REFRIGERATION DEVICE

Abstract

An object is to, upon occurrence of a disproportionation reaction of a refrigerant, suppress impacts of the disproportionation reaction in a refrigeration cycle. A refrigeration device of the present disclosure includes a compressor, a heat source-side heat exchanger, a use-side heat exchanger, an expansion mechanism, a switching valve that switches between a heating operation state in which the use-side heat exchanger is caused to operate as a condenser and a cooling operation state in which the heat source-side heat exchanger is caused to operate as a condenser, and a control device. A working medium containing an ethylene-based fluoroolefin is used as a refrigerant. Upon detecting, in the heating operation state, that pressure of the working medium in a high pressure part including the compressor and the condenser has increased to a threshold value or higher, the control device controls the switching valve so as to switch operation from the heating operation state to the cooling operation state.

Claims

1. A refrigeration device comprising: a compressor, a heat source-side heat exchanger, a use-side heat exchanger, an expansion mechanism, a switching valve that switches between a heating operation state in which the use-side heat exchanger is caused to operate as a condenser and a cooling operation state in which the heat source-side heat exchanger is caused to operate as a condenser, and a control device, wherein a working medium containing an ethylene-based fluoroolefin is used as a refrigerant, and upon detecting, in the heating operation state, that pressure of the working medium in a high pressure part including the compressor and the condenser has increased to a threshold value or higher, the control device controls the switching valve so as to switch operation from the heating operation state to the cooling operation state.

2. The refrigeration device according to claim 1, wherein the expansion mechanism includes an expansion valve positioned at an exit of the condenser, and upon detecting that the pressure of the working medium in the high pressure part including the compressor and the condenser has increased to the threshold value or higher, the control device causes the expansion valve to operate in a closing direction to a first opening degree, and subsequently, when the pressure increase of the working medium in the high pressure part has stopped, causes the expansion valve to operate in the closing direction to a second opening degree.

3. The refrigeration device according to claim 1, wherein a discharge pipe through which the compressor discharges compressed refrigerant is provided with pressure releasing means for releasing pressure when the pressure of the discharge pipe is equal to or higher than a set pressure value.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a diagram showing a configuration of an air conditioning device according to a first embodiment of the present invention.

[0010] FIG. 2 is a diagram showing a configuration of a compressor.

[0011] FIG. 3 is a diagram showing another configuration of the air conditioning device according to the first embodiment of the present invention.

[0012] FIG. 4 is a flowchart showing an operation of the air conditioning device according to the first embodiment.

[0013] FIG. 5 is a diagram showing a configuration of an air conditioning device according to a second embodiment of the present invention.

[0014] FIG. 6 is a diagram showing a configuration of an air conditioning device according to a third embodiment of the present invention.

[0015] FIG. 7 is a diagram showing a configuration of an air conditioning device according to a fourth embodiment of the present invention.

[0016] FIG. 8 is a diagram showing a configuration of an air conditioning device according to a fifth embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Findings and the Like on which the Present Disclosure is based

[0017] At the time when the present inventors conceived of the present disclosure, there was a proposal for using a refrigerant having a low Global Warming Potential (GWP) in refrigeration devices. For example, fluoroolefins having a carbon-carbon unsaturated bond in molecules thereof have advantages of having a high cooling capability and a low GWP. However, because refrigerants having a low GWP are easily decomposable, there is a possibility that a self-decomposition reaction called disproportionation may occur under specific conditions. When disproportionation occurs in a refrigerant, there is a possibility that pressure in a refrigerant circuit may increase drastically, and equipment may be damaged. Accordingly, the inventors found the problem where, upon the occurrence of such a disproportionation reaction in a refrigeration cycle, it is necessary to suppress impacts thereof. To solve this problem, we have arrived at a subject matter of the present disclosure.

[0018] Thus, the present disclosure will provide a refrigeration device capable of, upon the occurrence of a disproportionation reaction of a refrigerant, suppressing impacts of the disproportionation reaction in a refrigeration cycle.

[0019] A number of embodiments will be explained in detail below, with reference to the drawings; however, explanations that are more detailed than necessary may be omitted. For example, detailed explanations of matters that are already well known or duplicated explanations of substantially the same configurations may be omitted, to prevent the following description from being more redundant than necessary and to facilitate comprehension of people skilled in the art.

[0020] The accompanying drawings and the following description are provided to aid people skilled in the art to sufficiently understand the present disclosure and are not intended to limit the subject matters set forth in the patent claims.

First Embodiment

[0021] The following will describe a first embodiment, with reference to FIGS. 1 to 4.

1-1. Configuration of Air Conditioning Device

[0022] FIGS. 1 and 3 are diagrams showing configurations of an air conditioning device 1 according to the first embodiment. FIG. 2 is a diagram showing a configuration of a compressor 100 included in the air conditioning device 1.

[0023] The air conditioning device 1 shown in FIGS. 1 and 3 is an example to which a refrigeration circuit of the present invention is applied. FIG. 1 shows a cooling operation state of the air conditioning device 1, whereas FIG. 3 shows a heating operation state of the air conditioning device 1.

[0024] The air conditioning device 1 includes the compressor 100, heat exchangers 11a and 11b, expansion valves 12a and 12b, a heat exchanger 13, an expansion valve 14, a gas/liquid separator 15, a valve 16, four-way valves 21 and 22, and refrigerant pipes connecting these together. Further, the air conditioning device 1 includes a control device 10 that controls the expansion valves 12a and 12b, the expansion valve 14, the valve 16, and the four-way valves 21 and 22. The four-way valves 21 and 22 correspond to examples of a switching valve.

[0025] As explained later with reference to FIG. 2, the compressor 100 includes a suction port 104, a discharge tube 105, and an injection part 125. The compressor 100 sucks a refrigerant through the suction port 104, compresses the refrigerant, and discharges high-pressure refrigerant through the discharge tube 105.

[0026] The heat exchangers 11a and 11b are use-side heat exchangers that are installed in an indoor unit and that cool and heat a space to be air conditioned (hereinafter, air conditioned space). The heat exchanger 11a and the heat exchanger 11b are connected in parallel to each other. The heat exchanger 13 is a heat source-side heat exchanger installed in an outdoor unit. The heat exchanger 11a, the heat exchanger 11b, and the heat exchanger 13 are each provided with a fan.

[0027] Connected to the four-way valve 21 are: a pipe 41 connected to the suction port 104 of the compressor 100, a pipe 42 connected to the discharge tube 105, a pipe 44 connected to the heat exchangers 11a and 11b, and a pipe 46 connected to the heat exchanger 13. The pipe 41 corresponds to an example of a suction pipe. The pipe 42 corresponds to an example of a discharge pipe. The four-way valve 21 switches the connections of the pipes 41, 42, 44, and 46, under control of the control device 10.

[0028] Connected to the four-way valve 22 are: a pipe 45 connected to the heat exchangers 11a and 11b, a pipe 47 connected to the heat exchanger 13, and a pipe 48 and a pipe 49 connected to the gas/liquid separator 15. The pipe 49 is a pipe through which the refrigerant flows into the gas/liquid separator 15. The pipe 48 is a pipe through which the refrigerant flows out of the gas/liquid separator 15. The gas/liquid separator 15 is a tank storing therein the refrigerant that has flowed therein through the pipe 48, so that it is possible to separately take out liquid refrigerant and gas refrigerant therefrom. The gas/liquid separator 15 corresponds to an example of a refrigerant storage part. The four-way valve 22 switches the connections of the pipes 45, 47, 48, and 49, under control of the control device 10.

[0029] FIG. 1 shows a flow of the refrigerant in the cooling operation state by using the arrows with the symbol RC. FIG. 2 shows a flow of the refrigerant in the heating operation state by using the arrows with the symbol RH.

[0030] Further, in FIGS. 1 to 3 and FIGS. 5 to 7 (explained later), a flow of the refrigerant that is the same for the cooling operation state and the heating operation state is shown by using the arrows with the symbol R.

[0031] In the cooling operation state shown in FIG. 1, the four-way valve 21 connects the pipe 42 to the pipe 46 and connects the pipe 44 to the pipe 41. The four-way valve 22 connects the pipe 47 to the pipe 49 and connects the pipe 48 to the pipe 45.

[0032] In the cooling operation state of the air conditioning device 1, the refrigerant discharged from the compressor 100 into the discharge tube 105 flows into the heat exchanger 13 via the pipe 42 and the four-way valve 21 and is condensed by the heat exchanger 13. In other words, in the cooling operation state, the heat exchanger 13 functions as a condenser. The refrigerant condensed by the heat exchanger 13 flows into the gas/liquid separator 15 via the pipe 47, the four-way valve 22, and the pipe 49.

[0033] Further, in the cooling operation state, the liquid refrigerant is supplied from the gas/liquid separator 15 via the pipe 48 and the four-way valve 22 to the expansion valves 12a and 12b. The expansion valve 12a decompresses the refrigerant and supplies the decompressed refrigerant to the heat exchanger 11a. The expansion valve 12b decompresses the refrigerant and supplies the decompressed refrigerant to the heat exchanger 11b. The heat exchangers 11a and 11b function as evaporators in the cooling operation state, so as to vaporize the refrigerant decompressed by the expansion valves 12a and 12b. The refrigerant vaporized by the heat exchangers 11a and 11b is delivered to the compressor 100 via the pipe 44, the four-way valve 21, and the pipe 41.

[0034] In contrast, in the heating operation state, the four-way valve 21 connects the pipe 42 to the pipe 44 and connects the pipe 46 to the pipe 41. The four-way valve 22 connects the pipe 47 to the pipe 48 and connects the pipe 49 to the pipe 45.

