Refrigeration cycle device

Abstract

To suppress a total capacity of a compressor compared to a case of increasing a refrigerant circulation amount to ensure a refrigeration capacity.SOLUTION: A refrigeration cycle device comprises: a first compression element that compresses a sucked-in refrigerant and discharges it into a first flow path; a radiator that is provided in the first flow path, passes the refrigerant through and radiates heat extracted from the passing refrigerant; a branching part that branches the refrigerant after passing through the radiator in the first flow path into a first branch and a second branch; a first pressure reduction element that reduces a pressure of the refrigerant branched into the first branch and flows it into a second flow path; a heat exchanger that performs heat exchange between the refrigerant flowing through the second flow path and the refrigerant branched into the second branch; a second pressure reduction element that reduces a pressure of the refrigerant after heat exchange by the heat exchanger in the second branch; a cooler that cools an object by heat exchange between the refrigerant after pressure reduction by the second pressure reduction element and the object, and sucks the refrigerant after heat exchange into the first compression element; a second compression element that sucks in the refrigerant after heat exchange by the heat exchanger in the second flow path, compresses it, and discharges it into a third flow path; and a confluent part that makes the third flow path confluent with the first flow path.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes a compressor system in which a plurality of compressors are connected in parallel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, there is a refrigeration cycle device that secures refrigerating capacity by increasing the refrigerant circulation amount using the compressor system of Patent Document 1 and increasing the amount of refrigerant available for cooling an object. In such a refrigeration cycle device, as the refrigerating capacity required for cooling the object increases, it is necessary to increase the total capacity of the compressors. More specifically, it is necessary to increase the number of compressors or increase the capacity of each compressor, leading to an increase in equipment costs and an increase in the size of the entire refrigeration cycle device. The present disclosure proposes a refrigeration cycle device that suppresses the total capacity of compressors as compared with the case of securing refrigerating capacity by increasing the refrigerant circulation amount.

Means for Solving the Problems

[0005] The refrigeration cycle device from the first perspective includes a first compression element that compresses the inhaled refrigerant and discharges it into a first flow path, a radiator provided in the first flow path that allows the refrigerant to pass through and dissipates the heat extracted from the passing refrigerant, a branch portion that branches the refrigerant that has passed through the radiator in the first flow path into a first branch and a second branch, a first decompression element that decompresses the refrigerant branched into the first branch and causes it to flow into a second flow path, a heat exchanger that performs heat exchange between the refrigerant flowing through the second flow path and the refrigerant branched into the second branch, a second decompression element that decompresses the refrigerant that has undergone heat exchange by the heat exchanger in the second branch, a cooler that cools the object by heat exchange between the refrigerant decompressed by the second decompression element and the object, and sucks the refrigerant after heat exchange into the first compression element, a second compression element that sucks the refrigerant that has undergone heat exchange by the heat exchanger in the second flow path, compresses it, and discharges it into a third flow path, a merging portion that merges the third flow path into the first flow path, and is provided so as to connect the flow path between the cooler and the first compression element and the flow path between the merging portion and the radiator Switch the connection relationship of the flow path between a first state in which the cooler and the first compression element are connected and the confluence section and the radiator are connected, and a second state in which the cooler and the confluence section are connected and the first compression element and the radiator are connected. a refrigeration cycle device including a four-way switching valve. In this case, compared to the case where the refrigeration capacity is ensured by increasing the refrigerant circulation amount, the total capacity of the compressors is suppressed. The refrigeration cycle device from the second perspective is the refrigeration cycle device from the first perspective, wherein the merging portion merges the third flow path at a position after passing through the radiator in the first flow path, and includes a second radiator provided in the third flow path that allows the refrigerant compressed by the second compression element to pass through and dissipates the heat extracted. In this case, compared to the case where the merging portion merges the third flow path at a position before passing through the radiator in the first flow path, the heat dissipation from the radiator can be increased. The refrigeration cycle device from the third perspective is the refrigeration cycle device from the second perspective, wherein the capacity of the first compression element is larger than the capacity of the second compression element. In this case, compared to the case where the capacity of the first compression element is smaller than the capacity of the second compression element, the heat dissipation from the radiator can be increased. The refrigeration cycle device according to the fourth aspect is the refrigeration cycle device according to the third aspect, and includes a third pressure reducing element provided in the third flow path for reducing the pressure of the refrigerant after passing through the second radiator. In this case, the compression ratio in the second compression element can be set large. The refrigeration cycle device according to the fifth aspect is the refrigeration cycle device according to the second aspect, and includes a fourth pressure reducing element provided at a position in the first flow path after passing through the radiator and before the third flow path merges with the first flow path by the confluence portion for reducing the pressure of the refrigerant after passing through the radiator. In this case, the compression ratio in the first compression element can be set large. The refrigeration cycle device according to the sixth aspect is the refrigeration cycle device according to any one of the first to fifth aspects, and at least a part of the composition of the refrigerant is carbon dioxide. In this case, the heat dissipation in the radiator becomes larger than when using azeotropic refrigerant mixture without carbon dioxide. The refrigeration cycle device according to the seventh aspect includes a first temperature sensor provided at a position in the first flow path before passing through the radiator and before the third flow path merges with the first flow path by the confluence portion, a second temperature sensor provided at a position in the third flow path before merging with the first flow path by the confluence portion, and a control unit configured to perform control related to the circulation of the refrigerant based on the temperatures of the refrigerant measured by the first temperature sensor and the second temperature sensor. The control unit is a refrigeration cycle device configured to control so that the flow resistance of the first pressure reducing element increases when the temperature of the refrigerant measured in the first flow path is higher than the temperature of the refrigerant measured in the third flow path. In this case, the enthalpy difference between the refrigerant compressed by the first compression element and the refrigerant compressed by the second compression element becomes smaller. The refrigeration cycle device according to the eighth aspect includes a first temperature sensor provided at a position in the first flow path before passing through the radiator and before the third flow path joins by the confluence portion, a second temperature sensor provided at a position in the third flow path before joining the first flow path by the confluence portion, and a control unit that controls the circulation of the refrigerant based on the temperatures of the refrigerant measured by the first temperature sensor and the second temperature sensor. The control unit is a refrigeration cycle device that controls the flow rate of the second compression element to increase when the temperature of the refrigerant measured in the first flow path is higher than the temperature of the refrigerant measured in the third flow path. In this case, the enthalpy difference between the refrigerant compressed by the first compression element and the refrigerant compressed by the second compression element becomes smaller.

