Non-azeotropic mixed working medium heat pump system

Abstract

The utility model relates to the technical field of heat pumps, and discloses a non-azeotropic mixed working medium heat pump system which comprises a first refrigerant circulation loop and a second refrigerant circulation loop. A compressor, a condenser, a heat exchanger, a first throttle valve and an evaporator which are connected in sequence are arranged on the first refrigerant circulation loop; a refrigerant pump, a heat exchanger and a heat regenerator which are sequentially connected are arranged on the second refrigerant circulation loop, and the heat regenerator and the evaporator are oppositely arranged and suitable for mutual heat exchange; the heat exchanger is provided with a first heat exchange channel and a second heat exchange channel which exchange heat with each other, and the first heat exchange channel is connected between an outlet of the condenser and an inlet of the first throttling valve. And the second heat exchange channel is connected between the outlet of the refrigerant pump and the inlet of the heat regenerator. By arranging the heat regenerator, the evaporation temperature of the evaporator can be increased, the compression ratio of the compressor is reduced, and the energy efficiency ratio of the system is increased.

Description

Technical Field

[0001] This utility model relates to the field of heat pump technology, and in particular to a non-azeotropic mixed working fluid heat pump system. Background Technology

[0002] The basic working process of a heat pump system includes four main steps: compression, condensation, expansion, and evaporation. As a highly efficient and environmentally friendly energy conversion device, heat pumps can extract heat from low-temperature heat sources and transfer it to high-temperature heat sources, and are widely used in heating and hot water supply.

[0003] However, traditional heat pump systems experience a significant drop in efficiency or even fail to operate properly when running at low ambient temperatures, such as in cold regions or during winter. Specifically, the evaporator temperature decreases due to the drop in ambient temperature, leading to an increase in the compressor pressure ratio, a decrease in the heat pump system's energy efficiency ratio, and impacting the system's reliability and stability. Utility Model Content

[0004] The technical problem solved by this utility model is to provide a non-azeotropic mixed working fluid heat pump system, which effectively solves the problem that the evaporation temperature of the evaporator decreases due to the low temperature environment, resulting in an increase in the compressor pressure ratio and a decrease in the system energy efficiency ratio.

[0005] The above-mentioned technical problems are solved by the following technical solutions:

[0006] A non-azeotropic mixed working fluid heat pump system includes: a first refrigerant circulation loop and a second refrigerant circulation loop; the first refrigerant circulation loop is provided with a compressor, a condenser, a heat exchanger, a first throttling valve and an evaporator connected in sequence; the second refrigerant circulation loop is provided with a refrigerant pump, the heat exchanger and a regenerator connected in sequence, the regenerator and the evaporator being adapted to exchange heat with each other;

[0007] The heat exchanger has a first heat exchange channel and a second heat exchange channel that exchange heat with each other. The first heat exchange channel is connected to the pipeline between the outlet of the condenser and the inlet of the first throttling valve; the second heat exchange channel is connected to the pipeline between the outlet of the refrigerant pump and the inlet of the regenerator.

[0008] Compared with the prior art, the non-azeotropic mixed working fluid heat pump system of this utility model has the following advantages: This utility model connects the first heat exchange channel to the pipeline between the outlet of the condenser and the inlet of the first throttling valve, and the second heat exchange channel to the pipeline between the outlet of the refrigerant pump and the inlet of the regenerator. By selecting an appropriate refrigerant, the temperature of the refrigerant flowing into the first heat exchange channel is higher than the temperature of the refrigerant flowing into the second heat exchange channel; the temperature of the refrigerant flowing into the regenerator is higher than the temperature of the refrigerant flowing into the evaporator. During heating, the medium-temperature refrigerant flowing out of the condenser flows into the first heat exchange channel, and the low-temperature refrigerant in the refrigerant pump flows into the second heat exchange channel. Because the temperature of the low-temperature refrigerant in the second heat exchange channel is lower than that of the medium-temperature refrigerant in the first heat exchange channel, the low-temperature refrigerant in the second heat exchange channel exchanges heat with the medium-temperature refrigerant in the first heat exchange channel. This results in a greater subcooling of the medium-temperature refrigerant in the first heat exchange channel, reducing throttling losses and allowing for more complete liquefaction of the refrigerant after passing through the first throttling valve. This increases the cooling capacity per unit mass of refrigerant in the first refrigerant circulation loop. Subsequently, the heat-absorbing vaporized refrigerant in the second heat exchange channel enters the regenerator under the drive of the refrigerant pump. Since the temperature of the refrigerant flowing into the regenerator is higher than that flowing into the evaporator, the vaporized refrigerant in the regenerator releases heat, which raises the evaporator's evaporation temperature. When the evaporator temperature rises, not only does the compressor's compression ratio decrease, but the overall system efficiency also improves. Furthermore, the increased temperature of the airflow flowing through the evaporator delays the evaporator's frosting time, thus reducing the number of defrosting cycles and improving heating performance.