[0035] In the heating operation state of the air conditioning device 1, the refrigerant discharged through the discharge tube 105 flows into the heat exchangers 11a and 11b via the pipe 42 and the four-way valve 21 and is condensed by the heat exchangers 11a and 11b. In other words, in the heating operation state, the heat exchangers 11a and 11b function as a condenser. The refrigerant condensed by the heat exchangers 11a and 11b flows into the gas/liquid separator 15 via the pipe 45, the four-way valve 22, and the pipe 49.

[0036] Further, in the heating operation state, the liquid refrigerant is supplied from the gas/liquid separator 15 via the pipe 48 and the four-way valve 22 to the expansion valve 14. The expansion valve 14 decompresses the refrigerant and supplies the decompressed refrigerant to the heat exchanger 13. The heat exchanger 13 functions as an evaporator in the heating operation state, so as to vaporize the refrigerant decompressed by the expansion valve 14. The refrigerant vaporized by the heat exchanger 13 is sucked into the suction port 104 via the pipe 46, the four-way valve 21, and the pipe 41.

[0037] The control device 10 includes a processor such as a micro controller. By causing the processor to execute a program or by using a function of programmed hardware, the control device 10 controls the air conditioning device 1.

[0038] The control device 10 controls the four-way valve 21 and the four-way valve 22 so as to switch between the cooling operation state and the heating operation state. Further, in the cooling operation state, the control device 10 adjusts opening degrees of the expansion valves 12a and 12b. In the heating operation state, the control device 10 adjusts opening degrees of the expansion valve 14.

[0039] The control device 10 exercises control to open and close the valve 16 provided for the pipe 43. The valve 16 is configured by using an electric valve, an electromagnetic valve, or an expansion valve. When the valve 16 is an electric valve or an expansion valve, the control device 10 controls the opening and the closing of the valve 16 and adjusts opening degrees of the valve 16.

[0040] The air conditioning device 1 may include at least one selected from between: a temperature sensor (not shown) that detects a temperature of an electric motor 110; and a temperature sensor (not shown) that detects a temperature of a refrigerant discharged by a compression mechanism 120. These temperature sensors are connected to the control device 10. By obtaining detection values from the one or more temperature sensors, the control device 10 detects one or both of the temperature of the electric motor 110 and the temperature of the refrigerant discharged by the compression mechanism 120. Further, the control device 10 may calculate pressure of the refrigerant discharged by the compression mechanism 120, on the basis of the temperature of the refrigerant discharged by the compression mechanism 120.

[0041] The air conditioning device 1 may include a pressure sensor that detects pressure of the refrigerant discharged by the compression mechanism 120. Further, the air conditioning device 1 may include a heat exchanger temperature sensor (not shown) that detects temperatures of the heat exchangers 11a and 11b and the heat exchanger 13. In that situation, the control device 10 may calculate pressure and a temperature of the refrigerant discharged by the compression mechanism 120, on the basis of detection values from the heat exchanger temperature sensor; however, the abovementioned temperature sensors do not necessarily need to be provided.

[0042] The pipe 43 supplies the gas refrigerant from the gas/liquid separator 15 to the compressor 100. Because the pipe 43 supplies the refrigerant stored in the gas/liquid separator 15 to the compressor 100 by using the path different from the pipe 48 connected to the suction port 104, the pipe 43 may be referred to as a bypass pipe. The pipe 43 is connected to the injection part 125 of the compressor 100. As a result of the refrigerant being supplied to the injection part 125 by the pipe 43, the compressor 100 is cooled. The injection part 125 corresponds to an example of a refrigerant supply part. The pipe 43 corresponds to an example of a refrigerant pipe.

[0043] The pipe 42 connected to the discharge tube 105 is provided with a relief valve 60. In the example shown in FIGS. 1 and 3, the pipe 42 is provided with the relief valve 60. The relief valve 60 is a valve that automatically opens when the pressure of the refrigerant becomes equal to or higher than a set pressure value being set in advance so as to lower pressure of a compression chamber of the compression mechanism 120 and the discharge tube 105. The relief valve 60 corresponds to an example of pressure releasing means. The relief valve 60 may be provided for the discharge tube 105.

1-2. Configuration of Compressor

[0044] As shown in FIG. 2, the compressor 100 includes a container 102. The container 102 accommodates the compression mechanism 120 that compresses the refrigerant and the electric motor 110 that drives the compression mechanism 120.

[0045] The electric motor 110 includes a stator 111 and a rotor 112. A crankshaft 103 is linked to the rotor 112, while the crankshaft 103 is rotatably supported by bearings 107 and 108. As a result, the rotor 112 is held so as to be rotatable together with the crankshaft 103.

[0046] In the compressor 100, the electric motor 110 is, for example, positioned in a lower part of the interior space of the container 102, while the compression mechanism 120 is positioned above the electric motor 110. In a bottom part of the container 102, refrigeration machine oil (not shown) is stored.

[0047] The electric motor 110 is a so-called concentrated winding motor. The stator 111 includes teeth having a three-phase stator coil and a yoke connecting the teeth together. The stator coil of the stator 111 is connected to a driving circuit 116 of an inverter style, by a lead wire (not shown). The rotor 112 includes a permanent magnet and rotates together with the crankshaft 103, due to a rotating magnetic field generated by an electric current flowing through the stator 111. The driving circuit 116 outputs a drive current to the stator 111 according to control of the electric motor 110.

[0048] The compression mechanism 120 is a compression mechanism of a scroll style, for example. The compression mechanism 120 includes a fixed scroll 121 and a swinging scroll 122 combined with the fixed scroll 121. A space formed between the fixed scroll 121 and the swinging scroll 122 functions as the compression chamber. The compression mechanism 120 compresses the refrigerant, as a result of the swinging scroll 122 rotating together with the crankshaft 103. The refrigerant compressed by the compression mechanism 120 is discharged through the discharge tube 105.

[0049] The compressor 100 is a so-called internal low pressure compressor in which the compression mechanism 120 sucks and compresses the refrigerant flowing into the container 102 through the suction port 104. The refrigerant that has flowed into the container 102 through the suction port 104 is sucked by the compression mechanism 120 through an air gap being a space formed between the stator 111 and the rotor 112 of the electric motor 110, as indicated by the arrows RI. The electric motor 110 is cooled by the refrigerant flowing through the air gap.

[0050] The injection part 125 is a tube allowing communication between the inside and the outside of the container 102. A tip end of the injection part 125 opens into the compression chamber of the compression mechanism 120. As mentioned above, the injection part 125 has the pipe 43 connected thereto, so that the gas refrigerant is supplied thereto via the pipe 43.

[0051] As a result of the refrigerant flowing into the compression chamber from the injection part 125 via the pipe 43, the refrigerant in the gas/liquid separator 15 is sucked by the compression mechanism 120. As a result, because the gas refrigerant is extracted from the gas/liquid separator 15, the pressure of the refrigerant in the gas/liquid separator 15 is lowered, which results in an action where the refrigerant is allowed to expand in the gas/liquid separator 15.

[0052] On the inside of the container 102, the injection part 125 may have an opening at a suction port through which the compression mechanism 120 sucks the refrigerant from the inside of the container 102 or in the vicinity thereof. In that situation also, it is possible to have an action caused by which the gas refrigerant is extracted from the gas/liquid separator 15.

[1-3. Refrigerant]

[0053] The refrigerant used in the air conditioning device 1 is a working medium containing an ethylene-based fluoroolefin. The ethylene-based fluoroolefin contains at least one selected from the group consisting of, for example, 1, 1, 2-trifluoroethylene (HFO-1123), trans-1, 2-difluoroethylene (HFO-1132 (E)), cis-1, 2-difluoroethylene (HFO-1132 (Z)), 1,1-difluoroethylene (HFO-1132a), tetrafluoroethylene (CF2=CF2, HFO-1114), and monofluoroethylene (HFO-1141).

[0054] The working medium may contain two or more refrigerant components. In other words, the working medium may contain an ethylene-based fluoroolefin (e.g., 1, 1, 2-trifluoroethylene) selected from the above examples and a second refrigerant component. The second refrigerant component may be at least one refrigerant selected from the group consisting of: hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), saturated hydrocarbons, carbon dioxide, and other refrigerants. Examples of the hydrofluorocarbons include difluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane, pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, and heptafluorocyclopentane. Examples of the hydrofluoroolefins include monofluoropropene, trifluoropropene, tetrafluoropropene, pentafluoropropene, and hexafluorobutene. Examples of the saturated hydrocarbons include: ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methyl propane), methyl cyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2, 2-dimethyl propane), and methylcyclobutane. However, other hydrocarbons may be used. The second refrigerant component may contain a plurality of components. In other words, the second refrigerant component may contain two or more refrigerant components selected from the group consisting of hydrofluorocarbons, hydrofluoroolefins, saturated hydrocarbons, carbon dioxide, and other refrigerants.

[0055] The working medium used as the refrigerant in the air conditioning device 1 may contain a disproportionation inhibitor, in addition to the one or more refrigerant components. The disproportionation inhibitor may be saturated hydrocarbons, for example. The working medium may contain the disproportionation inhibitor that includes one or more components. Examples of the saturated hydrocarbons that can be used as the disproportionation inhibitor include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2, 2-dimethylpropane), and methylcyclobutane. However, other saturated hydrocarbons may be used. An example of particularly preferable disproportionation inhibitors is n-propane.

[0056] For example, the disproportionation inhibitor may be a haloalkane of which the carbon number is 1 or 2. Examples of the haloalkane of which the carbon number is 1, i.e., halomethane, that can be used as a disproportionation inhibitor include: (mono) iodomethane (CH3I), diiodomethane (CH2I2), dibromomethane (CH2Br2), bromomethane (CH3Br), dichloromethane (CH2Cl2), chloroiodomethane (CH2ClI), dibromochloromethane (CHBr2Cl), tetraiodomethane (CI4), carbon tetrabromide (CBr4), bromotrichloromethane (CBrCl3), dibromochloromethane (CBr2Cl2), tribromofluoromethane (CBr3F), fluorodiiodomethane (CHFI2), difluoroiodomethane (CHF2I), difluorodiiodomethane (CF2I2), dibromodifluoromethane (CBr2F2), and trifluoroiodomethane (CF3I), but other halomethanes may be used. Examples of the haloalkane of which the carbon number is 2, i.e., haloethane, that can be used as a disproportionation inhibitor include: 1, 1, 1-trifluoro-2-iodoethane (CF3CH2I), monoiodoethane (CH3CH2I), monobromoethane (CH3CH2Br), and 1, 1, 1-triiodoethane (CH3CI3).

