Mixed working medium refrigeration heat pump system and control method

Abstract

The invention discloses a mixed working medium refrigeration heat pump system and a control method. The heat pump system comprises a transcritical cycle structure and an adsorption and desorption mass transfer process unit. The critical cycle structure comprises a compressor, an oil separator, an oil return valve, a gas cooler, a back pressure valve, a gas-liquid separator, an electronic expansion valve and an evaporator which are connected with one another; the adsorption and desorption mass transfer process unit comprises a first pressure regulating valve, an adsorption and desorption device and a second pressure regulating valve which are connected with one another; a working medium inlet of the gas cooler is connected with a working medium outlet of the gas cooler through a first communicating pipeline, and a first coil pipe wound on the outer surface of the adsorption and desorption device is arranged in the first communicating pipeline; and a working medium inlet of the evaporator is connected with a working medium outlet of the evaporator through a second communicating pipeline, and a second coil pipe wound on the outer surface of the adsorption and desorption device is arranged in the second communicating pipeline. The performance of the refrigeration heat pump system can be remarkably improved through the component proportion in the mixed working medium and the exhaust pressure of the compressor.

Description

Technical Field

[0001] This invention relates to the fields of refrigeration and heating, adsorption refrigeration and heat pump technology, and in particular to a mixed working fluid refrigeration heat pump system and control method, specifically a variable component transcritical CO2 mixed working fluid refrigeration heat pump system and control method based on adsorption separation. Background Technology

[0003] Compared to pure working fluid, using non-azeotropic mixed working fluid can effectively improve the temperature matching of heat source and heat sink temperature change heat exchange. However, its performance improvement is closely related to boundary conditions (source and sink temperatures, temperature range). In actual heat pump applications, the source and sink temperatures rise and fall differently.

[0004] In most application scenarios, the temperature difference between the heat source and the heat sink is large. If a non-azeotropic working fluid subcritical cycle with a fixed composition is selected, it is impossible to simultaneously achieve source and sink temperature matching. Furthermore, there is mass transfer resistance at the gas-liquid interface during the phase change process, which leads to heat transfer deterioration and causes a bottleneck in the performance improvement of the heat pump heating system.

[0005] Therefore, there is an urgent need to develop a technology that can solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to address the technical deficiencies of existing technologies by providing a mixed working fluid refrigeration heat pump system and its control method.

[0007] Therefore, the present invention provides a mixed working fluid refrigeration heat pump system, which includes a transcritical cycle structure and an adsorption-desorption mass transfer process unit;

[0008] The critical cycle structure includes: a compressor, an oil separator, an oil return valve, a gas cooler, a back pressure valve, a gas-liquid separator, an electronic expansion valve, and an evaporator;

[0009] The working fluid outlet of the evaporator is connected to the working fluid inlet of the compressor;

[0010] The compressor's working fluid outlet is connected to the oil separator's working fluid inlet;

[0011] The lubricating oil outlet of the oil separator is connected to one end of the inlet of the return oil valve;

[0012] The working fluid outlet of the oil separator is connected to the working fluid inlet of the gas cooler;

[0013] The other end of the oil return valve is connected to the working fluid inlet of the compressor;

[0014] The working fluid outlet of the gas cooler is connected to one end of the inlet of the back pressure valve;

[0015] The other end of the back pressure valve is connected to the working fluid inlet of the gas-liquid separator;

[0016] The liquid working fluid outlet of the gas-liquid separator is connected to one end of the inlet of the electronic expansion valve;

[0017] The other end of the electronic expansion valve is connected to the working fluid inlet of the evaporator.

[0018] The adsorption-desorption mass transfer process unit includes: a first pressure regulating valve, an adsorption-desorption device, and a second pressure regulating valve;

[0019] The gas working fluid outlet of the gas-liquid separator is connected to one end of the inlet of the first pressure regulating valve;

[0020] The other end of the first pressure regulating valve is connected to the high-pressure end interface of the suction-desorption unit.

[0021] The low-pressure end interface of the suction-desorber is connected to one end inlet of the second pressure regulating valve;

[0022] The other end of the second pressure regulating valve is connected to the working fluid outlet of the evaporator in the transcritical cycle structure.

[0023] The working fluid inlet of the gas cooler in the transcritical cycle structure is connected to the working fluid outlet of the gas cooler through a first connecting pipe, and the first connecting pipe has a first coil wound around the outer surface of the adsorber.

[0024] The working fluid inlet of the evaporator in the transcritical cycle structure is connected to the working fluid outlet of the evaporator through a second connecting pipe, and the second connecting pipe has a second coil wound around the outer surface of the adsorber.

[0025] Furthermore, the present invention also provides a control method for a mixed working fluid refrigeration heat pump system as described above, including the following operating modes:

[0026] Step S1: Perform transcritical CO2 cycle operation of non-azeotropic working fluid;

[0027] Step S1 is specifically as follows: The low-temperature, low-pressure non-azeotropic working fluid flowing out of the evaporator's working fluid outlet is drawn into the compressor and compressed to a high-temperature, high-pressure non-azeotropic working fluid. Then, it enters the oil separator, where the oil carried by the non-azeotropic working fluid is separated and returned to the compressor through the oil return valve. At the same time, the non-azeotropic working fluid enters the gas cooler to exchange heat with the heat exchange fluid, which provides heat to the heat user. The non-azeotropic working fluid then flows through the back pressure valve to maintain the pressure on the high-pressure side of the system. Then, the working fluid undergoes gas-liquid separation in the gas-liquid separator. After that, the working fluid flows through the electronic expansion valve for throttling and pressure reduction, and then evaporates and absorbs heat in the evaporator, completing the transcritical CO2 cycle operation of the non-azeotropic working fluid.

[0028] Step S2: Perform a pressure swing adsorption cycle operation on a non-azeotropic working fluid;

[0029] Step S2 specifically involves: monitoring the actual circulating mass fraction C of CO2 in the non-azeotropic working fluid flowing out of the evaporator's working fluid outlet using a concentration detector. cir ;

[0030] At a certain moment, the optimal circulating mass fraction C of CO2 is... opt The actual circulating mass fraction of CO2 at this time, C cir Deviation between |C cir -C opt | has reached the preset allowable deviation ε C Then, according to C opt With C cir Based on the magnitude of the two values, corresponding preset adjustment operations are performed on the first and second pressure regulating valves.

