Refrigeration cycle device

Abstract

Provided is a highly reliable refrigeration cycle device. A refrigeration cycle device (100) comprises a refrigerant circuit (Q1) in which a compressor (1), a heat source-side heat exchanger (3), a receiver (5), an expansion valve (7), and a load-side heat exchanger (8) are sequentially connected in a loop. A refrigerant that is sealed in the refrigerant circuit (Q1) is a non-azeotropic refrigerant mixture including a first refrigerant, in which a disproportionation reaction can occur, and a second refrigerant, which has a lower saturation pressure than the first refrigerant. The refrigeration cycle device further comprises a pipe (K3) and an on / off valve (11) that allow a liquid refrigerant to flow out from the receiver (5) when the liquid level of the liquid refrigerant is at least a prescribed liquid level with reference to the bottom of the receiver (5).

Description

Refrigeration cycle equipment

[0001] The present disclosure relates to a refrigeration cycle device.

[0002] A known technique for suppressing the disproportionation reaction of a refrigerant is described in, for example, Patent Document 1. Patent Document 1 describes that when the refrigerant pressure on the high-pressure side of a refrigerant circuit reaches a third value, power supply to an electric element of a compressor is stopped.

[0003] Japanese Patent Application Laid-Open No. 2018-112396

[0004] In the technology described in Patent Document 1, the disproportionation reaction of the refrigerant is suppressed by stopping the supply of power to the electric element of the compressor, but there is room for further improvement in the reliability of the refrigeration cycle device.

[0005] Therefore, an object of the present disclosure is to provide a highly reliable refrigeration cycle device.

[0006] In order to solve the above-mentioned problems, the refrigeration cycle device according to the present disclosure includes a refrigerant circuit in which a compressor, a heat source side heat exchanger, a receiver, an expansion mechanism, and a load side heat exchanger are connected in sequence in a ring, the refrigerant sealed in the refrigerant circuit is a non-azeotropic refrigerant mixture containing a first refrigerant in which a disproportionation reaction can occur and a second refrigerant having a lower saturation pressure than the first refrigerant, and further includes a liquid refrigerant outflow means for causing liquid refrigerant whose liquid level relative to the bottom of the receiver is equal to or higher than a predetermined height to flow out of the receiver.

[0007] According to the present disclosure, a highly reliable refrigeration cycle device can be provided.

[0008] Fig. 1 is a configuration diagram of a refrigeration cycle device according to a first embodiment. Fig. 2 is a characteristic diagram showing the relationship between the dryness fraction of a refrigerant and the concentration of disproportionated components in the gas phase in the refrigeration cycle device according to the first embodiment. Fig. 3 is an explanatory diagram showing the relationship between the pressure, temperature, and concentration of a refrigerant and the likelihood of a disproportionation reaction occurring in the refrigeration cycle device according to the first embodiment. Fig. 4 is an explanatory diagram including a receiver and piping provided in the refrigeration cycle device according to the first embodiment. Fig. 5 is an explanatory diagram including a receiver and piping provided in a refrigeration cycle device according to a first modified example. Fig. 6 is an explanatory diagram including a receiver and piping provided in a refrigeration cycle device according to a second modified example. Fig. 7 is a configuration diagram of a refrigeration cycle device according to a second embodiment.

[0009] First Embodiment Configuration of Refrigeration Cycle Apparatus Fig. 1 is a configuration diagram of a refrigeration cycle apparatus 100 according to a first embodiment. Note that arrows in Fig. 1 indicate the direction of refrigerant flow. The refrigeration cycle apparatus 100 shown in Fig. 1 is an apparatus that performs refrigeration and air conditioning by circulating a refrigerant in a refrigeration cycle (heat pump cycle) in a refrigerant circuit Q1. Note that the refrigerant sealed in the refrigerant circuit Q1 is a non-azeotropic refrigerant mixture (a mixture of refrigerants with different boiling points) that includes a first refrigerant in which a disproportionation reaction can occur and a second refrigerant having a lower saturation pressure than the first refrigerant.

[0010] As the first refrigerant, for example, the following refrigerants are used (refrigerant numbers are shown in parentheses). That is, as the first refrigerant, trans-1,2-difluoroethylene (R1132(E)), 1,1,2-trifluoroethylene (R1123), cis-1,2-difluoroethylene (R1132(Z)), 1,1-difluoroethylene (R1132a) and the like are used. These first refrigerants are characterized by their extremely low global warming potential (GWP).

