Low-temperature working fluid pair and application thereof

Abstract

The application relates to a low-temperature working medium pair and application thereof, the low-temperature working medium pair comprising an absorbent and a refrigerant, the absorbent is used for absorbing the refrigerant and emitting heat, the refrigerant is used for absorbing heat and evaporating, the absorbent comprises an organic absorbent, an ionic liquid absorbent or is a composite absorbent; the refrigerant is HFO-1233zd (Z) or a composite refrigerant containing the component. The low-temperature working medium pair is used for fuel cell low-temperature waste heat utilization and other low-grade waste heat (building materials, metallurgy, food processing, chemical industry) utilization technologies based on the absorption refrigeration or heating principle, such as recovering industrial low-temperature waste heat by using the absorption technology to carry out refrigeration or heating, solar absorption heating or refrigeration.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energy recycling, and particularly relates to a low-temperature working medium pair and application thereof. BACKGROUND

[0002] At present, a large amount of low-grade waste heat (60-80 DEG C) in the industrial field cannot be efficiently utilized, and process chilled water is needed at the same time. In addition, the efficiency of chemical energy conversion to electrical energy of a low-temperature proton exchange membrane fuel cell is about 50%, and the remaining half of the energy is also dissipated in the form of low-grade waste heat (60-80 DEG C), and hydrogen fuel cell buses, logistics vehicles and other commercial vehicles, and hydrogen energy ships and hydrogen energy trams usually need to be refrigerated in summer. Utilizing a large amount of low-grade waste heat for refrigeration is important for industrial energy saving and comprehensive energy efficiency improvement of fuel cells.

[0003] Absorption refrigeration is an energy-saving technology for realizing refrigeration by using waste heat. However, the working medium pairs currently used are mainly lithium bromide / H2O and H2O / NH3. Commercial absorption refrigeration uses lithium bromide / H2O as the working medium pair, which requires a high driving heat source temperature, and needs an occurrence temperature higher than 90 o C to produce 5 o C of cold energy under typical working conditions, and has the problems of easy crystallization, narrow working temperature range, strong corrosion to ordinary metal materials, even stainless steel at high temperature, high price of the absorbent lithium bromide, etc. Absorption refrigeration using H2O / NH3 as the working medium pair also needs to work at a high driving temperature, and has the problems of corrosion, toxicity and explosion. Some newly proposed multi-component inorganic salt / H2O working medium pairs still have the problems of easy crystallization at low temperature, corrosion at high temperature, high viscosity, etc. Organic working medium pairs with alkanes and alcohols as refrigerants have the problems of weak absorption capacity, flammability and explosion, etc. New ion liquid / H2O working medium pairs also have the problems of poor absorption capacity, high viscosity and high cost due to the need to work at a high concentration. The different defects of the above different types of working medium pairs limit the application of absorption refrigeration in the field of low-temperature waste heat, and cause the low-grade waste heat of the industrial field and low-temperature proton exchange membrane fuel cells to be unable to be reasonably utilized, thereby reducing the comprehensive energy efficiency of the energy system. SUMMARY

[0004] In order to overcome the above problems in the prior art, the application provides a low-temperature working medium pair and application thereof, which are used to solve the above problems in the prior art.

[0005] A low-temperature working pair, the low-temperature working pair comprising an absorbent and a refrigerant, the absorbent being used for absorbing the refrigerant in an absorption heat pump absorber and releasing heat, the refrigerant being used for evaporating in an absorption heat pump evaporator and absorbing heat, the absorbent comprising an organic absorbent, an ionic liquid absorbent or being a composite absorbent; the refrigerant being HFO-1233zd(Z) or a composite refrigerant comprising the component.

[0006] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the organic absorbent being tetraethylene glycol dimethyl ether or polyethylene glycol monomethyl ether; the ionic liquid absorbent being one or several of imidazoles, quaternary ammoniums, quaternary phosphoniums, piperidines or pyridines.

[0007] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the imidazole ionic liquid absorbent being one or several of 1-butyl-2,3-dimethyl imidazole bromide, 1-butyl-2,3-dimethyl imidazole chloride, 1,3-dimethyl imidazole dimethyl phosphate or 1,3-dimethyl imidazole diethyl phosphate.