[0031] As can be seen from the technical solutions provided by the present invention above, compared with the prior art, the present invention provides a mixed working fluid refrigeration heat pump system and control method, which is scientifically designed. The system of the present invention adopts a variable component transcritical CO2 mixed working fluid refrigeration heat pump system based on adsorption separation. By adjusting the component ratio (i.e., mass percentage) in the mixed working fluid and the exhaust pressure of the compressor, it can ensure the coordinated matching of source and sink temperatures, and avoid the deterioration of phase change heat transfer during the heat release process through supercritical heat exchange without phase change, thus significantly improving the performance of the refrigeration heat pump system, which has great practical significance.

[0032] After testing, this invention, by employing a non-azeotropic mixed working fluid transcritical cycle structure, can balance both the heat source and sink sides, achieving efficient and coordinated temperature matching. By further adjusting the exhaust pressure, this invention can achieve a good match between the supercritical temperature curve and the heat sink. Simultaneously, by adjusting the cycle components, the temperature slip during the evaporation process can be actively controlled to ensure temperature matching on the heat source side. Furthermore, through the coordinated control of both the cycle components and the exhaust pressure (two degrees of freedom), a balance between heat source and sink temperature matching can be achieved. Attached Figure Description

[0033] Figure 1 The present invention provides a mixed working fluid refrigeration heat pump system, showing the relationship between the system COP (coefficient of performance) and the mass fraction of CO2 in the cycle under specific operating conditions;

[0034] Figure 2 A structural schematic diagram of a mixed working fluid refrigeration heat pump system provided by the present invention;

[0035] In the diagram: 1. Compressor; 2. Oil separator; 3. Oil return valve; 4. Gas cooler; 5. Back pressure valve;

[0036] 6. Gas-liquid separator; 7. Electronic expansion valve; 8. Evaporator; 9. Concentration detector; 10. First pressure regulating valve;

[0037] 11. Adsorption / Desorption Unit; 12. Second Pressure Regulating Valve; 13. First Throttle Valve; 14. First Check Valve 1; 15. Second Throttle Valve; 16. Second Check Valve; 17. Controller. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, 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., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0040] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0041] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0042] See Figure 1 , Figure 2 The present invention provides a mixed working fluid refrigeration heat pump system, including a transcritical cycle structure and an adsorption-desorption mass transfer process unit;

[0043] The transcritical cycle structure includes: compressor 1, oil separator 2, oil return valve 3, gas cooler 4, back pressure valve 5, gas-liquid separator 6, electronic expansion valve 7, and evaporator 8.

[0044] The working fluid outlet of evaporator 8 is connected to the working fluid inlet of compressor 1;

[0045] The working fluid outlet of compressor 1 is connected to the working fluid inlet a of oil separator 2;

[0046] The lubricating oil outlet b of the oil separator 2 is connected to one end of the inlet of the return oil valve 3;

[0047] The working fluid outlet c of oil separator 2 is connected to the working fluid inlet a of gas cooler 4;

[0048] The other end of the oil return valve 3 is connected to the working fluid inlet of the compressor 1;

[0049] The working fluid outlet b of the gas cooler 4 is connected to one end of the inlet of the back pressure valve 5;

[0050] The other end of the back pressure valve 5 is connected to the working fluid inlet a of the gas-liquid separator 6;

[0051] The liquid working fluid outlet b of the gas-liquid separator 6 is connected to one end inlet of the electronic expansion valve 7;

[0052] The other end of the electronic expansion valve 7 is connected to the working fluid inlet of the evaporator 8.

[0053] It should be noted that, based on the above-mentioned transcritical cycle structure, this invention can complete the transcritical CO2 cycle operation of non-azeotropic mixed working fluids.

[0054] The adsorption-desorption mass transfer process unit (i.e., the pressure swing adsorption cycle unit of the non-azeotropic mixed working fluid) includes: a first pressure regulating valve 10, an adsorption-desorption device 11 and a second pressure regulating valve 12, as well as a concentration detector 9, a first throttle valve 13, a first check valve 14, a second throttle valve 15 and a second check valve 16.

[0055] The gas working fluid outlet c of the gas-liquid separator 6 is connected to one end inlet of the first pressure regulating valve 10;

[0056] The other end outlet of the first pressure regulating valve 10 is connected to the high-pressure end interface a of the suction-desorption device 11.

[0057] The low-pressure end interface b of the adsorption-desorption device 11 is connected to one end inlet of the second pressure regulating valve 12;

[0058] The other end of the second pressure regulating valve 12 is connected to the working fluid outlet b of the evaporator 8 in the transcritical cycle structure.

[0059] The working fluid inlet a of the gas cooler 4 in the transcritical cycle structure is connected to the working fluid outlet b of the gas cooler 4 through a first connecting pipe, and the first connecting pipe has a first coil wound around the outer surface of the adsorber 11.

[0060] The working fluid inlet a of the evaporator 8 in the transcritical cycle structure is connected to the working fluid outlet b of the evaporator 8 through a second connecting pipe, and the second connecting pipe has a second coil wound around the outer surface of the adsorber 11.

[0061] It should be noted that, in the transcritical cycle structure, a branch of the working fluid at the working fluid inlet a of the gas cooler 4 is wound around the surface of the adsorber-desorber 11, providing the heat required for desorption, and then connected to the working fluid outlet b of the gas cooler 4. Similarly, a branch of the working fluid at the working fluid inlet a of the evaporator 8 is wound around the surface of the adsorber-desorber 11, absorbing the heat generated by adsorption, and then connected to the working fluid outlet b of the evaporator 8.

[0062] It should be noted that, based on the structural design of the adsorption-desorption mass transfer process unit described above, the pressure swing adsorption cycle operation of the non-azeotropic mixed working fluid can be completed in this invention.

[0063] In this invention, specifically, the first coil in the first connecting pipe and the second coil in the second connecting pipe are spaced apart and do not contact each other.

[0064] In this invention, specifically, the first coil in the first connecting pipe is provided with a first throttle valve 13 and a first check valve 14 in sequence on the connecting pipe between the first coil and the working fluid outlet b of the gas cooler 4.

[0065] In the second connecting pipe, the second coil is connected to the working fluid outlet b of the evaporator 8 by a second throttle valve 15 and a second check valve 16.