[0057] The working medium may contain a plurality of disproportionation inhibitors selected from any of the abovementioned saturated hydrocarbons and the abovementioned haloalkanes. Further, the working medium may contain a single type of saturated hydrocarbons. Alternatively, the working medium may contain two or more types of saturated hydrocarbons. Furthermore, the working medium may contain a single type of haloalkane. Alternatively, the working medium may contain two or more types of haloalkanes.

[0058] Preferable examples of the working medium include a mixture of 1,1,2-trifluoroethylene and n-propane. This working medium may contain the abovementioned second refrigerant component and may contain other components.

[0059] The working media listed above may contain inevitable impurities. Examples of the inevitable impurities include various types of additives including a stabilizer that may be added for the purpose of stabilization during transport or during storage, a remnant or a by-product of a synthetic raw material of a refrigerant component, and other substances that may inadvertently enter for other reasons.

[0060] It is possible to change, as appropriate, a mass ratio between 1, 1, 2-trifluoroethylene and n-propane contained in the working medium. Capabilities of a refrigeration cycle is correlated with mass ratios of the refrigerant components contained in the working medium. Accordingly, to maintain a certain capability of the refrigeration cycle, it is desirable to ensure that n-propane serving as the disproportionation inhibitor is contained in the working medium by 40% by mass or smaller.

1-4. Inhibiting Disproportionation Reactions

[0061] Ethylene-based fluoroolefins include, for example, ethylene-based fluoroolefins that may cause a disproportionation reaction. When an ethylene-based fluoroolefin is used as the refrigerant, there is an advantage that a low GWP is realized while achieving a high refrigeration capability. On the contrary, because ethylene-based fluoroolefins belong to a group of refrigerants that are easily decomposed, there is a possibility that a disproportionation reaction may occur under specific conditions. Such a disproportionation reaction is known to be a reaction in which radicals occur from molecules contained in a refrigerant, and self-decomposition of the refrigerant develops due to a chain reaction. When a disproportionation reaction has occurred, a drastic pressure increase may be caused in the refrigeration cycle.

[0062] Examples of the specific conditions under which a disproportionation reaction may occur include the refrigerant being at a high temperature, having high pressure, and having the refrigerant exposed to an electric discharge phenomenon. In other words, by eliminating or preventing one of high temperature, high pressure, and the electric discharge phenomenon, it is possible to prevent or inhibit disproportionation reactions of the refrigerant. Typical examples of the electric discharge phenomenon that may induce a disproportionation reaction include a short circuit occurring between stator coil windings of the stator 111 in the electric motor 110. This type of short circuit may be called a layer short circuit.

[0063] The air conditioning device 1 according to the present embodiment includes a configuration capable of inhibiting disproportionation reactions of the refrigerant.

[0064] The compressor 100 is an internal low pressure compressor. Accordingly, because the refrigerant pressure inside the container 102 is equal to the pressure on a suction side of the compression mechanism 120, the refrigerant does not easily go into a high-temperature and high-pressure state, in the electric motor 110 or in the surroundings thereof. Consequently, even when a layer short circuit has occurred in the electric motor 110, disproportionation reactions of the refrigerant are not easily induced.

[0065] On the inside of the container 102, because the refrigerant sucked through the suction port 104 reaches the compression mechanism 120 by passing through the air gap formed between the stator 111 and the rotor 112, the refrigerant passing through the air gap inhibits the temperature of the electric motor 110 from rising. Consequently, because the refrigerant in the electric motor 110 and in the surroundings thereof does not easily go into a high-temperature and high-pressure state, even when a layer short circuit has occurred in the electric motor 110, disproportionation reactions of the refrigerant are not easily induced.

[0066] The air conditioning device 1 includes the pipe 43 and the injection part 125 for supplying the liquid refrigerant to the compression chamber of the compressor 100. The control device 10 opens the valve 16 when the temperature of the compressor 100 satisfies a condition set in advance so that the refrigerant is supplied to the injection part 125. The condition set in advance may be, for example, the temperature of the compressor 100 being equal to or higher than a threshold value. The temperature of the compressor 100 may be, more specifically, the temperature of the electric motor 110 or the temperature of the refrigerant discharged by the compression mechanism 120. In that situation, the control device 10 opens the valve 16, upon detecting that either the temperature of the electric motor 110 or the temperature of the refrigerant discharged by the compression mechanism 120 has exceeded the threshold value. With this configuration, it is possible to cool the compression mechanism 120 and to inhibit disproportionation reactions.

[0067] In this situation, when the valve 16 is opened, in association with the refrigerant flowing out of the gas/liquid separator 15 into the pipe 43, it is possible to lower the pressure of the refrigerant in the gas/liquid separator 15 and to allow the refrigerant to expand in the gas/liquid separator 15. As a result, because the gas/liquid separator 15 functions as a type of heat exchanger, the gas/liquid separator 15 may be referred to as an intermediate cooler, for example. Due to this action, in the cooling operation state of the air conditioning device 1, the refrigerant discharged from the compressor 100 is decompressed at two stages, i.e., by the expansion valve 14 and by the gas/liquid separator 15. In other words, the expansion valve 14 and the gas/liquid separator 15 structure a two-stage expansion mechanism. An area in which the refrigerant has high temperature and high pressure in the cooling operation state is indicated in FIG. 1 with the symbol HP. Because the expansion valve 14 and the gas/liquid separator 15 structure the two-stage expansion mechanism, it is possible to limit the area HP to a small range. Consequently, if a disproportionation reaction has occurred in the refrigerant, it is possible to keep small the range in which a chain reaction of the refrigerant may propagate. In addition, because a two-stage expansion process is structured, it is possible to lower the temperature of the compression mechanism 120 and to thus inhibit disproportionation reactions more effectively.

[0068] The air conditioning device 1 is capable of controlling the opening and the closing of the valve 16 by employing the control device 10 and, for example, closes the valve 16 while there is a low possibility that a disproportionation reaction may occur. Accordingly, it is possible to enhance operation efficiency of the air conditioning device 1.

[0069] The air conditioning device 1 includes the relief valve 60. Consequently, even if a disproportionation reaction has occurred, because the relief valve 60 opens in response to an increase in the refrigerant pressure associated with the disproportionation reaction, it is possible to prevent the pressure in the refrigeration cycle from increasing excessively.

[0070] Furthermore, as explained above, by using the refrigerant containing an ethylene-based fluoroolefin and the disproportionation inhibitor in the air conditioning device 1, disproportionation reactions of the refrigerant are inhibited. The refrigerant containing an inert disproportionation inhibitor is able to inhibit disproportionation reactions of the ethylene-based fluoroolefin with a thermodilution effect. Further, certain types of disproportionation inhibitors are able to capture radicals, which is an active intermediate product that may occur in a disproportionation reaction. Consequently, by capturing the radicals occurring at an initial stage of the reaction, it is possible to prevent chain reactions and to inhibit the chain reactions from propagating. With these actions, it is possible to inhibit disproportionation reactions of the refrigerant.

1-5. Control Exercised by Control Device

[0071] Next, the control exercised by the control device 10 to inhibit disproportionation reactions of the refrigerant will be explained.

[0072] As explained above, the control device 10 exercises control to open the valve 16, when the temperature of the compressor 100 satisfies the condition set in advance.

[0073] Further, the control device 10 inhibits disproportionation reactions by bringing the four-way valves 21 and 22 and other valves into operation.

[0074] FIG. 4 is a flowchart showing an operation of the control device 10.

[0075] During an operation of the air conditioning device 1, the control device 10 monitors whether or not the refrigerant pressure in a high pressure part of the air conditioning device 1 has increased to a threshold value or higher (step S11). The high pressure part denotes a range in the air conditioning device 1 where high-pressure refrigerant flows and may include, for example, one of the compression mechanism 120, the discharge tube 105, and the area HP shown in FIG. 1. In the following sections, an example will be explained in which the control device 10 performs a judgment process on the pressure of the refrigerant discharged by the compression mechanism 120.

[0076] When the pressure is lower than the threshold value (step S11: No), the control device 10 continues the monitoring in step S11 in a cycle of prescribed periods. The threshold value is configured in the control device 10 in advance. The threshold value is a value of the pressure with which it is conjectured that a disproportionation reaction may have occurred in the refrigerant in the compressor 100 or the pressure under which there is a high possibility that a disproportionation reaction may occur.

[0077] When the control device 10 determines that the pressure of the refrigerant discharged by the compressor 100 has increased to the threshold value or higher (step S11: Yes), there is a high possibility that a disproportionation reaction may have occurred in the refrigerant in the high pressure part of the air conditioning device 1. In that situation, although not shown in FIG. 4, the control device 10 does not exercise the control of opening the valve 16 and causing the refrigerant to flow from the injection part 125 into the compression mechanism 120. Further, the control device 10 may exercise control so as to close the valve 16.

[0078] Upon determining that the pressure in the high pressure part has increased to the threshold value or higher (step S11: Yes), the control device 10 judges whether or not the air conditioning device 1 is performing a heating operation (step S12). When the air conditioning device 1 is performing a heating operation (step S12: Yes), the control device 10 brings the four-way valve 21 and the four-way valve 22 into operation, so as to switch the air conditioning device 1 to a cooling operation (step S13).