[0009] In one embodiment, the first refrigerant circulation loop is further provided with a liquid receiver, which has a refrigerant inlet and a liquid refrigerant outlet. The refrigerant inlet is connected to the outlet of the condenser, and the liquid refrigerant outlet is connected to the first heat exchange channel.

[0010] In one embodiment, the first refrigerant circulation loop contains at least two refrigerants with different boiling points, and the liquid receiver also has a gaseous refrigerant outlet; the non-azeotropic mixed working fluid heat pump system further includes a defrosting branch, one end of which is connected to the gaseous refrigerant outlet, and the other end is connected to the pipeline between the evaporator and the first throttling valve, and the defrosting branch is provided with a switching valve.

[0011] In one embodiment, the switching valve is a solenoid valve.

[0012] In one embodiment, the first refrigerant circulation loop contains at least two refrigerants with different boiling points, and the boiling point of the refrigerant in the second refrigerant circulation loop is lower than the boiling point of at least one refrigerant in the first refrigerant circulation loop.

[0013] In one embodiment, the liquid refrigerant outlet is located at the bottom of the reservoir, and the gaseous refrigerant outlet is located at the top of the reservoir.

[0014] In one embodiment, a second throttling valve is further provided on the first refrigerant circulation loop, and the second throttling valve is located between the refrigerant inlet of the condenser and the liquid receiver.

[0015] In one embodiment, an evaporator fan is also included, which drives air to flow sequentially through the regenerator and the evaporator.

[0016] In one embodiment, the first refrigerant circulation loop is further provided with a gas-liquid separator located between the evaporator and the compressor.

[0017] In one embodiment, the refrigerant pump is a variable frequency pump. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a connection diagram of a non-azeotropic mixed working fluid heat pump system according to an embodiment of the present invention;

[0020] Figure 2 for Figure 1 The diagram shows a control flow chart for a non-azeotropic mixed working fluid heat pump system.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Compressor; 2. Condenser; 3. Heat exchanger; 301. First heat exchange channel; 302. Second heat exchange channel; 4. First throttle valve; 5. Evaporator; 6. Refrigerant pump; 7. Regenerator; 8. Liquid receiver; 801. Refrigerant inlet; 802. Liquid refrigerant outlet; 803. Gas refrigerant outlet; 9. Second throttle valve; 10. Defrosting branch; 11. Switch valve; 12. Evaporator fan; 13. Gas-liquid separator. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", 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 application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] The following is combined Figure 1 and Figure 2 This invention describes a non-azeotropic mixed working fluid heat pump system (hereinafter referred to as non-azeotropic heat pump system for ease of description). It can be understood that the mixed working fluid refers to a mixed refrigerant formed by mixing at least two refrigerants with different boiling points.

[0028] According to embodiments of the present invention, such as Figure 1 As shown, the provided non-azeotropic heat pump system includes: a first refrigerant circulation loop and a second refrigerant circulation loop; the first refrigerant circulation loop is provided with a compressor 1, a condenser 2, a heat exchanger 3, a first throttle valve 4 and an evaporator 5 connected in sequence; the second refrigerant circulation loop is provided with a refrigerant pump 6, a heat exchanger 3 and a regenerator 7 connected in sequence, the regenerator 7 and the evaporator 5 are arranged opposite to each other and are suitable for mutual heat exchange;

[0029] The heat exchanger 3 has a first heat exchange channel 301 and a second heat exchange channel 302 that exchange heat with each other. The first heat exchange channel 301 is connected to the pipeline between the outlet of the condenser 2 and the inlet of the first throttle valve 4; the second heat exchange channel 302 is connected to the pipeline between the outlet of the refrigerant pump 6 and the inlet of the regenerator 7.