[0066] In this invention, specifically, a concentration detector 9 is installed on the connecting pipeline between the working fluid outlet of the evaporator 8 and the working fluid inlet of the compressor 1.

[0067] In this invention, specifically, the mixed working fluid heat pump system further includes a controller 17;

[0068] The controller 17 is communicatively connected to the signal control terminals of the first pressure regulating valve 10 and the second pressure regulating valve 12, respectively, and is used to control the opening and closing states of the first pressure regulating valve 10 and the second pressure regulating valve 12 by sending control signals.

[0069] In practice, the controller 17 can be a programmable logic controller (PLC), a central processing unit (CPU), a digital signal processor (DSP), or a microcontroller (MCU).

[0070] In this invention, in a specific implementation, any two interconnected devices that transfer working fluids or other substances to each other are connected by a hollow connecting pipe.

[0071] In this invention, specifically, the working fluid used in the mixed working fluid refrigeration heat pump system is a non-azeotropic mixed working fluid.

[0072] In practice, the non-azeotropic working fluid includes two components: an organic working fluid with low GWP (global warming potential) and carbon dioxide (CO2).

[0073] For example, in a non-azeotropic mixture, the mass fraction of the organic working fluid with low GWP (global warming potential) can be 0.1 (i.e., 10% by mass), and the mass fraction of carbon dioxide (CO2) can be 0.9 (i.e., 90% by mass). Among these, the preferred organic working fluid with low GWP is R1234ze(E).

[0074] It should be noted that, for the present invention, the non-azeotropic mixture of the two components, low-GWP organic working fluid and carbon dioxide (CO2), can reduce the transcritical CO2 cycle exhaust pressure and throttling loss.

[0075] It should be noted that, in the specific implementation of this invention, the low-grade heat source can be shallow geothermal energy (referring to the heat energy in the constant temperature layer tens to hundreds of meters below the surface, such as the heat in groundwater, surface water and underground soil), industrial waste heat energy (such as industrial hot wastewater), and domestic waste heat energy (including the cold and heat resources contained in domestic sewage).

[0076] In practice, a delivery pump can be installed on the pipeline of the low-grade heat source to generate pressure and realize the directional delivery of the medium (such as water or air). (For example, when the medium being delivered is gas, the delivery pump can be an air pump; when the medium being delivered is liquid, it can be a liquid pump.)

[0077] In the specific implementation of this invention, combined with Figure 2 As shown, the hot end of the evaporator 8 is provided with two inlets and outlets, namely inlet c and outlet d. The connection method of the evaporator 8 can include two types: circulating and direct flow.

[0078] 1. When the evaporator 8 adopts a circulating connection method, specifically: both the circulating inlet c and the circulating outlet d are connected to a low-grade heat source. The hot end inlet c of the circulating system is connected to one end of the conveying pipeline of the low-grade heat source located outside. Its function is to introduce the external low-grade heat source medium (such as hot groundwater) into the evaporator 8 to provide heat for the refrigerant in the evaporator 8 which is in a low-temperature state. The hot end outlet d is connected to the heat source circulation pipeline inside the building envelope (such as a building). Its function is to export the heat source medium after heat exchange to provide cooling supply to the building envelope (such as a building).

[0079] It should be noted that the building envelope refers to the walls, doors, windows, etc. that enclose the building space and can effectively resist the impact of adverse environments.

[0080] 2. When the evaporator 8 adopts a direct-flow connection, specifically: the direct-flow inlet c is connected to a low-grade heat source, and its function is to introduce the external low-grade heat source medium into the evaporator 8 to provide heat for the refrigerant in the evaporator 8 at a low temperature; one end (i.e., the inner end) of the hot end outlet d is connected to the heat exchange area of ​​the evaporator 8, and the other end (i.e., the outer end) of the hot end outlet d can be directly connected to the external environment (such as the atmosphere) or to the interior of the enclosure structure. After cooling the interior of the enclosure structure, it flows out from the enclosure structure and is discharged into the atmosphere; after heat exchange in the evaporator 8, the heat source medium with a reduced temperature is discharged through the hot end outlet d, and this low-temperature medium can be directly used to provide cooling for the space inside the enclosure structure; at this time, the heat source medium is of the type that does not need to be recovered (such as air), and the discharge process does not require an additional recovery treatment device, and can be directly discharged into the environment to complete the final treatment of the medium circulation.

[0081] Therefore, in this invention, when the evaporator 8 adopts a circulating connection method, the corresponding circulating low-grade heat source (e.g., groundwater) can be reinjected into the groundwater after cooling the building envelope, thus allowing for reuse. However, when the evaporator 8 adopts a direct-flow connection method, the corresponding direct-flow low-grade heat source (e.g., air) can be directly discharged into the atmosphere after cooling the building envelope, because low-grade heat sources like air are very common and do not require recycling. It should be noted that air contains low-grade heat energy.

[0082] In the specific implementation of this invention, combined with Figure 2 As shown, see Figure 2 As shown, the cold end of the gas cooler 4 is provided with two inlets and outlets, namely the cold end inlet c and the cold end outlet d. The connection method of the gas cooler 4 can include two types: circulation type and direct flow type.

[0083] 1. When the gas cooler 4 adopts a circulating connection method, specifically: the circulating inlet c and outlet d are connected to the two ends of the medium (e.g., water) circulation pipeline in the heat user end, respectively. The medium in the heat user end exchanges heat with the refrigerant through the gas cooler 4, causing the refrigerant to cool down and the medium in the heat user end to heat up. The heated medium in the heat user end is connected to the heat user end through the cold end outlet d of the gas cooler 4, providing heat to the heat user end. After being used in the heat user end and having lost heat, the low-temperature circulating medium re-enters the gas cooler 4 through the circulation pipeline in the heat user end from the cold end inlet c, so as to repeatedly participate in the heat exchange process of the refrigerant in the gas cooler 4.

[0084] It should be noted that, in this context, the heat user end can be a building that requires heat, and the medium for heat use can be water. This water is located in a circulating pipeline within the building, and this circulating pipeline can be equipped with a liquid pump to generate pressure and achieve directional transportation of the medium (e.g., water). For example, in a heating system, the radiators in a residential home and the areas covered by the air conditioning vents in the room, as well as the area covered by the air conditioning vents in an office building, are all considered heat users. In an industrial waste heat recovery system, production process equipment that needs to utilize waste heat for heating can also be considered a heat user end.