[0011] The first refrigerant is also called a high-pressure refrigerant because it has a relatively high saturation pressure (i.e., a low boiling point and therefore a high evaporation rate). The inclusion of the first refrigerant in the refrigerant circuit Q1 reduces pressure loss during refrigeration and ensures an enthalpy difference in the refrigeration cycle.

[0012] On the other hand, a disproportionation reaction may occur in the first refrigerant under certain conditions. Here, the "disproportionation reaction" refers to a phenomenon in which, when a certain amount of ignition energy is applied in a high-temperature, high-pressure environment, a certain reaction proceeds in a chain reaction, generating a large amount of reaction heat and a sudden increase in pressure.

[0013] The second refrigerant described above has a lower saturation pressure than the first refrigerant (i.e., it has a higher boiling point and is less likely to evaporate), and is therefore also referred to as a low-pressure refrigerant. Examples of such second refrigerants include the following (refrigerant numbers are shown in parentheses). Examples of the second refrigerant include 2,3,3,3-tetrafluoropropene (R1234yf), trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), and cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)). These second refrigerants also have the advantage of having a very low global warming potential (GWP). Furthermore, by including the second refrigerant in the refrigerant circuit Q1, the occurrence of disproportionation reactions can be suppressed compared to when the first refrigerant is used alone. In addition to the first and second refrigerants, difluoromethane (R32), CO2 (R744), or the like may be further added, depending on the refrigeration capacity and operating pressure required for the refrigeration unit.

[0014] 1 is used as, for example, a refrigerator, but is not limited to this. That is, the refrigeration cycle apparatus 100 can be applied to air conditioners such as multi-air conditioners for buildings, package air conditioners, and room air conditioners, as well as water heaters, air-conditioning water heaters, and chillers.

[0015] 1 , the refrigeration cycle apparatus 100 includes a compressor 1, a check valve 2, a heat source side heat exchanger 3, a first fan 4, a receiver 5, a shutoff valve 6, an expansion valve 7 (expansion mechanism), a load side heat exchanger 8, and a second fan 9. In addition to the above-described components, the refrigeration cycle apparatus 100 also includes pipes K1 to K3, an on-off valve 11, a capillary tube 12, a temperature sensor 13, and a control unit 14.

[0016] The refrigerant circuit Q1 is configured by sequentially connecting a compressor 1, a heat source side heat exchanger 3, a receiver 5, an expansion valve 7 (expansion mechanism), and a load side heat exchanger 8 in a ring shape. The refrigerant circulates in the refrigeration cycle (heat pump cycle) in the refrigerant circuit Q1.

[0017] The compressor 1 is a device that compresses a low-temperature, low-pressure gas refrigerant and discharges it as a high-temperature, high-pressure gas refrigerant. For example, a scroll compressor or a rotary compressor is used as this compressor 1. Although not shown in Figure 1, an accumulator is connected to the suction side of the compressor 1 for separating the refrigerant into gas and liquid.

[0018] The check valve 2 is a valve for preventing backflow of the refrigerant and is provided on the discharge side of the compressor 1. The check valve 2 allows the refrigerant to flow from the compressor 1 toward the heat source-side heat exchanger 3, while prohibiting reverse flow. The heat source-side heat exchanger 3 is a heat exchanger (condenser) that exchanges heat between the high-temperature, high-pressure refrigerant discharged from the compressor 1 and outside air sent in by a first fan 4. The first fan 4 is a fan that sends outside air into the heat source-side heat exchanger 3 and is provided near the heat source-side heat exchanger 3.

[0019] The receiver 5 is a tank that stores excess refrigerant, and is connected via a pipe K1 to the downstream side of the heat source side heat exchanger 3. The shutoff valve 6 is a solenoid valve that is closed during the refrigerant recovery operation, and is connected via a pipe K2 to the downstream side of the receiver 5.

[0020] The refrigerant recovery operation is an operation in which, when normal refrigeration cycle operation is stopped, the refrigerant on the load side, such as the load side heat exchanger 8, is moved to the heat source side heat exchanger 3 and the receiver 5 and recovered while driving the compressor 1. By performing such a refrigerant recovery operation, it is possible to prevent a large amount of liquid refrigerant from being sucked into the compressor 1 at the start of the next operation. Incidentally, while the refrigerant recovery operation is being performed, the shutoff valve 6 is closed, but is maintained in an open state during normal refrigeration cycle operation.

