Refrigeration cycle equipment

Abstract

To solve a problem that in a refrigeration cycle device that uses a non-azeotropic mixed refrigerant, there is a possibility that a composition of a refrigerant circulating in a refrigerant circuit might be deviated from a base composition and thus heat exchange performance and controllability might deteriorate.SOLUTION: A refrigeration cycle device 100 includes a compressor 21, a utilization side heat exchanger 31, a heat source side expansion valve 25, a heat source side heat exchanger 23, a main refrigerant circuit 10, a first accumulator 26 and a refrigerant evaporation mechanism 27. A non-azeotropic mixed refrigerant is included in the main refrigerant circuit 10. The first accumulator 26 is provided between the heat source side heat exchanger 23 and the compressor 21. The mixed refrigerant before sucked to the compressor 21 is stored in the first accumulator 26. The refrigerant evaporation mechanism 27 is provided between the first accumulator 26 and the compressor 21. The refrigerant evaporation mechanism 27 evaporates a liquid refrigerant stored in the first accumulator 26 and flowing from the first accumulator 26 toward the compressor 21.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] It relates to a refrigeration cycle device.

Background Art

[0002] Conventionally, a refrigeration cycle device using a zeotropic mixture refrigerant has been known. Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-20043), a refrigeration cycle device equipped with an accumulator connected to the suction side of a compressor and using a zeotropic mixture refrigerant obtained by mixing a low-boiling refrigerant and a high-boiling refrigerant is disclosed.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In such a refrigeration cycle device, the surplus refrigerant accumulated in the accumulator becomes a liquid refrigerant containing a large amount of high-boiling refrigerant, and the circulating refrigerant circulating in the refrigerant circuit of the refrigeration cycle device tends to be a refrigerant containing a large amount of low-boiling refrigerant. Therefore, the composition of the circulating refrigerant may deviate from the base composition of the zeotropic mixture refrigerant, and the heat exchange performance and controllability of the refrigeration cycle device may deteriorate.

Means for Solving the Problems

[0004] The refrigeration cycle device of the first aspect includes a compressor, a condenser, an expansion mechanism, an evaporator, a refrigerant circuit, a first container, and a first mechanism. In the refrigerant circuit, the compressor, the condenser, the expansion mechanism, and the evaporator are connected in a ring shape. A mixed refrigerant is enclosed in the refrigerant circuit. The mixed refrigerant is a zeotropic mixture refrigerant. The first container is provided between the evaporator and the compressor in the refrigerant circuit. The first container stores the mixed refrigerant before being sucked into the compressor. The first mechanism is provided between the first container and the compressor in the refrigerant circuit. The first mechanism evaporates the liquid refrigerant stored in the first container and flowing from the first container toward the compressor.

[0005] In the first type of refrigeration cycle system, the liquid refrigerant stored in the accumulator (first container) evaporates and is then drawn into the compressor to circulate through the refrigerant circuit. This prevents the composition of the refrigerant circulating in the refrigerant circuit from deviating from the base composition of the non-azeotropic mixed refrigerant sealed in the refrigerant circuit.

[0006] The refrigeration cycle apparatus in the second aspect is the refrigeration cycle apparatus in the first aspect, wherein the evaporator performs heat exchange between the mixed refrigerant before it is stored in the first container and the first fluid. The first mechanism performs heat exchange between the liquid refrigerant and the first fluid, heating the liquid refrigerant and causing it to evaporate.

[0007] In the refrigeration cycle system of the second perspective, a heat exchanger (first mechanism) similar to that of an evaporator can be used to evaporate the liquid refrigerant before it is drawn into the compressor.

[0008] The refrigeration cycle device in the third perspective is the refrigeration cycle device in the second perspective, wherein the first mechanism is connected to an evaporator.

[0009] The refrigeration cycle device of the fourth aspect is a refrigeration cycle device of the second or third aspect, wherein the first mechanism performs heat exchange between a first fluid, which has undergone heat exchange with a mixed refrigerant in an evaporator, and a liquid refrigerant.

[0010] The refrigeration cycle device of the fifth aspect is a refrigeration cycle device of any one of the first to fourth aspects, further comprising a second vessel. The second vessel is located in the refrigerant circuit between the first mechanism and the compressor and stores the mixed refrigerant before it is drawn into the compressor.

[0011] In the fifth-viewpoint refrigeration cycle system, the liquid refrigerant flowing from the first accumulator (first container) toward the compressor is partially evaporated and then stored in the second accumulator (second container) before being drawn into the compressor. The gaseous refrigerant in the second accumulator is sent to the compressor. This effectively suppresses deviations in the composition of the refrigerant circulating in the refrigerant circuit from the base composition.

[0012] The refrigeration cycle device of the sixth aspect is a refrigeration cycle device of any one of the first to fifth aspects, further comprising a bypass circuit and a switching mechanism. The bypass circuit is provided in the refrigerant circuit between the first container and the compressor. The bypass circuit bypasses the first mechanism. The switching mechanism switches between a first state in which the mixed refrigerant flows through the bypass circuit and a second state in which the mixed refrigerant does not flow through the bypass circuit.

[0013] In the refrigeration cycle system of the sixth perspective, for example, when the amount of refrigerant circulating in the refrigerant circuit is small, refrigerant can be circulated through a bypass circuit to suppress overheating of the refrigerant.

[0014] The refrigeration cycle device of the seventh aspect is the refrigeration cycle device of the sixth aspect, further comprising a control unit. The control unit controls a switching mechanism to switch between a first state and a second state according to the degree of superheating of the mixed refrigerant drawn into the compressor.

[0015] The refrigeration cycle device of the eighth aspect is a refrigeration cycle device of any one of the first to seventh aspects, wherein the first mechanism has a heating section for heating a mixed refrigerant.

[0016] In the refrigeration cycle system of the eighth perspective, the inhalation of liquid refrigerant into the compressor is effectively suppressed by heating and evaporating the liquid refrigerant before it is drawn into the compressor.

[0017] The refrigeration cycle device of the ninth aspect is a refrigeration cycle device of any one of the first to eighth aspects, wherein the mixed refrigerant includes an ethylene-based fluorinated hydrocarbon and a refrigerant with a higher boiling point than the ethylene-based fluorinated hydrocarbon.

[0018] The refrigeration cycle device of the 10th aspect is the refrigeration cycle device of the 9th aspect, and the ethylene-based fluorinated hydrocarbon is R1132(E) or R1123.