[0008] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the molar fraction of the absorbent in the low-temperature working pair ranging from 10% to 90%, the molar fraction being the ratio of the moles of the absorbent to the sum of the moles of the absorbent and the moles of the refrigerant.

[0009] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the composite absorbent comprising at least one absorbent, the molar fraction of each of the absorbents ranging from 0% to 100%.

[0010] The application further provides an application of the low-temperature working pair, the low-temperature working pair being used in low-grade waste heat of the principle of absorption refrigeration or heating.

[0011] According to the aspect and any possible implementation manner as above, further provided is an implementation manner, the low-temperature working pair being used in a fuel cell waste heat utilization system, the system comprising a fuel cell, a generating device, a condensing device, an evaporating device and an absorbing device.

[0012] The fuel cell is connected with the generating device and is used for providing waste heat.

[0013] The generating device is connected with the condensing device and the absorbing device, and outputs the low-temperature working pair accommodated therein to the condensing device or the absorbing device under refrigeration or heating conditions, respectively.

[0014] The evaporation device is used for evaporating the refrigerant of the low-temperature working pair output by the condensing device in a refrigeration working condition to form superheated steam of the refrigerant.

[0015] The absorption device is connected with the generating device and the evaporation device simultaneously, and is used for receiving the superheated steam and delivering the absorbent dilute solution of the low-temperature working pair to the generating device.

[0016] According to the aspect and any possible implementation manner described above, further provided is an implementation manner, wherein the system further comprises a heat exchange device arranged between the generating device and the absorption device.

[0017] According to the aspect and any possible implementation manner described above, further provided is an implementation manner, wherein the system further comprises a compression device arranged between the evaporation device and the absorption device, and used for condensing the superheated steam input to the absorption device.

[0018] According to the aspect and any possible implementation manner described above, further provided is an implementation manner, wherein the refrigeration working condition process specifically comprises:

[0019] S11. The valve between the heating radiator and the fuel cell is closed, and the valve between the generating device and the fuel cell is opened, the waste heat generated after the fuel cell is cooled is output to the generating device, the generating device heats the absorbent dilute solution from the absorption device, and part of the refrigerant superheated steam is evaporated and output to the condensing device;

[0020] S12. The condensing device condenses the refrigerant superheated steam and outputs the refrigerant superheated steam to the evaporation device;

[0021] S13. The evaporation device evaporates the condensed refrigerant to obtain saturated steam of the refrigerant, absorbs the heat of the equipment where the fuel cell is located in the evaporation process, and realizes refrigeration;

[0022] S14. The saturated steam flows into the absorption device, the absorbent concentrated solution in the generating device and the absorbent dilute solution in the absorption device are heated in the heat exchanger and then enter the absorption device, the absorbent concentrated solution absorbs the saturated steam and becomes the absorbent dilute solution, and heat is released in the absorption process, and cooling is realized through heat exchange with the environment;

[0023] The heating working condition process specifically comprises:

[0024] The valve between the heating radiator and the fuel cell is opened, and the valve between the generating device and the fuel cell is closed, the waste heat generated after the fuel cell is cooled is output to the heating radiator, and is used for heating the equipment where the fuel cell is located.

[0025] Advantages of the present application

[0026] Compared with the prior art, the present application has the following advantages:

[0027] The low-temperature working medium pair of the application, with the organic reagent, the ionic liquid or the multi-component mixed system thereof as the absorbent and HFO-1233zd(Z) as the refrigerant, can effectively recover and utilize low-grade waste heat, and solve the problem that the existing absorption refrigeration technology is difficult to utilize low-grade waste heat; meanwhile, the low-temperature absorption refrigeration working medium pair, taking tetraethylene glycol dimethyl ether as the absorbent and HFO-1233zd(Z) as the refrigerant as an example, has the advantages of no corrosion, low viscosity, low generation temperature, good economy, wide working range (can work below zero degrees) and reduced processing technology requirements.

