Refrigeration device

Abstract

The present invention can suppress the influence of a disproportionation reaction in a refrigeration cycle when the disproportionation reaction of a refrigerant has occurred. The refrigeration device comprises a compressor, a heat source side heat exchanger, a utilization side heat exchanger, an expansion mechanism, a switching valve and a control device. And a switching valve capable of switching between a heating operation state in which the utilization-side heat exchanger is operated as a condenser and a cooling operation state in which the heat-source-side heat exchanger is operated as a condenser, the switching valve using a working medium containing an ethylene-based fluoroolefin as a refrigerant. The control device controls the switching valve to switch from the heating operation state to the cooling operation state when the control device detects that the pressure of the working medium of the high-pressure part including the compressor and the condenser has increased to a threshold value or more in the heating operation state.

Description

Technical Field

[0001] The invention relates to a refrigeration device. Background Art

[0002] Patent Document 1 discloses a refrigerator using low GWP (Global Warming Potential). The refrigerator of Patent Document 1 uses a refrigerant containing trans-1,2-difluoroethylene (HFO-1132(E)), 2,3,3,3-tetrafluoro-1-propylene (R1234yf), trifluoroethylene (HFO-1123), and the like.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-59619 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The present invention provides a refrigeration device capable of suppressing the influence of the disproportionation reaction in a refrigeration cycle when the disproportionation reaction of a refrigerant occurs.

[0008] Technical solutions for solving technical problems

[0009] This specification incorporates the entire contents of Japanese Patent Application No. 2022-074973 filed on April 28, 2022.

[0010] The refrigeration device of the present invention includes: a compressor, a heat source side heat exchanger, a utilization side heat exchanger, an expansion mechanism, a switching valve and a control device. The switching valve can switch between a heating operation state in which the utilization side heat exchanger works as a condenser and a cooling operation state in which the heat source side heat exchanger works as a condenser. The refrigeration device uses a working medium containing ethylene-based fluoroolefin as a refrigerant. When the control device detects that the pressure of the working medium in the high-pressure part including the compressor and the condenser has risen above a threshold value in the heating operation state, the switching valve is controlled to switch from the heating operation state to the cooling operation state.

[0011] Effects of the Invention

[0012] The refrigeration apparatus of the present invention uses a working medium containing ethylene fluoroolefin as a refrigerant, thereby achieving low GWP and suppressing the influence of a disproportionation reaction of the refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a diagram showing the configuration of an air conditioning apparatus (air conditioning device) according to Embodiment 1 of the present invention.

[0014] Figure 2 It is a diagram showing the structure of a compressor.

[0015] Figure 3 It is a diagram showing the configuration of an air conditioning apparatus according to Embodiment 1 of the present invention.

[0016] Figure 4 This is a flowchart showing the operation of the air conditioning apparatus according to Embodiment 1.

[0017] Figure 5 It is a diagram showing the configuration of an air-conditioning apparatus according to Embodiment 2 of the present invention.

[0018] Figure 6 It is a diagram showing the configuration of an air-conditioning apparatus according to Embodiment 3 of the present invention.

[0019] Figure 7 It is a diagram showing the configuration of an air-conditioning apparatus according to Embodiment 4 of the present invention.

[0020] Figure 8 It is a diagram showing the configuration of an air-conditioning apparatus according to Embodiment 5 of the present invention. DETAILED DESCRIPTION

[0021] (Foundation, etc. that forms the basis of the present invention)

[0022] When the inventors came up with the present invention, they proposed using refrigerants with reduced global warming potential (GWP) in refrigeration devices. For example, fluoroolefins having carbon-carbon unsaturated bonds in the molecules have the advantages of high cooling capacity and low GWP. However, refrigerants with low GWP are easily decomposed, so under certain conditions, they may cause a self-decomposition reaction called disproportionation. If the refrigerant is disproportionated, the pressure in the refrigerant circuit rises sharply, which may cause damage to the equipment. Therefore, the inventors discovered the technical problem that when such a disproportionation reaction occurs in the refrigeration cycle, its influence needs to be suppressed, and in order to solve this technical problem, the subject matter of the present invention was completed.

[0023] Therefore, the present invention provides a refrigeration apparatus capable of suppressing the influence of the disproportionation reaction in the refrigeration cycle when the disproportionation reaction of the refrigerant occurs.

[0024] Hereinafter, the embodiments are described in detail with reference to the accompanying drawings. However, unnecessary detailed descriptions are sometimes omitted. For example, detailed descriptions of already known matters or repeated descriptions of substantially the same structures are sometimes omitted. This is to avoid the following description being too lengthy and to make it easy for those skilled in the art to understand.

[0025] In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present invention, and are not intended to limit the subject matter described in the claims.

[0026] (Implementation Method 1)

[0027] Below, use Figure 1 to Figure 4 Implementation method 1 will be described.

[0028] [1-1. Structure of air conditioning device]

[0029] Figure 1 and Figure 3 1 is a diagram showing the structure of an air conditioning device 1 according to Embodiment 1. Figure 2 1 is a diagram showing a configuration of a compressor 100 included in the air-conditioning apparatus 1 .

[0030] Figure 1 and Figure 3 The air-conditioning apparatus 1 shown is an example of a refrigeration circuit to which the present invention is applied. Figure 1 Indicates the cooling operation state of the air conditioner 1. Figure 3 Indicates the heating operation state of the air-conditioning device 1.

[0031] The air conditioner 1 includes a compressor 100, heat exchangers 11a, 11b, expansion valves 12a, 12b, a heat exchanger 13, an expansion valve 14, a gas-liquid separator 15, a valve 16, four-way valves 21, 22, and refrigerant pipes connecting them. In addition, the air conditioner 1 includes a control device 10 that controls the expansion valves 12a, 12b, the expansion valve 14, the valve 16, and the four-way valves 21, 22. The four-way valves 21, 22 correspond to an example of a switching valve.