[0019] The refrigeration cycle device of the 11th aspect is the refrigeration cycle device of the 10th aspect, wherein the mixed refrigerant contains 10.0% by mass or more of R1132(E). [Brief explanation of the drawing]

[0020] [Figure 1] It is a diagram showing an example of the overall configuration of the refrigeration cycle device 100 of the first embodiment. [Figure 2] It is a block diagram of the control unit 70. [Figure 3] It is a diagram showing a schematic configuration inside the first accumulator 26. [Figure 4] It is a diagram showing an example of the overall configuration of the refrigeration cycle device 200 of the second embodiment. [Figure 5] It is a Mollier diagram for explaining the state of the circulating refrigerant in the second embodiment. [Figure 6] It is a diagram showing an example of the overall configuration of the refrigeration cycle device 300 of the third embodiment. [Figure 7] It is a diagram showing a schematic configuration inside the second accumulator 36. [Figure 8] It is a Mollier diagram for explaining the state of the circulating refrigerant in the third embodiment. [Figure 9] It is a diagram showing an example of the overall configuration of the refrigeration cycle device 200 of modification example C. [Figure 10] It is a diagram showing an example of the overall configuration of the refrigeration cycle device 300 of modification example D. [Figure 11] It is a diagram showing an example of the overall configuration of the refrigeration cycle device 400 of modification example E. [Figure 12] It is a diagram showing an example of the overall configuration of the refrigeration cycle device 500 of modification example F.

Embodiments for Carrying out the Invention

[0021] <First Embodiment> (1) Configuration of the refrigeration cycle device 1 hundred The refrigeration cycle device 100 according to the present embodiment is an air conditioner that performs cooling operation and heating operation of a predetermined air-conditioned target space by a vapor compression refrigeration cycle.

[0022] As shown in Figure 1, the refrigeration cycle device 100 mainly comprises a heat source unit 2, a utilization unit 3, a liquid-side refrigerant connecting pipe 6, a gas-side refrigerant connecting pipe 7, a remote control 8, and a control unit 70. In the refrigeration cycle device 100, the heat source unit 2 and the utilization unit 3 are connected via the liquid-side refrigerant connecting pipe 6 and the gas-side refrigerant connecting pipe 7 to form a main refrigerant circuit 10 through which the refrigerant circulates.

[0023] In the refrigeration cycle device 100, a vapor compression type refrigeration cycle is performed in which the refrigerant sealed in the main refrigerant circuit 10 is compressed, condensed, depressurized, evaporated, and then compressed again.

[0024] The refrigeration cycle device 100 may be equipped with multiple user units 3. In this case, the main refrigerant circuit 10 is configured by connecting multiple user units 3 in parallel to one heat source unit 2.

[0025] The refrigerant sealed in the main refrigerant circuit 10 is a non-azeotropic mixed refrigerant. A non-azeotropic mixed refrigerant is a mixture of several types of refrigerants with different boiling points. For example, a non-azeotropic mixed refrigerant includes an ethylene-based fluorinated hydrocarbon and a refrigerant with a higher boiling point than the ethylene-based fluorinated hydrocarbon. For example, the ethylene-based fluorinated hydrocarbon is R1132(E) or R1123. For example, the refrigerant with a higher boiling point than the ethylene-based fluorinated hydrocarbon is R1234yf. In this case, the non-azeotropic mixed refrigerant is a mixed refrigerant containing, for example, 10.0% by mass or more of R1132(E).

[0026] (1-1) Heat source unit 2 The heat source unit 2 is installed outdoors, such as outside a building that has an air-conditioned space. As shown in Figure 1, the heat source unit 2 mainly includes a compressor 21, a four-way switching valve 22, a heat source side heat exchanger 23, a heat source side fan 24, a heat source side expansion valve 25, a first accumulator 26, a refrigerant evaporation mechanism 27, a liquid side shut-off valve 28, and a gas side shut-off valve 29.

[0027] The compressor 21 is a device that compresses the low-pressure refrigerant in the refrigeration cycle to a high-pressure level. The compressor 21 has a sealed structure in which a variable-volume compression element (not shown), such as a rotary or scroll type, is rotationally driven by a compressor motor 21a. The operating frequency (rotational speed of the compressor 21) of the compressor motor 21a can be controlled by an inverter.

[0028] The four-way switching valve 22 switches between the cooling operation connection state and the heating operation connection state by switching the connection state of the main refrigerant circuit 10. In the cooling operation connection state (dotted line state in Figure 1), the discharge side of the compressor 21 is connected to the gas side of the heat source side heat exchanger 23, and the suction side of the compressor 21 is connected to the gas side shut-off valve 29. In the heating operation connection state (solid line state in Figure 1), the discharge side of the compressor 21 is connected to the gas side shut-off valve 29, and the suction side of the compressor 21 is connected to the gas side of the heat source side heat exchanger 23. One of the connection ports of the four-way switching valve 22 is connected to the discharge side of the compressor 21 via the first piping 51.

[0029] The heat source side heat exchanger 23 functions as a heat exchanger (condenser) for high-pressure refrigerant in the refrigeration cycle during cooling operation, and as a heat absorber (evaporator) for low-pressure refrigerant in the refrigeration cycle during heating operation.

[0030] The heat source fan 24 supplies air from outside the space to be air-conditioned (such as outside air) into the heat source unit 2 to the heat source heat exchanger 23, and after heat exchange with the refrigerant in the heat source heat exchanger 23, it generates an airflow to discharge the air to the outside of the heat source unit 2. The heat source fan 24 is rotationally driven by the heat source fan motor 24a.

[0031] The heat source side expansion valve 25 is a throttling mechanism that has the function of reducing the pressure of the refrigerant. The heat source side expansion valve 25 is installed between the liquid side of the heat source side heat exchanger 23 and the liquid side shut-off valve 28. The heat source side expansion valve 25 is an electrically operated expansion valve whose opening degree can be adjusted by control by the control unit 70.

[0032] The first accumulator 26 is located between the suction side of the compressor 21 and one of the connection ports of the four-way switching valve 22. In the main refrigerant circuit 10 in heating operation mode, the first accumulator 26 is located between the compressor 21 and the heat source side heat exchanger 23. Inside the first accumulator 26 are the end of the second pipe 52 connected to the suction side of the compressor 21 and the end of the third pipe 53 connected to one of the connection ports of the four-way switching valve 22. The second pipe 52 and the third pipe 53 are connected to each other via the first accumulator 26.

[0033] The first accumulator 26 is a refrigerant container capable of temporarily storing excess refrigerant in the main refrigerant circuit 10 as liquid refrigerant. The refrigerant circulating in the main refrigerant circuit 10 flows through the third pipe 53 and into the first accumulator 26. The refrigerant stored inside the first accumulator 26 flows through the second pipe 52 and flows out of the first accumulator 26.

[0034] The refrigerant evaporation mechanism 27 is provided between the suction side of the compressor 21 and the first accumulator 26. The refrigerant evaporation mechanism 27 is provided in the second piping 52. The second piping 52 is divided by the refrigerant evaporation mechanism 27 into a discharge side piping 52a and a suction side piping 52b. The discharge side piping 52a connects the first accumulator 26 and the refrigerant evaporation mechanism 27. The suction side piping 52b connects the refrigerant evaporation mechanism 27 and the suction side of the compressor 21.

[0035] The liquid-side shut-off valve 28 is a manual valve located at the connection point between the heat source unit 2 and the liquid-side refrigerant communication pipe 6.