[0085] 2. When the gas cooler 4 uses a direct-flow connection, specifically: the direct-flow inlet c is connected to one end of an external heat sink (such as a tap water pipe). The heat sink exchanges heat with the refrigerant through the gas cooler 4, causing the refrigerant to cool down and the heat sink working medium (such as tap water) to heat up. The heated heat sink working medium is then connected to the heat user end through the outlet d of the gas cooler 4 (in this case, the heat user end can be a water pipe; for example, the outlet d of the gas cooler 4 is connected to one end of a water pipe, and the other end of the water pipe is equipped with a faucet), providing heat to the heat user. For example, in a heating system, the radiators in a residential home and the area covered by the air conditioning vents in the room, as well as the area covered by the air conditioning vents in an office building, are all considered heat users; in an industrial waste heat utilization system, production equipment that needs to utilize waste heat for heating can also be considered heat users.

[0086] To better understand the technical solution of this invention, the roles of the main components in the refrigeration cycle are described below:

[0087] Compressor 1: Used to compress the low-pressure gaseous refrigerant to increase its pressure and temperature, forming a high-temperature and high-pressure gaseous refrigerant, which is then delivered to the oil separator 2.

[0088] Oil separator 2: Used to process the high-temperature and high-pressure gaseous refrigerant from compressor 1, separating the lubricating oil carried in it, so that the high-temperature and high-pressure gaseous refrigerant can be delivered to gas cooler 4, avoiding the lubricating oil from entering the subsequent circulation and affecting the heat exchange effect. The separated lubricating oil can be returned to compressor 1 through oil return valve 3, etc., to ensure compressor lubrication.

[0089] Oil return valve 3: Used to control the return path of lubricating oil separated from oil separator 2, sending the lubricating oil back to compressor 1 to ensure normal operation.

[0090] Gas cooler 4: Used to receive high-temperature and high-pressure refrigerant from oil separator 2, cool it down by exchanging heat with heat sink, and turn it into low-temperature and low-pressure refrigerant, which is then delivered to back pressure valve 5.

[0091] Back pressure valve 5: Used to precisely regulate the discharge pressure of compressor 1 to adapt to changes in operating conditions and ensure the stability of cycle thermodynamic characteristics and expansion process.

[0092] Gas-liquid separator 6: Used to separate the incoming working fluid into liquid and gaseous working fluids. The liquid working fluid enters the electronic expansion valve 7, while the gaseous working fluid is prevented from entering the electronic expansion valve 7, which would affect the throttling effect.

[0093] Electronic expansion valve 7: Used to precisely regulate the refrigerant flow by adjusting the superheat at the outlet of evaporator 8. At the same time, electronic expansion valve 7 acts as a throttling and pressure-reducing valve, causing the refrigerant to become low-pressure and low-temperature before being delivered to evaporator 8.

[0094] Evaporator 8: Used to exchange heat between the low-pressure, low-temperature refrigerant from the electronic expansion valve 7 and a heat source (such as groundwater as a low-grade heat source). The refrigerant absorbs heat and evaporates into a low-pressure, high-temperature gaseous state, which is then delivered to the compressor 1.

[0095] Concentration detector 9: Used to detect the circulating components of the mixed working fluid and transmit the detection signal to the controller 17 to provide a basis for the controller to adjust the system operation.

[0096] First pressure regulating valve 10 and second pressure regulating valve 12: used to regulate the refrigerant pressure of the branch according to the system pressure requirements, maintain a specific pressure range, and deliver the fluid with regulated pressure to adjacent adapted components.

[0097] First throttle valve 13 and second throttle valve 15: used to throttle and reduce the pressure of the refrigerant, allowing the fluid to be delivered to subsequent components at a lower pressure.

[0098] First check valve 14 and second check valve 16: used to control the unidirectional flow of fluid, prevent backflow, and maintain circulation sequence and stability.

[0099] Controller 17: Used to receive signals from concentration detector 9, and send control commands to each pressure regulating valve according to preset programs and system operating parameters, and coordinate the operation of each component of the refrigeration cycle.

[0100] Adsorption-desorption unit 11: Used for adsorption or desorption processes to change the circulating composition of non-azeotropic working fluids.

[0101] In this invention, the adsorption-desorption mass transfer process unit (i.e., the non-azeotropic mixed working fluid pressure swing adsorption cycle unit) controls the pressure of the adsorption-desorption unit 11 by switching the pressure regulating valve, thereby achieving pressurization or depressurization. Different working fluid components compete for adsorption on the adsorbent surface and undergo selective adsorption or desorption. The adsorption amount changes with the pressure, and the adsorption or desorption response is fast, enabling rapid adjustment of the circulating components.

[0102] In this invention, by adjusting the circulating components, the temperature slippage of the evaporation process can be actively controlled to ensure temperature matching on the heat source side. Through the coordinated regulation of both the circulating components and the exhaust pressure (two degrees of freedom), a balance between source and sink temperature matching is achieved. Simultaneously, this invention winds two sets of coils around the surface of the adsorption-desorption unit 11. One set of coils (the second coil) uses the low-temperature working fluid from the inlet (working fluid inlet) of the evaporator 8. During adsorption, the working fluid inside the coil absorbs the heat generated by adsorption, accelerating the adsorption rate. The other set of coils (the first coil) uses the high-temperature working fluid from the inlet (working fluid inlet) of the gas cooler 4. During desorption, the working fluid inside the coil provides the heat required for desorption, accelerating the desorption rate. This invention utilizes the coils wound around the surface of the adsorption-desorption unit to regulate the temperature of adsorption and desorption, shortening the response time of the adsorption-desorption process.

[0103] The mixed-working-fluid heat pump system provided by this invention is a variable-component transcritical CO2 mixed-working-fluid heat pump system based on adsorption separation. Based on the mixed-working-fluid refrigeration heat pump system provided by this invention, this invention also provides a control method for the mixed-working-fluid refrigeration heat pump system, including the following operating modes:

[0104] Step S1: Perform transcritical CO2 cycle operation of non-azeotropic working fluid;

[0105] Step S1 is specifically as follows: The low-temperature, low-pressure non-azeotropic working fluid flowing out of the working fluid outlet of the evaporator 8 is drawn into the compressor 1 and compressed to a high-temperature, high-pressure non-azeotropic working fluid. Then it enters the oil separator 2, where the oil carried by the non-azeotropic working fluid is separated and returned to the compressor 1 through the oil return valve 3. At the same time, the non-azeotropic working fluid enters the gas cooler 4 to exchange heat with the heat exchange fluid, which provides heat to the heat user. The non-azeotropic working fluid then flows through the back pressure valve 5 to maintain the pressure on the high-pressure side of the system. Then, the working fluid achieves gas-liquid separation in the gas-liquid separator 6. After the working fluid flows through the electronic expansion valve 7 for throttling and pressure reduction, it evaporates and absorbs heat in the evaporator 8, completing the transcritical CO2 cycle operation of the non-azeotropic working fluid.