[0028] The low-temperature working medium pair can be used not only for fuel cell low-temperature waste heat utilization, but also for other low-grade waste heat (building materials, metallurgy, food processing, chemical industry) utilization technologies based on the principle of absorption refrigeration or heating, such as recovering industrial low-temperature waste heat for refrigeration or heating by using absorption technology, solar absorption heating or refrigeration, etc., and can be applied not only to commercial vehicles such as proton exchange membrane fuel cell refrigerated trucks, buses and the like, and to the transportation fields such as tramcars and ships, but also to distributed energy systems based on hydrogen fuel cells for cold, heat and electricity combined supply, which can effectively improve the comprehensive energy efficiency of fuel cells and has a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The figure is a schematic diagram of the system structure of the application.

[0030] In the figure, 1 is a proton exchange membrane fuel cell, 2 is a generator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a heating panel, 7 is a heat exchanger, 8 is a compressor, V1 to V8 are valves, TV1 and TV2 are throttles, F1 to F2 are flow meters, and P1 is a pump. DETAILED DESCRIPTION

[0031] In order to better understand the technical solutions of the application, the summary of the application includes but is not limited to the specific embodiments in the following, and similar technologies and methods should be regarded as within the scope of protection of the application. In order to make the technical problems, technical solutions and advantages of the application more clear, the following will be described in detail in combination with the drawings and specific embodiments.

[0032] It should be clear that the embodiments described in the application are only a part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the application.

[0033] The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the description of the application and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0034] The application provides a novel low-temperature absorption refrigeration or heating working pair, which contains an organic absorbent, an ionic liquid absorbent, and a composite absorbent, and a refrigerant HFO-1233zd(Z) or a composite refrigerant containing HFO-1233zd(Z). The novel absorption working pair is used for fuel cell low-temperature waste heat utilization, and is also used for other low-grade waste heat (building materials, metallurgy, food processing, and chemical industry) utilization technologies based on the principle of absorption refrigeration or heating, such as recovering industrial low-temperature waste heat for refrigeration or heating by using absorption technology, solar absorption heating or refrigeration, etc.

[0035] The application provides a low-temperature absorption working pair for absorption refrigeration or heating, which contains an absorbent and a refrigerant. The absorbent is used for absorbing the refrigerant in an absorption heat pump absorber and releasing heat. The refrigerant is used for evaporating in an absorption heat pump evaporator and absorbing heat. The absorbent is an organic absorbent, an ionic liquid absorbent, or a composite absorbent. The refrigerant is HFO-1233zd(Z) or a composite refrigerant containing HFO-1233zd(Z). The organic absorbent is tetraethylene glycol dimethyl ether or polyethylene glycol monomethyl ether. The ionic liquid is an imidazole, a quaternary ammonium, a quaternary phosphonium, a piperidine, a pyridine, or the like. For example, the ionic liquid is 1-butyl-2,3-dimethyl imidazole bromide, 1-butyl-2,3-dimethyl imidazole chloride, 1,3-dimethyl imidazole dimethyl phosphate, 1,3-dimethyl imidazole diethyl phosphate, or the like. The composite absorbent includes a combination of one or more of 1-butyl-2,3-dimethyl imidazole bromide and 1-butyl-2,3-dimethyl imidazole chloride, tetraethylene glycol dimethyl ether, and polyethylene glycol monomethyl ether.

[0036] The molar fraction of the absorbent in the low-temperature working pair is 10% to 90%, preferably 40% or 80%. The molar fraction is the ratio of the number of moles of the absorbent in the working pair to the sum of the number of moles of the absorbent and the number of moles of the refrigerant in the working pair.

[0037] The absorbent in the low-temperature working pair is an organic absorbent or an ionic liquid absorbent, or a composite absorbent composed of multiple absorbents. The molar fraction of each absorbent in the composite absorbent is 0% to 100%. When the molar fraction of one absorbent in the composite absorbent is 100% and the molar fraction of other absorbents is 0%, the absorbent is regarded as a single substance.