Brief Description of Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0007] First, a conventional technology to which the embodiments of the present invention are not applied will be described. FIG. 8 is a diagram for explaining a conventional refrigeration cycle device. (a) is a schematic diagram of a refrigerant circuit 10' in the conventional refrigeration cycle device, and (b) is a pressure-enthalpy line diagram showing the refrigeration cycle of the refrigerant circulating in the refrigerant circuit 10'. In FIG. 8(b), the horizontal axis represents specific enthalpy [kJ / kg], and the vertical axis represents absolute pressure [MPa.abs] based on absolute vacuum. In FIG. 8(a), the lines connecting the devices are pipes that form the flow path of the refrigerant. In FIG. 8(b), a thick line is used to show the refrigeration cycle 300'. The points 10a' to 10f' on the refrigeration cycle 300' correspond to the positions 10a' to 10f' of the refrigerant circuit 10' respectively. For this reason, the points 10a' to 10f' in the refrigeration cycle 300' are denoted as positions 10a' to 10f'. Further, in FIG. 8(b), in addition to the refrigeration cycle 300', a saturated liquid line 301, a saturated vapor line 302, a critical point 303, and a 45°C isotherm 304 of the carbon dioxide refrigerant are shown.

[0008] As shown in FIG. 8(a), the refrigerant circuit 10' includes two compressors 12', 13' connected in parallel, a radiator 14', a pressure reducing valve 18', and a cooler 19', and circulates carbon dioxide, which is an example of the refrigerant. More specifically, the refrigerant that has exchanged heat with the object after passing through the cooler 19' branches into two branches (position 10a') at the branch portion 30'. Of the branched refrigerant, the refrigerant flowing through one branch is compressed by the compressor 12', and the refrigerant flowing through the other branch is compressed by the compressor 13' and then merges at the merging portion 20' (position 10b'). The merged refrigerant dissipates heat by passing through the radiator 14' (position 10e'). Then, the refrigerant after heat dissipation is depressurized by passing through the pressure reducing valve 18' (position 10f') and passes through the cooler 19' again (position 10a').

[0009] At each position of the refrigerant circuit 10', the refrigeration cycle of the refrigerant is established by the change in the specific enthalpy and pressure of the refrigerant by each device. More specifically, as shown in Fig. 8(b), from position 10a' to position 10b', the pressure and specific enthalpy of the refrigerant increase due to compression by the compressors 12', 13' and the acquisition of compression heat. Also, from position 10b' to position 10e', the specific enthalpy of the refrigerant decreases due to heat dissipation in the radiator 14'. Further, from position 10e' to position 10f', the pressure of the refrigerant decreases due to decompression by the decompression valve 18'. Furthermore, from position 10f' to position 10a', the specific enthalpy of the refrigerant increases due to heat exchange with the object in the cooler 19'.

[0010] Here, in the refrigeration cycle device, the ability of the cooler to cool the object (which may be referred to as "refrigeration capacity") is determined according to the amount of heat (heat absorption) that the refrigerant passing through the cooler takes away from the object. Therefore, in the conventional refrigeration cycle device using the refrigerant circuit 10', the refrigeration capacity in the cooler 19' is determined according to the product of the change amount of the specific enthalpy when moving from position 10f' to position 10a' and the amount of refrigerant passing through the cooler 19'. In the conventional refrigeration cycle device using the refrigerant circuit 10', in order to increase the refrigeration capacity in the cooler 19', the refrigerant circulation amount in the refrigerant circuit 10' is increased, and the amount of refrigerant passing through the cooler 19' is increased. More specifically, the number of compressors connected in parallel with the compressors 12', 13' is increased, or the capacity of the compressors 12', 13' is increased. Therefore, in the conventional refrigeration cycle device using the refrigerant circuit 10', the larger the refrigeration capacity to be ensured, the larger the total capacity of the compressors. Note that the "total capacity" is the value obtained by summing up the capacities of all the compressors provided in the refrigerant circuit.

[0011] The refrigeration cycle device to which the embodiment of the present invention is applied has a configuration for suppressing the total capacity of the compressors as compared with the case of ensuring the refrigeration capacity by increasing the refrigerant circulation amount. Hereinafter, the embodiments of the present invention will be described in detail.

[0012] <First Embodiment> (Air conditioner 1) FIG. 1 is a diagram showing a schematic configuration example of the air conditioner 1 to which the present embodiment is applied. As shown in the figure, the air conditioner 1 to which the present embodiment is applied includes a refrigerant circuit 10 in which refrigerant circulates, and a control unit 50 that controls the circulation of the refrigerant in the refrigerant circuit 10. Note that the control unit 50 is connected to each device included in the refrigerant circuit 10 (described later with reference to FIG. 2) by wire or wirelessly, and can transmit a control signal to each device. Note that the air conditioner 1 is an example of a refrigeration cycle device in the present embodiment.

[0013] The air conditioner 1 cools the taken-in air and supplies it as cold air to the space, thereby cooling the space. More specifically, the air conditioner 1 extracts heat from the air by heat exchange between the refrigerant passing through a cooler (details will be described later with reference to FIG. 2) incorporated in the refrigerant circuit 10 and the air which is an example of the object, thereby cooling the air. Then, the cooled air is supplied as cold air from an outlet of the indoor unit (not shown) or the like to the space, thereby cooling the space.

[0014] (Control unit 50) The control unit 50 controls the circulation of the refrigerant in the refrigerant circuit 10 by transmitting a control signal to each device included in the refrigerant circuit 10. Also, the control unit 50 controls the amount of cold air supplied by the air conditioner 1 to the space. The control unit 50 according to the present embodiment has, for example, an operation panel or a controller that receives an operation from the user, and performs control according to an operation input such as a temperature setting or an air volume setting from the user. Also, for example, the control unit 50 has a temperature sensor that measures the temperature of the space, and performs control according to the measured value. Further, for example, the control unit 50 has a temperature sensor that measures the temperature of the refrigerant in the refrigerant circuit 10, and performs control according to the measured value. In addition, the control unit 50 may acquire information related to operations such as the effective value of the operation with respect to the control value for each device included in the refrigerant circuit 10, and perform control according to the acquired information.

[0015] (Refrigerant circuit 10) The refrigerant circuit 10 is a circuit that forms a refrigeration cycle of the refrigerant as it circulates and enables the cooling of an object through heat exchange with the refrigerant. More specifically, the refrigerant circuit 10 according to the present embodiment circulates while adjusting the specific enthalpy and pressure of carbon dioxide refrigerant, which is an example of the refrigerant, to form a refrigeration cycle of the carbon dioxide refrigerant, and extracts heat from the air through heat exchange on the low-pressure side to enable the cooling of the air. In the following description, the carbon dioxide refrigerant circulating in the refrigerant circuit 10 may sometimes be simply referred to as "refrigerant". Note that in the refrigerant circuit 10, not only the refrigerant but also a fluid different from the refrigerant, such as lubricating oil for ensuring lubrication in the compressors described later, may circulate.