[0106] In step S1, specifically, the non-azeotropic working fluid of the system consists of R1234ze(E) and CO2.

[0107] In step S1, specifically, in the above process, the non-azeotropic working fluid preferably includes CO2 with a mass fraction of 0.9 and R1234ze(E) with a mass fraction of 0.1.

[0108] Step S2: Perform a pressure swing adsorption cycle operation on a non-azeotropic working fluid;

[0109] Step S2 specifically involves monitoring the actual circulating mass fraction C of CO2 in the non-azeotropic mixture flowing out of the evaporator 8 using a concentration detector 9. cir (i.e., actual concentration);

[0110] At a certain moment, the optimal circulating mass fraction C of CO2 is... opt The actual circulating mass fraction of CO2 at this time, C cir Deviation between |C cir -C opt | has reached (i.e., is greater than or equal to) the preset allowable deviation ε C Then, according to C opt With C cir The numerical values ​​of the two valves are used to perform corresponding preset adjustments on the first pressure regulating valve 10 and the second pressure regulating valve 12. At this time, the previous operating cycle stops and the next operating cycle begins.

[0111] For example, in step S2, the mass fraction (i.e., concentration) of CO2 in the non-azeotropic mixture flowing out of the evaporator 8 is monitored in real time by the concentration detector 9. It is found that at a certain moment, the deviation |C| between the optimal circulating mass fraction of CO2 (0.89) and the actual circulating mass fraction of CO2 (0.9) at that time is... cir -C opt | is 0.01, | C cir -C opt The preset allowable deviation of 0.01 has been reached (i.e., greater than or equal to). At this point, the first pressure regulating valve 10 and the second pressure regulating valve 12 need to be adjusted accordingly.

[0112] In step S2, specifically, the actual circulating mass fraction C of CO2 can be directly detected and obtained in the non-azeotropic working fluid using the concentration detector 9. cir .

[0113] In this invention, specifically in its implementation, the optimal circulating mass fraction C of CO2 is... opt It is the mass fraction of circulating CO2 when the system COP (coefficient of performance) reaches its maximum value (i.e., the optimal value of system COP).

[0114] It should be noted that, as Figure 1 As shown, it is a curve showing the relationship between the system's COP (coefficient of performance) and the mass fraction of CO2 in the cycle under specific operating conditions. The specific operating parameters are: inlet temperature on the heat source side 25℃, outlet temperature on the heat source side 15℃; inlet temperature on the heat sink side 35℃, outlet temperature on the heat sink side 60℃; and the system exhaust pressure is set to 10MPa.

[0115] Depend on Figure 1The curve trend shows that, under the above operating conditions, the system COP and the change in circulating CO2 mass fraction exhibit a correlation: as the circulating CO2 mass fraction gradually increases, the system COP initially shows an upward trend, reaching its maximum value when the CO2 mass fraction reaches a certain specific value; if the circulating CO2 mass fraction continues to increase, the system COP then shows a downward trend. Based on this characteristic, this invention provides a circulating CO2 mass fraction that allows the system COP to reach its maximum value, and this key parameter is defined as the optimal circulating mass fraction C. opt .

[0116] Specific experimental data show that, under this operating condition, the optimal cycle mass fraction C opt The value is 0.92, corresponding to a system COP value (i.e., the optimal system COP) of 3.23. Further testing shows that when the circulating CO2 mass fraction is at the optimal circulating mass fraction C... opt When the CO2 fluctuates around 0.91 or 0.93, the system COP is 3.186 and 3.213 respectively, a maximum decrease of 1.36% relative to the optimal system COP (3.23). This decrease is not significant and does not substantially affect the efficient operation of the system. Based on this, this invention defines the circulating CO2 mass fraction relative to the optimal circulating mass fraction C. opt The preset allowable deviation range means that when the circulating CO2 mass fraction is within this range, the system COP can be maintained at a level close to the optimal value, ensuring stable and efficient operation of the system.

[0117] The above characteristics provide a basis for system parameter optimization, by controlling the circulating CO2 mass fraction at the optimal circulating mass fraction C. opt Within the preset allowable deviation range, the system's heating performance can be maximized, improving energy efficiency.

[0118] In practice, the controller 17 is used to control the opening or closing of the first pressure regulating valve 10 and the second pressure regulating valve 12.

[0119] In specific implementation, the controller 17 is communicatively connected to the concentration detector 9, and is used to collect the actual circulating mass fraction C of CO2 in the non-azeotropic mixture flowing out of the working fluid outlet of the evaporator 8 through the concentration detector 9. cir (i.e., actual concentration), and at a certain moment, the optimal circulating mass fraction C of CO2. opt The actual circulating mass fraction of CO2 at this time, C cir Deviation between |C cir -C opt |, and the preset allowable deviation ε C A comparison is made, and if the preset allowable deviation ε has been reached (i.e., greater than or equal to) the tolerance, the result is considered. C Then, according to Copt With C cir Based on the magnitude of the two values, corresponding preset adjustment operations are performed on the first pressure regulating valve 10 and the second pressure regulating valve 12 (specifically, corresponding opening or closing control operations, the specific control methods are described below).

[0120] In step S2, specifically, the adsorbent used in the adsorbent-desorber 11 is solid activated carbon with a porosity of 0.37.

[0121] In step S2, specifically, the detection interval of the concentration detector 9 is 1 minute, that is, it detects once every 1 minute.