[0038] The application also provides an application of the low-temperature working medium pair, which is used in low-grade waste heat of the principle of absorption refrigeration or heating, and particularly, the application is used in low-temperature waste heat of a fuel cell, as shown in the figure, a fuel cell waste heat utilization system of the application comprises a fuel cell, a generating device, a condensing device, an evaporating device and an absorption device. Figure 1

[0039] The fuel cell is connected with the generating device, and is used for providing waste heat.

[0040] The generating device is connected with the condensing device and the absorption device, and the low-temperature working medium pair in the generating device is output to the condensing device or the absorption device under the refrigeration or heating condition, and the low-temperature working medium pair comprises an absorbent and a refrigerant.

[0041] The evaporating device is used for evaporating the refrigerant output by the condensing device under the refrigeration condition, and forms saturated steam of the refrigerant.

[0042] The absorption device is connected with the generating device and the evaporating device, and is used for receiving the saturated steam and conveying the absorbent dilute solution to the generating device.

[0043] The generating device is realized by a generator 2, the condensing device is realized by a condenser 3, the evaporating device is realized by an evaporator 4, the absorption device is realized by an absorber 5, and the fuel cell is realized by a proton exchange membrane fuel cell 1.

[0044] The proton exchange membrane fuel cell 1 is connected with the generator 2 and a heating fin 6 in the equipment where the proton exchange membrane fuel cell 1 is located through pipelines, and the pipeline connected with the generator 2 is provided with valves V1 and V2, and the pipeline connected with the heating fin 6 is provided with valves V3 and V4, and the equipment can be a commercial vehicle such as a bus, a refrigerated vehicle, a tramcar, a logistics vehicle and a ship.

[0045] The low-temperature waste heat of the proton exchange membrane fuel cell 1 is transported to the generator 2, and is used as a driving heat source in the generator 2; and the low-temperature waste heat is connected with the heating fin 6, and is used for heating the artificial environment of a car.

[0046] Preferably, the absorbent is an organic reagent, an ionic liquid or a multi-element mixed system thereof, the organic reagent is tetraethylene glycol dimethyl ether, and the refrigerant is HFO-1233zd (Z).

[0047] The system further comprises a heat exchange device arranged between the generating device and the absorption device.

[0048] ​Preferably, the system further comprises a compression device arranged between the evaporation device and the absorption device for assisting the pressurization of the saturated steam input to the absorption device.

[0049] Preferably, the system further comprises a radiator connected to the fuel cell through a pipeline for receiving the waste heat generated by the fuel cell.

[0050] Preferably, the system further comprises a flow meter arranged between the condensation device and the evaporation device and between the generation device and the absorption device.

[0051] The generator 2 is connected to the condenser 3, and the superheated steam of the refrigerant HFO-1233zd(Z) generated by the generator 2 after absorbing the waste heat enters the condenser 3 to be condensed, and the condensation heat is cooled by heat exchange with the environment, i.e. the ambient air, and the condensed refrigerant HFO-1233zd(Z) is obtained by heat exchange cooling; the generator 2 is also connected to the absorber 5 through the heat exchanger 7, and the concentrated solution of the absorbent in the generator 2 enters the absorber 5 after heat exchange through the heat exchanger 7, and a throttle valve TV2 is arranged on the pipeline between the heat exchanger 7 and the absorber 5 for controlling the flow rate of the fluid in the pipeline;

[0052] The condenser 3 is connected to the evaporator 4, and the condensed refrigerant HFO-1233zd(Z) in the condenser 3 enters the evaporator 4 after passing through the flow meter F1, and is heated in the evaporator 4 to become saturated steam of the refrigerant HFO-1233zd(Z). In the refrigeration working condition, the evaporation heat absorption process absorbs heat from the refrigerant to achieve refrigeration, and the heat exchange medium in the heat exchanger in the evaporator is the refrigerant; in the heating working condition, the heat exchange with the ambient air absorbs heat, and the air is used as a low-temperature heat source to absorb heat from the environment by heat exchange with the air;