[0079] While the air conditioning device 1 is performing a heating operation, because high-pressure refrigerant is flowing to the heat exchanger 11a and the heat exchanger 11b, there is a possibility that a disproportionation reaction of the refrigerant may propagate to the heat exchangers 11a and 11b. To cope with this situation, when the air conditioning device 1 performs the cooling operation, the range in which high-pressure refrigerant flows is limited to the area HP in FIG. 1. Accordingly, by switching the operation state of the air conditioning device 1 to the cooling operation state in step S13, it is possible to prevent the disproportionation reaction from propagating to positions close to the air conditioned space. Consequently, because it is possible to prevent equipment positioned close to the air conditioned space from being damaged by a drastic pressure increase associated with the disproportionation reaction, there is an advantage that people in the air conditioned space will not be affected.

[0080] While the air conditioning device 1 is performing a cooling operation (step S12: No) or when the air conditioning device 1 has been switched from the heating operation state to the cooling operation state (step S13), the control device 10 exercises control so as to close at least one valve under the control to a first opening degree (step S14). In step S14, the control device 10 closes at least the expansion valve 14 to the first opening degree. In step S14, the control device 10 may exercise control so as to close the expansion valves 12a and 12b to the first opening degree.

[0081] The first opening degree is a prescribed opening degree that makes the valve more open than a fully-closed state. The first opening degree may be a value set in correspondence with each of the valves or may be a setting value used in common to all the valves. For example, when a fully-open state is 100%, the first opening degree may be 10%. As a result of the control device 10 closing the valve, it is possible to inhibit the disproportionation reaction from propagating beyond the valve. Further, if the valve were fully closed, there would be a possibility that the pressure increase associated with the disproportionation reaction might become a drastic change. Thus, it is effective to close the valve to the first opening degree, instead of the fully-closed state.

[0082] The control device 10 monitors whether or not the pressure increase in the high pressure part has stopped (step S15). When the pressure increase has not stopped (step S15: No), the monitoring in step S15 is continued with a cycle of prescribed periods. When it is determined that the pressure increase has stopped (step S15: Yes), the control device 10 exercises control to close the valve which was closed to the first opening degree in step S14, to the fully-closed state (step S16). Subsequently, the control device 10 performs a notification process (step S17). The notification process in step S17 is sufficient as long as it is possible to notify a manager who manages the air conditioning device 1 of the occurrence of the disproportionation reaction and may be carried out in any form. For example, in step S17, the control device 10 may notify a device that manages the air conditioning device 1 of the occurrence of the disproportionation reaction, may cause information to be displayed on a display of a remote control device used for operating the air conditioning device 1, or may cause information to be displayed on a display included in the indoor unit of the air conditioning device 1. Further, a sound or an image may be output under control of the control device 10.

[0083] When exercising the control in FIG. 4, the control device 10 may stop the compressor 100 at a point in time during steps S12 through S16.

[0084] In steps S11 and S15 described above, the control device 10 may estimate the pressure of the refrigerant discharged by the compressor 100 on the basis of the temperature of the refrigerant discharged by the compressor 100 and/or the temperatures of the heat exchangers 11a and 11b and the heat exchanger 13, so as to perform the judgment process on the basis of the estimated pressure.

[0085] In the description above, the example was explained in which the control device 10 judges the pressure of the refrigerant discharged by the compressor 100 in steps S11 and S15; however, this configuration is merely an example. In another example, the control device 10 may perform the judgment process on the basis of the temperature of the refrigerant discharged by the compressor 100. In that situation, the control device 10 may directly detect the temperature of the refrigerant discharged by the compressor 100 by using a temperature sensor or may perform the judgment process on the basis of a temperature of the refrigerant discharged by the compressor 100 that is estimated on the basis of the pressure of the discharged refrigerant or the temperatures of the heat exchangers 11a and 11b and the heat exchanger 13.

[0086] The four-way valves 21 and 22 of the air conditioning device 1 are preferably each configured by using a four-way valve or an electromagnetic open/close valve that operates on low differential pressure. In a configuration where pilot four-way switching valves are used as the four-way valves 21 and 22, if the valves are four-way valves or electromagnetic open/close valves operating on low differential pressure, there is an advantage that the switching from the heating operation state to the cooling operation state in step S13 is performed quickly.

1-6. Advantageous Effects, Etc.

[0087] As explained above, the air conditioning device 1 according to the first embodiment includes the compressor 100, the heat exchanger 13 serving as the heat source-side heat exchanger, the heat exchangers 11a and 11b serving as the use-side heat exchangers, and the expansion mechanism. The air conditioning device 1 includes: the four-way valves 21 and 22 that switch between the heating operation state in which the heat exchangers 11a and 11b are caused to operate as a condenser and the cooling operation state in which the heat exchanger 13 is caused to operate as a condenser; and the control device 10. As the refrigerant, the air conditioning device 1 uses the working medium containing the ethylene-based fluoroolefin. Upon detecting that, in the heating operation state, the pressure of the working medium in the high pressure part including the compressor 100 and the condenser has increased to the threshold value or higher, the control device 10 controls the four-way valves 21 and 22 to switch the operation from the heating operation state to the cooling operation state.

[0088] With the above configuration, the air conditioning device 1 is able to realize a low GWP by using the working medium containing the ethylene-based fluoroolefin. In addition, when there is a possibility that a disproportionation reaction may have occurred in the refrigerant or when it is conjectured that a disproportionation reaction may have occurred, the air conditioning device 1 keeps small the area HP where the high-pressure refrigerant flows, by switching the air conditioning device 1 from the heating operation state to the cooling operation state. As a result, it is possible to limit the area HP where the pressure of the refrigerant drastically increases due to the disproportionation reaction and to thus suppress impacts of the disproportionation reaction in the refrigeration cycle. For example, when the heat exchangers 11a and 11b are installed in the air conditioned space of the air conditioning device 1 or in the vicinity thereof, the control exercised by the control device 10 is able to prevent or inhibit the impacts of the disproportionation reaction from spreading to the air conditioned space.

[0089] The expansion mechanism includes the expansion valve 14 or the expansion valves 12a and 12b positioned at the exit of the condenser. The air conditioning device 1 includes the control device 10 that controls the expansion valves 12a, 12b, and 14. Upon detecting that the pressure of the working medium in the high pressure part of the air conditioning device 1 has increased to the threshold value or higher, the control device 10 causes one of the expansion valves 12a, 12b, and 14 to operate in a closing direction to the first opening degree, and subsequently, when the pressure increase of the working medium in the high pressure part has stopped, causes the expansion valve to operate in the closing direction to a second opening degree. The second opening degree may correspond to the fully-closed state, for example. The high pressure part may include the compressor 100 and the condenser, for example.

[0090] With the above configuration, when there is a possibility that a disproportionation reaction may have occurred in the refrigerant or when it is conjectured that a disproportionation reaction may have occurred, it is possible to inhibit the pressure increase associated with the disproportionation reaction. Further, by closing the valve to the second opening degree after the pressure increase in the high pressure part has stopped, it is possible to inhibit the disproportionation reaction from propagating with higher certainty.

[0091] In the air conditioning device 1, the pipe 42 through which the compressor 100 discharges the compressed refrigerant is provided with the relief valve 60 that releases pressure when the pressure of the pipe 42 is equal to or higher than the set pressure value. With the above configuration, when the pressure of the pipe 42 has drastically increased in association with the occurrence of a disproportionation reaction, it is possible to release the pressure of the pipe 42 and to thus reduce impacts of the disproportionation reaction.

[0092] Further, in the air conditioning device 1, the compressor 100 includes the suction port 104 through which the working medium is sucked in, the compression mechanism 120 that compresses the working medium that has been sucked in through the suction port 104, and the injection part 125 that supplies the working medium to the compression mechanism 120 by using the path different from the suction port 104. The compressor 100 is an internal low pressure compressor in which the compression mechanism 120, together with the electric motor 110, is accommodated in the container 102, so that the compression mechanism 120 sucks and compresses the working medium present in the container 102. In the cooling operation state, the heat exchanger 13 serves as a condenser, whereas the heat exchangers 11a and 11b serve as an evaporator. In the heating operation state, the heat exchangers 11a and 11b serve as a condenser, whereas the heat exchanger 13 serves as an evaporator.

[0093] With the above configuration, the air conditioning device 1 is able to realize a low GWP by using the working medium containing the ethylene-based fluoroolefin. Further, by having the refrigerant supplied from the injection part 125 to the compression mechanism 120 and by lowering the pressure of the working medium in the container 102, it is possible to realize a configuration in which disproportionation reactions of the ethylene-based fluoroolefin do not easily occur. Consequently, it is possible to inhibit disproportionation reactions which might be caused when a refrigerant having a low GWP is used.

[0094] Further, the air conditioning device 1 includes the gas/liquid separator 15 provided between the condenser and the evaporator and the pipe 43 through which the gas working medium is delivered from the gas/liquid separator 15 to the injection part 125. The expansion mechanism structures the two-stage expansion process that includes the expansion valve 14 or the expansion valves 12a and 12b being positioned at the exit of the condenser and operating as a first-stage decompression mechanism and the gas/liquid separator 15.

[0095] With the above configuration, in the air conditioning device 1, it is possible to limit the area where the high-pressure refrigerant flows to a small range and to thus realize a configuration in which disproportionation reactions of the refrigerant do not easily propagate. In addition, by structuring the two-stage expansion process, it is possible to realize a configuration in which the temperature rise of the compression mechanism 120 is suppressed, and disproportionation reactions do not easily occur.

[0096] The air conditioning device 1 includes the pipe 41 connected to the suction port 104 of the compressor 100 or the pipe 43 through which the working medium flows into the container 102 accommodating the electric motor 110. The air conditioning device 1 includes the valve 16 that opens and closes the pipe 43 and the control device 10 that controls the valve 16. The control device 10 exercises control to open the valve 16 when the temperature of the compression mechanism 120 satisfies the condition set in advance.