[0032] As reference Figure 2 As described later, the compressor 100 includes a suction port 104 , a discharge pipe 105 , and an injection portion 125 . The compressor 100 sucks in refrigerant from the suction port 104 , compresses the refrigerant, and discharges the high-pressure refrigerant from the discharge pipe 105 .

[0033] Heat exchangers 11a and 11b are provided in the indoor unit and are utilization-side heat exchangers for cooling and heating the air-conditioned space. Heat exchangers 11a and 11b are connected in parallel. Heat exchanger 13 is a heat source-side heat exchanger provided in the outdoor unit. Fans are provided in heat exchangers 11a, 11b, and 13, respectively.

[0034] The four-way valve 21 is connected to a pipe 41 connected to the suction port 104 of the compressor 100, a pipe 42 connected to the discharge pipe 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 connection of the pipes 41, 42, 44, and 46 under the control of the control device 10.

[0035] The four-way valve 22 is connected to a pipe 45 connected to the heat exchangers 11a and 11b, a pipe 47 connected to the heat exchanger 13, and pipes 48 and 49 connected to the gas-liquid separator 15. The pipe 49 is a pipe for allowing the refrigerant to flow into the gas-liquid separator 15, and the pipe 48 is a pipe for the refrigerant to flow out of the gas-liquid separator 15. The gas-liquid separator 15 is a container that stores the refrigerant flowing in from the pipe 48 and can separate and take out the liquid refrigerant and the gas refrigerant. The gas-liquid separator 15 corresponds to an example of a refrigerant storage unit. The four-way valve 22 switches the connection of the pipes 45, 47, 48, and 49 under the control of the control device 10.

[0036] exist Figure 1 In FIG. 1 , the arrows with reference symbol RC indicate the flow of the refrigerant in the cooling operation state. Figure 2 In FIG. 1 , the flow of the refrigerant in the heating operation state is indicated by arrows denoted by reference symbol RH.

[0037] In addition, Figure 1 to Figure 3 and the following Figure 5 to Figure 7 In FIG. 1 , the arrows with reference symbol R indicate the flow of the refrigerant common to the cooling operation state and the heating operation state.

[0038] exist Figure 1 In the cooling operation state shown, 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.

[0039] In the cooling operation state of the air conditioner 1, the refrigerant discharged from the compressor 100 to the discharge pipe 105 flows into the heat exchanger 13 via the pipe 42 and the four-way valve 21, and condenses in the heat exchanger 13. That is, in the cooling operation state, the heat exchanger 13 functions as a condenser. The refrigerant condensed in the heat exchanger 13 flows into the gas-liquid separator 15 via the pipe 47, the four-way valve 22, and the pipe 49.

[0040] In addition, in the cooling operation state, the liquid refrigerant is supplied from the gas-liquid separator 15 to the expansion valves 12a and 12b through the pipe 48 and the four-way valve 22. The expansion valve 12a decompresses the refrigerant and supplies it to the heat exchanger 11a, and the expansion valve 12b decompresses the refrigerant and supplies it to the heat exchanger 11b. The heat exchangers 11a and 11b function as evaporators in the cooling operation state, and vaporize the refrigerant decompressed by the expansion valves 12a and 12b. The refrigerant vaporized in the heat exchangers 11a and 11b is transported to the compressor 100 through the pipe 44, the four-way valve 21 and the pipe 41.

[0041] On the other hand, 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.

[0042] In the heating operation state of the air conditioner 1, the refrigerant discharged from the discharge pipe 105 flows into the heat exchangers 11a and 11b through the pipe 42 and the four-way valve 21, and condenses in the heat exchangers 11a and 11b. That is, in the heating operation state, the heat exchangers 11a and 11b function as condensers. The refrigerant condensed in the heat exchangers 11a and 11b flows into the gas-liquid separator 15 through the pipe 45, the four-way valve 22 and the pipe 49.

[0043] Furthermore, in the heating operation state, the liquid refrigerant is supplied from the gas-liquid separator 15 to the expansion valve 14 through the pipe 48 and the four-way valve 22. The expansion valve 14 decompresses the refrigerant and supplies it to the heat exchanger 13. The heat exchanger 13 functions as an evaporator in the heating operation state, and vaporizes the refrigerant decompressed by the expansion valve 14. The refrigerant vaporized in the heat exchanger 13 is sucked into the suction port 104 through the pipe 46, the four-way valve 21 and the pipe 41.

[0044] The control device 10 includes a processor such as a microcontroller. The control device 10 controls the air conditioning device 1 by executing a program on the processor or by using the functions of programmed hardware.

[0045] The control device 10 controls the four-way valve 21 and the four-way valve 22 to switch between the cooling operation state and the heating operation state. In addition, the control device 10 adjusts the opening of the expansion valves 12a and 12b in the cooling operation state. The control device 10 adjusts the opening of the expansion valve 14 in the heating operation state.

[0046] The control device 10 controls the opening and closing of the valve 16 provided in the pipe 43. The valve 16 is composed of an electric valve, a solenoid 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 closing of the valve 16 and adjusts the opening degree of the valve 16.

[0047] The air conditioning device 1 may also include one or more of a temperature sensor (not shown) for detecting the temperature of the motor 110 and a temperature sensor (not shown) for detecting the temperature of the refrigerant discharged from the compression mechanism 120. These temperature sensors are connected to the control device 10. The control device 10 detects one or both of the temperature of the motor 110 and the temperature of the refrigerant discharged from the compression mechanism 120 by acquiring the detection values ​​of the temperature sensors. In addition, the control device 10 may also calculate the pressure of the refrigerant discharged from the compression mechanism 120 based on the temperature of the refrigerant discharged from the compression mechanism 120.

[0048] The air conditioning device 1 may also include a pressure sensor for detecting the pressure of the refrigerant discharged from the compression mechanism 120. In addition, the air conditioning device 1 may also include a heat exchanger temperature sensor (not shown) for detecting the temperature of the heat exchangers 11a, 11b and the heat exchanger 13. In this case, the control device 10 may calculate the pressure and temperature of the refrigerant discharged from the compression mechanism 120 based on the detection value of the heat exchanger temperature sensor, or may be configured not to include the above-mentioned temperature sensor.