[0122] In step S2, specifically, according to C opt With C cir Based on the magnitude of the two values, corresponding preset adjustment operations are performed on the first pressure regulating valve 10 and the second pressure regulating valve 12, specifically including the following operations:

[0123] If C cir >C opt Then, the first pressure regulating valve 10 opens and the second pressure regulating valve 12 closes, causing the pressure in the adsorbent-desorber 11 to increase. Simultaneously, the first coil on the gas cooler 4 side operates, raising the temperature of the adsorbent-desorber 11. At this time, all the non-azeotropic mixture circulating in the heat pump system is adsorbed by the adsorbent in the adsorbent-desorber 11. However, because the change in CO2 adsorption is greater than (specifically, significantly greater than) that of the other non-azeotropic mixture, the actual circulating mass fraction of CO2, C... cir Decrease until |C cir -C opt |<ε C At this point, the first pressure regulating valve 10 closes, and the regulation ends;

[0124] If C cir <C opt Then, the first pressure regulating valve 10 closes and the second pressure regulating valve 12 opens, causing the pressure in the adsorbent-desorber 11 to decrease. Simultaneously, the second coil on the evaporator 8 side operates, lowering the temperature of the adsorbent-desorber 11. All the non-azeotropic mixture in the adsorbent-desorber 11 is desorbed by the adsorbent. However, because the change in CO2 desorption is greater than (specifically, significantly greater than) that of the other non-azeotropic mixture, the actual circulating mass fraction of CO2, C... cir Increase until |C is satisfied. cir -C opt |<ε C At this point, the second pressure regulating valve 12 closes, and the regulation ends.

[0125] It should be noted that, for this invention, after the aforementioned preset adjustment operations, the heat pump can now operate stably under the new circulation ratio (i.e., the new mass fraction ratio of the two working substances in the mixed working fluid). When the mass fraction (i.e., concentration) of CO2 in the non-azeotropic mixed working fluid is monitored by the concentration detector 9, and deviation analysis is performed, |C| reappears. cir -C opt |>ε C If the pressure swing occurs, the current operating cycle terminates, and the next cycle begins again through the action of the two pressure regulating valves, ensuring continuous control of the circulating components. This process is repeated to complete the pressure swing adsorption cycle of the non-azeotropic working fluid.

[0126] In specific implementation, another preferred non-azeotropic working fluid in the non-azeotropic mixture is R1234ze(E).

[0127] In terms of specific implementation, the concentration detector 9 is a carbon dioxide concentration detector.

[0128] To better understand the technical solution of the present invention, the working principle of the present invention will be explained below with reference to embodiments.

[0129] Example

[0130] In the embodiments, the non-azeotropic working fluid specifically includes CO2 with a mass fraction of 0.9 and R1234ze(E) with a mass fraction of 0.1.

[0131] The present invention provides a control method for a mixed working fluid refrigeration heat pump system, comprising the following operating modes:

[0132] Step S1: Perform transcritical CO2 cycle operation of non-azeotropic working fluid;

[0133] Step S1 is specifically as follows: The low-temperature, low-pressure non-azeotropic working fluid flowing out of the working fluid outlet of the evaporator 8 is drawn into the compressor 1 and compressed to a high-temperature, high-pressure non-azeotropic working fluid. Then it enters the oil separator 2, where the oil carried by the non-azeotropic working fluid is separated and returned to the compressor 1 through the oil return valve 3. At the same time, the non-azeotropic working fluid enters the gas cooler 4 to exchange heat with the heat exchange fluid, which provides heat to the heat user. The non-azeotropic working fluid then flows through the back pressure valve 5 to maintain the pressure on the high-pressure side of the system. Then, the working fluid achieves gas-liquid separation in the gas-liquid separator 6. After the working fluid flows through the electronic expansion valve 7 for throttling and pressure reduction, it evaporates and absorbs heat in the evaporator 8, completing the transcritical CO2 cycle operation of the non-azeotropic working fluid.

[0134] In step S1, specifically, in heating mode, the heat source can be groundwater and the heat sink can be the heat user end; in cooling mode, the heat source can be the heat user end and the heat sink can be industrial wastewater. The operating temperature range of the gas cooler 4 is 10 to 140°C, the evaporation temperature range of the evaporator 8 is -40 to 10°C, the suction pressure range of the compressor 1 is 1 to 4 MPa, and the discharge pressure range is 6 to 13 MPa.

[0135] In step S1, specifically, when the evaporator 8 exchanges heat with the external fluid, the narrow temperature difference range is 3 to 5°C, and the fluid superheat range at the working fluid outlet of the evaporator 8 is 2 to 3°C.

[0136] The inlet water temperature range of the heat source is 20 to 40℃, and the outlet water temperature range is -5 to 15℃.

[0137] In step S1, specifically, the water supply temperature range of the gas cooler 4 is 8 to 18°C, and the water return temperature range of the gas cooler 4 is 45 to 65°C.

[0138] For gas cooler 4, for every 1°C increase in the supply water temperature on the heat sink side, the return water temperature increases by 2°C.

[0139] Step S2: Perform a pressure swing adsorption cycle operation on a non-azeotropic working fluid;

[0140] Step S2 specifically involves monitoring the actual circulating mass fraction C of CO2 in the non-azeotropic mixture flowing out of the evaporator 8 using a concentration detector 9. cir (i.e., actual concentration);

[0141] When the optimal circulating mass fraction C of CO2 is at a certain moment opt (Specifically equal to 0.89) and the actual circulating mass fraction of CO2 at this time, C cir The deviation between (specifically equal to 0.9) and |C cir -C opt | equals 0.01, reaching (i.e., greater than or equal to) the preset allowable deviation ε C When (specifically equal to 0.01), corresponding preset adjustment operations are performed on the first pressure regulating valve 10 and the second pressure regulating valve 12, because C cir >C optSpecifically, the first pressure regulating valve 10 is opened and the second pressure regulating valve 12 is closed, causing the pressure in the adsorbent-desorber 11 to increase. Simultaneously, the first coil on the gas cooler 4 side operates, raising the temperature of the adsorbent-desorber 11. At this time, the non-azeotropic working fluid composed of R1234ze(E) and CO2 circulating in the heat pump system is adsorbed by the adsorbent in the adsorbent-desorber 11. However, because the change in CO2 adsorption is greater than (specifically significantly greater than) that of R1234ze(E), the actual circulating mass fraction C of CO2 decreases. cir Decrease until |C cir -C opt1 If |<0.01, the first pressure regulating valve 10 is closed, and the regulation ends;

[0142] In the above process, the adsorbent used in the adsorption-desorption device 11 is solid activated carbon with a porosity of 0.37; the detection interval of the concentration detector 9 is 1 minute, that is, it is detected once every 1 minute.