[0036] The gas-side shut-off valve 29 is a manual valve located at the connection point between the heat source unit 2 and the gas-side refrigerant communication pipe 7.

[0037] The heat source unit 2 has a heat source unit control unit 20 that controls the operation of each component that makes up the heat source unit 2. The heat source unit control unit 20 constitutes the control unit 70. The heat source unit control unit 20 is, for example, a microcomputer including a CPU and memory. The heat source unit control unit 20 is connected to the user unit control unit 30 of the user unit 3 via a communication line and transmits and receives control signals and the like.

[0038] (1-2) Unit 3 The utilization unit 3 is installed on the walls and ceilings of rooms and other spaces that are to be air-conditioned. As shown in Figure 1, the utilization unit 3 mainly consists of a utilization-side heat exchanger 31 and a utilization-side fan 32.

[0039] The user-side heat exchanger 31 functions as a heat absorber (evaporator) for the low-pressure refrigerant in the refrigeration cycle during cooling operation, and as a heat radiator (condenser) for the high-pressure refrigerant in the refrigeration cycle during heating operation. The piping extending from the liquid side of the user-side heat exchanger 31 is connected to the liquid-side refrigerant communication pipe 6. The piping extending from the gas side of the user-side heat exchanger 31 is connected to the gas-side refrigerant communication pipe 7. As a result, the compressor 21, the heat source-side heat exchanger 23, the heat source-side expansion valve 25, and the user-side heat exchanger 31 are connected in a ring shape to the main refrigerant circuit 10.

[0040] The user-side fan 32 supplies air from the space to be air-conditioned into the user-side heat exchanger 31, where it exchanges heat with the refrigerant, and then generates an airflow for discharge into the space to be air-conditioned. The user-side fan 32 is rotationally driven by the user-side fan motor 32a.

[0041] The user unit 3 has a user unit control unit 30 that controls the operation of each component that makes up the user unit 3. The user unit control unit 30 constitutes the control unit 70. The user unit control unit 30 is, for example, a microcomputer including a CPU and memory. The user unit control unit 30 is connected to the heat source unit control unit 20 of the heat source unit 2 via a communication line and transmits and receives control signals and the like.

[0042] (1-3) Remote control 8 The remote control 8 is placed in the space to be air-conditioned, or in a specific space within a building that has such a space. The remote control 8 functions as an input device for the user of the refrigeration cycle unit 100 to input various instructions to the refrigeration cycle unit 100. For example, the user can operate the remote control 8 to switch the operating state of the refrigeration cycle unit 100 (heating operation or cooling operation) or adjust the set temperature of the space to be air-conditioned. The remote control 8 also functions as a display device for displaying the operating state of the refrigeration cycle unit 100 and predetermined notification information. The remote control 8 is connected to the heat source unit control unit 20 and the utilization unit control unit 30 via a communication line and transmits and receives signals to each other.

[0043] (1-4) Control Unit 70 In the refrigeration cycle device 100, the heat source unit control unit 20 and the utilization unit control unit 30 are connected via a communication line to form a control unit 70, which is hardware that controls the operation of the refrigeration cycle device 100. Control by the control unit 70 is achieved by the integrated operation of the heat source unit control unit 20 and the utilization unit control unit 30.

[0044] As shown in Figure 2, the control unit 70 is electrically connected to the actuators included in the heat source unit 2. Specifically, the actuators included in the heat source unit 2 are the compressor motor 21a of the compressor 21, the heat source side expansion valve 25, and the heat source side fan motor 24a of the heat source side fan 24. The control unit 70 is also electrically connected to the remote control 8 and the actuators included in the user unit 3. Specifically, the actuator included in the user unit 3 is the user side fan motor 32a of the user side fan 32.

[0045] As shown in Figure 2, the control unit 70 mainly comprises a storage unit 71, a communication unit 72, a mode control unit 73, an actuator control unit 74, and a display control unit 75. Each of these elements realizes a specific function of the control unit 70. The control unit 70 performs these functions by executing control programs stored in ROM, RAM, flash memory, etc.

[0046] The memory unit 71 receives requests from other elements of the control unit 70 and stores predetermined information in a predetermined memory area. This predetermined information includes, for example, the results of calculations performed by the control unit 70 and commands input to the remote control 8.

[0047] The communication unit 72 functions as a communication interface for sending and receiving signals with each device connected to the control unit 70. The communication unit 72 receives a request from the actuator control unit 74 and transmits a predetermined signal to the designated actuator. The communication unit 72 receives a signal output from the remote control 8, etc., and requests the storage unit 71 to store it in a predetermined memory area.

[0048] The mode control unit 73 performs operations such as switching the operating mode of the refrigeration cycle device 100.

[0049] The actuator control unit 74 controls the operation of each actuator included in the refrigeration cycle device 100 based on a control program. For example, the actuator control unit 74 controls the rotational speed of the compressor 21, the opening degree of the heat source side expansion valve 25, the rotational speed of the heat source side fan 24, and the rotational speed of the user side fan 32 in real time according to the set temperature, etc.

[0050] The display control unit 75 is a functional unit that controls the operation of the remote control 8, which acts as a display device. The display control unit 75 causes the remote control 8 to output predetermined information in order to notify the user of information related to the operating status and condition of the refrigeration cycle device 100. For example, the display control unit 75 causes the remote control 8's display to show information such as the operating mode and set temperature.

[0051] (2) Operating mode of the refrigeration cycle unit 100 The refrigeration cycle unit 100, which is an air conditioning system, operates in either a cooling mode or a heating mode to adjust the temperature and humidity of the air in the space to be air-conditioned. The control unit 70 determines which operating mode, cooling mode or heating mode, should be used based on instructions input by the user to the remote control 8.

[0052] (2-1) Cooling operation mode In cooling operation mode, the control unit 70 sets the four-way switching valve 22 to the cooling operation connection state and performs cooling operation in the space to be air-conditioned. In cooling operation mode, the control unit 70 controls the rotation speed of the compressor 21, for example, so that the evaporation temperature of the refrigerant in the main refrigerant circuit 10 becomes the target evaporation temperature.

[0053] In cooling operation mode, the gaseous refrigerant discharged from the compressor 21 of the heat source unit 2 passes through the first pipe 51 and the four-way switching valve 22 and flows through the heat source side heat exchanger 23. The refrigerant flowing through the heat source side heat exchanger 23 dissipates heat or condenses by exchanging heat with the outside air, and then flows toward the heat source side expansion valve 25. The control unit 70 controls the opening degree of the heat source side expansion valve 25, which is located between the heat source side heat exchanger 23 and the user side heat exchanger 31, so that conditions such as the degree of subcooling of the heat source side heat exchanger 23 and the degree of superheating of the user side heat exchanger 31 are met.