[0016] FIG. 2 is a schematic diagram of the refrigerant circuit 10 according to the first embodiment. As shown in the figure, the refrigerant circuit 10 according to the first embodiment includes compressors 12 and 13 that compress the refrigerant, a radiator 14 that extracts heat from the refrigerant and dissipates heat, a refrigerant-refrigerant heat exchanger 17 that performs heat exchange between the refrigerants, motor-operated valves 16 and 18 whose opening degrees can be adjusted, and a cooler 19 that cools the air through heat exchange with the passing refrigerant. Further, the refrigerant circuit 10 includes a temperature sensor 501 that measures the temperature of the refrigerant compressed and discharged by the compressor 12, and a temperature sensor 502 that measures the temperature of the refrigerant compressed and discharged by the compressor 13. In addition to the above-described devices, the refrigerant circuit 10 may also include a pressure sensor and a temperature sensor that measure the pressure and temperature of the refrigerant at each point, a receiver that can store the refrigerant, a pressure switch as a protection mechanism, a filter, a heat sink, an oil separator, and the like.

[0017] In FIG. 2, the lines connecting the devices are flow paths through which the refrigerant flows, for example, pipes made of metal. As shown in the figure, a branch portion 15 for branching the flow path and a confluence portion 20 for merging the flow paths are provided in the flow path of the refrigerant circuit 10. Here, the section from the compressor 12 to the branch portion 15 is denoted as the first flow path 101, the section from the electric valve 16 to the compressor 13 is denoted as the second flow path 102, the section from the compressor 13 to the confluence portion 20 is denoted as the third flow path 103, and the section from the electric valve 18 to the compressor 12 is denoted as the fourth flow path 104. Also, among the flow paths branched by the branch portion 15, one connected to the electric valve 16 is denoted as the first branch 151, and the other connected to the cooler 19 via the electric valve 18 is denoted as the second branch 152. Each flow path may be constituted by a single pipe without joints, or may be constituted by connecting two or more pipes by a flange structure or the like (not shown). Also, various devices may be included in the middle of the flow path.

[0018] The compressor 12 is a device that compresses the refrigerant sucked from the fourth flow path 104 and discharges it to the first flow path 101. Also, the compressor 13 is a device that compresses the refrigerant sucked from the second flow path 102 and discharges it to the third flow path 103. The mechanisms of the compressors 12 and 13 are not limited, and various mechanisms such as a swing type, a scroll type, and a rotary type may be used. The compressors 12 and 13 compress and discharge the sucked refrigerant at a compression ratio (= pressure of the discharged refrigerant / pressure of the sucked refrigerant) set according to the control from the control unit 50 (see FIG. 1). In the compressors 12 and 13 according to the present embodiment, for example, the operating frequency and the amount of the refrigerant sucked / discharged are controlled according to the control signal from the control unit 50. Note that the "operating frequency" is the frequency of the operation of the component for compressing the refrigerant, which is performed inside the compressor. Specifically, for example, it is the frequency of the swing of the swing body in a swing type compressor, or the frequency of the rotation of the rotating body in a scroll type compressor or a rotary type compressor. The compressor 12 is an example of a first compression element, and the compressor 13 is an example of a second compression element.

[0019] The radiator 14 is a device that is provided in the first flow path 101 and extracts heat from the refrigerant by heat exchange between the passing refrigerant and a fluid such as air or water, and dissipates the heat. As shown in the figure, in the refrigerant circuit 10 according to the first embodiment, the radiator 14 is provided between the confluence portion 20 and the branch portion 15 in the first flow path 101. As the radiator 14, various heat exchangers such as a tube type heat exchanger or a plate type heat exchanger can be used, for example. In the radiator 14, the fluid that has exchanged heat with the refrigerant is heated by the heat extracted from the refrigerant. Therefore, for example, by using air as the fluid and supplying the heated air into the space as warm air, it may be used for heating the space. Also, for example, by using water as the fluid and supplying the heated water to the user, it may be used for hot water supply. Thus, the radiator 14 can also be used as a heater for heating the fluid.

[0020] The motor-operated valves 16 and 18 are configured to include a valve such as a ball valve and a motor that drives the valve, and the motor adjusts the pressure of the refrigerant flowing by adjusting the opening degree of the valve. More specifically, the motor-operated valve 16 is provided between the first branch 151 and the second flow path 102, applies a throttle expansion according to the opening degree of the valve to the refrigerant flowing in from the first branch 151 to reduce the pressure, and flows it into the second flow path 102. Further, the motor-operated valve 18 is provided between the refrigerant-refrigerant heat exchanger 17 and the cooler 19 in the second branch 152, applies a throttle expansion according to the opening degree of the valve to the refrigerant flowing in from the refrigerant-refrigerant heat exchanger 17 side to reduce the pressure, and flows it into the cooler 19 side. Note that the opening degree of the motor-operated valve 16 and the opening degree of the motor-operated valve 18 are adjusted by driving and controlling each motor according to a control signal from the control unit 50. Also, the motor-operated valves 16 and 18 have a flow resistance corresponding to their respective opening degrees. The flow resistance is an index of the difficulty of the refrigerant flowing through the motor-operated valves 16 and 18. The higher the opening degree, the higher the flow resistance because the refrigerant is more difficult to flow, and the lower the opening degree, the lower the flow resistance because the refrigerant is easier to flow. Here, the motor-operated valve 16 is an example of a first pressure reducing element, and the motor-operated valve 18 is an example of a second pressure reducing element. Note that as a pressure reducing element that can be controlled by the control unit 50 (see FIG. 1), in addition to the motor-operated valve, a solenoid valve that drives the valve by a solenoid or the like may be used.

[0021] The refrigerant-refrigerant heat exchanger 17 is a device that performs heat exchange between the refrigerant flowing through the second flow path 102 and the refrigerant flowing through the second branch 152. More specifically, the refrigerant-refrigerant heat exchanger 17 branches into the first branch 151 at the branch portion 15, and performs heat exchange between the refrigerant flowing through the second flow path 102 in a state of being depressurized by the electric valve 16 and the refrigerant branched into the second branch 152 at the branch portion 15. In the heat exchange in the refrigerant-refrigerant heat exchanger 17, the refrigerant flowing through the second flow path 102 extracts heat from the refrigerant flowing through the second branch 152, and as a result, the refrigerant flowing through the second branch 152 is cooled.