[0021] The expansion valve 7 shown in Fig. 1 is a valve that reduces the pressure of the refrigerant condensed in the heat source-side heat exchanger 3. The load-side heat exchanger 8 is a heat exchanger (evaporator) that exchanges heat between the refrigerant flowing through its heat transfer tubes (not shown) and the air (air in the space to be air-conditioned) sent from a second fan 9. The second fan 9 is a fan that sends air to the load-side heat exchanger 8 and is installed near the load-side heat exchanger 8. The air cooled by the heat exchange with the refrigerant in the load-side heat exchanger 8 is then blown out into the space to be air-conditioned.

[0022] The pipe K3 shown in Fig. 1 is a pipe for causing liquid refrigerant to flow out of the receiver 5 when the liquid level in the receiver 5 reaches or exceeds a predetermined height h. In the example of Fig. 1, the pipe K3 is inserted into the side surface of the receiver 5. The upstream end of the pipe K3 is provided at a position where the height relative to the bottom of the receiver 5 is the predetermined height h. The downstream end of the pipe K3 is connected to the suction side of the compressor 1. Note that a configuration in which the downstream end of the pipe K3 is connected to the suction side of an accumulator (not shown) is also included in the term "connected to the suction side of the compressor 1."

[0023] The on-off valve 11 is a solenoid valve that is opened when liquid refrigerant is allowed to flow out from the receiver 5 through the pipe K3, and is provided on the pipe K3. When the liquid level of the liquid refrigerant in the receiver 5 is equal to or higher than a predetermined height h, the on-off valve 11 is opened to guide the liquid refrigerant to the suction side of the compressor 1 through the pipe K1. The "liquid refrigerant outflow means" that causes the liquid refrigerant, whose liquid level relative to the bottom of the receiver 5 is equal to or higher than the predetermined height h, to flow out of the receiver 5 includes the pipe K3 and the on-off valve 11.

[0024] 1 is a thin metal tube for reducing the pressure of the refrigerant flowing through the pipe K3. The capillary tube 12 is provided in the pipe K3 downstream of the on-off valve 11. The temperature sensor 13 is a sensor for detecting the temperature of the refrigerant flowing from the receiver 5 through the pipe K3. The temperature sensor 13 is provided in the pipe K1 downstream of the capillary tube 12. The detected value of the temperature sensor 13 is outputted to the control unit 14.

[0025] Although not shown in the figure, the control unit 14 has a hardware configuration including electronic circuits such as a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and various interfaces. The CPU reads out programs stored in the ROM and loads them into the RAM, causing the CPU to execute various processes. The control unit 14 controls the compressor 1, the first fan 4, the shutoff valve 6, the expansion valve 7, the second fan 9, the on-off valve 11, and other components in a predetermined manner. The processing of the control unit 14 will be described later.

[0026] <Regarding the Disproportionation Reaction> As described above, the refrigerant sealed in the refrigerant circuit Q1 is a non-azeotropic refrigerant mixture containing a first refrigerant and a second refrigerant. The first refrigerant is a high-pressure refrigerant with a low boiling point that evaporates relatively easily. On the other hand, the second refrigerant is a low-pressure refrigerant with a high boiling point that evaporates relatively little. As a result, the greater the amount of liquid refrigerant stored in the receiver 5, the greater the amount of first refrigerant contained in the liquid refrigerant. Due to the difference in boiling points, more of the first refrigerant evaporates inside the receiver 5 and becomes gaseous refrigerant. As a result, the concentration of the first refrigerant in the gaseous refrigerant inside the receiver 5 increases, making it more likely that a disproportionation reaction will occur in the first refrigerant the next time the compressor 1 is started.

[0027] For example, when the liquid and gas phase refrigerants inside the receiver 5 reach a predetermined equilibrium state while the compressor 1 is stopped (when the compressor is not operating or when the thermostat is off), the concentrations of the first refrigerant and the second refrigerant tend to differ between the liquid refrigerant and the gas refrigerant. In other words, the ratio (concentration) of the first refrigerant in the gas refrigerant becomes higher than the ratio (concentration) of the first refrigerant in the liquid refrigerant. In addition, a similar phenomenon can occur, for example, when a large amount of liquid refrigerant is recovered into the receiver 5 during refrigerant recovery operation.

[0028] Fig. 2 is a characteristic diagram showing the relationship between the dryness fraction of the refrigerant and the concentration of disproportionation components in the gas phase (see also Fig. 1 as appropriate). The horizontal axis of Fig. 2 represents the dryness fraction of the refrigerant inside the receiver 5. Here, the dryness fraction of the refrigerant is the ratio of the mass of the dry vapor refrigerant to the mass of the vapor refrigerant. The vertical axis of Fig. 2 represents the concentration of disproportionation components in the gas phase inside the receiver 5. In other words, the ratio (mass percent concentration) of the gaseous first refrigerant, which can cause a disproportionation reaction, in the gas refrigerant inside the receiver 5 is the concentration of disproportionation components in the gas phase.