[0049] The pipe 43 supplies the gaseous refrigerant from the gas-liquid separator 15 to the compressor 100. The pipe 43 supplies the refrigerant stored in the gas-liquid separator 15 to the compressor 100 through a path different from the pipe 48 connected to the suction port 104, and therefore can be called a bypass pipe. The pipe 43 is connected to the injection portion 125 of the compressor 100. The refrigerant is supplied to the injection portion 125 through the pipe 43, thereby cooling the compressor 100. The injection portion 125 corresponds to an example of a refrigerant supply portion. The pipe 43 corresponds to an example of a refrigerant pipe.

[0050] A relief valve (relief valve, safety valve) 60 is provided in the pipe 42 connected to the discharge pipe 105. Figure 1 and Figure 3 In the example of , a relief valve 60 is provided in the pipe 42. The relief valve 60 is a valve that automatically opens when the pressure of the refrigerant becomes a preset set pressure or more, so that the pressure of the compression chamber of the compression mechanism 120 and the discharge pipe 105 is reduced. The relief valve 60 corresponds to an example of a pressure relief unit. The relief valve 60 can also be provided in the discharge pipe 105.

[0051] [1-2. Compressor structure]

[0052] like Figure 2 As shown, the compressor 100 includes a container 102. The container 102 accommodates a compression mechanism 120 for compressing refrigerant and a motor 110 for driving the compression mechanism 120.

[0053] The electric motor 110 includes a stator 111 and a rotor 112. The crankshaft 103 is coupled to the rotor 112, and the crankshaft 103 is rotatably supported by bearings 107 and 108. Thus, the rotor 112 is held rotatably together with the crankshaft 103.

[0054] In the compressor 100, the motor 110 is located, for example, at the lower portion of the internal space of the container 102, and the compression mechanism 120 is located above the motor 110. At the bottom of the container 102, refrigeration oil (not shown) is stored.

[0055] The motor 110 is a so-called concentrated winding motor. The stator 111 includes teeth having a three-phase stator winding and a yoke connecting the teeth. The stator winding of the stator 111 is connected to an inverter-type drive circuit 116 through a lead wire (not shown). The rotor 112 has a permanent magnet and rotates together with the crankshaft 103 by a rotating magnetic field generated by a current flowing through the stator 111. The drive circuit 116 outputs a drive current to the stator 111 under the control of the motor 110.

[0056] The compression mechanism 120 is, for example, a scroll type compression mechanism. The compression mechanism 120 includes a fixed scroll 121 and a swing scroll 122 combined with the fixed scroll 121, and the space between the fixed scroll 121 and the swing scroll 122 functions as a compression chamber. The compression mechanism 120 compresses the refrigerant by rotating the swing scroll 122 together with the crankshaft 103. The refrigerant compressed by the compression mechanism 120 is discharged through the discharge pipe 105.

[0057] The compressor 100 is a so-called internal low-pressure type compressor in which the compression mechanism 120 sucks and compresses the refrigerant flowing into the container 102 through the suction port 104. As shown by the arrow RI, the refrigerant flowing into the container 102 from the suction port 104 is sucked into the compression mechanism 120 through the space between the stator 111 and the rotor 112 of the motor 110, that is, the air gap. The motor 110 is cooled by the refrigerant flowing through the air gap.

[0058] The injection portion 125 is a pipe that communicates the inside and outside of the container 102, and the front end of the injection portion 125 opens to the compression chamber of the compression mechanism 120. As described above, the pipe 43 is connected to the injection portion 125, and the gas refrigerant is supplied through the pipe 43.

[0059] The refrigerant flows from the injection portion 125 into the compression chamber via the pipe 43, whereby the refrigerant in the gas-liquid separator 15 is sucked into the compression mechanism 120. Thus, since the gaseous refrigerant is taken out from the gas-liquid separator 15, the pressure of the refrigerant in the gas-liquid separator 15 is reduced, and an effect of expanding the refrigerant is generated in the gas-liquid separator 15.

[0060] The injection portion 125 may be opened inside the container 102 at or near the suction port through which the compression mechanism 120 sucks the refrigerant inside the container 102. In this case, the function of taking out the gaseous refrigerant from the gas-liquid separator 15 can also be produced.

[0061] [1-3. Refrigerant]

[0062] The refrigerant used in the air conditioner 1 is a working medium containing ethylene-based fluoroolefins. Ethylene-based fluoroolefins include, for example, any one or more of 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).

[0063] The working medium may also contain two or more refrigerant components. That is, it may contain an ethylene fluoroolefin selected from the above examples (e.g., 1,1,2-trifluoroethylene) and a second refrigerant component. As the second refrigerant component, one or more refrigerants selected from hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), saturated hydrocarbons, carbon dioxide or other refrigerants may be cited. Examples of the hydrofluorocarbons (hydrofluorocarbons) include difluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane, pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane and heptafluorocyclopentane. Examples of hydrofluoroolefins include monofluoropropylene, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene and hexafluorobutene. As saturated hydrocarbons, for example, ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), and methylcyclobutane can be listed, but other hydrocarbons can also be used. The second refrigerant component can include multiple components. That is, the second refrigerant component can also include two or more refrigerant components selected from hydrofluorocarbons, hydrofluoroolefins, saturated hydrocarbons, carbon dioxide, and other refrigerants.

[0064] The working medium used as a refrigerant in the air-conditioning device 1 may also contain a disproportionation inhibitor in addition to the refrigerant components. The disproportionation inhibitor is, for example, a saturated hydrocarbon. The working medium may also contain a disproportionation inhibitor composed of one or more components. Saturated hydrocarbons used as disproportionation inhibitors include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), and methylcyclobutane, but other saturated hydrocarbons may also be used. As a particularly preferred disproportionation inhibitor, n-propane may be mentioned.