[0143] Then, after a period of operation, during which the actual circulating mass fraction C of CO2 flowing out of the working fluid outlet of evaporator 8 was monitored by concentration detector 9, the same method was used. cir (i.e., actual concentration), to find the optimal circulating mass fraction C of CO2 at a certain moment. opt (Specifically equal to 0.91) and the actual circulating mass fraction of CO2 at this time, C cir The deviation (specifically equal to 0.9) is 0.01, which meets the preset allowable deviation of 0.01. At this point, corresponding preset adjustment operations need to be performed on the first pressure regulating valve 10 and the second pressure regulating valve 12, because C cir <C opt Specifically, the first pressure regulating valve 10 is closed, and the second pressure regulating valve 12 is opened, causing the pressure in the adsorbent-desorber 11 to decrease. Simultaneously, the second coil on the evaporator 8 side operates, lowering the temperature of the adsorbent-desorber 11. The non-azeotropic working fluid composed of R1234ze(E) and CO2 within the adsorbent-desorber 11 is desorbed by the adsorbent. However, because the change in CO2 desorption is greater than (specifically significantly greater than) that of R1234ze(E), the actual circulating mass fraction of CO2, C, is reduced. cir Increase until |C is satisfied. cir -C opt2 If |<0.01, the second pressure regulating valve 12 is closed, and the regulation ends.

[0144] At this point, the heat pump can operate stably under the new circulation ratio (i.e., the new mass fraction ratio of the two working fluids in the mixed working fluid). When the mass fraction (i.e., concentration) of CO2 in the non-azeotropic mixed working fluid is monitored by the concentration detector 9 and deviation analysis is performed, |C| reappears. cir -C optIf the value is greater than 0.01, the current operating cycle terminates, and the next cycle is initiated again by the action of the two pressure regulating valves to ensure continuous control of the circulating components. This process is repeated to complete the pressure swing adsorption cycle operation of the non-azeotropic working fluid.

[0145] Compared with the prior art, the mixed working fluid refrigeration heat pump system provided by the present invention has the following beneficial effects:

[0146] 1. To address the issues of source-sink temperature matching and component control in conventional heat pumps, this invention adds an adsorbent-desorber to a conventional CO2 mixed-workpiece heat pump. The adsorbent-desorber is filled with adsorbent, and its high-pressure and low-pressure ends are connected to the high-pressure and low-pressure piping of the system, respectively. The pressure of the adsorbent-desorber is controlled by switching two pressure regulating valves, thereby achieving pressurization or depressurization. Different working fluid components compete for adsorption on the adsorbent surface, resulting in selective adsorption or desorption, with the adsorption amount changing with pressure. The large pressure difference between the high and low pressures in the transcritical CO2 mixed-workpiece cycle leads to a short equilibrium time for the pressure-driven adsorption or desorption process, resulting in a fast adsorption or desorption response and enabling rapid adjustment of the circulating components. Adjusting the circulating components allows for active control of the temperature glide during the evaporation process to ensure temperature matching on the heat source side.

[0147] 2. Compared with traditional transcritical working fluid cycles, the non-azeotropic mixed working fluid transcritical cycle operation in this invention can not only ensure the matching of source and sink temperatures, but also avoid the deterioration of phase change heat transfer during the heat release process through supercritical heat exchange without phase change, thus significantly improving the performance of the refrigeration heat pump cycle.

[0148] 3. The refrigerant in the non-azeotropic mixed working fluid transcritical CO2 cycle operation of the present invention is a mixed working fluid composed of low GWP organic working fluid and CO2, which can reduce the transcritical CO2 cycle exhaust pressure and throttling loss, and will not decompose under high temperature conditions. It is safe, non-toxic, and environmentally friendly.

[0149] 4. This invention involves winding two sets of coils around the surface of the adsorption-desorption device. One set of coils (the second coil) draws the low-temperature working fluid from the evaporator inlet. During adsorption, the working fluid inside the coil absorbs the heat generated by adsorption, accelerating the adsorption rate. The other set of coils (the first coil) draws the high-temperature working fluid from the gas cooler 4 inlet. During desorption, the working fluid inside the coil provides the heat required for desorption, accelerating the desorption rate. By utilizing the coils wound around the surface of the adsorption-desorption device, the temperature of adsorption and desorption is regulated, shortening the response time of the adsorption-desorption process.

[0150] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A mixed working fluid refrigeration heat pump system, characterized in that, Includes transcritical cycle structures and adsorption / desorption mass transfer process units; The critical cycle structure includes: a compressor (1), an oil separator (2), an oil return valve (3), a gas cooler (4), a back pressure valve (5), a gas-liquid separator (6), an electronic expansion valve (7), and an evaporator (8); The working fluid outlet of the evaporator (8) is connected to the working fluid inlet of the compressor (1); The working fluid outlet of the compressor (1) is connected to the working fluid inlet a of the oil separator (2); The lubricating oil outlet b of the oil separator (2) is connected to one end of the inlet of the return oil valve (3); The working fluid outlet c of the oil separator (2) is connected to the working fluid inlet a of the gas cooler (4); The other end of the oil return valve (3) is connected to the working fluid inlet of the compressor (1); The working fluid outlet b of the gas cooler (4) is connected to one end of the inlet of the back pressure valve (5); The other end outlet of the back pressure valve (5) is connected to the working fluid inlet a of the gas-liquid separator (6); The liquid working fluid outlet b of the gas-liquid separator (6) is connected to one end inlet of the electronic expansion valve (7); The other end outlet of the electronic expansion valve (7) is connected to the working fluid inlet of the evaporator (8); The adsorption-desorption mass transfer process unit includes: a first pressure regulating valve (10), an adsorption-desorption device (11), and a second pressure regulating valve (12); The gas working medium outlet c of the gas-liquid separator (6) is connected to one end inlet of the first pressure regulating valve (10); The other end outlet of the first pressure regulating valve (10) is connected to the high-pressure end interface a of the adsorption / desorption device (11); The low-pressure end port b of the adsorption-desorption device (11) is connected to one end inlet of the second pressure regulating valve (12); The other end of the second pressure regulating valve (12) is connected to the working fluid outlet b of the evaporator (8) in the transcritical cycle structure. The working fluid inlet a of the gas cooler (4) in the transcritical cycle structure is connected to the working fluid outlet b of the gas cooler (4) through a first connecting pipe, and the first connecting pipe has a first coil wrapped around the outer surface of the adsorber (11). The working fluid inlet a of the evaporator (8) in the transcritical cycle structure is connected to the working fluid outlet b of the evaporator (8) through a second connecting pipe, and the second connecting pipe has a second coil wrapped around the outer surface of the adsorber (11).