[0030] In this embodiment of the invention, the first heat exchange channel 301 is connected to the pipeline between the outlet of the condenser 2 and the inlet of the first throttle valve 4, while the second heat exchange channel 302 is connected to the pipeline between the outlet of the refrigerant pump 6 and the inlet of the regenerator 7. By selecting an appropriate refrigerant, the temperature of the refrigerant flowing into the first heat exchange channel 301 is higher than the temperature of the refrigerant flowing into the second heat exchange channel 302; the temperature of the refrigerant flowing into the regenerator 7 is higher than the temperature of the refrigerant flowing into the evaporator 5. During heating, the medium-temperature refrigerant flowing out of the condenser 2 flows into the first heat exchange channel 301, and the low-temperature refrigerant in the refrigerant pump 6 flows into the second heat exchange channel 302. Because the temperature of the low-temperature refrigerant in the second heat exchange channel 302 is lower than that of the medium-temperature refrigerant in the first heat exchange channel 301, the low-temperature refrigerant in the second heat exchange channel 302 will exchange heat with the medium-temperature refrigerant in the first heat exchange channel. This allows the medium-temperature refrigerant in the first heat exchange channel 301 to achieve a greater degree of subcooling, reducing throttling losses and enabling more complete liquefaction of the refrigerant after passing through the first throttling valve 4, thereby increasing the cooling capacity per unit mass of refrigerant in the first refrigerant circulation loop. Subsequently, the heat-absorbing vaporized refrigerant in the second heat exchange channel 302 will enter the regenerator 7 under the drive of the refrigerant pump 6. Since the temperature of the refrigerant flowing into the regenerator 7 is higher than that of the refrigerant flowing into the evaporator 5, the vaporized refrigerant in the regenerator 7 will release heat, which will raise the evaporation temperature of the evaporator 5. When the evaporation temperature of the evaporator 5 increases, not only will the compression ratio of the compressor 1 decrease, but the overall energy efficiency of the system will also improve. Furthermore, the increased temperature of the airflow passing through the evaporator 5 can delay the frosting time of the evaporator 5, thereby reducing the number of defrosting cycles within the same period and improving the heating effect.

[0031] It should be noted that the compression ratio of compressor 1 decreases because as the evaporation temperature of evaporator 5 increases, the evaporation pressure of evaporator 5 also rises due to the correlation between the refrigerant's saturation pressure and saturation temperature. Since the suction pressure of compressor 1 is essentially equal to the pressure inside evaporator 5, the suction pressure of compressor 1 also increases. Simultaneously, with condensation conditions remaining constant, the discharge pressure remains stable. Therefore, the compression ratio of compressor 1 (the ratio of discharge pressure to suction pressure) decreases. Regarding the system energy efficiency ratio, on one hand, the decrease in compression ratio reduces the workload of compressor 1, reducing the electrical energy consumption of the motor driving compressor 1, i.e., lower power consumption. On the other hand, the increased evaporation temperature increases the temperature difference between the refrigerant and the cooled medium, enhancing heat transfer and increasing the cooling capacity of evaporator 5. Since the energy efficiency ratio is the ratio of cooling capacity to power consumption, the increased cooling capacity and decreased power consumption result in a higher system energy efficiency ratio.

[0032] The effects of this embodiment will be explained below with specific examples:

[0033] Taking an outdoor ambient temperature of -30℃ and a condensing temperature of 45℃ as an example. Since evaporator 5 requires heat exchange due to temperature difference, its evaporation temperature is set at -35℃. At this point, the difference between the condensing and evaporating temperatures is 45℃ - (-35℃) = 80℃. After adding a second refrigerant circulation loop, the outdoor air temperature after passing through the regenerator 7 is -22℃, and the evaporation temperature can be raised to -27℃. At this point, the difference between the condensing and evaporating temperatures is 45℃ - (-27℃) = 72℃. It can be seen that by increasing the evaporating temperature by 8℃, the pressure ratio of compressor 1 can be reduced, and the system's energy efficiency ratio can be improved.

[0034] It should be further explained that, in this embodiment, the compressor 1 compresses the low-temperature, low-pressure gaseous refrigerant input to the evaporator 5 into a high-temperature, high-pressure gaseous refrigerant; the condenser 2 condenses the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1, turning it into a high-pressure, medium-temperature liquid refrigerant. During this process, the high-temperature, high-pressure gaseous refrigerant dissipates heat into the surrounding environment through the condenser 2. In this embodiment, the first throttling valve 4 throttles and reduces the pressure of the high-pressure liquid refrigerant exiting the condenser 2, turning it into a low-pressure, low-temperature liquid refrigerant, thus allowing it to enter the evaporator 5 for evaporation and heat absorption.