[0065] The disproportionation inhibitor may be a halogenated alkane having 1 or 2 carbon atoms. Examples of the halogenated alkane having 1 carbon atom used as the disproportionation inhibitor, i.e., methyl halides, include (mono) methyl iodide (CH3I), dimethyl iodide (CH2I2), dimethyl bromide (CH2Br2), methyl bromide (CH3Br), dichloromethane (CH2Cl2), chloroiodomethane (CH2ClI), dibromochloromethane (CHBr2Cl), tetraiodomethane (CI4), carbon tetrabromide (CBr4), bromotrichloromethane (CBrCl3), dibromodichloromethane (CBr2Cl2), tribromofluoromethane (CBr3F), fluorodiiodomethane (CHFI2), difluoroiodomethane (CHF2I), difluorodiiodomethane (CF2I2), dibromodifluoromethane (CBr2F2), trifluoroiodomethane (CF3I), and other methyl halides may also be used. Examples of the halogenated alkane having 2 carbon atoms used as the disproportionation inhibitor, i.e., halogenated ethane, include 1,1,1-trifluoro-2-iodoethane (CF3CH2I), monoiodoethane (CH3CH2I), monobromoethane (CH3CH2Br), and 1,1,1-triiodoethane (CH3CI3).

[0066] The working medium may contain a plurality of disproportionation inhibitors selected from the above-mentioned saturated hydrocarbons and the above-mentioned halogenated alkanes. In addition, the working medium may contain one saturated hydrocarbon, or may be a working medium containing two or more saturated hydrocarbons. In addition, the working medium may contain one halogenated alkanes, or may be a working medium containing two or more halogenated alkanes.

[0067] A preferred example of the working medium is a mixture containing 1,1,2-trifluoroethylene and n-propane. The working medium may contain the second refrigerant component described above, or may contain other components.

[0068] Each of the above working media may contain inevitable impurities, which include various additives including stabilizers added for the purpose of stabilization during transportation and storage, residual parts or by-products of synthetic raw materials of refrigerant components, and substances mixed for other reasons.

[0069] The mass ratio of 1,1,2-trifluoroethylene to n-propane contained in the working medium can be changed appropriately. The capacity of the refrigeration cycle is related to the mass ratio of the refrigerant components contained in the working medium. Therefore, in order to maintain the capacity of the refrigeration cycle, n-propane as a disproportionation inhibitor is preferably configured to contain only 40% by mass or less in the working medium.

[0070] [1-4. Inhibition of dismutation reaction]

[0071] Ethylene fluoroolefins include, for example, ethylene fluoroolefins that undergo a disproportionation reaction. When ethylene fluoroolefins are used as refrigerants, they have the advantages of low GWP and high refrigeration capacity. On the other hand, ethylene fluoroolefins are refrigerants that are easily decomposed, so they may undergo a disproportionation reaction under specific conditions. The disproportionation reaction is known as a reaction in which free radicals are generated from molecules contained in the refrigerant and the refrigerant undergoes self-decomposition through a chain reaction. If a disproportionation reaction occurs, the pressure in the refrigeration cycle rises sharply.

[0072] Specific conditions under which the disproportionation reaction can occur include high temperature and high pressure of the refrigerant and exposure of the refrigerant to a discharge phenomenon. In other words, by eliminating or preventing any one of high temperature, high pressure and a discharge phenomenon, the disproportionation reaction of the refrigerant can be prevented or suppressed. A typical example of a discharge phenomenon that induces a disproportionation reaction is a short circuit generated between stator windings of the stator 111 in the motor 110. This short circuit is called a layer short.

[0073] The air-conditioning apparatus 1 of the present embodiment has a structure that suppresses the disproportionation reaction of the refrigerant.

[0074] The compressor 100 is an internal low-pressure type. Therefore, since the refrigerant pressure inside the container 102 is equal to the pressure on the suction side of the compression mechanism 120, the refrigerant is unlikely to become a high-temperature and high-pressure state in and around the motor 110. Therefore, even if an interlayer short circuit occurs in the motor 110, it is unlikely to induce a disproportionation reaction of the refrigerant.

[0075] In the container 102, the refrigerant sucked from the suction port 104 reaches the compression mechanism 120 through the air gap between the stator 111 and the rotor 112, so the temperature rise of the motor 110 can be suppressed by the refrigerant passing through the air gap. Therefore, the refrigerant in and around the motor 110 is not likely to become a high-temperature and high-pressure state, so even if an interlayer short circuit occurs in the motor 110, it is not likely to induce a disproportionation reaction of the refrigerant.

[0076] The air conditioning device 1 includes a pipe 43 and an injection portion 125 for supplying liquid refrigerant to the compression chamber of the compressor 100. The control device 10 opens the valve 16 and supplies the refrigerant to the injection portion 125 when the temperature of the compressor 100 satisfies a preset condition. The preset condition is, for example, that the temperature of the compressor 100 is above a threshold value. In detail, the temperature of the compressor 100 refers to the temperature of the motor 110 or the temperature of the discharged refrigerant of the compression mechanism 120. In this case, the control device 10 opens the valve 16 when it is detected that the temperature of the motor 110 or the temperature of the discharged refrigerant of the compression mechanism 120 exceeds the threshold value. Thereby, the compression mechanism 120 can be cooled and the disproportionation reaction can be suppressed.

[0077] Here, when the valve 16 is opened, the pressure of the refrigerant in the gas-liquid separator 15 decreases as the refrigerant flows out of the gas-liquid separator 15 to the piping 43, and the refrigerant can be expanded in the gas-liquid separator 15. Thus, the gas-liquid separator 15 functions as a heat exchanger, so the gas-liquid separator 15 can be called an intercooler, for example. Through this function, in the cooling operation state of the air-conditioning device 1, the refrigerant discharged from the compressor 100 is decompressed in two stages (two stages) in the expansion valve 14 and the gas-liquid separator 15. That is, the expansion valve 14 and the gas-liquid separator 15 constitute a two-stage (two-stage) expansion mechanism. The area where the refrigerant becomes high temperature and high pressure in the cooling operation state is Figure 1 The area indicated by the reference numeral HP in the figure. By forming a two-stage expansion mechanism by the expansion valve 14 and the gas-liquid separator 15, the area HP can be limited to a narrower range. Therefore, even in the case of a disproportionation reaction of the refrigerant, the range of the chain reaction of the refrigerant can be reduced. Furthermore, by forming a two-stage expansion stroke, the temperature of the compression mechanism 120 can be lowered, and the disproportionation reaction can be more effectively suppressed.