[0054] The refrigerant, depressurized by the heat source side expansion valve 25, flows into the utilization unit 3 through the liquid side shut-off valve 28 and the liquid side refrigerant connecting pipe 6, and flows through the utilization side heat exchanger 31. The refrigerant flowing through the utilization side heat exchanger 31 absorbs heat or evaporates by exchanging heat with the air in the space to be air-conditioned, and then flows through the gas side refrigerant connecting pipe 7 and flows into the heat source unit 2 from the gas side shut-off valve 29. The refrigerant that has flowed into the heat source unit 2 passes through the four-way switching valve 22, the third pipe 53, the first accumulator 26, and the second pipe 52, and is drawn back into the compressor 21. In the first accumulator 26, any liquid refrigerant that has not evaporated in the utilization side heat exchanger 31 is stored as excess refrigerant.

[0055] (2-2) Heating operation mode In heating operation mode, the control unit 70 sets the four-way switching valve 22 to the heating operation connection state and performs heating operation in the space to be air-conditioned. In heating operation mode, the control unit 70 controls the rotation speed of the compressor 21, for example, so that the condensation temperature of the refrigerant in the main refrigerant circuit 10 becomes the target condensation temperature.

[0056] In heating operation mode, the gaseous refrigerant discharged from the compressor 21 of the heat source unit 2 flows into the utilization unit 3 through the first pipe 51, the four-way switching valve 22, the gas-side shut-off valve 29, and the gas-side refrigerant connecting pipe 7, and flows through the utilization-side heat exchanger 31. The refrigerant flowing through the utilization-side heat exchanger 31 dissipates heat or condenses by exchanging heat with the air in the space to be air-conditioned, then flows through the liquid-side refrigerant connecting pipe 6 and flows into the heat source unit 2 from the liquid-side shut-off valve 28. The refrigerant that has flowed into the heat source unit 2 is depressurized by the heat source-side expansion valve 25. The control unit 70 controls the opening degree of the heat source-side expansion valve 25, located between the utilization-side heat exchanger 31 and the heat source-side heat exchanger 23, so that conditions such as the degree of subcooling of the utilization-side heat exchanger 31 and the degree of superheating of the heat source-side heat exchanger 23 reach predetermined target values ​​are met.

[0057] The refrigerant, depressurized by the heat source-side expansion valve 25, flows through the heat source-side heat exchanger 23. The refrigerant flowing through the heat source-side heat exchanger 23 absorbs heat or evaporates by exchanging heat with the outdoor air, and then passes through the four-way switching valve 22, the third pipe 53, the first accumulator 26, and the second pipe 52 before being drawn back into the compressor 21. In the first accumulator 26, any liquid refrigerant that did not evaporate completely in the heat source-side heat exchanger 23 is stored as excess refrigerant.

[0058] (3) Detailed configuration (3-1) First accumulator 26 As shown in Figure 3, the first accumulator 26 has a first casing 26a, which is a container for storing refrigerant. The second pipe 52 (discharge pipe 52a) and the third pipe 53 are fixed to the first casing 26a, passing through the top surface of the first casing 26a. Inside the first casing 26a, the second pipe 52 and the third pipe 53 extend vertically.

[0059] Inside the first casing 26a, the lower end 52m of the second pipe 52 is located below the lower end 53m of the third pipe 53. The height of the lower end 52m of the second pipe 52 is set to be below the height 26b of the liquid refrigerant level stored inside the first casing 26a during operation of the refrigeration cycle device 100. For example, the height of the lower end 52m of the second pipe 52 is set to be below the height of the vertical center of the first casing 26a. Therefore, the liquid refrigerant stored inside the first casing 26a flows into the second pipe 52 from the lower end 52m and out of the first casing 26a.

[0060] (3-2) Refrigerant evaporation mechanism 27 The refrigerant evaporation mechanism 27 evaporates the liquid refrigerant stored in the first accumulator 26 and flowing from the first accumulator 26 toward the compressor 21. The liquid refrigerant flowing out of the first accumulator 26 and through the discharge-side piping 52a flows into the refrigerant evaporation mechanism 27. In the refrigerant evaporation mechanism 27, at least a portion of the incoming liquid refrigerant evaporates to become gaseous refrigerant. The refrigerant flowing out of the refrigerant evaporation mechanism 27 flows through the suction-side piping 52b and is drawn into the compressor 21.

[0061] The specific form of the refrigerant evaporation mechanism 27 is not limited as long as it has a mechanism capable of evaporating at least a portion of the liquid refrigerant. In this embodiment, as shown in Figure 1, the refrigerant evaporation mechanism 27 has a heating unit 27a. The heating unit 27a is, for example, a heater that heats the refrigerant passing through the refrigerant evaporation mechanism 27. In this case, the control unit 70 may have a function to adjust the output of the heating unit 27a to control the amount of heat supplied to the refrigerant passing through the refrigerant evaporation mechanism 27. It is preferable that the refrigerant evaporation mechanism 27 evaporates all of the liquid refrigerant flowing in from the discharge side pipe 52a. In this case, only the gaseous refrigerant generated by the evaporation of the liquid refrigerant flows through the suction side pipe 52b.

[0062] (4) Features (4-1) Of the refrigerant circulating in the main refrigerant circuit 10, any liquid refrigerant that does not completely evaporate in the evaporator (heat source side heat exchanger 23 or utilization side heat exchanger 31) is stored in the first accumulator 26 as excess refrigerant. Normally, the volume of the heat source side heat exchanger 23 is larger than the volume of the utilization side heat exchanger 31. Therefore, the amount of refrigerant required in the cooling operation mode, when the heat source side heat exchanger 23 functions as a condenser, is greater than the amount of refrigerant required in the heating operation mode, when the utilization side heat exchanger 31 functions as a condenser. For this reason, if the amount of refrigerant required in the cooling operation mode is sealed into the main refrigerant circuit 10, excess refrigerant is likely to be generated in the heating operation mode. Hereinafter, the main refrigerant circuit 10 is assumed to be connected to the heating operation state.

[0063] The refrigerant sealed in the main refrigerant circuit 10 is a non-azeotropic mixed refrigerant, which is a mixture of a low-boiling point refrigerant and a high-boiling point refrigerant. The boiling point of the high-boiling point refrigerant is higher than that of the low-boiling point refrigerant. Therefore, the liquid refrigerant stored in the first accumulator 26 has a composition in which the content of the high-boiling point refrigerant is higher than the content of the low-boiling point refrigerant. On the other hand, the gaseous refrigerant stored in the first accumulator 26 has a composition in which the content of the low-boiling point refrigerant is higher than the content of the high-boiling point refrigerant. Therefore, when the gaseous refrigerant stored in the first accumulator 26 is supplied to the main refrigerant circuit 10 as a circulating refrigerant, the high-boiling point refrigerant gradually accumulates in the first accumulator 26. As a result, the content of the high-boiling point refrigerant in the circulating refrigerant decreases, and the composition of the circulating refrigerant may deviate from the base composition. The base composition is the composition of the non-azeotropic mixed refrigerant when it is sealed in the main refrigerant circuit 10.