[0035] Furthermore, in this embodiment, the refrigerant flowing in the first refrigerant circulation loop is a mixture of multiple refrigerants with different boiling points. The refrigerant flowing in the second refrigerant circulation loop is a low-temperature refrigerant such as R170 refrigerant (ethane refrigerant) or R744 (carbon dioxide refrigerant). It can be understood that "low-temperature refrigerant" here refers to a refrigerant in the second refrigerant circulation loop whose boiling point is lower than that of at least one refrigerant in the first refrigerant circulation loop. Preferably, the boiling point of the refrigerant in the second refrigerant circulation loop is lower than the boiling points of all refrigerants in the first refrigerant circulation loop. Secondly, the refrigerant pump 6 in this embodiment can be a variable frequency pump. This allows for flexible adjustment of the flow rate of the low-temperature refrigerant in the second refrigerant circulation loop as needed, thereby regulating the heat exchange effect of the heat exchanger 3 and the regenerator 7.

[0036] In one embodiment, such as Figure 1 As shown, a liquid receiver 8 is also provided in the first refrigerant circulation loop. The liquid receiver 8 has a refrigerant inlet 801 and a liquid refrigerant outlet 802. The refrigerant inlet 801 is connected to the outlet of the condenser 2, and the liquid refrigerant outlet 802 is connected to the first heat exchange channel 301. It can be understood that since the first refrigerant circulation loop contains a mixture of refrigerants with different boiling points, the refrigerant flowing out of the condenser 2 has both gaseous and liquid states. In order to ensure that the refrigerant flowing in the subsequent pipeline is mainly liquid, this embodiment sets up a liquid receiver 8 to separate the gaseous and liquid refrigerants, ensuring that only the liquid refrigerant participates in the subsequent heat exchange process.

[0037] In one embodiment, such as Figure 1 As shown, the first refrigerant circulation loop contains at least two refrigerants with different boiling points, and the receiver 8 also has a gaseous refrigerant outlet 803. The non-azeotropic mixed working fluid heat pump system also includes a defrosting branch 10, one end of which is connected to the gaseous refrigerant outlet 803, and the other end is connected to the pipeline between the evaporator 5 and the first throttling valve 4. A switching valve 11 is provided on the defrosting branch 10. When the evaporator 5 operates in a low-temperature environment for a long time, frost will form on its surface. If the frost layer on the surface of the evaporator 5 is not removed in time, it will gradually thicken over time, hindering the heat exchange between the evaporator 5 and the outside environment, resulting in a significant decrease in the heat exchange efficiency of the evaporator 5. Based on this, this embodiment uses the defrosting branch 10 to connect the gaseous refrigerant outlet 803 of the receiver 8 to the inlet of the evaporator 5, which can introduce the relatively high-temperature gaseous refrigerant into the evaporator 5 and use its own heat to defrost, thereby ensuring the heat exchange efficiency of the evaporator 5. Secondly, by installing a switch valve 11 on the defrosting branch 10, the defrosting branch 10 can be flexibly opened as needed, and the proportion of low-boiling-point refrigerant and high-boiling-point refrigerant in the first refrigerant circulation loop can be reasonably controlled.

[0038] It can be understood that this is to enable better gas-liquid separation of the mixed refrigerant in the reservoir 8, and to allow both liquid and gaseous refrigerant to drain smoothly from the reservoir 8. In one embodiment, the liquid refrigerant outlet 802 is located at the bottom of the reservoir 8, and the gaseous refrigerant outlet 803 is located at the top of the reservoir 8.

[0039] In one embodiment, the first refrigerant circulation loop contains at least two refrigerants with different boiling points, and the boiling point of the refrigerant in the second refrigerant circulation loop is lower than the boiling point of at least one refrigerant in the first refrigerant circulation loop. Preferably, the boiling point of the refrigerant in the second refrigerant circulation loop is lower than the boiling points of all the refrigerants in the first refrigerant circulation loop, and the critical temperature of the refrigerant flowing through the regenerator 7 is greater than the evaporation temperature of the evaporator 5. This ensures that the refrigerant in the second refrigerant circulation loop exchanges heat with the mixed refrigerant in the first heat exchange channel 301, allowing the mixed refrigerant in the first heat exchange channel 301 to achieve a greater degree of subcooling.