2. The mixed working fluid refrigeration heat pump system as described in claim 1, characterized in that, The first coil in the first connecting pipe and the second coil in the second connecting pipe are distributed alternately.

3. The mixed working fluid refrigeration heat pump system as described in claim 1, characterized in that, The first coil in the first connecting pipeline is provided with a first throttle valve (13) and a first check valve (14) in sequence on the connecting pipeline between the first coil and the working fluid outlet b of the gas cooler (4). The second coil in the second connecting pipe is provided with a second throttle valve (15) and a second check valve (16) in sequence on the connecting pipe between the working fluid outlet b of the evaporator (8).

4. The mixed working fluid refrigeration heat pump system as described in claim 1, characterized in that, A concentration detector (9) is installed on the connecting pipe between the working fluid outlet of the evaporator (8) and the working fluid inlet of the compressor (1).

5. The mixed working fluid refrigeration heat pump system as described in claim 1, characterized in that, It also includes the controller (17); The controller (17) is communicatively connected to the signal control terminals of the first pressure regulating valve (10) and the second pressure regulating valve (12), respectively, and is used to control the opening and closing states of the first pressure regulating valve (10) and the second pressure regulating valve (12) by sending control signals.

6. The mixed working fluid refrigeration heat pump system as described in claim 1, characterized in that, Non-azeotropic working fluids, consisting of two components: low-GWP organic working fluids and carbon dioxide (CO2); The low-GWP organic working fluid is R1234ze(E).

7. A control method for a mixed working fluid refrigeration heat pump system as described in any one of claims 1 to 6, characterized in that, The following working modes are included: Step S1: Perform transcritical CO2 cycle operation of non-azeotropic working fluid; The specific steps of step S1 are as follows: the low-temperature and low-pressure non-azeotropic mixed working fluid flowing out of the working fluid outlet of the evaporator (8) is sucked into the compressor (1) and compressed to a high-temperature and high-pressure non-azeotropic mixed working fluid. Then it enters the oil separator (2), where the oil carried by the non-azeotropic mixed working fluid is separated out by the oil separator (2) and returned to the compressor (1) through the return oil valve (3). At the same time, the non-azeotropic mixed working fluid enters the gas cooler (4) to exchange heat with the heat exchange fluid, which provides heat to the heat user. The non-azeotropic mixed working fluid then flows through the back pressure valve (5) to maintain the pressure on the high-pressure side of the system. Then the working fluid achieves gas-liquid separation of the non-azeotropic mixed working fluid in the gas-liquid separator (6). After the working fluid flows through the electronic expansion valve (7) for throttling and pressure reduction, it evaporates and absorbs heat in the evaporator (8), completing the transcritical CO2 cycle operation of the non-azeotropic mixed working fluid. Step S2: Perform a pressure swing adsorption cycle operation on a non-azeotropic working fluid; Step S2 specifically involves monitoring the actual circulating mass fraction C of CO2 in the non-azeotropic mixture flowing out of the evaporator (8) using a concentration detector (9). cir ; At a certain moment, the optimal circulating mass fraction C of CO2 is... opt The actual circulating mass fraction of CO2 at this time, C cir Deviation between |C cir -C opt | has reached the preset allowable deviation ε C Then, according to C opt With C cir Based on the magnitude of the two values, the first pressure regulating valve (10) and the second pressure regulating valve (12) are adjusted accordingly using preset methods.

8. The control method as described in claim 7, characterized in that, In step S2, the controller (17) is communicatively connected to the concentration detector (9) to collect the actual circulating mass fraction C of CO2 in the non-azeotropic mixture flowing out of the working fluid outlet of the evaporator (8) via the concentration detector (9). cir And at some point, the optimal circulating mass fraction C of CO2 will be... opt The actual circulating mass fraction of CO2 at this time, C cir Deviation between |C cir -C opt |, and the preset allowable deviation ε C Compare the results; if the preset allowable deviation ε has been reached... C Then, according to C opt With C cir Based on the magnitude of the two values, the first pressure regulating valve (10) and the second pressure regulating valve (12) are adjusted accordingly using preset methods.

9. The control method as described in claim 7, characterized in that, In step S2, according to C opt With C cir Based on the magnitude of the two values, corresponding preset adjustment operations are performed on the first pressure regulating valve (10) and the second pressure regulating valve (12), specifically including the following operations: If C cir >C opt Then the first pressure regulating valve (10) opens and the second pressure regulating valve (12) closes, causing the pressure of the adsorbent-desorber (11) to rise. At the same time, the first coil on the gas cooler (4) side operates, causing the temperature of the adsorbent-desorber (11) to rise. At this time, the non-azeotropic mixture circulating in the heat pump system is adsorbed by the adsorbent in the adsorbent-desorber (11). However, since the change in the amount of CO2 adsorbed is greater than that of the other non-azeotropic mixture, the actual circulating mass fraction of CO2 C is lower. cir Decrease until |C cir -C opt |<ε C At this time, the first pressure regulating valve (10) is closed, and the regulation is terminated.

10. The control method as described in claim 7, characterized in that, In step S2, according to C opt With C cir Based on the magnitude of the two values, corresponding preset adjustment operations are performed on the first pressure regulating valve (10) and the second pressure regulating valve (12), specifically including the following operations: If C cir <C opt Then the first pressure regulating valve (10) closes and the second pressure regulating valve (12) opens, causing the pressure of the adsorbent-desorber (11) to decrease. At the same time, the second coil on the evaporator (8) side operates, causing the temperature of the adsorbent-desorber (11) to decrease. All non-azeotropic working fluids in the adsorbent-desorber (11) are desorbed by the adsorbent in the adsorbent-desorber. However, since the change in the amount of CO2 desorbed is greater than that of the other non-azeotropic working fluid in the non-azeotropic working fluid, the actual circulating mass fraction of CO2 C is lower. cir Increase until |C is satisfied. cir -C opt |<ε C At this time, the second pressure regulating valve (12) is closed, and the regulation is terminated.

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