[0078] The air conditioner 1 can control the opening and closing of the valve 16 by the control device 10, for example, closing the valve 16 in a state where the possibility of the disproportionation reaction is low. Therefore, the operation efficiency of the air conditioner 1 can be improved.

[0079] The air conditioning apparatus 1 includes the release valve 60. Therefore, even when the disproportionation reaction occurs, by opening the release valve 60 in response to the increase in the refrigerant pressure caused by the disproportionation reaction, it is possible to prevent an excessive increase in the pressure in the refrigeration cycle.

[0080] In addition, as described above, by using a refrigerant containing ethylene fluoroolefin and a disproportionation inhibitor in the air conditioning device 1, the disproportionation reaction of the refrigerant is suppressed. The refrigerant containing an inactive disproportionation inhibitor suppresses the disproportionation reaction of ethylene fluoroolefin by the thermal dilution effect. In addition, a certain disproportionation inhibitor captures free radicals that are active intermediates generated in the disproportionation reaction. Thus, by capturing free radicals generated in the initial stage of the reaction, a chain reaction can be prevented and the transmission of the chain reaction can be suppressed. Through these effects, the disproportionation reaction of the refrigerant can be suppressed.

[0081] [1-5. Control by control device]

[0082] Here, the control performed by the control device 10 to suppress the disproportionation reaction of the refrigerant will be described.

[0083] As described above, the control device 10 performs control to open the valve 16 when the temperature of the compressor 100 satisfies a preset condition.

[0084] In addition, the control device 10 suppresses the disproportionation reaction by operating the four-way valve 21 , the four-way valve 22 and other valves.

[0085] Figure 4 : is a flowchart showing the operation of the control device 10 .

[0086] The control device 10 monitors whether the refrigerant pressure of the high-pressure part of the air-conditioning device 1 rises above a threshold value during the operation of the air-conditioning device 1 (step S11). The high-pressure part refers to the range where the high-pressure refrigerant flows in the air-conditioning device 1, for example, including the compression mechanism 120, the discharge pipe 105 and the Figure 1 Here, an example in which the control device 10 determines the pressure of the refrigerant discharged from the compression mechanism 120 will be described.

[0087] When the pressure is lower than the threshold value (step S11; No), the control device 10 continues the monitoring of step S11 for a predetermined time period. The threshold value is preset in the control device 10. The threshold value is a pressure at which the refrigerant in the compressor 100 is estimated to have undergone a disproportionation reaction, or a pressure value at which a disproportionation reaction is highly likely to have occurred.

[0088] When the control device 10 determines that the pressure of the refrigerant discharged from the compressor 100 has risen to or above the threshold value (step S11; yes), it is highly likely that a disproportionation reaction of the refrigerant has occurred in the high-pressure section of the air-conditioning device 1. In this case, the control device 10 does not control the opening of the valve 16 to allow the refrigerant to flow from the injection section 125 into the compression mechanism 120, but Figure 4 Furthermore, the control device 10 can also control the closing valve 16.

[0089] When the control device 10 determines that the pressure of the high-pressure portion has risen to or above the threshold value (step S11: Yes), it determines whether the air conditioner 1 is in heating operation (step S12). When the air conditioner 1 is in heating operation (step S12: Yes), the control device 10 operates the four-way valve 21 and the four-way valve 22 to switch the air conditioner 1 to cooling operation (step S13).

[0090] In the heating operation of the air conditioner 1, the high-pressure refrigerant flows through the heat exchangers 11a and 11b, so the disproportionation reaction of the refrigerant may be transmitted to the heat exchangers 11a and 11b. Figure 1Therefore, by switching the operation state of the air conditioner 1 to the cooling operation state in step S13, the disproportionation reaction can be prevented from being transmitted to a position close to the conditioned space (conditioned space). As a result, since the rapid pressure rise associated with the disproportionation reaction can be prevented from causing damage to equipment close to the conditioned space, there is an advantage that it will not affect people in the conditioned space.

[0091] When the air conditioner 1 is in cooling operation (step S12: No), and when the air conditioner 1 is switched from the heating operation state to the cooling operation state (step S13), the control device 10 controls the valve of the control object to be closed to the first opening degree (step S14). In step S14, the control device 10 closes at least the expansion valve 14 to the first opening degree. The control device 10 may also control the expansion valves 12a and 12b to be closed to the first opening degree in step S14.

[0092] The first opening is a prescribed opening in a state where the valve is open compared to the fully closed state. The first opening may be a value set corresponding to each valve, or may be a setting value common to all valves. For example, when the fully open state is set to 100%, the first opening may be set to 10%. By closing the valve by the control device 10, the disproportionation reaction may be suppressed from passing over the valve. In addition, if the valve is fully closed, the pressure rise accompanying the disproportionation reaction may change more sharply, so it is effective to set the valve to the first opening instead of fully closing the valve.

[0093] The control device 10 monitors whether the rise of the pressure in the high-pressure part has stopped (step S15). If the rise of the pressure has not stopped (step S15: No), the monitoring of step S15 is continued for a predetermined time period. If it is determined that the rise of the pressure has stopped (step S15: Yes), the control device 10 controls the valve closed to the first opening in step S14 to be closed to a fully closed state (step S16). Thereafter, the control device 10 performs a report (step S17). The report of step S17 is not limited as long as it can inform the manager who manages the air-conditioning device 1 of the occurrence of the disproportionation reaction. For example, the control device 10 can report the occurrence of the disproportionation reaction to the device that manages the air-conditioning device 1 in step S17, or can display it on the display of the remote control device that operates the air-conditioning device 1, or can display it on the display of the indoor unit of the air-conditioning device 1. In addition, sound and image can also be output through the control of the control device 10.