[0029] The threshold M shown in FIG. th is a concentration threshold value that serves as a criterion for determining whether or not a disproportionation reaction of the first refrigerant may occur, and is set in advance based on prior experiments, etc. In other words, when the concentration of the disproportionation component in the gas phase (the concentration of the gaseous first refrigerant) is greater than or equal to the threshold M th When the concentration of the disproportionated components in the gas phase is equal to or higher than the threshold value M th If the temperature is less than 100°C, the disproportionation reaction of the first refrigerant is unlikely to occur.

[0030] 2 is the upper limit of the ambient temperature of the receiver 5 (e.g., 45°C). Furthermore, the lower limit of the ambient temperature of the receiver 5 (e.g., -40°C) is the lower limit of the ambient temperature of the receiver 5 (e.g., -40°C). As indicated by the lines corresponding to the upper limit of the temperature T1 and the lower limit of the temperature T2, the lower the quality fraction of the refrigerant inside the receiver 5, the higher the concentration of the disproportionated components in the gas phase. Furthermore, the gradient of each line, which is obtained when the concentration of the disproportionated components in the gas phase increases with a decrease in the quality fraction of the refrigerant, becomes steeper as the ambient temperature of the receiver 5 decreases.

[0031] Incidentally, when comparing cases where the dryness fraction value is the same, the lower the ambient temperature of the receiver 5, the more the second refrigerant liquefies, and therefore the higher the concentration of the gaseous first refrigerant (i.e., the higher the concentration of the disproportionated components in the gas phase).

[0032] 2 is the lower limit of the quality of the refrigerant present inside the receiver 5. This lower limit x1 is the value when the concentration of the disproportionated components in the gas phase at the upper limit temperature T1 is equal to or lower than the threshold M thThe upper limit value x2 is set to the value of the quality fraction when the concentration of disproportionated components in the gas phase at the lower limit temperature T2 reaches the threshold value M th It is set to the dryness value when it reaches

[0033] For example, suppose that R1132(E) is used as the first refrigerant and R1234yf is used as the second refrigerant, and a refrigerant obtained by mixing these refrigerants at a predetermined ratio is sealed in the refrigerant circuit Q1. Specifically, suppose that the mass ratio of R1132(E) to the refrigerant sealed in the refrigerant circuit Q1 is 20% or more and 35% or less, with the remainder being R1234yf. In this case, if the upper limit temperature T1 is 45°C and the lower limit temperature T2 is −40°C, the lower limit value x1 of the quality fraction is 0.025 kg / kg, and the upper limit value x2 is 0.5 kg / kg.

[0034] The allowable range of the dryness fraction of the refrigerant inside the receiver 5 (a dryness fraction range of 0.025 or more and 0.5 or less) can be converted into a void fraction of 0.19 or more and 0.9 or less. Here, the void fraction is the ratio of the volume of the gas phase to the total volume. The allowable range can be converted into a volume ratio of the liquid phase of 0.1 or more and 0.81 or less. In other words, the ratio of a predetermined height h (the installation height of the upstream end of the pipe K3: see FIG. 1) to the height H from the bottom to the top surface of the receiver 5 falls within the range of 0.1≦h / H≦0.81. By providing the upstream end of the pipe K3 so as to fall within this range, the concentration of disproportionated components in the gas phase (the concentration of the gaseous first refrigerant) can be reduced to the threshold value M th It can be reduced to the following.

[0035] Fig. 3 is an explanatory diagram showing the relationship between the pressure, temperature, and concentration of the refrigerant and the likelihood of the disproportionation reaction occurring (see also Fig. 1 as appropriate). Note that the horizontal axis of Fig. 3 represents the pressure inside the receiver 5, and the vertical axis represents the temperature inside the receiver 5 (i.e., the ambient temperature of the receiver 5). The dashed line in Fig. 3 represents the concentration of the first refrigerant (e.g., R1132(E)) contained in the gas refrigerant inside the receiver 5. A hatched area S1 in Fig. 3 indicates the operating range of the refrigeration cycle apparatus 100 (see Fig. 1).