[0053] The evaporator 4 is connected to the absorber 5 through the compressor 8, and the saturated steam of the refrigerant HFO-1233zd(Z) enters the absorber 5 to be absorbed by the concentrated solution of the absorbent from the generator 2, and the absorption process releases heat. In the refrigeration working condition, the heat released by the absorption process is cooled by heat exchange with the ambient air; in the heating working condition, the heat released by the absorption process is used for heating, i.e. heating the artificial environment such as the car cabin of the fuel cell vehicle;

[0054] The absorber 5 is also connected to the generator 2, and after absorbing the saturated steam of the refrigerant HFO-1233zd(Z) from the generator 2, the concentrated solution of the absorbent becomes a dilute solution of the absorbent, which is pumped by the pump P1 and heat exchanged through the heat exchanger 7, and then enters the generator 2, and is driven by the low-temperature waste heat delivered by the fuel cell to regenerate the concentrated solution of the absorbent;

[0055] The low-temperature absorption working pair used in the application, wherein, as described above, the absorbent comprises one of an organic reagent, an ionic liquid, or a multi-component mixed system, such as a plurality of composite absorbents; and the refrigerant is HFO-1233zd (Z), i.e., cis-chlorotrifluoropropene, or a composite refrigerant containing HFO-1233zd (Z), which has a boiling point of 39 o C, higher than other hydrofluoroalkene refrigerants, and is liquid at room temperature, facilitating operation; has a freezing point lower than -100 o C, and is not prone to crystallization; is essentially non-toxic, safe, and non-explosive; has an approximate ozone layer destruction coefficient of 0, low greenhouse effect, and is environmentally friendly; the molar fraction of the absorbent in the low-temperature working pair ranges from 10% to 90%, which is the ratio of the number of moles of the absorbent to the sum of the number of moles of the absorbent and the number of moles of the refrigerant in the working pair; the absorbent has a relatively high boiling point and a relatively low saturated vapor, and is chemically stable. The working pair has the advantages of low viscosity, low occurrence temperature, good economy, almost no corrosion, wide working range, and reduced processing technology requirements, compared with the existing commercial lithium bromide / H2O working pair.

[0056] The compressor 8 in the system is used to increase the working pressure in the absorber 5 through compressor-assisted pressurization in extremely hot climates, to reduce the working pressure in the evaporator 4 and the evaporation temperature of the refrigerant HFO-1233zd (Z), to meet the summer refrigeration requirements of hydrogen energy fuel cell vehicles, or low-temperature refrigeration requirements of refrigerated trucks, etc.; and is used to increase the working pressure in the absorber 5 through compressor-assisted pressurization in extremely cold climates, to increase the heat release temperature when the concentrated solution of the absorbent in the absorber 5 absorbs the vapor of the refrigerant HFO-1233zd (Z), to achieve heating in a temporary parking state or when the fuel cell stops working, or cold start of a proton exchange membrane fuel cell.

[0057] The system not only can utilize low-grade waste heat of the low-temperature fuel cell to achieve refrigeration, but also can achieve refrigeration or heating in a parking state through absorption-type thermochemical energy storage, and can achieve refrigeration or heating under extreme conditions and cold start of the fuel cell through compressor assistance, thereby improving the overall energy efficiency of the fuel cell.

[0058] Preferably, the refrigeration working condition process and the heating working condition process in the fuel cell waste heat utilization system of the application are as follows:

[0059] The refrigeration working condition process specifically includes:

[0060] S11. Closing the valve between the heating panel and the fuel cell, and opening the valve between the generating device and the fuel cell, the waste heat generated after the fuel cell is cooled is output to the generating device, the generating device heats the dilute solution of the absorbent from the absorption device, and part of the refrigerant is evaporated to output superheated vapor to the condensing device.