[0094] exist Figure 4 In the control, the control device 10 may stop the compressor 100 at any timing of steps S12 to S16.

[0095] The control device 10 may also estimate the pressure of the refrigerant discharged from the compressor 100 based on the temperature of the refrigerant discharged from the compressor 100 and the temperatures of the heat exchangers 11a, 11b and 13 in the above-mentioned steps S11 and S15, and judge the estimated pressure.

[0096] In the above description, an example is shown in which the control device 10 determines the pressure of the refrigerant discharged from the compressor 100 in step S11 and step S15, but this is only an example. The control device 10 may also make a determination based on the temperature of the refrigerant discharged from the compressor 100. In this case, the control device 10 may directly detect the temperature of the refrigerant discharged from the compressor 100 using a temperature sensor, or may make a determination based on the pressure of the refrigerant discharged, or the temperature of the refrigerant discharged from the compressor 100 estimated based on the temperature of the heat exchangers 11a, 11b, and the heat exchanger 13.

[0097] The four-way valves 21 and 22 of the air conditioning device 1 are preferably composed of low-pressure differential working four-way valves or electromagnetic on-off valves. In the structure where the four-way valves 21 and 22 use pilot-type four-way switching valves, when low-pressure differential working four-way valves or electromagnetic on-off valves are used, there is an advantage of quickly switching from the heating operation state to the cooling operation state in step S13.

[0098] [1-6. Effects, etc.]

[0099] As described above, the air conditioning device 1 of Embodiment 1 includes a compressor 100, a heat exchanger 13 as a heat source side heat exchanger, heat exchangers 11a, 11b as a utilization side heat exchanger, and an expansion mechanism. The air conditioning device 1 includes four-way valves 21, 22 and a control device 10, and the four-way valves 21, 22 switch between a heating operation state in which the heat exchangers 11a, 11b work as condensers and a cooling operation state in which the heat exchanger 13 works as a condenser. The air conditioning device 1 uses a working medium containing ethylene fluoroolefin as a refrigerant. When the control device 10 detects that the pressure of the working medium of the high-pressure part including the compressor 100 and the condenser has risen to a threshold value in the heating operation state, the four-way valves 21, 22 are controlled to switch from the heating operation state to the cooling operation state.

[0100] Thus, the air-conditioning device 1 can achieve low GWP by using a working medium containing ethylene fluoroolefins. In addition, when there is a possibility that a disproportionation reaction of the refrigerant has occurred, or when it is inferred that a disproportionation reaction has occurred, the air-conditioning device 1 switches the air-conditioning device 1 from the heating operation state to the cooling operation state, so that the area HP where the high-pressure refrigerant flows is narrowed. Thus, the area HP where the pressure of the refrigerant rises sharply due to the disproportionation reaction can be limited, thereby suppressing the influence of the disproportionation reaction in the refrigeration cycle. For example, when the heat exchangers 11a and 11b are arranged in the conditioned space of the air-conditioning device 1 or in the vicinity thereof, the influence of the disproportionation reaction can be prevented or suppressed from spreading to the conditioned space through the control of the control device 10.

[0101] The expansion mechanism includes an expansion valve 14 or expansion valves 12a, 12b arranged at the outlet of the condenser. The air conditioning device 1 includes a control device 10 that controls the expansion valves 12a, 12b, 14. When the control device 10 detects that the pressure of the working medium of the high-pressure part of the air conditioning device 1 has risen above a threshold value, it causes any one of the expansion valves 12a, 12b, 14 to move in the closing direction to a first opening degree, and then, when the pressure of the working medium of the high-pressure part stops rising, it causes the expansion valve to move in the closing direction to a second opening degree. The second opening degree is, for example, a fully closed state. The high-pressure part includes, for example, a compressor 100 and a condenser.

[0102] Thus, when a disproportionation reaction of the refrigerant is likely to have occurred or when it is estimated that a disproportionation reaction has occurred, the pressure rise caused by the disproportionation reaction can be suppressed. Furthermore, after the pressure rise of the high-pressure portion stops, the valve is closed to the second opening degree, so that the propagation of the disproportionation reaction can be more reliably suppressed.

[0103] The air conditioning apparatus 1 includes a relief valve 60 for releasing the pressure in the pipe 42 through which the compressor 100 discharges the compressed refrigerant when the pressure in the pipe 42 is equal to or higher than a set pressure.

[0104] Thus, when the pressure in the pipe 42 suddenly increases due to the occurrence of the disproportionation reaction, the pressure in the pipe 42 can be released, and the influence of the disproportionation reaction can be reduced.

[0105] In the air conditioner 1, the compressor 100 includes: an inlet 104 for sucking a working medium, a compression mechanism 120 for compressing the working medium sucked from the inlet 104, and an injection portion 125 for supplying the working medium to the compression mechanism 120 through a path different from the inlet 104. The compressor 100 is an internal low-pressure type compressor, in which the compression mechanism 120 is accommodated in the container 102 together with the motor 110, and the compression mechanism 120 sucks the working medium inside the container 102 and then compresses it. In the cooling operation state, the condenser is the heat exchanger 13, and the evaporator is the heat exchanger 11a, 11b. In the heating operation state, the condenser is the heat exchanger 11a, 11b, and the evaporator is the heat exchanger 13.

[0106] Thus, the air conditioning device 1 can achieve low GWP by using the working medium containing ethylene fluoroolefin. In addition, by supplying the refrigerant from the injection portion 125 to the compression mechanism 120 and making the working medium inside the container 102 low pressure, a structure is achieved in which the disproportionation reaction of ethylene fluoroolefin is difficult to occur. Therefore, the disproportionation reaction when using a refrigerant with a low GWP can be suppressed.