[0040] In one embodiment, the switching valve 11 is a solenoid valve. It is understood that setting the switching valve 11 as a solenoid valve facilitates the integration of the solenoid valve with the control system, automating the opening and closing of the defrosting branch 10, reducing manual intervention, and improving system reliability.

[0041] In one embodiment, such as Figure 1 As shown, a second throttling valve 9 is also provided in the first refrigerant circulation loop, located between the outlet of the condenser 2 and the refrigerant inlet 801 of the receiver 8. Since the first refrigerant circulation loop also includes a first throttling valve 4, the mixed refrigerant with different boiling points undergoes two throttling processes in one cycle. This means that compared to the single throttling in a traditional heat pump system, by setting two throttling valves, the pressure drop during each throttling can be reduced, thus decreasing the temperature difference before and after throttling. Secondly, since the mixed refrigerant in the first refrigerant circulation loop exchanges heat with the low-temperature refrigerant in the second refrigerant circulation loop within the heat exchanger 3, the temperature difference across the first throttling valve 4 (the temperature difference between the inlet and outlet of the first throttling valve 4) can be further reduced, decreasing heat loss during throttling and thereby improving the heating performance of the non-azeotropic heat pump system.

[0042] The effects of this embodiment will be explained below with specific examples:

[0043] Taking a condenser 2 outlet temperature of 45℃ and an evaporator 5 inlet temperature of -35℃ as an example, the throttling temperature difference of a traditional heat pump system would reach 80℃. However, this application, by setting a second throttling valve 9 at the outlet of condenser 2, can adjust the temperature of the mixed refrigerant to about 20℃. Subsequently, by connecting the outlet of the second throttling valve 9 to the first heat exchange channel 301 of heat exchanger 3, the mixed refrigerant can exchange heat with the low-temperature refrigerant in the second heat exchange channel 302 of heat exchanger 3, thereby adjusting the temperature of the mixed refrigerant at the outlet of the first heat exchange channel 301 to about -30℃. That is to say, the throttling temperature difference of the second throttling valve 9 is 45℃ - 20℃ = 25℃, the throttling temperature difference of the first throttling valve 4 is -30℃ - (-35℃) = 5℃, and the total throttling temperature difference is 25℃ + 5℃ = 30℃. As can be seen, compared with the throttling temperature difference of traditional heat pump systems, the non-azeotropic heat pump system of this application embodiment can reduce the total throttling temperature difference, reduce heat loss during the throttling process, and improve the heating performance of the system.

[0044] In one embodiment, such as Figure 1 As shown, it also includes an evaporator fan 12, which drives air to flow sequentially through the regenerator 7 and the evaporator 5. In this embodiment, the evaporator fan 12 is provided on the side of the evaporator 5 away from the regenerator 7. The negative pressure generated by the evaporator fan 12 can be used to make the high-temperature air located on the side of the regenerator 7 flow through the evaporator 5, thereby completing the purpose of heating the evaporator 5. It should be noted that the high-temperature air in this embodiment refers to the air whose temperature rises after being heated by the regenerator 7 from the low-temperature air that was originally located near the evaporator 5. Therefore, "high temperature" here is not an absolute value, but a "relative value".

[0045] In one embodiment, such as Figure 1 As shown, a gas-liquid separator 13 is also provided on the first refrigerant circulation loop, located between the evaporator 5 and the compressor 1. By providing a gas-liquid separator 13 between the outlet of the evaporator 5 and the inlet of the compressor 1, the liquid refrigerant in the gas-liquid mixture coming out of the evaporator 5 can be separated, preventing the liquid refrigerant from entering the compressor 1, protecting the compressor 1, and extending the service life of the compressor 1.

[0046] like Figure 2 As shown below, the specific control method of the non-azeotropic mixed working fluid heat pump system according to an embodiment of this utility model is described:

[0047] The inlet temperature T1 and outlet temperature T2 of the heat exchanger 3 located at both ends of the first heat exchange channel 301 are collected, and the difference between T1 and T2 is compared with the preset minimum temperature difference B1 and the preset maximum temperature difference B2.