[0022] The cooler 19 is provided in the fourth flow path 104, and is a device that extracts heat from the air and cools the air by heat exchange between the passing refrigerant and the air. As the cooler 19, a heat exchanger such as a tube type heat exchanger can be used. In the cooler 19, heat exchange is performed with the refrigerant, and the cooled air is supplied to the space through a ventilation path (not shown) to cool the space. Thereby, the cooling function of the air conditioner 1 (see FIG. 1) is realized.

[0023] The circulation of the refrigerant in the refrigerant circuit 10 will be described. In the refrigerant circuit 10 according to the first embodiment, the refrigerant (position 10a) after cooling the air by passing through the cooler 19 is compressed by the compressor 12 and discharged into the first flow path 101 (position 10b). The refrigerant discharged into the first flow path 101 merges with the third flow path 103 at the merging portion 20 (position 10c), dissipates heat by passing through the radiator 14, and then branches into the first branch 151 and the second branch 152 at the branch portion 15 (position 10d). The refrigerant branched into the first branch 151 is depressurized by the electric valve 16 and flows into the second flow path 102 (position 10g), and performs heat exchange with the refrigerant branched into the second branch 152 in the refrigerant-refrigerant heat exchanger 17 (position 10h). Then, it is compressed by the compressor 13 and discharged into the third flow path 103 (position 10i), and merges with the first flow path 101 at the merging portion 20 (position 10c). On the other hand, the refrigerant (position 10e) after branching into the second branch 152 and performing heat exchange in the refrigerant-refrigerant heat exchanger 17 is depressurized by the electric valve 18 (position 10f), and then passes through the cooler 19 to cool the air (position 10a). Through such circulation of the refrigerant, the refrigerant circuit 10 forms a refrigeration cycle of the refrigerant.

[0024] (Refrigeration cycle) The refrigeration cycle in the refrigerant circuit 10 will be described in detail with reference to FIGS. 2 and 3. FIG. 3 is a pressure-enthalpy diagram showing a refrigeration cycle 300 of the refrigerant circulating in the refrigerant circuit 10 according to the first embodiment. In FIG. 3, the horizontal axis represents specific enthalpy [kJ / kg], and the vertical axis represents absolute pressure [MPa.abs] based on absolute vacuum. In FIG. 3, the refrigeration cycle 300 is indicated by a thick line. Points 10a to 10i on the refrigeration cycle 300 correspond to positions 10a to 10i of the refrigerant circuit 10 shown in FIG. 2. Therefore, points 10a to 10i in the refrigeration cycle 300 are denoted as positions 10a to 10i. In addition to the refrigeration cycle 300, FIG. 3 shows a saturated liquid line 301, a saturated vapor line 302, a critical point 303, and a 45°C isotherm 304 of the carbon dioxide refrigerant.

[0025] In the refrigerant circuit 10 according to the first embodiment, since the refrigerant compressed by the compressor 12 and having obtained compression heat is discharged into the first flow path 101, the pressure and specific enthalpy of the refrigerant increase from position 10a to position 10b in the refrigeration cycle 300. Further, since the third flow path 103 merges at the confluence portion 20, the specific enthalpy of the refrigerant changes from position 10b to position 10c. Furthermore, since the refrigerant after merging dissipates heat by heat exchange with a fluid in the radiator 14, the specific enthalpy of the refrigerant decreases from position 10c to position 10d. Note that the refrigerant at position 10c is in a state of being pressurized and heated by the compressors 12 and 13, and has a high temperature exceeding, for example, 45°C. Therefore, even if the fluid for heat exchange in the radiator 14 is, for example, at about room temperature (15°C to 25°C), it can take heat from the refrigerant.

[0026] At position 10d, the first branch 151 branched at the branch portion 15 is depressurized by the electric valve 16 and flows into the second flow path 102. Therefore, the pressure of the refrigerant decreases from position 10d to position 10g. Along with this pressure decrease, the temperature of the refrigerant flowing through the second flow path 102 decreases and becomes lower than the temperature of the refrigerant flowing through the second branch 152. For this reason, the refrigerant flowing through the second flow path 102 takes heat from the refrigerant in the first branch 151 through heat exchange between the refrigerant in the first branch 151 in the refrigerant-refrigerant heat exchanger 17, and the specific enthalpy increases from position 10g to position 10h. On the contrary, since the refrigerant in the second branch 152 is deprived of heat by heat exchange, the specific enthalpy decreases from position 10d to position 10e.

[0027] After the refrigerant in the second branch 152 passes through the refrigerant-refrigerant heat exchanger 17, it is depressurized by the electric valve 18. Therefore, the pressure of the refrigerant decreases from position 10e to position 10f. Then, the depressurized refrigerant exchanges heat with air in the cooler 19 and takes heat away. Therefore, the specific enthalpy of the refrigerant increases from position 10f to position 10a. Note that the refrigerant at position 10f is in a state of being depressurized and cooled by the electric valve 18 and is sufficiently low in temperature with respect to the air to be cooled. Therefore, in the cooler 19, heat can be taken away from the air that is the object of heat exchange. Also, after the refrigerant in the second flow path 102 passes through the refrigerant-refrigerant heat exchanger 17, it is compressed by the compressor 13 to obtain compression heat. Therefore, the pressure and specific enthalpy of the refrigerant increase from position 10h to position 10i.

[0028] As described above, the refrigeration cycle 300 of the refrigerant circuit 10 is established. Here, the refrigerant that cools the air in the cooler 19 has its heat taken away by the heat exchange between the refrigerants in the refrigerant-refrigerant heat exchanger 17 before the pressure reduction by the electric valve 18. For this reason, the refrigerant (position 10f in FIGS. 2 and 3) that cools the air in the cooler 19 of the refrigerant circuit 10 is in a state with a lower specific enthalpy than the refrigerant (position 10f' in FIG. 8) that cools the air in the cooler 19' of the conventional refrigerant circuit 10'. As a result, in the refrigerant circuit 10, compared with the case where heat exchange between the refrigerants is not performed as in the conventional refrigerant circuit 10', the amount of heat taken away by the refrigerant per unit amount in the cooler 19 increases, and the refrigerating capacity can be ensured without increasing the circulation amount of the refrigerant.

[0029] Note that in the refrigerant circuit 10, a part of the carbon dioxide refrigerant in the refrigeration cycle 300 becomes a supercritical state, and the change in the density of the refrigerant accompanying the change in the pressure of the refrigerant becomes larger than in the case where it is not in the supercritical state. For this reason, the refrigerating capacity that can be ensured with respect to the compression work of the compressors 12 and 13 is large compared with the case where the refrigerant does not pass through the supercritical state. This is the same for the refrigerant circuits according to the second to fourth embodiments described later.