[0064] In the refrigeration cycle device 100 of this embodiment, the excess liquid refrigerant stored in the first accumulator 26 flows into the discharge pipe 52a and is supplied to the refrigerant evaporation mechanism 27. In the refrigerant evaporation mechanism 27, the liquid refrigerant supplied from the discharge pipe 52a evaporates to generate gaseous refrigerant. The gaseous refrigerant flows into the suction pipe 52b and is drawn into the compressor 21. Therefore, in the refrigeration cycle device 100, the compressor 21 is drawn in gaseous refrigerant generated by the evaporation of the liquid refrigerant stored in the first accumulator 26.

[0065] Therefore, in the refrigeration cycle device 100, gaseous refrigerant generated from liquid refrigerant with a higher content of high-boiling-point refrigerant than low-boiling-point refrigerant circulates in the main refrigerant circuit 10, thereby suppressing a decrease in the high-boiling-point refrigerant content of the circulating refrigerant. As a result, liquid refrigerant containing a large amount of high-boiling-point refrigerant is gradually stored in the first accumulator 26, and deviation of the composition of the circulating refrigerant from the base composition is suppressed. If the composition of the circulating refrigerant deviates from the base composition, the heat exchange performance and controllability of the refrigeration cycle device 100 may decrease. Therefore, even if a large amount of excess refrigerant is stored in the first accumulator 26 during heating operation mode, the refrigeration cycle device 100 can suppress a decrease in heat exchange performance and controllability.

[0066] (4-2) In the refrigeration cycle device 100, the refrigerant evaporation mechanism 27 evaporates the liquid refrigerant supplied from the discharge pipe 52a to produce gaseous refrigerant. The gaseous refrigerant produced in the refrigerant evaporation mechanism 27 flows through the suction pipe 52b and is drawn into the compressor 21. Therefore, when all the liquid refrigerant supplied from the discharge pipe 52a evaporates in the refrigerant evaporation mechanism 27, the drawing of liquid refrigerant into the compressor 21 is suppressed. Consequently, the refrigeration cycle device 100 can suppress the occurrence of malfunctions of the compressor 21 and other components caused by the drawing of liquid refrigerant into the compressor 21.

[0067] (4-3) In the refrigeration cycle device 100, a non-azeotropic mixed refrigerant is sealed in the main refrigerant circuit 10. The non-azeotropic mixed refrigerant includes, for example, ethylene-based fluorinated hydrocarbons such as R1123 as a low-boiling point refrigerant. When R1123 generates radicals, it may change into other compounds through a disproportionation reaction. This disproportionation reaction is accompanied by a large amount of heat release. Therefore, if the content of low-boiling point refrigerant in the circulating refrigerant increases, the reliability of the refrigeration cycle device 100 may decrease.

[0068] In the refrigeration cycle device 100, the refrigerant evaporation mechanism 27 suppresses deviation of the circulating refrigerant composition from the base composition, thereby suppressing an increase in the content of low-boiling-point refrigerant in the circulating refrigerant. Therefore, the refrigeration cycle device 100 can suppress a decrease in reliability caused by refrigerant disproportionation reactions.

[0069] <Second Embodiment> The basic configuration and operation of the refrigeration cycle device 200 of this embodiment are the same as those of the refrigeration cycle device 100 of the first embodiment. The following description will focus on the differences between the refrigeration cycle device 200 of this embodiment and the refrigeration cycle device 100 of the first embodiment.

[0070] In this embodiment, as shown in Figure 4, the refrigerant evaporation mechanism 27 is a heat exchanger installed near the heat source side heat exchanger 23. In heating operation mode, the heat source side heat exchanger 23 performs heat exchange between the refrigerant before it is stored in the first accumulator 26 and the heat exchange fluid. The heat exchange fluid is air, such as outside air. The refrigerant evaporation mechanism 27 performs heat exchange between the liquid refrigerant stored in the first accumulator 26 and the heat exchange fluid that is exchanged in the heat source side heat exchanger 23. The heat exchange fluid is supplied to the heat source side heat exchanger 23 by the heat source side fan 24.

[0071] The specific form of the refrigerant evaporation mechanism 27 is not limited as long as it has a mechanism capable of performing heat exchange between the liquid refrigerant and the heat exchange fluid. For example, the refrigerant evaporation mechanism 27 may be a heat exchanger having the same configuration as the heat source side heat exchanger 23. Thus, in the refrigeration cycle device 200, a heat exchanger similar to the heat source side heat exchanger 23 can be used as the refrigerant evaporation mechanism 27.

[0072] The refrigerant evaporation mechanism 27 heats and evaporates the liquid refrigerant by performing heat exchange between the liquid refrigerant and the heat exchange fluid. Preferably, the refrigerant evaporation mechanism 27 evaporates all of the liquid refrigerant supplied from the discharge side pipe 52a and supplies only gaseous refrigerant to the suction side pipe 52b.

[0073] Next, using the Mollier diagram shown in Figure 5, the changes in the state and composition of the refrigerant circulating in the main refrigerant circuit 10 of the refrigeration cycle device 200 during heating operation mode will be explained. Figure 5 shows the saturated liquid line L1, the dry saturated vapor line L2, and the critical point CP of the refrigerant. The critical point CP is the high-pressure end point of the saturated liquid line L1 and the dry saturated vapor line L2. The base composition of the refrigerant consists of 50% by mass of R1132(E) and 50% by mass of R1234yf. In this case, R1132(E) is a low-boiling point refrigerant, and R1234yf is a high-boiling point refrigerant. Hereinafter, refrigerants having the same or approximately the same composition as the base composition will be referred to as "base composition refrigerants".

[0074] When the refrigeration cycle unit 200 is started, the low-pressure gaseous refrigerant of the base composition (P1 shown in Figure 5; the same applies hereafter) is drawn into the compressor 21. The gaseous refrigerant drawn into the compressor 21 is compressed to become the high-pressure gaseous refrigerant of the base composition (P1 → P2). The high-pressure gaseous refrigerant of the base composition condenses by exchanging heat with the air in the conditioned space in the user-side heat exchanger 31 to become the liquid refrigerant of the base composition (P2 → P3). The liquid refrigerant of the base composition is depressurized by the heat source-side expansion valve 25 to become a gas-liquid two-phase refrigerant of the base composition (P3 → P4). A portion of the liquid refrigerant contained in the gas-liquid two-phase refrigerant of the base composition evaporates by exchanging heat with the outside air in the heat source-side heat exchanger 23 (P4 → P5). The gas-liquid two-phase refrigerant after evaporation is stored in the first accumulator 26 (P5 → P6). Liquid refrigerant (P7) and gaseous refrigerant (P8) are stored in the first accumulator 26. The liquid refrigerant (P7) in the first accumulator 26 has a composition in which the content of R1234yf is greater than the content of R1132(E). The gaseous refrigerant (P8) in the first accumulator 26 has a composition in which the content of R1132(E) is greater than the content of R1234yf. The liquid refrigerant (P7) in the first accumulator 26 evaporates into gaseous refrigerant by heat exchange with the outside air in the refrigerant evaporation mechanism 27 (P7 → P9). The gaseous refrigerant (P9) has a composition in which the content of R1234yf is greater than the content of R1132(E). The gaseous refrigerant (P9) is drawn back into the compressor 21 (P9 → P1).

