0061] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-power fuel cell combined heat and power storage system, characterized in that: The high-power fuel cell cogeneration energy storage system comprises: a high-power proton exchange membrane fuel cell power generation unit, a power supply energy storage unit and a heating and cooling unit; The power supply and energy storage unit includes a first condenser, a first circulation pump, a first heat exchanger, an expander, a generator and an energy storage battery; the outlet of the first condenser is connected to the inlet of the first circulation pump, the outlet of the first circulation pump is connected to the inlet of the liquid working medium of the first heat exchanger, the outlet of the liquid working medium of the first heat exchanger is connected to the inlet of the expander, and the outlet of the expander is connected to the inlet of the first condenser; the expander is connected to the generator, and the generator supplies power to the energy storage battery; The heating and cooling unit comprises an absorber, a second circulating pump, a second heat exchanger, a third heat exchanger, a high temperature generator, a low temperature generator and a pressure reducing valve; the refrigerant outlet of the absorber is connected to the inlet of the second circulating pump, the outlet of the second circulating pump is connected to the cold source inlet of the second heat exchanger, the cold source outlet of the second heat exchanger is connected to the cold source inlet of the third heat exchanger, the cold source outlet of the third heat exchanger is connected to the high temperature generator, the high temperature generator is connected to the heat source inlet of the third heat exchanger, the heat source outlet of the third heat exchanger is connected to the low temperature generator, the low temperature generator is connected to the heat source inlet of the second heat exchanger, the heat source outlet of the second heat exchanger is connected to the pressure reducing valve, and the pressure reducing valve is connected to the refrigerant inlet of the absorber; and the high temperature generator is connected to the low temperature generator; The coolant of the fuel cell in the high-power proton exchange membrane fuel cell power generation unit flows out from the coolant outlet, first flows through the first heat exchanger of the power supply and energy storage unit, then flows through the high-temperature generator of the heating and cooling unit, and then flows back into the fuel cell through the coolant inlet of the fuel cell.

2. The high-power fuel cell combined heat and power storage system according to claim 1, characterized in that: The heating and cooling unit also includes a second condenser, an expansion valve and an evaporator, wherein the second condenser is connected downstream of the low-temperature generator, the expansion valve is connected downstream of the second condenser, the evaporator is connected downstream of the expansion valve, and the evaporator is connected to the absorber.

3. The high-power fuel cell combined heat and power storage system according to claim 2, characterized in that: The high-power fuel cell cogeneration energy storage system also includes a heating circuit, and the hot water pipeline passes through the second condenser, the absorber and the first condenser in sequence and is connected to the insulated water tank.

4. The high-power fuel cell combined heat and power storage system according to claim 2, characterized in that: The high-power fuel cell cogeneration energy storage system also includes a cooling circuit, and a cold water pipeline passes through an evaporator.

5. The high-power fuel cell combined heat and power storage system according to claim 1, characterized in that: The electric energy generated by the fuel cell is provided to the user after passing through an AC / DC converter or is used to supply power to an energy storage battery; when the user needs it, the electric energy stored in the energy storage battery is provided to the user after passing through an AC / DC converter.

6. The high-power fuel cell combined heat and power storage system according to claim 1, characterized in that: The refrigerant in the heating and cooling unit is a mixed liquid of ammonia or a water / lithium bromide solution.

7. The high-power fuel cell combined heat and power storage system according to claim 1, characterized in that: The liquid working medium in the power supply and energy storage unit adopts a working medium with a low boiling point characteristic.

8. A working method of the high-power fuel cell combined heat and power storage system according to any one of claims 1 to 7, characterized in that: The working method is as follows: After the fuel cell is started, the liquid working medium in the first condenser enters the first heat exchanger under the action of the first circulation pump, and exchanges heat with the high-temperature coolant of the fuel cell through the first heat exchanger. The liquid working medium is heated and evaporated to form a high-pressure steam working medium. The high-pressure steam working medium enters the expander to push the expander to do work. The expander outputs mechanical work to the outside, and the generator connected to the expander starts to generate electricity. The electric energy generated by the generator enters the energy storage battery to form a backup energy source. The high-pressure steam working medium is converted into a low-pressure steam working medium after passing through the expander. The low-pressure steam working medium enters the first condenser and is condensed into a liquid working medium, which continues to circulate under the action of the first circulation pump. The low-temperature liquid refrigerant in the absorber, under the action of the second circulation pump, passes through the second heat exchanger and the third heat exchanger in sequence to reach the high-temperature generator. In the high-temperature generator, the low-temperature liquid refrigerant exchanges heat with the high-temperature coolant of the fuel cell, and the water in the low-temperature liquid refrigerant evaporates to form a primary flow water vapor. The evaporated concentrated liquid refrigerant enters the third heat exchanger again to exchange heat with the low-temperature liquid refrigerant, so that the low-temperature liquid refrigerant recovers the waste heat of the concentrated liquid refrigerant; then the concentrated liquid refrigerant enters the low-temperature generator, and at the same time, the primary flow water vapor formed by evaporation in the high-temperature generator enters the low-temperature generator as a heat source, and further exchanges heat with the concentrated liquid refrigerant in the low-temperature generator, so that the water in the concentrated liquid refrigerant further evaporates to form a secondary flow water vapor. The concentrated liquid refrigerant after the secondary evaporation enters the second heat exchanger again, and further exchanges heat with the low-temperature liquid refrigerant to recover more heat; then the concentrated liquid refrigerant flows back to the absorber after passing through the pressure reducing valve.

9. The working method according to claim 8, characterized in that: The working method also includes: The primary flow water vapor and the secondary flow water vapor leave the low-temperature generator and enter the second condenser for condensation. The liquid water formed after condensation passes through the expansion valve to form low-temperature liquid water. The low-temperature liquid water enters the evaporator. In the evaporator, the low-temperature liquid water absorbs heat and becomes liquid water at room temperature. Then the liquid water at room temperature enters the absorber and mixes with the concentrated liquid refrigerant flowing back into the absorber.

10. The working method according to claim 9, characterized in that: The working method also includes: The water in the hot water pipe exchanges heat with the primary flow water vapor and the secondary flow water vapor in the second condenser and absorbs heat; then it enters the absorber and exchanges heat with the liquid refrigerant, and the water in the hot water pipe further absorbs heat and heats up; next, the water in the hot water pipe enters the first condenser and exchanges heat with the low-pressure steam working medium, and the water in the hot water pipe further absorbs heat and heats up; finally, the water in the hot water pipe flows into the insulated water tank, providing hot water to users at any time when they need it; The water in the cold water pipe exchanges heat with low-temperature liquid water in the evaporator. The low-temperature liquid water absorbs heat and becomes liquid water at room temperature. The water in the cold water pipe releases heat and its temperature decreases, providing cold water to users at any time when they need it.

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