[0030] Here, using FIGS. 2, 8, and Table 1, the performance of the refrigerant circuit 10 according to the first embodiment and the conventional refrigerant circuit 10' is compared. Table 1 is a table showing the capacities and coefficients of performance (COP: Coefficient Of Performance) of the compressors 12, 13 / 12', 13' in the air conditioner 1 using the refrigerant circuit 10 according to the first embodiment and the air conditioner using the conventional refrigerant circuit 10'. Note that COP is a value obtained by dividing the cooling effect by the cooler 17 / 17' of the refrigerant circuit 10 / 10' by the power consumption related to the operation of the refrigerant circuit 10 / 10', and corresponds to the efficiency of the cooling effect with respect to the power consumption.

[0031]

Table 1

[0032] As shown in Table 1, when the capacity of the compressor 12 in the refrigerant circuit 10 is 106 cc and the capacity of the compressor 13 is 33 cc, and the total capacity is 139 cc, the COP of the air conditioner 1 is 1.90. On the other hand, when the capacity of the compressors 12' and 13' in the conventional refrigerant circuit 10' is 81.5 cc and the total capacity is 163 cc, the COP of the air conditioner is 1.60. That is, when the total capacity and COP in the air conditioner using the conventional refrigerant circuit 10' are taken as 100% (reference), in the air conditioner 1 using the refrigerant circuit 10, the total capacity can be suppressed to 85% while the COP can be improved to 119%.

[0033] As described above, in the air conditioner 1 using the refrigerant circuit 10, since the refrigerating capacity is ensured by the heat exchange between the refrigerants in the refrigerant-refrigerant heat exchanger 17, compared with the case of using the conventional refrigerant circuit 10 in which the refrigerating capacity is ensured by increasing the refrigerant circulation amount, even when the total capacity of the compressors is suppressed, the cooling effect in the air conditioner 1 can be enhanced.

[0034] (Control by the control unit 50) Incidentally, the control unit 50 (see FIG. 1) of the air conditioner 1 may control the circulation of the refrigerant based on the temperature of the refrigerant measured by the temperature sensors 501 and 502 (see FIG. 2). For example, when the temperature of the refrigerant measured by the temperature sensor 501 is higher than the temperature of the refrigerant measured by the temperature sensor 502, the control unit 50 may lower the opening degree of the motor-operated valve 16 to control so that the flow resistance increases. Also, for example, when the temperature of the refrigerant measured by the temperature sensor 501 is higher than the temperature of the refrigerant measured by the temperature sensor 502, the control unit 50 may increase the amount of the refrigerant sucked by the compressor 13 to control so that the refrigerant flow rate in the compressor 13 increases. By performing these controls, the enthalpy difference between the refrigerant compressed by the compressor 12 (position 10b in FIG. 2) and the refrigerant compressed by the compressor 13 (position 10i in FIG. 2) becomes smaller. As a result, the compression ratio in the compressor 13 can be set larger. Note that the positions where the temperature sensors 501 and 502 used for control are provided are not limited to the positions illustrated in FIG. 2. It is sufficient that the temperature sensor 501 is provided at a position before passing through the radiator 14 in the first flow path 101 and before the third flow path 103 merges by the merging portion 20, and the temperature sensor 502 is provided at a position before merging into the first flow path 101 by the merging portion 20.

[0035] <Second Embodiment> (Refrigerant Circuit 10-2) The air conditioner 1 to which the second embodiment is applied is different from the above-described first embodiment in that it includes a refrigerant circuit 10-2 instead of the refrigerant circuit 10 (see FIG. 2). FIG. 4 is a schematic diagram of the refrigerant circuit 10-2 according to the second embodiment. As shown in the figure, the refrigerant circuit 10-2 according to the second embodiment differs from the refrigerant circuit 10 according to the first embodiment only in that a radiator 21 is provided in the third flow path 103 and the merging portion 20 merges the third flow path 103 at a position after passing through the radiator 14 in the first flow path 101. Therefore, for the components common between the refrigerant circuit 10 and the refrigerant circuit 10-2, the same names and reference numerals are used for description, and detailed description thereof is omitted.

[0036] The radiator 21 is a device that is provided in the third flow path 103 and extracts heat from the refrigerant and dissipates the heat by heat exchange between the passing refrigerant and a fluid such as air or water. In other words, the radiator 21 takes heat away from the refrigerant compressed by the compressor 13 by heat exchange between the refrigerant compressed by the compressor 13 and the fluid. As the radiator 21, the same heat exchanger as the radiator 14 can be used. Also, like the radiator 14, the radiator 21 can be used as a heater for heating a fluid. The radiator 21 is an example of a second radiator.

[0037] In the refrigerant circuit 10-2, the refrigerant after cooling air by passing through the cooler 19 is compressed by the compressor 12 and discharged into the first flow path 101. The refrigerant discharged into the first flow path 101 dissipates heat by passing through the radiator 14, and after the third flow path 103 merges at the confluence part 20, it branches into a first branch 151 and a second branch 152 at the branch part 15. The refrigerant branched into the first branch 151 is decompressed by the electric valve 16 and flows into the second flow path 102, and heat exchange is performed with the refrigerant branched into the first branch 151 in the refrigerant-refrigerant heat exchanger 17. Then, it is compressed by the compressor 13 and discharged into the third flow path 103, dissipates heat by passing through the radiator 21, and then merges into the first flow path 101 at the confluence part 20. On the other hand, the refrigerant that has branched into the second branch 152 and has undergone heat exchange in the refrigerant-refrigerant heat exchanger 17 is decompressed by the electric valve 18 and then passes through the cooler 19 to cool the air. By such circulation of the refrigerant, the refrigerant circuit 10-2 forms a refrigeration cycle of the refrigerant.

[0038] Also in the second embodiment using the refrigerant circuit 10-2 described above, similar to the first embodiment, compared with the case of using the conventional refrigerant circuit 10 that ensures refrigerating capacity by increasing the refrigerant circulation amount, the total capacity of the compressors is suppressed. Further, in the refrigerant circuit 10-2, since the confluence part 20 merges the third flow path 103 at a position after passing through the radiator 14 in the first flow path 101, the heat dissipation from the radiator 14 can be increased compared with the case of merging the third flow path 103 at a position before passing through the radiator 14.