[0061] S12. The condensed refrigerant superheated vapor is output to the evaporating device by the condensing device;

[0062] S13. The condensed refrigerant is evaporated by the evaporating device to obtain saturated vapor of the refrigerant, and the evaporating process absorbs heat of the equipment where the fuel cell is located, thereby realizing refrigeration;

[0063] S14. The saturated vapor flows into the absorbing device, and a concentrated solution of the absorbing agent in the absorbing device and a dilute solution of the absorbing agent in the absorbing device are heated in the heat exchanger and then enter the absorbing device, the concentrated solution of the absorbing agent absorbs the saturated vapor and becomes the dilute solution of the absorbing agent, and heat is released in the absorbing process, thereby realizing cooling through heat exchange with the environment;

[0064] The heating working condition process specifically includes:

[0065] The valve between the heating radiator and the fuel cell is opened, and the valve between the generating device and the fuel cell is closed, and the waste heat generated after the fuel cell is cooled is output to the heating radiator to supply heat to the equipment where the fuel cell is located.

[0066] Preferably, in the refrigeration process, the dilute solution of the absorbing agent in the absorbing device enters the generating device again to be regenerated into the concentrated solution of the absorbing agent by using the waste heat, thereby entering the next refrigeration cycle.

[0067] Specifically,

[0068] In the refrigeration working condition:

[0069] The valves V3, V4, V5 and V7 are closed, and the valves V1, V2, V6 and V8 are opened. The proton exchange membrane fuel cell 1 is cooled in a water cooling manner, and the waste heat generated is used as a driving heat source of the generator 2 in the low-temperature absorption refrigeration subsystem, the dilute solution of the absorbing agent in the absorber 5 is heated in the generator 2, part of the refrigerant hydrogen fluoride alkene HFO-1233zd(Z) is evaporated, the concentration regeneration of the absorbing solution is realized, and the concentrated solution of the absorbing agent such as an organic reagent, an ionic liquid or a multi-component mixed system is obtained;

[0070] The superheated vapor of the refrigerant hydrogen fluoride alkene HFO-1233zd(Z) generated by the generator 2 is condensed in the condenser 3 and then flows into the evaporator 4 through the throttling valve TV1. The superheated vapor is condensed in the condenser 3 and releases heat, thereby realizing cooling through heat exchange with the environment;

[0071] In the evaporator 4, the refrigerant water is used as a low-temperature heat source to heat the refrigerant HFO-1233zd(Z) in the evaporator 4. The refrigerant water is used as a heat exchange medium in the heat exchanger in the evaporator 4. The HFO-1233zd(Z) absorbs heat in the evaporator 4 and evaporates into saturated steam of the refrigerant HFO-1233zd(Z). During the evaporation of the refrigerant HFO-1233zd(Z), heat is absorbed from the refrigerant water, which is cooled to provide refrigeration for commercial vehicles such as fuel cell refrigerated trucks, buses, and trolleybuses, and ships, etc. in summer. The refrigerant water is used as a heat exchange medium, which is cooled in the evaporator and used for refrigeration in fuel cell refrigerated trucks, buses, and trolleybuses, and ships, etc.

[0072] The saturated steam of the refrigerant HFO-1233zd(Z) in the evaporator 4 flows into the absorber 5. The concentrated solution of the absorbent in the generator 2 and the dilute solution of the absorbent in the absorber 5 are heated in the heat exchanger 7 and then enter the absorber 5. In the absorber 5, the concentrated solution of the absorbent absorbs the saturated steam of the refrigerant HFO-1233zd(Z) and becomes a dilute solution of the absorbent. During the absorption process, heat is released, which is removed by heat exchange with the environment to cool the absorber 5.

[0073] In the absorber 5, the concentrated solution of the absorbent absorbs the saturated steam of the refrigerant HFO-1233zd(Z) and becomes a dilute solution of the absorbent, which enters the generator 2 again and is regenerated into a concentrated solution of the absorbent by using the low-temperature waste heat of the fuel cell, so as to enter the next refrigeration cycle.

[0074] In extreme hot weather, the above refrigeration process can be assisted by the compressor 8 to increase the working pressure in the absorber 5 and reduce the working pressure in the evaporator 4, thereby reducing the evaporation temperature of the refrigerant HFO-1233zd(Z) in the evaporator 4 to meet the summer refrigeration requirements of hydrogen energy fuel cell vehicles or the low-temperature refrigeration requirements of refrigerated trucks, etc.