[0048] In response to B1≤(T1-T2)≤B2, the evaporation temperature T3 and outlet temperature T4 of evaporator 5 are collected, and the difference between T4 and T3 is compared with the preset minimum superheat D1 and the preset maximum superheat D2. In response to (T4-T3)<D1 or (T4-T3)>D2, the opening of the first throttle valve 4 is adjusted.

[0049] In response to (T1-T2) < B1 or (T1-T2) > B2, adjust the speed of refrigerant pump 6.

[0050] This embodiment of the invention compares the difference between T1 and T2 with preset minimum temperature difference B1 and preset maximum temperature difference B2 to obtain the heat exchange situation between the medium-temperature refrigerant in the first heat exchange channel 301 and the low-temperature refrigerant in the second heat exchange channel 302 of the heat exchanger 3. Based on the heat exchange situation, it can be determined whether the speed of the refrigerant pump 6 needs to be adjusted. If the heat exchange situation meets the preset requirements, the difference between T4 and T3 can be compared with preset minimum superheat D1 and preset maximum superheat D2 to obtain the evaporation heat absorption information of the evaporator 5. Based on this heat exchange information, it can be determined whether the opening of the first throttle valve 4 needs to be adjusted to ensure that the evaporation heat absorption effect of the evaporator 5 always meets the preset requirements. If the heat exchange situation does not meet the preset requirements, the speed of the refrigerant pump 6 needs to be adaptively adjusted to change the heat exchange effect of the medium-temperature and low-temperature refrigerants in the heat exchanger 3 until it is within the preset range. In this way, the non-azeotropic mixed working fluid heat pump system of this utility model can be ensured to increase the evaporation temperature of the evaporator 5, reduce the compression ratio of the compressor 1, and improve the overall energy efficiency ratio of the system.

[0051] In one embodiment, such as Figure 2 As shown, in response to (T4-T3) < D1 or (T4-T3) > D2, the opening of the first throttle valve 4 is adjusted, including:

[0052] In response to (T4-T3) < D1, the opening of the first throttle valve 4 is reduced; in response to (T4-T3) > D2, the opening of the first throttle valve 4 is increased; and / or,

[0053] In response to (T1-T2) < B1 or (T1-T2) > B2, the speed of refrigerant pump 6 is adjusted, including:

[0054] In response to (T1-T2) < B1, the speed of refrigerant pump 6 is increased; in response to (T1-T2) > B2, the speed of refrigerant pump 6 is decreased.

[0055] Understandably, if (T4-T3) < D1, it means that the evaporator 5 has a relatively poor evaporative heat absorption effect. Therefore, it is necessary to reduce the opening of the first throttle valve 4 to increase the temperature difference between the refrigerant inside the evaporator 5 and the external environment, so that the evaporator 5 can absorb heat more efficiently. Conversely, if (T4-T3) > D2, it means that the evaporator 5 has an excessively strong evaporative heat absorption effect. Therefore, it is necessary to increase the opening of the first throttle valve 4 to reduce the temperature difference between the refrigerant inside the evaporator 5 and the external environment, so as to avoid the evaporator 5 absorbing excessive heat.

[0056] Similarly, if (T1-T2) < B1, it means that the heat exchange between the medium-temperature and low-temperature refrigerants in heat exchanger 3 is insufficient. Therefore, it is necessary to increase the speed of refrigerant pump 6 so that the low-temperature refrigerant can flow at a faster rate in the second refrigerant circulation loop, shortening the residence time of the low-temperature refrigerant in the second heat exchange channel 302. Conversely, if (T1-T2) > B2, it means that the heat exchange between the medium-temperature and low-temperature refrigerants in heat exchanger 3 is excessive. Therefore, it is necessary to decrease the speed of refrigerant pump 6 so that the low-temperature refrigerant can flow at a slower rate in the second refrigerant circulation loop, prolonging the residence time of the low-temperature refrigerant in the second heat exchange channel 302.

[0057] In one embodiment, such as Figure 2 As shown, a second throttling valve 9 is also provided on the first refrigerant circulation loop. The second throttling valve 9 is located between the condenser 2 and the first heat exchange channel 301. Before collecting the inlet temperature T1 and outlet temperature T2 of the heat exchanger 3 at both ends of the first heat exchange channel 301 and comparing the difference between T1 and T2 with the preset minimum temperature difference B1 and the preset maximum temperature difference B2, the following steps are also included:

[0058] The inlet temperature T1 of heat exchanger 3 in the first heat exchange channel 301 is compared with the preset minimum temperature A1 and the preset maximum temperature A2.