[0075] Through the above process, the composition of the circulating refrigerant in the refrigeration cycle device 200 stabilizes with a higher content of high-boiling-point refrigerant (R1234yf) than low-boiling-point refrigerant (R1132(E)). Therefore, the refrigeration cycle device 200 can suppress the decrease in reliability caused by the disproportionation reaction of low-boiling-point refrigerants such as R1132(E).

[0076] <Third Embodiment> The basic configuration and operation of the refrigeration cycle device 300 in this embodiment are the same as those of the refrigeration cycle device 200 in the second embodiment. The following description will focus on the differences between the refrigeration cycle device 300 in this embodiment and the refrigeration cycle device 200 in the second embodiment.

[0077] In this embodiment, as shown in Figure 6, the refrigeration cycle device 300 includes a refrigerant evaporation mechanism 27. The refrigerant evaporation mechanism 27 has the same function and configuration as the refrigerant evaporation mechanism 27 of the refrigeration cycle device 200 of the second embodiment.

[0078] As shown in Figure 6, the refrigeration cycle device 300 further comprises a second accumulator 36. In the main refrigerant circuit 10, the second accumulator 36 is located between the compressor 21 and the refrigerant evaporation mechanism 27. The second accumulator 36 stores refrigerant that has undergone heat exchange by the refrigerant evaporation mechanism 27 and is not yet drawn into the compressor 21.

[0079] In this embodiment, the suction side piping 52b is divided into a first suction side piping 52b1 and a second suction side piping 52b2 by a second accumulator 36. The first suction side piping 52b1 connects the refrigerant evaporation mechanism 27 to the second accumulator 36. The second suction side piping 52b2 connects the second accumulator 36 to the suction side of the compressor 21. The first suction side piping 52b1 and the second suction side piping 52b2 are connected to each other via the second accumulator 36.

[0080] The second accumulator 36 is a refrigerant container capable of temporarily storing the refrigerant that passes through the refrigerant evaporation mechanism 27 and flows from the refrigerant evaporation mechanism 27 towards the compressor 21. The refrigerant that passes through the refrigerant evaporation mechanism 27 and flows through the first suction side piping 52b1 flows into the second accumulator 36. The refrigerant stored in the second accumulator 36 flows through the second suction side piping 52b2 and flows out of the second accumulator 36. The refrigerant that flows out of the second accumulator 36 flows through the second suction side piping 52b2 and is drawn into the compressor 21.

[0081] As shown in Figure 7, the second accumulator 36 has a second casing 36a, which is a container for storing refrigerant. The first suction pipe 52b1 and the second suction pipe 52b2 are fixed to the second casing 36a, passing through the top surface of the second casing 36a. Inside the second casing 36a, the first suction pipe 52b1 and the second suction pipe 52b2 extend vertically.

[0082] Inside the second casing 36a, the lower end 52m1 of the first suction pipe 52b1 is at approximately the same height as the lower end 52m2 of the second suction pipe 52b2. The lower ends 52m1 of the first suction pipe 52b1 and 52m2 of the second suction pipe 52b2 are set to be above the liquid level 36b of the liquid refrigerant stored inside the second casing 36a during operation of the refrigeration cycle device 100. For example, the lower ends 52m1 of the first suction pipe 52b1 and 52m2 of the second suction pipe 52b2 are located near the upper end of the second casing 36a inside the second accumulator 36. Therefore, the liquid refrigerant stored inside the second casing 36a is prevented from flowing into the second suction pipe 52b2 from its lower end 52m2 and out of the second casing 36a.

[0083] Next, using the Mollier diagram shown in Figure 8, the changes in the state and composition of the refrigerant circulating in the main refrigerant circuit 10 of the refrigeration cycle device 300 during heating operation mode will be explained. The refrigerant has the same composition as the refrigerant circulating in the main refrigerant circuit 10 of the refrigeration cycle device 200 in the second embodiment.

[0084] When the refrigeration cycle unit 200 is started, the low-pressure gas refrigerant of the base composition (P1 shown in Figure 8; the same applies hereafter) is drawn into the compressor 21. The gas refrigerant drawn into the compressor 21 is compressed to become the high-pressure gas refrigerant of the base composition (P1 → P2). The high-pressure gas refrigerant of the base composition condenses in the user-side heat exchanger 31 by exchanging heat with the air in the space to be air-conditioned, becoming the liquid refrigerant of the base composition (P2 → P3). The liquid refrigerant of the base composition is depressurized in the heat source-side expansion valve 25 to become a gas-liquid two-phase refrigerant of the base composition (P3 → P4). A portion of the liquid refrigerant contained in the gas-liquid two-phase refrigerant of the base composition evaporates in the heat source-side heat exchanger 23 by exchanging heat with the outside air (P4 → P5). The gas-liquid two-phase refrigerant after evaporation is stored in the first accumulator 26 (P5 → P6). Liquid refrigerant (P7) and gaseous refrigerant (P8) are stored in the first accumulator 26. The liquid refrigerant (P7) in the first accumulator 26 has a composition in which the content of R1234yf is greater than the content of R1132(E). The gaseous refrigerant (P8) in the first accumulator 26 has a composition in which the content of R1132(E) is greater than the content of R1234yf. A portion of the liquid refrigerant (P7) in the first accumulator 26 evaporates into a gaseous refrigerant by heat exchange with the outside air in the refrigerant evaporation mechanism 27. As a result, in the refrigerant evaporation mechanism 27, the liquid refrigerant (P7) in the first accumulator 26 becomes a gaseous two-phase refrigerant (P7 → P9). The gaseous two-phase refrigerant generated in the refrigerant evaporation mechanism 27 is stored in the second accumulator 36 (P9 → P10). Liquid refrigerant (P11) and gaseous refrigerant (P12) are stored in the second accumulator 36. The liquid refrigerant (P11) and gaseous refrigerant (P12) in the second accumulator 36 have a composition in which the content of R1234yf is greater than the content of R1132(E). However, the content of R1234yf in the gaseous refrigerant (P12) in the second accumulator 36 is less than the content of R1234yf in the liquid refrigerant (P11). Therefore, the gaseous refrigerant (P12) in the second accumulator 36 has a composition closer to the base composition than the liquid refrigerant (P11). The gaseous refrigerant (P12) is then drawn back into the compressor 21 (P12 → P1).