[0097] With the above configuration, when the temperature of the compression mechanism 120 satisfies the condition set in advance, it is possible to lower the pressure of the refrigerant in the gas/liquid separator 15 and to allow the refrigerant to expand in the gas/liquid separator 15, by extracting the refrigerant from the gas/liquid separator 15 via the pipe 43. Consequently, by causing the gas/liquid separator 15 to function as an intermediate cooler, it is possible to structure the two-stage expansion process with the expansion valve 14 and the gas/liquid separator 15.

[0098] The air conditioning device 1 includes the heat exchanger 13 serving as the heat source-side heat exchanger and the heat exchangers 11a and 11b serving as the use-side heat exchangers. The air conditioning device 1 includes the four-way valves 21 and 22 that switch between the heating operation state in which the heat exchangers 11a and 11b are caused to operate as a condenser and the cooling operation state in which the heat exchanger 13 is caused to operate as a condenser. Upon detecting that, in the heating operation state, the pressure of the working medium in the high pressure part including the compressor 100 and the condenser has increased to the threshold value or higher, the control device 10 controls the four-way valves 21 and 22 to switch the operation from the heating operation state to the cooling operation state.

[0099] With the above configuration, in the heating operation state, when it is conjectured that a disproportionation reaction may have occurred in the high pressure part of the air conditioning device 1, it is possible to limit the area where the high-pressure refrigerant flows, by switching the operation to the cooling operation state. With this configuration, it is possible to inhibit the disproportionation reaction from propagating. In addition, as a result of switching the air conditioning device 1 to the cooling operation state, because the high-pressure refrigerant no longer flows into the heat exchangers 11a and 11b serving as the use-side heat exchangers, it is possible to avoid the situation where impacts of the disproportionation reaction spread to the air conditioned space.

[0100] The four-way valves 21 and 22 may each be configured by using a four-way valve or an electromagnetic open/close valve that operates on low differential pressure. In that situation, in the heating operation state, when it is conjectured that a disproportionation reaction may have occurred in the high pressure part of the air conditioning device 1, it is possible to quickly switch the operation to the cooling operation state.

Second Embodiment

[0101] FIG. 5 is a diagram showing a configuration of an air conditioning device 2 according to a second embodiment. The air conditioning device 2 shown in FIG. 5 is an example to which a refrigeration circuit of the present invention is applied.

2-1. Configuration of Air Conditioning Device

[0102] In the air conditioning device 2, the heat exchangers 11a, 11b, and 13, the expansion valves 12a, 12b, and 14, the gas/liquid separator 15, the valve 16, the four-way valves 21 and 22, the pipes 41 to 49, and the relief valve 60 are the same as those in the air conditioning device 1 explained in the first embodiment. These same elements will be referred to by using the same reference characters, and explanations thereof will be omitted.

[0103] The air conditioning device 2 includes a compressor 200. The compressor 200 is a two-stage compressor including a first compressor 100A and a second compressor 100B. Except for not including the injection part 125, the first compressor 100A and the second compressor 100B each have the same configuration as the compressor 100. For example, the first compressor 100A and the second compressor 100B each have the same suction port 104 as that of the compressor 100. The suction port 104 of the first compressor 100A corresponds to an example of a suction part of the entire compressor 200. In the following sections, explanations of the configurations of the first compressor 100A and the second compressor 100B will be omitted.

[0104] The first compressor 100A is connected to the pipe 41, compresses the gas refrigerant supplied through the pipe 41, and discharges the compressed refrigerant into a connection pipe 201. The connection pipe 201 is a pipe connecting a discharge side of the first compressor 100A to a suction side of the second compressor 100B. The second compressor 100B sucks the refrigerant through the connection pipe 201, compresses the refrigerant, and discharges the compressed high-pressure refrigerant into the pipe 42.

[0105] As explained above, the first compressor 100A is the compressor on the first stage and corresponds to an example of a first compression mechanism. The second compressor 100B is the compressor on the second stage and corresponds to an example of a second compression mechanism.

[0106] To the connection pipe 201, the pipe 43 is connected in an injection part 202. Accordingly, while the valve 16 is open, it is possible, in association with the refrigerant flowing out of the gas/liquid separator 15 into the pipe 43, to lower the pressure of the refrigerant in the gas/liquid separator 15 and to allow the refrigerant to expand in the gas/liquid separator 15. Accordingly, similarly to the first embodiment, the gas/liquid separator 15 functions as a type of heat exchanger. Due to this action, in the cooling operation state of the air conditioning device 2, the refrigerant is decompressed at two stages, i.e., by the expansion valve 14 and by the gas/liquid separator 15. In other words, the expansion valve 14 and the gas/liquid separator 15 structure a two-stage expansion mechanism. An area in which the refrigerant has high temperature and high pressure in the cooling operation state is the high pressure part of the air conditioning device 2, which includes one of the compressor 200, the pipes 42 and 46, and the four-way valve 21. As a result of the expansion valve 14 and the gas/liquid separator 15 structuring the two-stage expansion mechanism, it is possible to limit the area HP to a small range. Accordingly, if a disproportionation reaction of the refrigerant has occurred, it is possible to keep small the range in which a chain reaction of the refrigerant may propagate. Further, by structuring the two-stage expansion process, it is possible to lower the temperature of the compression mechanism 120 and to thus inhibit disproportionation reactions more effectively. The injection part 202 corresponds to an example of a refrigerant supply part.

[0107] The four-way valve 21 and the four-way valve 22 are connected to a control device 20. The four-way valve 21 and the four-way valve 22 operate according to control exercised by the control device 20 and switch between the cooling operation state and the heating operation state of the air conditioning device 2.

[0108] The compressor 200 may be a compound compressor that accommodates, in a single container, a first compression mechanism on the first stage and a second compression mechanism on the second stage. In that situation, by using a configuration in which the pipe 43 is connected to a suction side of the second compression mechanism, it is possible to expect the same effects as those achieved by the air conditioning device 2 shown in FIG. 4.

2-2. Refrigerant

[0109] The refrigerant used in the air conditioning device 2 is the working medium described as the refrigerant of the air conditioning device 1 in the first embodiment. In other words, the air conditioning device 2 uses the working medium containing an ethylene-based fluoroolefin as the refrigerant. The working medium may contain two or more refrigerant components. Further, the working medium used as the refrigerant in the air conditioning device 2 may contain a disproportionation inhibitor, in addition to the one or more refrigerant components. The working medium may contain a plurality of disproportionation inhibitors selected from the group consisting of saturated hydrocarbons and haloalkanes. Further, the working medium may contain a single type of saturated hydrocarbons. Alternatively, the working medium may contain two or more types of saturated hydrocarbons. Furthermore, the working medium may contain a single type of haloalkane. Alternatively, the working medium may contain two or more types of haloalkanes.

[0110] Preferable examples of the working medium include a mixture of 1,1,2-trifluoroethylene and n-propane which also contains inevitable impurities. The working medium may contain the abovementioned second refrigerant component and may contain other components.

2-3. Control device

[0111] The air conditioning device 2 includes the control device 20. The control device 20 includes a processor such as a micro controller. By causing the processor to execute a program or by using a function of programmed hardware, the control device 20 controls the air conditioning device 2.

[0112] The control device 20 is connected to the four-way valve 21 and the four-way valve 22. The four-way valve 21 switches the connections of the pipes 41, 42, 44, and 46, under control of the control device 20. The four-way valve 22 switches the connections of the pipes 45, 47, 48, and 49, under control of the control device 20.

[0113] The control device 20 switches between the cooling operation state and the heating operation state, by bringing the four-way valve 21 and the four-way valve 22 into operation. In other words, while the air conditioning device 2 is performing a cooling operation, the control device 20 causes the four-way valve 21 to connect the pipe 41 to the pipe 44 and to connect the pipe 42 to the pipe 46. Also, the control device 20 causes the four-way valve 22 to connect the pipe 48 to the pipe 45 and to connect the pipe 47 to the pipe 49. While the air conditioning device 2 is performing a heating operation, the control device 20 causes the four-way valve 21 to connect the pipe 41 to the pipe 46 and to connect the pipe 42 to the pipe 44. Also, the control device 20 causes the four-way valve 22 to connect the pipe 49 to the pipe 45 and to connect the pipe 47 to the pipe 48.

[0114] To the control device 20, the expansion valves 12a and 12b, the expansion valve 14, and the valve 16 are connected. In the cooling operation state, the control device 20 brings the expansion valve 14 into the fully-open state and adjusts opening degrees of the expansion valves 12a and 12b. In the heating operation state, the control device 20 brings the expansion valves 12a and 12b into the fully-open state and adjusts opening degrees of the expansion valve 14.

[0115] The air conditioning device 2 may include at least one selected from between: a temperature sensor (not shown) that detects temperatures of an electric motor included in the first compressor 100A and/or an electric motor included in the second compressor 100B; and a temperature sensor (not shown) that detects the temperature of the refrigerant discharged by the second compressor 100B. These temperature sensors are connected to the control device 20. The control device 20 detects one or both of the temperatures of the one or more electric motors and the temperature of the refrigerant discharged by the second compressor 100B, by obtaining detection values from the one or more temperature sensors. Further, the control device 20 may calculate pressure of the refrigerant discharged by the second compressor 100B, on the basis of the temperature of the refrigerant discharged by the second compressor 100B.

[0116] Further, the air conditioning device 2 may include a pressure sensor that detects the pressure of the refrigerant discharged by the second compressor 100B. In addition, the air conditioning device 2 may include a heat exchanger temperature sensor (not shown) that detects temperatures of the heat exchangers 11a and 11b and the heat exchanger 13. In that situation, on the basis of detection values of the heat exchanger temperature sensor, the control device 20 may calculate the pressure or temperature of the refrigerant discharged by the second compressor 100B; however, the abovementioned temperature sensors do not necessarily need to be provided.