[0039] Here, in the refrigerant circuit 10-2 according to the second embodiment, the capacity of the compressor 12 is preferably larger than the capacity of the compressor 13. With such a configuration, the heat dissipation from the radiator 14 can be increased compared with the case where the capacity of the compressor 12 is smaller than the capacity of the compressor 13.

[0040] <The Third Embodiment> (Refrigerant Circuit 10-3) The air conditioner 1 to which the third embodiment is applied is different from the first embodiment described above in that it includes a refrigerant circuit 10-3 instead of the refrigerant circuit 10 (see FIG. 2). FIG. 5 is a schematic diagram of a refrigerant circuit 10-3 according to the third embodiment. As shown in the figure, the refrigerant circuit 10-3 according to the third embodiment is different from the refrigerant circuit 10-2 according to the second embodiment only in that it includes an electric valve 22 that reduces the pressure of the refrigerant after it passes through the radiator 21. Therefore, for the components common to the refrigerant circuit 10-2 and the refrigerant circuit 10-3, the same names and reference numerals are used for description, and detailed descriptions thereof are omitted.

[0041] The electric valve 22 is provided at a position after the refrigerant passes through the radiator 21 in the third flow path 103 and reduces the pressure of the passing refrigerant. As the electric valve 22, the same configuration as that of the electric valves 16 and 18 can be used, and the opening degree can be adjusted by the control unit 50. The electric valve 22 is an example of a third decompression element.

[0042] In the refrigerant circuit 10-3, the refrigerant after cooling the air by passing through the cooler 19 is compressed by the compressor 12 and discharged into the first flow path 101. The refrigerant discharged into the first flow path 101 dissipates heat by passing through the radiator 14, and after the third flow path 103 joins at the confluence 20, it branches into a first branch 151 and a second branch 152 at the branch portion 15. The refrigerant branched into the first branch 151 is decompressed by the electric valve 16 and flows into the second flow path 102, and heat exchange is performed with the refrigerant branched into the first branch 151 in the refrigerant-refrigerant heat exchanger 17. Then, it is compressed by the compressor 13 and discharged into the third flow path 103, dissipates heat by passing through the radiator 21, and then is decompressed by the electric valve 22 and joins the first flow path 101 at the confluence 20. On the other hand, the refrigerant that branches into the second branch 152 and performs heat exchange in the refrigerant-refrigerant heat exchanger 17 is decompressed by the electric valve 18 and then passes through the cooler 19 to cool the air. By such circulation of the refrigerant, the refrigerant circuit 10-3 forms a refrigeration cycle of the refrigerant.

[0043] Also in the third embodiment using the refrigerant circuit 10-3 described above, compared with the case of using the conventional refrigerant circuit 10 that ensures refrigerating capacity by increasing the refrigerant circulation amount, similar to the first and second embodiments, the total capacity of the compressors is suppressed. Further, in the refrigerant circuit 10-3, since the refrigerant compressed by the compressor 13 is decompressed by the motor-operated valve 22, the compression ratio in the compressor 13 can be increased compared with the case where the motor-operated valve 22 is not provided.

[0044] <Fourth Embodiment> (Refrigerant Circuit 10-4) The air conditioner 1 to which the fourth embodiment is applied is different from the first embodiment described above in that it includes a refrigerant circuit 10-4 instead of the refrigerant circuit 10 (see FIG. 2). FIG. 6 is a schematic diagram of the refrigerant circuit 10-4 according to the fourth embodiment. As shown in the figure, the refrigerant circuit 10-4 according to the fourth embodiment is different from the refrigerant circuit 10-2 according to the second embodiment only in that it includes a motor-operated valve 23 that decompresses the refrigerant after it has passed through the radiator 14. Therefore, for the components common between the refrigerant circuit 10-2 and the refrigerant circuit 10-4, the same names and reference numerals are used for representation, and detailed descriptions thereof are omitted.

[0045] The motor-operated valve 23 is provided at a position in the first flow path 101 after passing through the radiator 14 and before the confluence of the third flow path 103 by the confluence portion 20, and decompresses the passing refrigerant. As the motor-operated valve 23, a configuration similar to that of the motor-operated valves 16, 18, and 22 can be used, and the opening degree can be adjusted by the control unit 50. The motor-operated valve 23 is an example of a fourth decompression element.

[0046] In the refrigerant circuit 10-4, the refrigerant after cooling the air by passing through the cooler 19 is compressed by the compressor 12 and discharged into the first flow path 101. The refrigerant discharged into the first flow path 101 dissipates heat by passing through the radiator 14 and is depressurized by the motor-operated valve 23. Then, after the third flow path 103 joins at the confluence section 20, it branches into a first branch 151 and a second branch 152 at the branch section 15. The refrigerant branched into the first branch 151 is depressurized by the motor-operated valve 16 and flows into the second flow path 102, and heat exchange is performed with the refrigerant branched into the second branch 152 in the refrigerant-refrigerant heat exchanger 17. Then, it is compressed by the compressor 13 and discharged into the third flow path 103, dissipates heat by passing through the radiator 21, and then joins the first flow path 101 at the confluence section 20. On the other hand, the refrigerant that has branched into the second branch 152 and has undergone heat exchange in the refrigerant-refrigerant heat exchanger 17 is depressurized by the motor-operated valve 18 and then passes through the cooler 19 to cool the air. By such circulation of the refrigerant, the refrigerant circuit 10-4 forms a refrigeration cycle of the refrigerant.

[0047] Also in the fourth embodiment using the above-described refrigerant circuit 10-4, as in the first to third embodiments, compared with the case of using the conventional refrigerant circuit 10 that ensures refrigerating capacity by increasing the refrigerant circulation amount, the total capacity of the compressors is suppressed. Further, in the refrigerant circuit 10-4, since the refrigerant compressed by the compressor 12 is depressurized by the motor-operated valve 23, the compression ratio in the compressor 12 can be increased compared with the case where the motor-operated valve 23 is not provided.

[0048] <Application Example> (Switching between Cooling and Heating) Incidentally, in the air conditioner 1, there may be a case of switching between a cooling function of supplying cold air to a space to cool the space and a heating function of supplying warm air to the space to heat the space. In this case, if the heat exchanger that cools the air in the cooling function and the heat exchanger that heats the air in the heating function are made common, the supply path of the air used for heat exchange and the ventilation path for supplying the cold air / warm air after heat exchange to the space can be made common. The refrigerant circuit of the application example includes switching means for switching the cooler 19 (see FIGS. 2 and 4 to 6) in the above-described embodiment to a state of being a heat exchanger that cools air in the cooling function and a state of being a heat exchanger that heats air in the heating function.