[0085] Through the above process, the composition of the circulating refrigerant in the refrigeration cycle device 300 stabilizes with a higher content of high-boiling-point refrigerant (R1234yf) than low-boiling-point refrigerant (R1132(E)). Therefore, the refrigeration cycle device 300 can suppress the decrease in reliability caused by the disproportionation reaction of low-boiling-point refrigerants such as R1132(E).

[0086] Furthermore, in the refrigeration cycle device 300, the circulating refrigerant has a composition closer to the base composition compared to the refrigeration cycle device 200 of the second embodiment. Therefore, the refrigeration cycle device 300 can effectively suppress deviations in the composition of the circulating refrigerant from the base composition.

[0087] <Variation> (1) Variation A In the second and third embodiments, the refrigerant evaporation mechanism 27 may be connected to the heat source side heat exchanger 23. Specifically, the refrigerant evaporation mechanism 27 may be a heat exchanger integrated with the heat source side heat exchanger 23. Alternatively, although the refrigerant evaporation mechanism 27 is a heat exchanger independent of the heat source side heat exchanger 23, it may also be a heat exchanger that is physically connected to the heat source side heat exchanger 23.

[0088] (2) Modification B In the second and third embodiments, the refrigerant evaporation mechanism 27 may be provided to perform heat exchange between the heat exchange fluid, which has been heat-exchanged with the refrigerant in the heat source side heat exchanger 23, and the liquid refrigerant. Specifically, in the direction in which the heat exchange fluid flows, the refrigerant evaporation mechanism 27 may be provided downstream of the heat source side heat exchanger 23.

[0089] (3) Variation C The refrigeration cycle device 200 of the second embodiment may further include a bypass circuit 60 and a switching mechanism 62, as shown in Figure 9. The bypass circuit 60 is provided in the main refrigerant circuit 10 between the first accumulator 26 and the compressor 21. The bypass circuit 60 bypasses the refrigerant evaporation mechanism 27. In Figure 9, the bypass circuit 60 is shown by a dotted line.

[0090] The switching mechanism 62 switches between a first state in which the refrigerant flows through the bypass circuit 60 and a second state in which the refrigerant does not flow through the bypass circuit 60. In the first state, the refrigerant flowing through the discharge pipe 52a bypasses the refrigerant evaporation mechanism 27 by passing through the bypass circuit 60 and flows into the suction pipe 52b. In the second state, the refrigerant flowing through the discharge pipe 52a passes through the refrigerant evaporation mechanism 27 without passing through the bypass circuit 60 and flows into the suction pipe 52b.

[0091] The switching mechanism 62 includes at least one of a first flow path regulating valve 62a and a second flow path regulating valve 62b. The first flow path regulating valve 62a is a solenoid valve provided in the bypass circuit 60. The second flow path regulating valve 62b is a solenoid valve provided between the point where the bypass circuit 60 branches off from the main refrigerant circuit 10 and the refrigerant evaporation mechanism 27. In the first state, the first flow path regulating valve 62a is open and the second flow path regulating valve 62b is closed. In the second state, the first flow path regulating valve 62a is closed and the second flow path regulating valve 62b is open.

[0092] The control unit 70 controls the switching mechanism 62 to switch between the first state and the second state according to the degree of superheating of the refrigerant drawn into the compressor 21. Specifically, the control unit 70 switches between the first state and the second state by changing the open / closed state of the first flow path regulating valve 62a and the second flow path regulating valve 62b.

[0093] The refrigeration cycle device 200 may further include a sensor 64 for detecting the degree of superheating of the refrigerant drawn into the compressor 21. The sensor 64 is mounted near the outlet of the refrigerant evaporation mechanism 27. The sensor 64 measures, for example, the temperature of the refrigerant flowing through the suction side piping 52b.

[0094] When the refrigeration cycle device 200 is in the second state, the refrigerant is heated by the refrigerant evaporation mechanism 27 before being drawn into the compressor 21. Therefore, if the amount of circulating refrigerant is small, the degree of superheating of the refrigerant drawn into the compressor 21 will increase, which may reduce the compression efficiency of the compressor 21. For this reason, the control unit 70 switches from the second state to the first state when the degree of superheating of the refrigerant detected by the sensor 64 exceeds a predetermined value. As a result, the refrigerant flows through the bypass circuit 60 before being drawn into the compressor 21, reducing the degree of superheating of the refrigerant drawn into the compressor 21.

[0095] Furthermore, the control unit 70 may control the opening degrees of the first flow control valve 62a and the second flow control valve 62b so that the degree of superheating of the refrigerant drawn into the compressor 21 is within a predetermined range. For example, the control unit 70 may control the opening degrees of the first flow control valve 62a and the second flow control valve 62b so that a portion of the refrigerant flowing through the main refrigerant circuit 10 bypasses the refrigerant evaporation mechanism 27, while the remainder passes through the refrigerant evaporation mechanism 27.

[0096] (4) Modification D The refrigeration cycle device 300 of the third embodiment may further include a bypass circuit 60 and a switching mechanism 62, as shown in Figure 10. The bypass circuit 60 is provided in the main refrigerant circuit 10 between the first accumulator 26 and the second accumulator 36. The bypass circuit 60 bypasses the refrigerant evaporation mechanism 27. In Figure 10, the bypass circuit 60 is shown by a dotted line.

[0097] The switching mechanism 62 switches between a first state in which the refrigerant flows through the bypass circuit 60 and a second state in which the refrigerant does not flow through the bypass circuit 60. In the first state, the refrigerant flowing through the discharge pipe 52a bypasses the refrigerant evaporation mechanism 27 by passing through the bypass circuit 60 and flows into the first suction pipe 52b1. In the second state, the refrigerant flowing through the discharge pipe 52a passes through the refrigerant evaporation mechanism 27 without passing through the bypass circuit 60 and flows into the first suction pipe 52b1.

[0098] The switching mechanism 62 includes at least one of a first flow path regulating valve 62a and a second flow path regulating valve 62b. The first flow path regulating valve 62a is a solenoid valve provided in the bypass circuit 60. The second flow path regulating valve 62b is a solenoid valve provided between the point where the bypass circuit 60 branches off from the main refrigerant circuit 10 and the refrigerant evaporation mechanism 27. In the first state, the first flow path regulating valve 62a is open and the second flow path regulating valve 62b is closed. In the second state, the first flow path regulating valve 62a is closed and the second flow path regulating valve 62b is open.

[0099] The control unit 70 controls the switching mechanism 62 to switch between the first state and the second state according to the degree of superheating of the refrigerant drawn into the compressor 21. Specifically, the control unit 70 switches between the first state and the second state by changing the open / closed state of the first flow path regulating valve 62a and the second flow path regulating valve 62b.

[0100] The refrigeration cycle device 300 may further include a sensor 64 for detecting the degree of superheating of the refrigerant drawn into the compressor 21. The sensor 64 is mounted near the outlet of the refrigerant evaporation mechanism 27. The sensor 64 measures, for example, the temperature of the refrigerant flowing through the first suction side piping 52b1.