[0036] As shown in FIG. 3 , the lower the pressure and temperature inside the receiver 5, the higher the concentration of the first refrigerant contained in the gas refrigerant. As a result, a disproportionation reaction is more likely to occur in the first refrigerant. In the example of FIG. 3 , a portion of the dashed-dotted curve corresponding to "high concentration" falls within the operating range (region S1) of the refrigeration cycle apparatus 100. To avoid this situation, it is desirable to maintain a low concentration of the gaseous first refrigerant inside the receiver 5. Therefore, in the first embodiment, the amount of liquid refrigerant stored in the receiver 5 is kept below a predetermined value to suppress an increase in the concentration of the first refrigerant contained in the gas refrigerant.

[0037] The control unit 14 shown in FIG. 1 performs the following control, for example. That is, when the on-off valve 11 is opened during the refrigerant recovery operation and the detected value of the temperature sensor 13 falls below a predetermined value, the control unit 14 stops the refrigerant recovery operation (i.e., stops the compressor 1). Then, the control unit 14 closes the on-off valve 11 when or after the refrigerant recovery operation is stopped. The predetermined value is a temperature threshold that serves as a criterion for determining whether the refrigerant flowing through the pipe K3 is in a liquid phase, and is set in advance. Note that when the refrigerant flowing through the pipe K3 is in a liquid phase, the detected value of the temperature sensor 13 is lower than when the refrigerant is in a gas phase.

[0038] By performing the above-described control, when the liquid level of the liquid refrigerant stored in the receiver 5 reaches pipe K3 (i.e., when the liquid refrigerant flows through pipe K3), the refrigerant recovery operation is stopped. As a result, an increase in the concentration of the gaseous first refrigerant inside the receiver 5 is suppressed, and ultimately, the disproportionation reaction of the first refrigerant is also suppressed. Incidentally, when the control unit 14 stops the refrigerant recovery operation, it is possible that the liquid level of the liquid refrigerant in the receiver 5 slightly exceeds the height h of pipe K3, but this does not particularly hinder the suppression of the disproportionation reaction of the first refrigerant.

[0039] Furthermore, for example, the control unit 14 may open the on-off valve 11 for a predetermined time while the compressor 1 is stopped (during shutdown or thermo-off). This is because, while the compressor 1 is stopped, the gas and liquid phases of the refrigerant reach an equilibrium state inside the receiver 5, and the concentration of the gaseous first refrigerant is likely to increase. The predetermined time is preset as a time sufficient for the portion of the refrigerant exceeding the height h of the pipe K3 to flow out when the liquid level in the receiver 5 exceeds the height h of the pipe K3.

[0040] When the on-off valve 11 is opened while the compressor 1 is stopped, if the liquid refrigerant level is higher than the height h of the upstream end of the pipe K3, the liquid refrigerant flows out of the receiver 5 through the pipe K3. As a result, the height position of the liquid refrigerant in the receiver 5 is kept below the height h of the upstream end of the pipe K3, thereby suppressing the disproportionation reaction of the first refrigerant. Incidentally, when this control is performed, there is no particular need to use the detection value of the temperature sensor 13.

[0041] FIG. 4 is an explanatory diagram including the receiver 5 and pipes K1, K2, and K3. In the example of FIG. 4, pipe K1 is inserted into the top of the receiver 5. Pipe K1 is a pipe that guides refrigerant condensed in the heat source-side heat exchanger 3 (see FIG. 1) to the receiver 5. Another pipe K2 is inserted into the bottom of the receiver 5. Pipe K2 is a pipe that guides refrigerant from the receiver 5 to the expansion valve 7 (see FIG. 1). Pipe K3 is inserted into a predetermined position on the side of the receiver 5. Specifically, pipe K3 is inserted horizontally at a position where the height position relative to the bottom of the receiver 5 is a predetermined height h. Pipe K3 is a pipe that guides refrigerant from the receiver 5 to the suction side of the compressor 1.

[0042] The pipe K3 has an inner diameter (opening) of a predetermined thickness. The predetermined height h shown in Fig. 4 is set, for example, based on the center position of the opening of the pipe K3 in the height direction. Note that the predetermined height h may also be set based on the lower end or upper end of the opening of the pipe K3.

[0043] The height h of the upstream end of the pipe K3 is preferably set within the range specified by the following formula (1): where A in formula (1) is the horizontal cross-sectional area of ​​the receiver 5.L is the lower limit of the volume of the liquid refrigerant in the receiver 5 that can suppress the disproportionation reaction of the first refrigerant when the ambient temperature of the receiver 5 is at a predetermined lower limit of the temperature. H is the upper limit of the volume of the liquid refrigerant in the receiver 5 that can suppress the disproportionation reaction of the first refrigerant when the ambient temperature of the receiver 5 is at a predetermined upper limit of the temperature.