[0107] In addition, the air conditioning device 1 has a gas-liquid separator 15 disposed between the condenser and the evaporator, and a pipe 43 for conveying a gaseous working medium from the gas-liquid separator 15 to the injection portion 125. The expansion mechanism includes an expansion valve 14 or expansion valves 12a, 12b disposed at the outlet of the condenser and operating as a first-stage pressure reducing mechanism, and the gas-liquid separator 15 to form a two-stage (two-stage) expansion stroke.

[0108] Thus, the area where the high-pressure refrigerant flows can be limited to a narrow range in the air-conditioning device 1, thereby realizing a structure in which the disproportionation reaction of the refrigerant is not easily transmitted. In addition, by forming a two-stage expansion stroke, the temperature rise of the compression mechanism 120 can be suppressed, and a structure in which the disproportionation reaction is not easily generated can be realized.

[0109] The air conditioning device 1 includes a pipe 43 that allows a working medium to flow into a pipe 41 connected to a suction port 104 of a compressor 100 or a container 102 that accommodates a motor 110. The air conditioning device 1 includes a valve 16 that opens and closes the pipe 43 and a control device 10 that controls the valve 16. The control device 10 controls the valve 16 to open when the temperature of the compression mechanism 120 satisfies a preset condition.

[0110] Thus, when the temperature of the compression mechanism 120 satisfies a preset condition, refrigerant is extracted from the gas-liquid separator 15 via the pipe 43, thereby reducing the pressure of the refrigerant in the gas-liquid separator 15 and expanding the refrigerant in the gas-liquid separator 15. Therefore, the gas-liquid separator 15 can function as an intercooler, and a two-stage (two-stage) expansion stroke is formed in the expansion valve 14 and the gas-liquid separator 15.

[0111] The air conditioner 1 has a heat exchanger 13 as a heat source side heat exchanger and heat exchangers 11a, 11b as a utilization side heat exchanger. The air conditioner 1 includes four-way valves 21, 22, which switch between a heating operation state in which the heat exchangers 11a, 11b operate as condensers and a cooling operation state in which the heat exchanger 13 operates as a condenser. When the control device 10 detects that the pressure of the working medium of the high-pressure part including the compressor 100 and the condenser rises to or above a threshold value in the heating operation state, the control device 10 controls the four-way valves 21, 22 to switch from the heating operation state to the cooling operation state.

[0112] Thus, in the heating operation state, when it is inferred (estimated) that a disproportionation reaction occurs in the high-pressure part of the air conditioner 1, by switching to the cooling operation state, the area where the high-pressure refrigerant flows can be limited. Thus, the propagation of the disproportionation reaction can be suppressed. In addition, by switching the air conditioner 1 to the cooling operation state, the high-pressure refrigerant does not flow through the heat exchangers 11a and 11b as the utilization side heat exchangers, so the influence of the disproportionation reaction can be avoided from affecting the conditioned space.

[0113] The four-way valves 21 and 22 may be low-pressure differential four-way valves or electromagnetic on-off valves. In this case, in the heating operation state, when it is inferred that a disproportionation reaction occurs in the high-pressure portion of the air conditioner 1, the cooling operation state can be quickly switched.

[0114] (Implementation Method 2)

[0115] Figure 5 This is a diagram showing the configuration of an air-conditioning apparatus 2 according to Embodiment 2. Figure 5 The air-conditioning apparatus 2 shown is an example of a refrigeration circuit to which the present invention is applied.

[0116] [2-1 Structure of air conditioning device]

[0117] In the air conditioner 2, the heat exchangers 11a, 11b, 13, the expansion valves 12a, 12b, 14, the gas-liquid separator 15, the valve 16, the four-way valves 21, 22, the pipes 41 to 49, and the relief valve 60 are common to the air conditioner 1 described in Embodiment 1. The same reference numerals are given to these common structures and their description is omitted.

[0118] 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. The first compressor 100A and the second compressor 100B do not include an injection portion 125, but have a common structure with the compressor 100 except for this point. For example, the first compressor 100A and the second compressor 100B have the same suction port 104 as the compressor 100, and the suction port 104 of the first compressor 100A corresponds to an example of a suction portion of the entire compressor 200. Hereinafter, the structure of the first compressor 100A and the second compressor 100B will be omitted.

[0119] The first compressor 100A is connected to the pipe 41, compresses the gas refrigerant supplied from the pipe 41, and discharges the compressed refrigerant to the connecting pipe 201. The connecting pipe 201 is a pipe connecting the discharge side of the first compressor 100A and the suction side of the second compressor 100B. The second compressor 100B sucks the refrigerant from the connecting pipe 201 and compresses it, and discharges the compressed high-pressure refrigerant to the pipe 42.

[0120] Thus, the first compressor 100A is a first-stage compressor, and corresponds to an example of a first compression mechanism. The second compressor 100B is a second-stage compressor, and corresponds to an example of a second compression mechanism.

[0121] In the connecting pipe 201, the pipe 43 is connected to the injection part 202. Thus, when the valve 16 is opened, the pressure of the refrigerant in the gas-liquid separator 15 is reduced as the refrigerant flows out from the gas-liquid separator 15 to the pipe 43, and the refrigerant can be expanded in the gas-liquid separator 15. Thus, as in Embodiment 1, the gas-liquid separator 15 functions as a heat exchanger. Through this function, in the cooling operation state of the air-conditioning device 2, the refrigerant is decompressed in two stages (two stages) in the expansion valve 14 and the gas-liquid separator 15. That is, the expansion valve 14 and the gas-liquid separator 15 constitute a two-stage (two-stage) expansion mechanism. The area where the refrigerant becomes high temperature and high pressure in the cooling operation state is the high-pressure part of the air-conditioning device 2, including any one of the compressor 200, the pipes 42, 46 and the four-way valve 21. By constituting a two-stage (two-stage) expansion mechanism by the expansion valve 14 and the gas-liquid separator 15, the area HP can be limited to a narrow range. Therefore, if a disproportionation reaction of the refrigerant occurs, the range of the chain reaction transmission of the refrigerant can be reduced. In addition, by forming a two-stage expansion stroke, the temperature of the compression mechanism 120 can be reduced, and the disproportionation reaction can be more effectively suppressed. The injection portion 202 corresponds to an example of a refrigerant supply portion.