[0075] In the heating mode

[0076] Close the valves V1, V2, V5, V6, V7, and V8, and open the valves V3 and V4. The cooling water circulates to remove the low-temperature waste heat of the proton exchange membrane fuel cell and supplies the heating radiators to provide heating for the artificial environment of the fuel cell vehicle cabin in cold seasons.

[0077] In the energy storage mode, the energy storage mode is used to store part of the waste heat of the fuel cell in the form of chemical potential energy while providing refrigeration in summer or heating in winter. The stored energy is used for refrigeration in summer or heating in winter and cold start when the fuel cell is in a stopped state.

[0078] In winter energy storage mode, open valves V1, V2, V3 and V4, close valves V5, V6, V7 and V8. Part of the cooling water circulates to take away the low-temperature waste heat of the proton exchange membrane fuel cell, which is used for heating the artificial environment of the fuel cell vehicle cabin in cold seasons. Part of the low-temperature waste heat of the proton exchange membrane fuel cell is used to drive the generator 2. The concentrated solution of refrigerant HFO-1233zd(Z) and absorbent stored in the generator 2 enters the generator 2 through the flow regulating valves F1 and F2. The dilute solution of absorbent in the absorber 5 is heated by the waste heat of the proton exchange membrane fuel cell, and the refrigerant HFO-1233zd(Z) is evaporated to obtain a concentrated solution of absorbent, which is stored in the generator 2. The evaporated refrigerant HFO-1233zd(Z) enters the condenser 3 to be condensed to obtain liquid refrigerant HFO-1233zd(Z), which is stored in the condenser 3. Thus, the low-temperature waste heat of the proton exchange membrane fuel cell is converted into chemical potential energy and stored.

[0079] In summer energy storage mode, close valves V3, V4, V5 and V7, and open valves V1, V2, V6 and V8. By adjusting the flow regulating valves F1 and F2, the concentrated solution of absorbent flowing into the absorber 5 and the refrigerant flowing into the evaporator 4 are reduced, and the concentrated solution of absorbent and the refrigerant are stored in the generator 2 and the condenser 3 respectively. In this way, the excess waste heat of the fuel cell is stored in the form of chemical potential energy while meeting the cooling load demand in summer.

[0080] In energy release mode

[0081] In summer temporary parking state or fuel cell stop working, close valves V1, V2, V3, V4, V5 and V7, and open valves V6 and V8. By adjusting the flow regulating valves F1 and F2, the concentrated solution of absorbent flowing into the absorber 5 and the refrigerant HFO-1233zd(Z) flowing into the evaporator 4 are increased.

[0082] The refrigerant water as a low-temperature heat source heats the refrigerant HFO-1233zd(Z) in the evaporator 4, and the refrigerant HFO-1233zd(Z) evaporates and absorbs heat, and flows into the absorber 5. The refrigerant HFO-1233zd(Z) evaporates and absorbs heat in the evaporator 4, realizes refrigeration, and meets the summer refrigeration demand of the hydrogen energy fuel cell vehicle;

[0083] In extreme hot weather, the above energy release process can reduce the evaporation temperature of the refrigerant HFO-1233zd(Z) in the evaporator 4 with the assistance of the compressor 8, meet the summer refrigeration demand of the hydrogen energy fuel cell vehicle, or the low-temperature refrigeration demand of the refrigerated truck, etc.

[0084] In winter temporary parking state or fuel cell stop working, close valves V1, V2, V3, V4, V6 and V8, open valves V5, V7.

[0085] The concentrated solution of absorbent in absorber 5 absorbs refrigerant HFO-1233zd(Z) vapor and releases heat, and heating is achieved in absorber 5, and the generated heat is supplied through the heating coil 6 to meet the winter heating demand of hydrogen fuel cell vehicles;

[0086] In extremely cold weather, the above energy release process can increase the working pressure in absorber 5 with the assistance of compressor 8, so that the heat release temperature of the concentrated solution of absorbent in absorber 5 when absorbing refrigerant HFO-1233zd(Z) vapor is increased, the heating temperature is increased, and heating is achieved in the temporary parking state or fuel cell stop working; or used for cold start of proton exchange membrane fuel cell, at this time, close valves V1, V2, V6 and V8, open valves V3, V4, V5 and V7.