[0117] The control device 20 exercises control so as to open and close the valve 16. The valve 16 is configured by using an electric valve, an electromagnetic valve, or an expansion valve. When the valve 16 is an electric valve or an expansion valve, the control device 20 controls the opening and the closing of the valve 16 and adjusts opening degrees of the valve 16.

2-4. Control Exercised by Control Device

[0118] Under control of the control device 20, the air conditioning device 2 inhibits disproportionation reactions of the refrigerant. For example, as explained above, the control device 20 exercises control so as to open the valve 16, when the temperature of the electric motor or the temperature of the refrigerant discharged by the second compressor 100B exceeds a threshold value. Further, by bringing the four-way valves 21 and 22 and other valves into operation, the control device 20 inhibits disproportionation reactions.

[0119] For example, the control device 20 performs the operation explained with reference to FIG. 4. When the refrigerant pressure in the high pressure part of the air conditioning device 2 has increased to the threshold value or higher, the control device 20 exercises control so as to switch the air conditioning device 2 from the heating operation state to the cooling operation state. In this situation, the high pressure part of the air conditioning device 2 may be, for example, the second compressor 100B, the pipe 42, and/or the like.

[0120] Further, while the air conditioning device 2 is performing a cooling operation and when the air conditioning device 2 has been switched from the heating operation state to the cooling operation state, the control device 20 exercises control so as to close at least one valve under the control to the first opening degree. Further, when the pressure increase in the high pressure part has stopped, the control device 20 exercises control so as to close the valve which were closed to the first opening degree, into the fully-closed state. Subsequently, the control device 20 performs a notification process. While exercising the control in these manners, the control device 20 may stop the compressor 200.

2-5. Advantageous Effects, Etc.

[0121] As explained above, similarly to the air conditioning device 1 described in the first embodiment, the air conditioning device 2 according to the second embodiment is able, upon the occurrence of a disproportionation reaction of the refrigerant, to suppress impacts of the disproportionation reaction in the refrigeration cycle.

[0122] In other words, the air conditioning device 2 includes the compressor 200, the heat exchanger 13 serving as the heat source-side heat exchanger, the heat exchangers 11a and 11b serving as the use-side heat exchangers, and the expansion mechanism. The air conditioning device 2 includes: the four-way valves 21 and 22 that switch between the heating operation state in which the heat exchangers 11a and 11b are caused to operate as a condenser and the cooling operation state in which the heat exchanger 13 is caused to operate as a condenser; and the control device 20. The air conditioning device 2 uses the working medium containing the ethylene-based fluoroolefin as the refrigerant. Upon detecting, in the heating operation state, that the pressure of the working medium in the high pressure part including the compressor 200 and the condenser has increased to the threshold value or higher, the control device 20 controls the four-way valves 21 and 22 so as to switch the operation from the heating operation state to the cooling operation state.

[0123] With the above configuration, the air conditioning device 2 realizes a low GWP, by using the working medium containing the ethylene-based fluoroolefin. Further, when there is a possibility that a disproportionation reaction may have occurred in the refrigerant or when it is conjectured that a disproportionation reaction may have occurred, the air conditioning device 2 keeps small the area HP where the high-pressure refrigerant flows, by switching the air conditioning device 2 from the heating operation state to the cooling operation state. As a result, it is possible to limit the area where the pressure of the refrigerant may drastically increase due to the disproportionation reaction and to thus suppress impacts of the disproportionation reaction.

[0124] The expansion mechanism of the air conditioning device 2 includes the expansion valve 14 or the expansion valves 12a and 12b positioned at the exit of the condenser. The control device 20 controls the expansion valves 12a, 12b, and 14. Upon detecting that the pressure of the working medium in the high pressure part of the air conditioning device 2 has increased to the threshold value or higher, the control device 20 causes one of the expansion valves 12a, 12b, and 14 to operate in the closing direction to the first opening degree, and subsequently, when the pressure increase of the working medium in the high pressure part has stopped, causes the expansion valve to operate in the closing direction to the second opening degree. The second opening degree may correspond to the fully-closed state, for example. The high pressure part includes the compressor 200 and the condenser, for example.

[0125] With the above configuration, when there is a possibility that a disproportionation reaction may have occurred in the refrigerant or when it is conjectured that a disproportionation reaction may have occurred, it is possible to inhibit the pressure increase associated with the disproportionation reaction. Further, by closing the valve to the second opening degree after the pressure increase in the high pressure part has stopped, it is possible to inhibit the disproportionation reaction from propagating with higher certainty.

[0126] In the air conditioning device 2, the pipe 42 through which the compressor 200 discharges the compressed refrigerant is provided with the relief valve 60 that releases pressure when the pressure of the pipe 42 is equal to or higher than the set pressure value. With the above configuration, when the pressure of the pipe 42 has drastically increased in association with the occurrence of a disproportionation reaction, it is possible to release the pressure of the pipe 42 and to thus reduce impacts of the disproportionation reaction.

[0127] Further, in the air conditioning device 2, the compressor 200 is the two-stage compressor including the suction port 104 through which the working medium is sucked, the first compressor 100A that compresses the working medium sucked through the suction port 104, the second compressor 100B that compresses the working medium compressed by the first compressor 100A. The air conditioning device 2 includes the injection part 202 that supplies the working medium to a position between the first compressor 100A and the second compressor 100B.

[0128] With the above configuration, the air conditioning device 2 is able to realize a low GWP by using the working medium containing the ethylene-based fluoroolefin. Further, by employing the injection part 202 to supply the refrigerant to the connection pipe 201 provided between the first compressor 100A and the second compressor 100B, it is possible to lower the temperature of the refrigerant discharged by the compressor 200 and to thereby realize a configuration in which disproportionation reactions of the ethylene-based fluoroolefin do not easily occur. Consequently, it is possible to inhibit disproportionation reactions which might be caused when a refrigerant having a low GWP is used.

[0129] Further, by employing the two-stage compressor 200, the air conditioning device 2 is able to keep compression ratios small in the first compressor 100A and in the second compressor 100B. As a result, it is possible to reduce compression losses and to reduce loads on the electric motors in the compressor 200. It is therefore expected to be possible to inhibit temperatures of the electric motors from rising.

[0130] Further, upon detecting, in the heating operation state of the air conditioning device 2, that the pressure of the working medium in the high pressure part has increased to the threshold value or higher, the control device 20 controls the four-way valves 21 and 22 so as to switch the operation from the heating operation state to the cooling operation state. As a result, when it is conjectured that a disproportionation reaction may have occurred in the high pressure part in the heating operation state, it is possible to limit the area where the high-pressure refrigerant flows, by switching the operation to the cooling operation state. With this configuration, it is possible to inhibit the disproportionation reaction from propagating. Further, in the cooling operation state, because the high-pressure refrigerant no longer flows into the heat exchangers 11a and 11b serving as the use-side heat exchangers, it is possible to avoid the situation where impacts of the disproportionation reaction spread to the air conditioned space.

[0131] Further, the air conditioning device 2 includes the pipe 43 through which the working medium flows from the gas/liquid separator 15 to the injection part 202. The air conditioning device 2 includes the valve 16 that opens and closes the pipe 43 and the control device 20 that controls the valve 16. The control device 20 exercises the control so as to open the valve 16 when the temperature of the compressor 200 satisfies the condition set in advance.

[0132] With the above configuration, when the temperature of the compressor 200 satisfies the condition set in advance, it is possible to lower the pressure of the refrigerant in the gas/liquid separator 15 and to allow the refrigerant to expand in the gas/liquid separator 15, by extracting the refrigerant from the gas/liquid separator 15 via the pipe 43. Accordingly, it is possible to cause the gas/liquid separator 15 to function as an intermediate cooler and to thus structure the two-stage expansion process with the expansion valve 14 and the gas/liquid separator 15. Consequently, when the situation arises where a disproportionation reaction may easily occur in the compressor 200, it is possible to resolve the situation. Further, when it is conjectured that a disproportionation reaction may have occurred in the compressor 200, it is possible to inhibit or stop the disproportionation reaction.

Third Embodiment

[0133] FIG. 6 is a diagram showing a configuration of an air conditioning device 1A according to a third embodiment. The air conditioning device 1A shown in FIG. 6 is an example to which a refrigeration circuit of the present invention is applied.

[0134] The air conditioning device 1A has a configuration obtained by providing the air conditioning device 1 explained with reference to FIGS. 1 to 4 with a pipe 55 and a valve 56. Because the configurations of the elements other than the pipe 55 and the valve 56 are the same as those explained in the first embodiment, the same elements will be referred to by using the same reference characters, and explanations thereof will be omitted.

[0135] The pipe 55 is a refrigerant pipe connecting the pipe 48 to the pipe 41. The pipe 55 is provided with the valve 56. The valve 56 is configured by using an electromagnetic valve, for example, and opens and closes according to control of the control device 10. The valve 56 may be configured by using an electromagnetic valve. In that situation, in addition to the opening and the closing of the valve 56, the control device 10 is also capable of adjusting opening degrees of the valve 56. The pipe 55 corresponds to an example of an electric motor cooling circuit, whereas the valve 56 corresponds to an example of an electric motor cooling valve.

[0136] While the valve 56 is in an open sate, the refrigerant flows from the pipe 48 to the pipe 41 through the pipe 55. The refrigerant flowing through the pipe 55 is liquid refrigerant flowing from the gas/liquid separator 15 into the pipe 48. The refrigerant reaches the suction port 104 through the pipe 41 and is supplied to the inside of the container 102.