[0049] FIG. 7 is a diagram for explaining the refrigerant circuit 10-5 of the application example. As shown in the figure, the refrigerant circuit 10-5 of the application example is different from the refrigerant circuit 10 according to the first embodiment only in that it includes a four-way switching valve 60 that switches the connection relationship of the four-way flow paths. Therefore, for the components common between the refrigerant circuit 10 and the refrigerant circuit 10-5, the same names and reference numerals are used for notation, and detailed descriptions are omitted.

[0050] The four-way switching valve 60 is provided so as to connect the flow path between the cooler 19 and the compressor 12 and the flow path between the confluence section 20 and the radiator 14. Then, under the control from the control unit 50, the connection relationship of the flow paths is switched between a first state in which the cooler 19 and the compressor 12 are connected and the confluence section 20 and the radiator 14 are connected, and a second state in which the cooler 19 and the confluence section 20 are connected and the compressor 12 and the radiator 14 are connected. Note that the four-way switching valve 60 is an example of the switching means, and switching may be performed using other configurations.

[0051] In the refrigerant circuit 10-5 in the first state, the refrigerant circulates in the same manner as the refrigerant circuit 10 described with reference to FIG. 2, and the air that exchanges heat in the cooler 19 is cooled. Thereby, the cooling function of the air conditioner 1 is realized. On the other hand, in the refrigerant circuit 10-5 in the second state, the refrigerant circulates in a manner different from the first state, and the pressure and specific enthalpy of the refrigerant change in a path opposite to the refrigeration cycle 300 described with reference to FIG. 3. More specifically, the refrigerant compressed by the compressors 12 and 13 merges at the merging portion 20 and then passes through the cooler 19. Here, the refrigerant passing through the cooler 19 is in a state of being pressurized and heated by the compressors 12 and 13 and is sufficiently hot with respect to the air that is the heat exchange partner. Therefore, the air that is the heat exchange partner in the cooler 19 takes heat from the refrigerant and is heated. Thereby, the heating function of the air conditioner 1 is realized.

[0052] In the example of FIG. 7, switching means is applied to the refrigerant circuit 10 according to the first embodiment and shown as the refrigerant circuit 10-5 of the application example. However, the same switching means can also be applied to the refrigerant circuits 10-2, 10-3, and 10-4 according to the second, third, and fourth embodiments. In addition, also in the air conditioner 1 of the second, third, and fourth embodiments described above and the application example to which the switching means is applied, the control unit 50 may control the circulation of the refrigerant based on the temperature of the refrigerant measured by the temperature sensors 501 and 502 (see FIGS. 2 and 4 to 7).

[0053] <Others> In the above-described embodiments, the case where the refrigeration cycle device is applied to the air conditioner 1 has been described as an example, but the application range is not limited. It may be applied to various devices that cool objects, such as a cold storage warehouse, a refrigerator, and an ice maker. Also, as described above with reference to FIG. 2, it may be applied to various devices that heat objects, such as a heating appliance, a water heater, and a water supply heater, by utilizing the heat dissipation in the radiator 14.

[0054] In addition, as an example of the refrigerant circulating in each refrigerant circuit, carbon dioxide refrigerant has been exemplified, but the type of refrigerant is not limited. A mixed refrigerant in which carbon dioxide and other components are mixed may be used, or a single refrigerant or a mixed refrigerant that does not contain carbon dioxide may be used. However, by using a refrigerant containing carbon dioxide in at least a part of the composition, such as the carbon dioxide refrigerant of the above-described embodiment, heat dissipation in the radiators 14 and 21 is increased as compared with the case of using azeotropic non-mixed refrigerant that does not contain carbon dioxide.

[0055] Furthermore, the first compression element and the second compression element may be integrated into one device, and the operation for compression in each compression element may be realized by a common motor or the like. However, by using separate devices for each compression element as in the compressors 12 and 13 of the above-described embodiment, each compression element can be individually controlled according to the state of the refrigerant being inhaled and the like. Also, instead of the compressor 12, a plurality of compressors connected in parallel may be used, or instead of the compressor 13, a plurality of compressors connected in parallel may be used. Also in this case, the total capacity can be made smaller as compared with the case of increasing the refrigerant circulation amount in the conventional refrigerant circuit 10' to ensure the refrigerating capacity.

[0056] In the above-described embodiment, an electric valve or a solenoid valve is used as the decompression element in order to enable control of the opening degree by the control unit 50. When control by the control unit 50 is not performed, a capillary tube, an orifice plate, or the like may be used for each decompression element.

[0057] Furthermore, in the above-described embodiment, it is exemplified that the refrigerant is branched into two branches, the first branch 151 and the second branch 152, but it may be branched into three or more branches including the first branch 151 and the second branch 152. Corresponding to this, a plurality of flow paths including the third flow path 103 may merge into the first flow path 101. When branching into three or more branches, the branching may be performed at a plurality of branching portions including the branching portion 15, and the merging may be performed at a plurality of merging portions including the merging portion 20.

[0058] <Appendix> The above-described embodiments can be understood as follows. The air conditioner 1 of the above-described embodiment includes a compressor 12 that compresses the inhaled refrigerant and discharges it to the first flow path 101, a radiator 14 provided in the first flow path 101 that allows the refrigerant to pass through and dissipates the heat extracted from the passing refrigerant, a branch portion 15 that branches the refrigerant that has passed through the radiator 14 in the first flow path 101 into a first branch 151 and a second branch 152, an electric valve 16 that decompresses the refrigerant branched into the first branch 151 and causes it to flow into the second flow path 102, a refrigerant-refrigerant heat exchanger 17 that performs heat exchange between the refrigerant flowing through the second flow path 102 and the refrigerant branched into the second branch 152, an electric valve 18 that decompresses the refrigerant that has undergone heat exchange by the refrigerant-refrigerant heat exchanger 17 in the second branch 152, a cooler 19 that cools the air by heat exchange between the refrigerant decompressed by the electric valve 18 and the air and causes the refrigerant after the heat exchange to be inhaled by the compressor 12, a compressor 13 that inhales the refrigerant that has undergone heat exchange by the refrigerant-refrigerant heat exchanger 17 in the second flow path 102, compresses it, and discharges it to the third flow path 103, and a merging portion 20 that merges the third flow path 103 into the first flow path 101, and includes refrigerant circuits 10, 10-2, 10-3, 10-4, 10-5. In this case, compared with an air conditioner provided with a conventional refrigerant circuit 10' that increases the refrigerant circulation amount to ensure the refrigerating capacity, the total capacity of the compressors 12 and 13 is suppressed.