[0101] When the refrigeration cycle device 300 is in the second state, the refrigerant is heated by the refrigerant evaporation mechanism 27 before being drawn into the compressor 21. Therefore, if the amount of circulating refrigerant is small, the degree of superheating of the refrigerant drawn into the compressor 21 will increase, which may reduce the compression efficiency of the compressor 21. For this reason, the control unit 70 switches from the second state to the first state when the degree of superheating of the refrigerant detected by the sensor 64 exceeds a predetermined value. As a result, the refrigerant flows through the bypass circuit 60 before being drawn into the compressor 21, reducing the degree of superheating of the refrigerant drawn into the compressor 21.

[0102] Furthermore, the control unit 70 may control the opening degrees of the first flow control valve 62a and the second flow control valve 62b so that the degree of superheating of the refrigerant drawn into the compressor 21 is within a predetermined range. For example, the control unit 70 may control the opening degrees of the first flow control valve 62a and the second flow control valve 62b so that a portion of the refrigerant flowing through the main refrigerant circuit 10 bypasses the refrigerant evaporation mechanism 27, while the remainder passes through the refrigerant evaporation mechanism 27.

[0103] (5) Variation E The basic configuration and operation of the refrigeration cycle device 400 in this modified example are the same as those of the refrigeration cycle device 100 in the first embodiment. The following description will focus on the differences between the refrigeration cycle device 400 in this modified example and the refrigeration cycle device 100 in the first embodiment.

[0104] As shown in Figure 11, the refrigeration cycle device 400 includes a refrigerant evaporation mechanism 27 located inside the heat source unit 2. The refrigerant evaporation mechanism 27 performs heat exchange between the liquid refrigerant flowing out of the first accumulator 26 and through the discharge side pipe 52a, and the refrigerant before it is heat-exchanged with the heat exchange fluid in the heat source side heat exchanger 23. As a result, the refrigerant evaporation mechanism 27 evaporates at least a portion of the liquid refrigerant flowing through the discharge side pipe 52a and supplies it to the suction side pipe 52b.

[0105] (6) Modification F The basic configuration and operation of the modified refrigeration cycle device 500 are the same as those of the refrigeration cycle device 100 of the first embodiment. The following description will focus on the differences between the modified refrigeration cycle device 500 and the refrigeration cycle device 100 of the first embodiment.

[0106] As shown in Figure 12, the refrigeration cycle device 500 includes a refrigerant evaporation mechanism 27 located inside the heat source unit 2. The refrigerant evaporation mechanism 27 performs heat exchange between the liquid refrigerant flowing out of the first accumulator 26 and through the discharge pipe 52a, and the gaseous refrigerant immediately after being compressed by the compressor 21. As a result, the refrigerant evaporation mechanism 27 evaporates at least a portion of the liquid refrigerant flowing through the discharge pipe 52a and supplies it to the suction pipe 52b.

[0107] (7) Variation G The refrigeration cycle device 200 of modified example C and the refrigeration cycle device 300 of modified example D further include a bypass circuit 60 and a switching mechanism 62. The bypass circuit 60 and the switching mechanism 62 may also be applied to the refrigeration cycle device 100 of the first embodiment, the refrigeration cycle device 400 of modified example E, and the refrigeration cycle device 500 of modified example F.

[0108] While embodiments of this disclosure have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of this disclosure as described in the claims. [Explanation of Symbols]

[0109] 10: Main refrigerant circuit (refrigerant circuit) 21: Compressor 23: Heat source side heat exchanger (evaporator, condenser) 25: Heat source side expansion valve (expansion mechanism) 26: First accumulator (first container) 27: Refrigerant evaporation mechanism (first mechanism) 27a: Heating part 31: Heat exchanger on the user side (condenser, evaporator) 36: Second accumulator (second container) 60: Bypass circuit 62: Switching mechanism 70: Control Unit 100: Refrigeration cycle equipment [Prior art documents] [Patent Documents]

[0110] [Patent Document 1] Japanese Patent Publication No. 2015-200431

Claims

1. Compressor (21) and Condenser (31, 23) and Expansion mechanism (25), Evaporator (23, 31) and The compressor, the condenser, the expansion mechanism, and the evaporator are connected in a ring, and a refrigerant circuit (10) into which a mixed refrigerant is sealed, In the refrigerant circuit, a first container (26) is provided between the evaporator and the compressor, and stores the mixed refrigerant before it is drawn into the compressor, The refrigerant circuit includes a first mechanism (27) provided between the first container and the compressor, which evaporates the liquid refrigerant stored in the first container and flowing from the first container toward the compressor, A second pipe (52) connects the first mechanism and the first container, Equipped with, The aforementioned mixed refrigerant is a non-azeotropic mixed refrigerant, The mixed refrigerant stored in the first container flows out of the first container only through the second pipe. Inside the first container, the height of the lower end (52m) of the second pipe is lower than the height of the vertical center of the first container. Refrigeration cycle device (100).

2. The evaporator performs heat exchange between the mixed refrigerant before it is stored in the first container and the first fluid. The first mechanism performs heat exchange between the liquid refrigerant and the first fluid, heating the liquid refrigerant and causing it to evaporate. The refrigeration cycle apparatus according to claim 1.

3. The first mechanism is connected to the evaporator, The refrigeration cycle apparatus according to claim 2.

4. The first mechanism performs heat exchange between the first fluid, which has undergone heat exchange with the mixed refrigerant in the evaporator, and the liquid refrigerant. The refrigeration cycle apparatus according to claim 2 or 3.

5. The refrigerant circuit further includes a second container (36) provided between the first mechanism and the compressor, which stores the mixed refrigerant before it is drawn into the compressor. A refrigeration cycle apparatus according to any one of claims 1 to 3.

6. In the refrigerant circuit, a bypass circuit (60) is provided between the first container and the compressor, which bypasses the first mechanism. A switching mechanism (62) that switches between a first state in which the mixed refrigerant flows through the bypass circuit and a second state in which the mixed refrigerant does not flow through the bypass circuit, Furthermore, A refrigeration cycle apparatus according to any one of claims 1 to 3.

7. The system further includes a control unit (70) that controls the switching mechanism to switch between the first state and the second state according to the degree of superheating of the mixed refrigerant drawn into the compressor. The refrigeration cycle apparatus according to claim 6.

8. The first mechanism has a heating section (27a) for heating the mixed refrigerant, A refrigeration cycle apparatus according to any one of claims 1 to 3.

9. The mixed refrigerant comprises an ethylene-based fluorinated hydrocarbon and a refrigerant with a higher boiling point than the ethylene-based fluorinated hydrocarbon. A refrigeration cycle apparatus according to any one of claims 1 to 3.

10. The ethylene-based fluorinated hydrocarbon is R1132(E) or R1123. The refrigeration cycle apparatus according to claim 9.

11. The aforementioned mixed refrigerant contains 10.0% by mass or more of R1132(E). The refrigeration cycle apparatus according to claim 10.

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