[0137] Accordingly, when the valve 56 is opened, the liquid refrigerant is supplied to the electric motor 110 through the suction port 104. In the process of being sucked into the compression mechanism 120 through the suction port 104, the refrigerant cools the electric motor 110. The pipe 55 may directly be connected to the container 102 accommodating the electric motor 110. In that situation also, by causing the liquid refrigerant to be supplied to the container 102 through the pipe 55, it is possible to lower the temperature of the electric motor 110. In particular, as shown in FIG. 2, in the configuration in which the refrigerant sucked through the suction port 104 passes through the air gap formed between the stator 111 and the rotor 112, it is possible to cool the electric motor 110 more effectively.

[0138] In the air conditioning device 1A, the control device 10 exercises the abovementioned control to open and close the valve 16 as well as the control shown in FIG. 4.

[0139] Further, when the temperature of the compressor 100 satisfies a condition set in advance, the control device 10 exercises control so as to open the valve 56. The condition set in advance may be, for example, a threshold value for the temperature of the compressor 100. More specifically, the condition may be either the temperature of the compressor 100 or the temperature of the refrigerant discharged by the compression mechanism 120. When either the temperature of the electric motor 110 or the temperature of the refrigerant discharged by the compression mechanism 120 exceeds the threshold value, the control device 10 opens the valve 56. The control device 10 is able to lower the temperature of the electric motor 110 by opening the valve 56 so that the liquid refrigerant is supplied to the electric motor 110. As a result, it is possible to inhibit disproportionation reactions by cooling the electric motor 110.

[0140] As explained above, the air conditioning device 1A according to the third embodiment includes: the pipe 55 through which the liquid working medium flows into the container 102 of the compressor 100 through the pipe 41; the valve 56 that opens and closes the pipe 55, and the control device 10 that controls the valve 56. When the temperature of the compressor 100 satisfies the condition set in advance, the control device 10 exercises the control to open the valve 56.

[0141] With the above configuration, it is possible to cool the electric motor 110 with the liquid refrigerant. For example, when the situation arises where the electric motor 110 has a high temperature and a disproportionation reaction may easily occur in the refrigerant or when the situation arises where occurrence of a disproportionation reaction in the refrigerant is conjectured, it is possible to cool the electric motor 110. Consequently, it is possible to inhibit or stop the disproportionation reaction of the refrigerant.

Fourth Embodiment

[0142] FIG. 7 is a diagram showing a configuration of an air conditioning device 2A according to a fourth embodiment. The air conditioning device 2A shown in FIG. 7 is an example to which a refrigeration circuit of the present invention is applied.

[0143] The air conditioning device 2A has a configuration obtained by providing the air conditioning device 2 explained with reference to FIG. 5 with a pipe 57, a valve 58, and a valve 59. Because the configurations of the elements other than the pipe 57, the valve 58, and the valve 59 are the same as those explained in the second embodiment, the same elements will be referred to by using the same reference characters, and explanations thereof will be omitted.

[0144] One end of the pipe 57 is connected to the pipe 48 so that the liquid refrigerant flows from the gas/liquid separator 15 into the pipe 57. The pipe 57 branches into two passages at a branch part 205. The pipe 57 is connected to a connection pipe 201 at a connection part 203 and is connected to the pipe 41 at a connection part 204. The valve 58 is provided between the branch part 205 and the connection part 203. The valve 59 is provided between the branch part 205 and the connection part 204.

[0145] The valve 58 and the valve 59 may each be configured by using an electromagnetic valve, for example, and open and close according to control of the control device 20. The valves 58 and 59 may each be configured by using an electromagnetic valve. In that situation, in addition to the opening and the closing of the valves 58 and 59, the control device 20 is also capable of adjusting opening degrees of each of the valves 58 and 59. The pipe 57 corresponds to an example of an electric motor cooling circuit, whereas the valves 58 and 59 correspond to examples of electric motor cooling valves.

[0146] While the valve 58 is in an open state, the liquid refrigerant stored in the gas/liquid separator 15 flows into the connection pipe 201 through the pipe 57. The refrigerant cools the second compressor 100B by being sucked into the second compressor 100B and evaporated inside of the second compressor 100B.

[0147] While the valve 59 is in an open state, the liquid refrigerant stored in the gas/liquid separator 15 flows into the pipe 41 through the pipe 57. The refrigerant cools the first compressor 100A by being sucked into the first compressor 100A and evaporated inside of the first compressor 100A.

[0148] In the air conditioning device 2A, the control device 20 exercises the abovementioned control to open and close the valve 16 as well as the control shown in FIG. 4, as explained in the second embodiment.

[0149] Further, when the temperature of the compressor 200 satisfies a condition set in advance, the control device 20 exercises control so as to open the valves 58 and 59. The condition set in advance may be, for example, a threshold value for the temperature of the compressor 200. More specifically, the condition may be the temperature of the electric motor included in the first compressor 100A and/or the electric motor included in the second compressor 100B or the temperature of the refrigerant discharged by the first compressor 100A and/or by the second compressor 100B. When either the temperature of the electric motor in the second compressor 100B or the temperature of the refrigerant discharged by the second compressor 100B exceeds the threshold value, for example, the control device 20 opens the valve 58. The control device 20 is able to lower the temperature of the electric motor in the second compressor 100B and the refrigerant discharged by the second compressor 100B, by opening the valve 58 so that the liquid refrigerant is sucked into the second compressor 100B. Further, for example, the control device 20 opens the valve 59 when the temperature of the electric motor in the first compressor 100A or the temperature of the refrigerant discharged by the first compressor 100A has exceeded the threshold value. The control device 20 is able to lower the temperature of the electric motor in the first compressor 100A and the refrigerant discharged by the first compressor 100A, by opening the valve 59 so that the liquid refrigerant is sucked into the first compressor 100A. Consequently, it is possible to inhibit or prevent disproportionation reactions by cooling the compressor 200.

[0150] As explained above, the air conditioning device 2A according to the fourth embodiment includes the pipe 57 through which the liquid working medium flows into the compressor 200 via the pipe 43, the valves 58 and 59 that open and close the pipe 57, and the control device 20 that controls the valves 58 and 59. When the temperature of the compressor 200 satisfies the condition set in advance, the control device 20 exercises the control so as to open the valves 58 and 59.

[0151] With the above configuration, it is possible to cool the compressor 200, by causing the refrigerant to flow into the compressor 200 via the pipe 43. For example, when the situation arises where the electric motor included in the first compressor 100A or the second compressor 100B has a high temperature and a disproportionation reaction may easily occur in the refrigerant or when the situation arises where occurrence of a disproportionation reaction in the refrigerant is conjectured, it is possible to cool the electric motor. Consequently, it is possible to inhibit or stop the disproportionation reaction of the refrigerant.

Fifth Embodiment

[0152] FIG. 8 is a diagram showing a configuration of an air conditioning device 3 according to a fifth embodiment. The air conditioning device 3 shown in FIG. 8 is an example to which a refrigeration circuit of the present invention is applied.

[0153] The air conditioning device 3 has elements that are the same as a part of the air conditioning device 1 explained with reference to FIGS. 1 to 4. The same elements will be referred to by using the same reference characters as those in the first embodiment, and explanations thereof will be omitted.

[0154] The present disclosure is applicable not only to the air conditioning devices 1, 1A, 2, and 2A of the first to the fourth embodiments described above, but also to refrigeration devices capable of operating while switching between a cooling operation and a heating operation. The air conditioning device 3 corresponds to an example of such a type of refrigeration device.

[0155] The air conditioning device 3 includes the heat exchangers 11a and 11b serving as the use-side heat exchangers, the expansion valves 12a and 12b provided for pipes connected to the heat exchangers 11a and 11b, the heat exchanger 13 serving as the heat source-side heat exchanger, and the expansion valve 14 provided for the pipe 47 connected to the heat exchanger 13. Further, the air conditioning device 3 includes the compressor 100 and the four-way valve 21 that switches between the heat exchangers 11a, 11b, and the heat exchanger 13 so as to be connected to the pipe 42 on a discharge side of the compressor 100.

[0156] The air conditioning device 3 includes a control device 10A that controls the four-way valve 21. Similarly to the control device 10, the control device 10A includes a processor such as a microcontroller or the like. By causing the processor to execute a program or by using a function of programmed hardware, the control device 10A controls the air conditioning device 3. The control device 10A controls the four-way valve 21 so as to switch between the cooling operation state and the heating operation state.

[0157] In other words, by using the four-way valve 21, the control device 10A connects the pipe 42 through which the compressor 100 discharges the high-pressure refrigerant, to the pipe 46 connected to the heat exchanger 13 and also connects the pipe 44 connected to the heat exchangers 11a and 11b to the pipe 41 provided on a suction side of the compressor 100. With this configuration, the air conditioning device 3 performs the cooling operation. In the cooling operation state, the high-pressure refrigerant discharged by the compressor 100 is condensed by the heat exchanger 13 and delivered to the heat exchangers 11a and 11b via the expansion valves 12a and 12b. The refrigerant is decompressed by the expansion valves 12a and 12b, evaporated by the heat exchangers 11a and 11b, and sucked into the compressor 100 via the pipe 41. FIG. 8 shows the cooling operation state of the air conditioning device 3. In the cooling operation state, the high pressure part HP includes, for example, the compressor 100, the pipe 42 through which the high-pressure refrigerant flows, the four-way valve 21, and the heat exchanger 13.

[0158] When the air conditioning device 3 performs a heating operation under control of the control device 10A, the high-pressure refrigerant discharged by the compressor 100 is condensed by the heat exchangers 11a and 11b and delivered to the heat exchanger 13 via the expansion valve 14. The refrigerant is decompressed by the expansion valve 14, evaporated by the heat exchanger 13, and sucked into the compressor 100 through the pipe 41. In the heating operation state of the air conditioning device 3, the area HP includes, although not shown, the compressor 100, the pipe 42, the four-way valve 21, and the heat exchangers 11a and 11b.