[0059] When A1≤T1≤A2, the difference between T1 and T2 is compared with the preset minimum temperature difference B1 and the preset maximum temperature difference B2;

[0060] When T1 < A1 or T1 > A2, in response to T1 < A1, the opening degree of the second throttle valve 9 is increased; in response to T1 > A2, the opening degree of the second throttle valve 9 is decreased.

[0061] Understandably, if T1 < A1, it means that the throttling loss of the mixed refrigerant when passing through the second throttling valve 9 is large, and the temperature of the mixed refrigerant entering the first heat exchange channel 301 is low. Therefore, it is necessary to increase the opening of the first throttling valve 4. Conversely, if T1 > A2, it means that the throttling loss of the mixed refrigerant when passing through the second throttling valve 9 is small, and the temperature of the mixed refrigerant entering the first heat exchange channel 301 is high. Therefore, it is necessary to decrease the opening of the first throttling valve 4.

[0062] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0063] The specific embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A non-azeotropic mixed working fluid heat pump system, characterized in that, include: A first refrigerant circulation loop and a second refrigerant circulation loop; the first refrigerant circulation loop is provided with a compressor (1), a condenser (2), a heat exchanger (3), a first throttle valve (4) and an evaporator (5) connected in sequence; the second refrigerant circulation loop is provided with a refrigerant pump (6), the heat exchanger (3) and a regenerator (7) connected in sequence, the regenerator (7) and the evaporator (5) being adapted to exchange heat with each other; The heat exchanger (3) has a first heat exchange channel (301) and a second heat exchange channel (302) for mutual heat exchange. The first heat exchange channel (301) is connected to the pipeline between the outlet of the condenser (2) and the inlet of the first throttle valve (4). The second heat exchange channel (302) is connected to the pipeline between the outlet of the refrigerant pump (6) and the inlet of the regenerator (7).

2. The non-azeotropic mixed working fluid heat pump system according to claim 1, characterized in that: The first refrigerant circulation loop is also provided with a liquid reservoir (8), which has a refrigerant inlet (801) and a liquid refrigerant outlet (802). The refrigerant inlet (801) is connected to the outlet of the condenser (2), and the liquid refrigerant outlet (802) is connected to the first heat exchange channel (301).

3. The non-azeotropic mixed working fluid heat pump system according to claim 2, characterized in that: The liquid storage tank (8) also has a gaseous refrigerant outlet (803); the non-azeotropic mixed working fluid heat pump system also includes a defrosting branch (10), one end of which is connected to the gaseous refrigerant outlet (803), and the other end is connected to the pipeline between the evaporator (5) and the first throttle valve (4). The defrosting branch (10) is provided with a switch valve (11).

4. The non-azeotropic mixed working fluid heat pump system according to claim 3, characterized in that: The switching valve (11) is a solenoid valve.

5. The non-azeotropic mixed working fluid heat pump system according to claim 3, characterized in that: The first refrigerant circulation loop contains at least two refrigerants with different boiling points, and the boiling point of the refrigerant in the second refrigerant circulation loop is lower than the boiling point of at least one refrigerant in the first refrigerant circulation loop.

6. The non-azeotropic mixed working fluid heat pump system according to claim 3, characterized in that: The liquid refrigerant outlet (802) is located at the bottom of the liquid reservoir (8), and the gaseous refrigerant outlet (803) is located at the top of the liquid reservoir (8).

7. The non-azeotropic mixed working fluid heat pump system according to claim 2, characterized in that: The first refrigerant circulation loop is also provided with a second throttle valve (9), which is located between the condenser (2) and the refrigerant inlet (801) of the liquid receiver (8).

8. The non-azeotropic mixed working fluid heat pump system according to any one of claims 1 to 7, characterized in that: It also includes an evaporator fan (12) for driving air to flow sequentially through the regenerator (7) and the evaporator (5).

9. The non-azeotropic mixed working fluid heat pump system according to any one of claims 1 to 7, characterized in that: The first refrigerant circulation loop is also provided with a gas-liquid separator (13) located between the evaporator (5) and the compressor (1).

10. The non-azeotropic mixed working fluid heat pump system according to any one of claims 1 to 7, characterized in that: The refrigerant pump (6) is a variable frequency pump.

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