[0087] The above description shows and describes several preferred embodiments of the present application, but as previously described, it should be understood that the present application is not limited to the forms disclosed herein, should not be considered as excluding other embodiments, and can be used in various other combinations, modifications and environments, and can be modified within the scope of the application described herein, by the above teaching or related technical or knowledge. The modifications and changes made by those skilled in the art without departing from the spirit and scope of the present application shall be within the scope of protection of the appended claims of the present application.

Claims

1. A low temperature working fluid pair, characterized in that The low-temperature working medium pair is used in low-grade waste heat of an absorption refrigeration or heating principle, and the low-temperature working medium pair comprises an absorbent and a refrigerant, the absorbent is used for absorbing the refrigerant and emitting heat, the refrigerant is used for absorbing heat and evaporating, the absorbent comprises an organic absorbent, the refrigerant is HFO-1233zd(Z) or a composite refrigerant containing HFO-1233zd(Z), the boiling point of HFO-1233zd(Z) is 39 DEG C, HFO-1233zd(Z) is in a liquid state at room temperature, and the freezing point of HFO-1233zd(Z) is lower than -100 DEG C, and the organic absorbent is tetraethylene glycol dimethyl ether, and the mole fraction of the organic absorbent ranges from 10% to 90%.

2. The cryogenic working fluid pair of claim 1, wherein The mole fraction is a ratio of the number of moles of the absorbent to the sum of the number of moles of the absorbent and the number of moles of the refrigerant.

3. Use of a working fluid pair according to any one of claims 1-2, characterized in that The low-temperature working medium pair is used in a fuel cell waste heat utilization system.

4. Use of a low temperature working fluid pair according to claim 3, characterized in that The system comprises a fuel cell, a generating device, a condensing device, an evaporating device and an absorbing device. The fuel cell is connected with the generating device and is used for providing waste heat. The generating device is connected with the condensing device and the absorbing device, and the low-temperature working medium pair contained in the generating device is output to the condensing device or the absorbing device under refrigeration or heating conditions. The evaporating device is used for evaporating the refrigerant of the low-temperature working medium pair output by the condensing device under the refrigeration condition, and forms superheated steam of the refrigerant. The absorbing device is connected with the generating device and the evaporating device, and is used for receiving the superheated steam and conveying the absorbent dilute solution of the low-temperature working medium pair to the generating device.

5. Use of a low temperature working fluid pair according to claim 4, characterized in that The system further comprises a heat exchange device arranged between the generating device and the absorbing device.

6. Use of a low temperature working fluid pair according to claim 4, characterized in that The system further comprises a compression device arranged between the evaporating device and the absorbing device, and used for condensing the superheated steam input to the absorbing device.

7. The use of a low temperature working fluid pair according to claim 4, wherein The refrigeration condition process specifically comprises: S11. closing a valve between the heating radiator and the fuel cell, opening a valve between the generating device and the fuel cell, outputting the waste heat generated after the fuel cell is cooled to the generating device, heating the absorbent dilute solution from the absorbing device in the generating device, and evaporating part of the refrigerant superheated steam to output to the condensing device; S12. condensing the refrigerant superheated steam in the condensing device and outputting to the evaporating device; S13. evaporating the refrigerant after condensation to obtain saturated steam of the refrigerant, absorbing heat of the equipment where the fuel cell is arranged in the evaporating process, and realizing refrigeration; S14. the saturated steam flows into the absorbing device, the absorbent concentrated solution in the generating device and the absorbent dilute solution in the absorbing device are heat-exchanged in the heat exchanger and then enter the absorbing device, the absorbent concentrated solution absorbs the saturated steam and becomes the absorbent dilute solution, and heat is emitted in the absorption process, and cooling is realized by heat exchange with the environment; The heating condition process specifically comprises: opening the valve between the heating radiator and the fuel cell, closing the valve between the generating device and the fuel cell, outputting the waste heat generated after the fuel cell is cooled to the heating radiator, and using the waste heat to heat the equipment where the fuel cell is arranged.

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