[0044] V L / A≦h≦V U / A ... (1)

[0045] In this way, the pipe K3 (liquid refrigerant outflow means) is provided at a position where the liquid storage amount is such that the disproportionation reaction does not occur, thereby preventing the gaseous first refrigerant from becoming highly concentrated inside the receiver 5 while the compressor 1 is stopped or during the refrigerant recovery operation.

[0046] <Effects> According to the first embodiment, liquid refrigerant whose liquid level relative to the bottom of the receiver 5 is equal to or greater than a predetermined height is allowed to flow out of the receiver 5. This makes it possible to prevent the gaseous first refrigerant from becoming highly concentrated inside the receiver 5 while the compressor 1 is stopped or during refrigerant recovery operation. Therefore, the occurrence of a disproportionation reaction in the first refrigerant is prevented the next time the compressor 1 is started, thereby improving the reliability of the refrigeration cycle apparatus 100.

[0047] <First Modification> Fig. 5 is an explanatory diagram including the receiver 5 and pipes K1, K2, and K4 provided in a refrigeration cycle apparatus according to a first modification. As shown in Fig. 5, the pipe K4 may be inserted vertically from the bottom of the receiver 5. The pipe K4 is a pipe (liquid refrigerant outflow means) for causing liquid refrigerant whose liquid level, relative to the bottom of the receiver 5, is equal to or greater than a predetermined height h to flow out of the receiver 5. Note that the height h of the upstream end of the pipe K4 relative to the bottom of the receiver 5 is the same as in the first embodiment. Even with this configuration, the same effects as in the first embodiment can be achieved.

[0048] Fig. 6 is an explanatory diagram including the receiver 5 and pipes K1, K2, and K5 provided in a refrigeration cycle apparatus according to a second modified example. As shown in Fig. 6, the pipe K5 may be inserted vertically from the top of the receiver 5. The pipe K5 is a pipe (liquid refrigerant outflow means) for allowing liquid refrigerant whose liquid level, relative to the bottom of the receiver 5, is equal to or higher than a predetermined height to flow out of the receiver 5. Note that the height h of the upstream end of the pipe K5, relative to the bottom of the receiver 5, is the same as in the first embodiment. Even with this configuration, the same effects as in the first embodiment can be achieved.

[0049] Incidentally, the liquid refrigerant flows through the pipe K5 due to the pressure difference between the upstream and downstream sides of the pipe K5. In other words, the refrigerant rises due to the pressure difference through the vertical portion of the pipe K5, so even with the configuration shown in Figure 6, there is no particular risk of any problems with the flow of the refrigerant.

[0050] Second Embodiment In the second embodiment, the liquid refrigerant flows out from the receiver 5 through a predetermined pipe K6 (see FIG. 7). In addition, the second embodiment is configured such that an on-off valve 15 (see FIG. 7) is provided instead of the on-off valve 11 (see FIG. 1), the capillary tube 12 (see FIG. 1), and the temperature sensor 13 (see FIG. 1) described in the first embodiment. Note that the rest of the second embodiment is the same as the first embodiment. Therefore, only the parts that are different from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0051] Fig. 7 is a configuration diagram of a refrigeration cycle apparatus 100A according to the second embodiment. As shown in Fig. 7, the refrigeration cycle apparatus 100A includes a compressor 1, a check valve 2, a heat source side heat exchanger 3, a first fan 4, a receiver 5, a shutoff valve 6, an expansion valve 7 (expansion mechanism), a load side heat exchanger 8, a second fan 9, a control unit 14, a pipe K6, and an on-off valve 15.

[0052] The pipe K6 is a pipe for preventing an excessive amount of liquid refrigerant (an amount exceeding a predetermined height h) from being stored in the receiver 5. The upstream end of the pipe K6 is inserted into the side surface of the receiver 5. More specifically, the upstream end of the pipe K6 is provided at a position where the height relative to the bottom of the receiver 5 is the predetermined height h. Note that the height h of the upstream end of the pipe K6 is the same as in the first embodiment, and therefore description thereof will be omitted. The downstream end of the pipe K6 is connected to another pipe K2 that guides refrigerant from the receiver 5 to the expansion valve 7 (expansion mechanism). More specifically, the downstream end of the pipe K6 is connected downstream of the point where the shutoff valve 6 is provided in the pipe K2.