[0159] As explained above, the air conditioning device 3 is a refrigeration device capable of, by using the four-way valve 21, switching between the cooling operation in which the heat exchanger 13 is caused to operate as a condenser and the heating operation in which the heat exchangers 11a and 11b are caused to operate as a condenser while the heat exchanger 13 is caused to operate as an evaporator, under the control of the control device 10A.

[0160] The air conditioning device 3 may include at least one selected from between: a temperature sensor (not shown) that detects the temperature of the electric motor 110; and a temperature sensor (not shown) that detects the temperature of the refrigerant discharged by the compression mechanism 120. These temperature sensors are connected to the control device 10A. By obtaining detection values from the one or more temperature sensors, the control device 10A detects one or both of the temperature of the electric motor 110 and the temperature of the refrigerant discharged by the compression mechanism 120. Further, on the basis of the temperature of the refrigerant discharged by the compression mechanism 120, the control device 10A may calculate the pressure of the refrigerant discharged by the compression mechanism 120. The air conditioning device 3 may include a pressure sensor that detects the pressure of the refrigerant discharged by the compression mechanism 120. In addition, the air conditioning device 3 may include a heat exchanger temperature sensor (not shown) that detects the temperatures of the heat exchangers 11a and 11b and the heat exchanger 13. In that situation, on the basis of detection values of the heat exchanger temperature sensor, the control device 10A may calculate the pressure or the temperature of the refrigerant discharged by the compression mechanism 120; however, the temperature sensors do not necessarily need to be provided.

[0161] Similarly to the control device 10, the control device 10A exercises the control shown in FIG. 4. In other words, upon detecting that the pressure of the refrigerant in the high pressure part HP has increased to the threshold value or higher during a heating operation of the air conditioning device 3, the control device 10A switches the air conditioning device 3 into a cooling operation.

[0162] As explained above, the air conditioning device 3 includes the compressor 100, the heat exchanger 13 serving as the heat source-side heat exchanger, the heat exchangers 11a and 11b serving as the use-side heat exchangers, and the expansion mechanism. The air conditioning device 3 includes: the four-way valve 21 that switch between the heating operation state in which the heat exchangers 11a and 11b are caused to operate as a condenser and the cooling operation state in which the heat exchanger 13 is caused to operate as a condenser; and the control device 10A. As the refrigerant, the air conditioning device 3 uses the working medium containing the ethylene-based fluoroolefin. Upon detecting, in the heating operation state, that the pressure of the working medium in the high pressure part including the compressor 100 and the condenser has increased to the threshold value or higher, the control device 10A controls the four-way valve 21 so as to switch the operation from the heating operation state to the cooling operation state.

[0163] With the above configuration, the air conditioning device 3 is able to realize a low GWP by using the working medium containing the ethylene-based fluoroolefin. Further, when there is a possibility that a disproportionation reaction may have occurred in the refrigerant or when it is conjectured that a disproportionation reaction may have occurred, the air conditioning device 3 keeps small the area HP where the high-pressure refrigerant flows, by switching the air conditioning device 3 from the heating operation state to the cooling operation state. With this configuration, it is possible to limit the area HP in which the pressure of the refrigerant may drastically increase due to the disproportionation reaction. It is therefore possible to suppress impacts of the disproportionation reaction in the refrigeration cycle. For example, when the heat exchangers 11a and 11b are installed in the air conditioned space of the air conditioning device 3 or in the vicinity thereof, the control exercised by the control device 10A is able to prevent or inhibit the impacts of the disproportionation reaction from spreading to the air conditioned space.

[0164] The expansion mechanism includes the expansion valve 14 or the expansion valves 12a and 12b positioned at the exit of the condenser. The air conditioning device 3 includes the control device 10A that controls the expansion valves 12a, 12b, and 14. Upon detecting that the pressure of the working medium in the high pressure part of the air conditioning device 3 has increased to the threshold value or higher, the control device 10A causes one of the expansion valves 12a, 12b, and 14 to operate in the closing direction to the first opening degree, and subsequently, when the pressure increase of the working medium in the high pressure part has stopped, causes the expansion valve to operate in the closing direction to the second opening degree. The second opening degree corresponds to the fully-closed state, for example. The high pressure part includes the compressor 100 and the condenser, for example.

[0165] With the above configuration, when there is a possibility that a disproportionation reaction may have occurred in the refrigerant or when it is conjectured that a disproportionation reaction may have occurred, it is possible to inhibit the pressure increase associated with the disproportionation reaction. Further, by closing the valve to the second opening degree after the pressure increase in the high pressure part has stopped, it is possible to inhibit the disproportionation reaction from propagating with higher certainty.

[0166] Similarly to the air conditioning device 1, in the air conditioning device 3 also, it is acceptable to provide the pipe 42 through which the compressor 100 discharges the compressed refrigerant, with the relief valve 60 that releases pressure when the pressure of the pipe 42 is equal to or higher than a set pressure value. In that situation, when the pressure of the pipe 42 has drastically increased in association with the occurrence of a disproportionation reaction, it is possible to release the pressure of the pipe 42 and to thereby reduce impacts of the disproportionation reaction.

OTHER EMBODIMENTS

[0167] A number of embodiments have thus been explained as examples disclosed in the present application. However, possible techniques of the present disclosure are not limited to those examples and may be applied to other embodiments arrived at by applying changes, substitutions, addition, omission, or the like. Further, it is also possible to arrive at a new embodiment by combining together any of the constituent elements described in the above embodiments.

[0168] Thus, other embodiments will be explained below as examples.

[0169] In the above embodiments, the configuration was explained as an example in which the relief valve 60 which may be called an overflow valve is used as the pressure releasing means provided for the pipe 42; however, this is merely an example. The pressure releasing means may be a rupture disc that is ruptured to release pressure, when the pressure of the pipe 42 is equal to or higher than the set pressure value,.

[0170] The compressor 100, the first compressor 100A, and the second compressor 100B in the above embodiments do not each necessarily need to be a scroll compressor and may each be a rotary compressor or a reciprocating compressor.

[0171] Configurations of the various types of sensors provided for the air conditioning devices 1, 1A, 2, and 2A are arbitrary. For example, the air conditioning device 1 may include a temperature sensor that detects the temperatures of the heat exchangers 11a, 11b, and 13. The same applies to the air conditioning devices 1A, 2, and 2A. Further, the air conditioning devices 1 and 1A may each include a refrigerant temperature sensor that detects the temperature of the refrigerant discharged by the compressor 100. Furthermore, the air conditioning devices 2 and 2A may each include a refrigerant temperature sensor that detects the temperature of the refrigerant discharged by the compressor 200. These sensors may be connected to the control devices 10 and 20, as appropriate. It is satisfactory as long as the control devices 10 and 20 are able to obtain detection values of the sensors.

Configurations Supported by the Above Embodiments

[0172] The above embodiments support the following configurations:

Supplements

[0173] (Feature 1): A refrigeration device including: a compressor, a heat source-side heat exchanger, a use-side heat exchanger, an expansion mechanism, a switching valve that switches between a heating operation state in which the use-side heat exchanger is caused to operate as a condenser and a cooling operation state in which the heat source-side heat exchanger is caused to operate as a condenser, and a control device. A working medium containing an ethylene-based fluoroolefin is used as a refrigerant. Upon detecting, in the heating operation state, that pressure of the working medium in a high pressure part including the compressor and the condenser has increased to a threshold value or higher, the control device controls the switching valve so as to switch operation from the heating operation state to the cooling operation state.

[0174] (Feature 2): The refrigeration device presented as Feature 1 in which the expansion mechanism includes an expansion valve positioned at an exit of the condenser; and upon detecting that the pressure of the working medium in the high pressure part including the compressor and the condenser has increased to the threshold value or higher, the control device causes the expansion valve to operate in a closing direction to a first opening degree, and subsequently, when the pressure increase of the working medium in the high pressure part has stopped, causes the expansion valve to operate in the closing direction to a second opening degree.

[0175] (Feature 3): The refrigeration device presented as Feature 1 or Feature 2 in which a discharge pipe through which the compressor discharges compressed refrigerant is provided with pressure releasing means for releasing pressure when pressure of the discharge pipe is equal to or higher than a set pressure value.

INDUSTRIAL APPLICABILITY

[0176] As explained above, the refrigeration device according to the present invention is applicable to air conditioning devices that cool and heat an air conditioned space, cold storage devices including refrigerators and/or freezers having a function of switching between cooling and heating, refrigeration systems combining any of these, and other purposes.

REFERENCE SIGNS LIST

[0177] 1, 1A, 2, 2A, 3 air conditioning device (refrigeration device) [0178] 10, 10A, 20 control device [0179] 11a, 11b heat exchanger (use-side heat exchanger) [0180] 12a, 12b expansion valve [0181] 13 heat exchanger (heat source-side heat exchanger) [0182] 14 expansion valve [0183] 15 gas/liquid separator (refrigerant storage part) [0184] 16 valve [0185] 20 control device [0186] 21, 22 four-way valve (switching valve) [0187] 41 pipe (suction pipe) [0188] 42 pipe (discharge pipe) [0189] 43 pipe (refrigerant pipe) [0190] 44, 45, 46, 47, 48, 49 pipe [0191] 55, 57 pipe (electric motor cooling circuit) [0192] 56, 58, 59 valve (electric motor cooling valve) [0193] 60 relief valve (pressure releasing means) [0194] 100, 200 compressor [0195] 102 container [0196] 103 crankshaft [0197] 104 suction port (suction part) [0198] 105 discharge tube [0199] 107, 108 bearing [0200] 110 electric motor [0201] 111 stator [0202] 112 rotor [0203] 116 driving circuit [0204] 120 compression mechanism [0205] 125 injection part (refrigerant supply part) [0206] 100A first compressor (first compression mechanism) [0207] 100B second compressor (second compression mechanism) [0208] 201 connection pipe [0209] 202 injection part (refrigerant supply part) [0210] 203 connection part [0211] 204 connection part [0212] 205 branch part