[0059] In the refrigerant circuit 10-2 according to the second embodiment, the merging portion 15 merges the third flow path 103 at a position after passing through the radiator 14 in the first flow path 101. Further, a radiator 21 that allows the refrigerant compressed by the compressor 13 to pass through and dissipates the heat extracted is provided in the third flow path 103. In this case, compared with the case where the merging portion 15 merges the third flow path 103 at a position before passing through the radiator 14 in the first flow path 101, the heat dissipation from the radiator 14 can be increased.

[0060] Also, in the refrigerant circuit 10-2, the capacity of the compressor 12 is larger than the capacity of the compressor 13. In this case, compared with the case where the capacity of the compressor 12 is smaller than the capacity of the compressor 13, the heat dissipation from the radiator 14 can be increased.

[0061] In the refrigerant circuit 10-3 according to the third embodiment, in addition to the configuration of the refrigerant circuit 10-2, an electric valve 22 for decompressing the refrigerant after passing through the radiator 21 is provided in the third flow path 103. In this case, the compression ratio in the compressor 13 can be set large.

[0062] In the refrigerant circuit 10-4 according to the fourth embodiment, in addition to the configuration of the refrigerant circuit 10-2, an electric valve 23 for decompressing the refrigerant after passing through the radiator 14 is provided at a position in the first flow path 101 after passing through the radiator 14 and before the third flow path 103 joins by the confluence portion 20. In this case, the compression ratio in the compressor 12 can be set large.

[0063] Here, in the air conditioner 1 of the above-described embodiment, a carbon dioxide refrigerant is used. In this case, the heat radiation in the radiator 14 becomes larger than when a non-azeotropic refrigerant mixture containing no carbon dioxide is used.

[0064] Also, in the air conditioner 1 of the above-described embodiment, temperature sensors 501 and 502 for measuring the temperature of the refrigerant are provided at a position before passing through the radiator 14 in the first flow path 101 and before the third flow path 103 joins by the confluence portion 15, and at a position in the third flow path 103 before joining to the first flow path 101 by the confluence portion 15, respectively. Then, when the temperature of the refrigerant measured by the temperature sensor 501 is higher than the temperature of the refrigerant measured in the third flow path 103, the control unit 50 of the air conditioner 1 may control so that the flow resistance of the electric valve 16 increases. In this case, the enthalpy difference between the refrigerant compressed by the compressor 12 and the refrigerant compressed by the compressor 13 becomes smaller.

[0065] Furthermore, in the air conditioner 1 of the above-described embodiment, the control unit 50 may control so that the flow rate of the compressor 13 increases when the temperature of the refrigerant measured in the first flow path 101 is higher than the temperature of the refrigerant measured in the third flow path 103. Also in this case, the enthalpy difference between the refrigerant compressed by the compressor 12 and the refrigerant compressed by the compressor 13 becomes smaller.

[0066] Although the embodiments have been described above, it will be understood that various changes in form and detail can be made without departing from the gist and scope of the claims. For example, a part of each component may be omitted, or other functions may be added to each component. Also, for example, the components included in one configuration example may be interchanged with the components included in another configuration example, or the components included in one configuration example may be added to another configuration example.

Description of Reference Numerals

[0067] 1... air conditioner, 10, 10-2, 10-3, 10-4, 10-5... refrigerant circuit, 12, 13... compressor, 14, 21... radiator, 15... branch section, 16, 18, 22, 23... motor-operated valve, 17... refrigerant-refrigerant heat exchanger, 19... cooler, 20... confluence section, 50... control section, 60... switching circuit, 101... first flow path, 102... second flow path, 103... third flow path, 151... first branch, 152... second branch, 501, 502... temperature sensor

Claims

1. It is possible to switch between a first state for realizing a cooling function and a second state for realizing a heating function, In the first state, a first compression element that compresses the inhaled refrigerant and discharges it into a first flow path, A radiator provided in the first flow path that allows the refrigerant to pass through and dissipates the heat extracted from the passing refrigerant, A branch portion that branches the refrigerant that has passed through the radiator in the first flow path into a first branch and a second branch, A first decompression element that decompresses the refrigerant branched to the first branch and causes it to flow into a second flow path, A heat exchanger that performs heat exchange between the refrigerant flowing through the second flow path and the refrigerant branched to the second branch, A second decompression element that decompresses the refrigerant that has undergone heat exchange by the heat exchanger in the second branch, A cooler that cools the object by heat exchange between the refrigerant decompressed by the second decompression element and the object, and causes the refrigerant after heat exchange to be inhaled by the first compression element, A second compression element that inhales the refrigerant that has undergone heat exchange by the heat exchanger in the second flow path, compresses it, and discharges it into a third flow path, A merging portion that merges the third flow path into the first flow path, A four-way switching valve provided so as to connect the flow path between the cooler and the first compression element and the flow path between the merging portion and the radiator, The four-way switching valve is connected between the cooler and the first compression element, and between the merging portion and the radiator in the first state, and between the cooler and the merging portion, and between the first compression element and the radiator, and the cooler functions as a heat exchanger that heats the object by heat exchange between the refrigerant and the object. A refrigeration cycle device characterized by switching the connection relationship of the flow path to the second state.

2. The capacity of the first compression element is larger than the capacity of the second compression element. The refrigeration cycle device according to claim 1.

3. At least a part of the composition of the refrigerant is carbon dioxide. The refrigeration cycle device according to claim 1.

4. A first temperature sensor provided at a position in the first flow path before passing through the radiator and before the third flow path merges with the first flow path by the merging portion in the first state, and a second temperature sensor provided at a position in the third flow path before merging into the first flow path by the merging portion, A control unit that controls the circulation of the refrigerant based on the temperatures of the refrigerant measured by the first temperature sensor and the second temperature sensor. When the temperature of the refrigerant measured in the first flow path is higher than the temperature of the refrigerant measured in the third flow path, the control unit controls so that the flow resistance of the first pressure reducing element increases. The refrigeration cycle apparatus according to any one of claims 1 to 3, characterized by the above.

5. A first temperature sensor provided at a position in the first flow path before passing through the radiator and before the third flow path merges with the first flow path by the merging portion in the first state, and a second temperature sensor provided at a position in the third flow path before merging with the first flow path by the merging portion. A control unit that performs control related to the circulation of the refrigerant based on the temperatures of the refrigerant measured by the first temperature sensor and the second temperature sensor. When the temperature of the refrigerant measured in the first flow path is higher than the temperature of the refrigerant measured in the third flow path, the control unit controls so that the flow rate of the second compression element increases. The refrigeration cycle apparatus according to any one of claims 1 to 3, characterized by the above.

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