[0053] The on-off valve 15 shown in Fig. 7 is a solenoid valve provided on the pipe K6 for switching between flow and blocking of the refrigerant through the pipe K6. During normal refrigeration cycle operation, the on-off valve 15 is maintained in a closed state. Furthermore, while the compressor 1 is stopped (during shutdown or thermo-off), the control unit 14 opens the on-off valve 15 for a predetermined time at a predetermined timing. Alternatively, the control unit 14 may open the on-off valve 15 for at least a portion of the refrigerant recovery operation. This allows the amount of liquid refrigerant stored in the receiver 5 to be kept below a predetermined value (a volume defined by the height h of the upstream end of the pipe K6).

[0054] In addition, the ``liquid refrigerant outflow means'' that causes liquid refrigerant whose liquid level relative to the bottom of the receiver 5 is equal to or higher than a predetermined height h to flow out of the receiver 5 is composed of a pipe K6 and an opening / closing valve 15.

[0055] <Effects> According to the second embodiment, the configuration is simpler than that of the first embodiment, which reduces the manufacturing cost of the refrigeration cycle apparatus 100A. Furthermore, similar to the first embodiment, the disproportionation reaction of the first refrigerant can be suppressed.

[0056] <<Modifications>> Although the refrigeration cycle apparatus 100, 100A according to the present disclosure have been described above in each embodiment, the present disclosure is not limited to these descriptions and various modifications can be made. For example, in the first embodiment, the refrigeration cycle apparatus 100 (see FIG. 1 ) is described as including an expansion valve 7 (expansion mechanism), but the present disclosure is not limited to this. That is, an expansion mechanism such as a capillary tube may be provided instead of the expansion valve 7 (or together with the expansion valve 7). The same can be said for the second embodiment.

[0057] In the first embodiment, the refrigeration cycle apparatus 100 (see FIG. 1 ) is described as having the check valve 2 and the shutoff valve 6, but this is not limiting. For example, the check valve 2 and the shutoff valve 6 may be omitted as appropriate. Furthermore, in a configuration in which the shutoff valve 6 is omitted, the expansion valve 7 may be closed during the refrigerant recovery operation. The same applies to the second embodiment.

[0058] In addition, in each embodiment, the first refrigerant is any one of R1132(E), R1123, R1132(Z), and R1132a, but the present invention is not limited thereto. That is, any other predetermined refrigerant capable of causing a disproportionation reaction may be used as the first refrigerant.

[0059] In addition, although the embodiments have been described with reference to cases where any one of R1234yf, R1234ze(E), and R1234ze(Z) is used as the second refrigerant, this is not limiting. For example, one or more of R1234yf, R1234ze(E), and R1234ze(Z) may be used as the second refrigerant. Furthermore, another specified refrigerant having a lower saturation pressure than the first refrigerant may be used as the second refrigerant.

[0060] Although each embodiment has been described with reference to a case where the receiver 5 is installed vertically, each embodiment can also be applied to a configuration where the receiver 5 is installed horizontally or at an angle. In this case, the height h of the pipe K3 (see FIG. 1) and the pipe K6 (see FIG. 7) is set based on the vertical height from the bottom of the receiver 5.

[0061] Although the second embodiment has been described with reference to a case where the downstream end of the pipe K6 (see FIG. 7 ) is connected between the shutoff valve 6 and the expansion valve 7, this is not limiting. For example, the downstream end of the pipe K6 may be connected between the receiver 5 and the shutoff valve 6. In this configuration, the control unit 14 appropriately opens the on-off valve 15 during the refrigerant recovery operation. This allows liquid refrigerant to be stored at least inside the pipe K6, thereby keeping the liquid refrigerant level in the receiver 5 at or below the level of the upstream end of the pipe K6. Because the shutoff valve 6 is kept closed during the refrigerant recovery operation, the refrigerant pressure in the heat-source-side heat exchanger 3 increases as the amount of liquid refrigerant stored in the receiver 5 increases, resulting in an increase in the discharge pressure of the compressor 1. When the detected value of the discharge pressure of the compressor 1 reaches a predetermined value, the control unit 14 stops the refrigerant recovery operation and closes the on-off valve 15. This prevents an excessive amount of liquid refrigerant from being stored in the receiver 5, and ultimately prevents the concentration of the gaseous first refrigerant inside the receiver 5 from increasing.

[0062] Furthermore, the respective embodiments and modifications can be combined as appropriate. For example, the second embodiment (see FIG. 7) and the first modification (see FIG. 5) may be combined so that the pipe K4 is inserted into the bottom of the receiver 5. Furthermore, the second embodiment (see FIG. 7) and the second modification (see FIG. 6) may be combined so that the pipe K5 is inserted into the top of the receiver 5.

[0063] Furthermore, in each embodiment, a case has been described in which the refrigeration cycle apparatus 100 is not particularly provided with a four-way valve, but this is not limited thereto. For example, when the refrigeration cycle apparatus 100 is used as an air conditioner, a four-way valve (not shown) for switching the refrigerant flow path between the cooling cycle and the heating cycle may be provided. In addition, well-known components such as a subcooler may be added as appropriate. Note that when the refrigeration cycle apparatus 100 is applied to an air conditioner or the like, the outdoor heat exchanger and the indoor heat exchanger that function as a condenser correspond to the "heat source side heat exchanger," and the one that functions as an evaporator corresponds to the "load side heat exchanger."

[0064] Furthermore, each embodiment has been described in detail to clearly explain the present disclosure, and is not necessarily limited to having all of the described configurations. Furthermore, it is possible to appropriately add, delete, or replace part of the configuration of each embodiment with other configurations. Furthermore, the above-described mechanisms and configurations are those considered necessary for explanation, and do not necessarily represent all mechanisms and configurations of the product.

[0065] REFRIGERATION CYCLE DEVICE K1 PIPE K2 PIPE (ANOTHER PIPE) K3, K4, K5, K6 PIPE (LIQUID REFRIGERANTING MEANS) Q1 REFRIGERANTING CIRCUIT

Claims

1. A refrigeration cycle device comprising a refrigerant circuit in which a compressor, a heat source side heat exchanger, a receiver, an expansion mechanism, and a load side heat exchanger are connected in sequence in a ring, wherein the refrigerant sealed in the refrigerant circuit is a non-azeotropic refrigerant mixture containing a first refrigerant in which a disproportionation reaction can occur and a second refrigerant having a lower saturation pressure than the first refrigerant, and further comprising liquid refrigerant outlet means for causing liquid refrigerant whose liquid level relative to the bottom of the receiver is equal to or higher than a predetermined height to flow out of the receiver.

2. The refrigeration cycle device according to claim 1, wherein the predetermined height h is within the range expressed by the following formula (1): L / A≦h≦V U / A (1) where A in equation (1) is the horizontal cross-sectional area of ​​the receiver, and V L is the lower limit of the volume of the liquid refrigerant in the receiver that can suppress the disproportionation reaction of the first refrigerant when the ambient temperature of the receiver is at a predetermined lower limit of temperature, and V H is the upper limit of the volume of the liquid refrigerant in the receiver that can suppress the disproportionation reaction of the first refrigerant when the ambient temperature of the receiver is at a predetermined upper limit of the temperature.

3. The refrigeration cycle device according to claim 1, wherein the refrigerant sealed in the refrigerant circuit is a non-azeotropic refrigerant mixture made by mixing the first refrigerant, R1132(E), and the second refrigerant, R1234yf, and the ratio of the predetermined height h to the height H from the bottom to the top of the receiver is within the range of 0.1≦h / H≦0.

81.

4. The refrigeration cycle device according to claim 1, wherein the first refrigerant is any one of R1132(E), R1123, R1132(Z), and R1132a.

5. The refrigeration cycle device according to claim 1, characterized in that the second refrigerant includes one or more of R1234yf, R1234ze(E), and R1234ze(Z).

6. The refrigeration cycle device according to claim 1, wherein the upstream end of the pipe constituting the liquid refrigerant outflow means is located at a position where the height relative to the bottom of the receiver is the predetermined height, and the downstream end of the pipe is connected to the suction side of the compressor.

7. The refrigeration cycle device according to claim 6, further comprising: an on-off valve provided in the piping; a capillary tube for reducing the pressure of the refrigerant flowing through the piping; and a control unit for opening the on-off valve for a predetermined period of time while the compressor is stopped.

8. A refrigeration cycle device as described in claim 6, comprising: an on-off valve provided in the piping; a capillary tube for reducing the pressure of the refrigerant flowing through the piping; and a temperature sensor for detecting the temperature of the refrigerant flowing through the piping, and a control unit for stopping the refrigerant recovery operation when the on-off valve is opened during execution of a refrigerant recovery operation and the detected value of the temperature sensor falls below a predetermined value.

9. The refrigeration cycle device according to claim 1, wherein the upstream end of the pipe constituting the liquid refrigerant outflow means is provided at a position where the height relative to the bottom of the receiver is the predetermined height, and the downstream end of the pipe is connected to another pipe that guides the refrigerant from the receiver to the expansion mechanism.

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