[0122] The four-way valve 21 and the four-way valve 22 are connected to the control device 20. The four-way valve 21 and the four-way valve 22 operate according to the control of the control device 20 to switch the cooling operation state and the heating operation state of the air conditioner 2.

[0123] The compressor 200 may also be a composite compressor in which a first compression mechanism of a first stage and a second compression mechanism of a second stage are accommodated in one container. In this case, as long as the structure of connecting the pipe 43 to the suction side of the second compression mechanism can be realized. Figure 4 The air conditioning device 2 shown functions in the same way.

[0124] [2-2. Refrigerant]

[0125] The refrigerant used in the air-conditioning device 2 is the working medium described as the refrigerant of the air-conditioning device 1 in Embodiment 1. That is, the air-conditioning device 2 uses a working medium containing ethylene fluoroolefin as a refrigerant. The working medium may also contain two or more refrigerant components. In addition, the working medium used as a refrigerant in the air-conditioning device 2 may also contain a disproportionation inhibitor in addition to the refrigerant components. The working medium may contain a plurality of disproportionation inhibitors selected from saturated hydrocarbons and halogenated alkanes. In addition, the working medium may contain one saturated hydrocarbon, or may be a working medium containing two or more saturated hydrocarbons. In addition, the working medium may contain one halogenated alkanes, or may be a working medium containing two or more halogenated alkanes.

[0126] A preferred example of the working medium is a mixture containing 1,1,2-trifluoroethylene and n-propane and containing inevitable impurities. The working medium may contain the second refrigerant component described above, and may contain other components.

[0127] [2-3. Control device]

[0128] The air conditioning device 2 includes a control device 20. The control device 20 includes a processor such as a microcontroller. The control device 20 controls the air conditioning device 2 by executing a program with the processor or by functions of programmed hardware.

[0129] 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 connection of the pipes 41, 42, 44, and 46 under the control of the control device 20. In addition, the four-way valve 22 switches the connection of the pipes 45, 47, 48, and 49 under the control of the control device 20.

[0130] The control device 20 operates the four-way valve 21 and the four-way valve 22 to switch the cooling operation state and the heating operation state. That is, when the air conditioner 2 performs the cooling operation, the control device 20 connects the pipe 41 with the pipe 44 and connects the pipe 42 with the pipe 46 through the four-way valve 21. In addition, the control device 20 connects the pipe 48 with the pipe 45 and connects the pipe 47 with the pipe 49 through the four-way valve 22.

[0131] When the air conditioner 2 performs heating operation, the controller 20 connects the pipe 41 to the pipe 46 and the pipe 42 to the pipe 44 through the four-way valve 21. In addition, the controller 20 connects the pipe 49 to the pipe 45 and the pipe 47 to the pipe 48 through the four-way valve 22.

[0132] The expansion valves 12a and 12b, the expansion valve 14, and the valve 16 are connected to the control device 20. The control device 20 fully opens the expansion valve 14 (fully opened state) in the cooling operation state and adjusts the opening degree of the expansion valves 12a and 12b. The control device 20 fully opens the expansion valves 12a and 12b in the heating operation state and adjusts the opening degree of the expansion valve 14.

[0133] The air conditioning device 2 may also include: a temperature sensor (not shown) for detecting the temperature of the motor of the first compressor 100A and / or the motor of the second compressor 100B, and a temperature sensor (not shown) for detecting the temperature of the refrigerant discharged from the second compressor 100B. These temperature sensors are connected to the control device 20. The control device 20 detects either or both of the temperature of the motor and the temperature of the refrigerant discharged from the second compressor 100B by acquiring the detection values ​​of the temperature sensors. In addition, the control device 20 may also calculate the pressure of the refrigerant discharged from the second compressor 100B based on the temperature of the refrigerant discharged from the second compressor 100B.

[0134] In addition, the air conditioning device 2 may also include a pressure sensor for detecting the pressure of the refrigerant discharged from the second compressor 100B. In addition, the air conditioning device 2 may also include a heat exchanger temperature sensor (not shown) for detecting the temperature of the heat exchangers 11a, 11b and the heat exchanger 13. In this case, the control device 20 may calculate the pressure and temperature of the refrigerant discharged from the second compressor 100B based on the detection value of the heat exchanger temperature sensor, or may be configured not to include the above-mentioned temperature sensor.

[0135] The control device 20 controls the opening and closing of the valve 16. The valve 16 is composed of an electric valve, a solenoid 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 closing of the valve 16 and adjusts the opening degree of the valve 16.

[0136] [2-4. Control by control device]

[0137] The air conditioning device 2 suppresses the disproportionation reaction of the refrigerant by the control of the control device 20. For example, as described above, the control device 20 controls the valve 16 to open when the temperature of the motor or the temperature of the discharged refrigerant of the second compressor 100B exceeds a threshold value. In addition, the control device 20 suppresses the disproportionation reaction by operating the four-way valve 21, the four-way valve 22 and other valves.

[0138] The control device 20 performs, for example, a reference Figure 4 When the refrigerant pressure of the high-pressure part of the air-conditioning device 2 rises above the threshold value, the control device 20 performs control to switch the air-conditioning device 2 from the heating operation state to the cooling operation state. Here, the high-pressure part of the air-conditioning device 2 is, for example, the second compressor 100B, the pipe 42, etc.

[0139] In addition, the control device 20 controls the valve of the control object to be closed to the first opening when the air conditioner 2 is in cooling operation and when the air conditioner 2 is switched from the heating operation state to the cooling operation state. Furthermore, when the pressure rise of the high-pressure part stops, the control device 20 controls the valve closed to the first opening degree to be closed to the fully closed state. Thereafter, the control device 20 performs a report. During the execution of these controls, the control device 20 may also stop the compressor 200.

[0140] [2-5. Effects, etc.]

[0141] As described above, the air-conditioning apparatus 2 according to Embodiment 2, like the air-conditioning apparatus 1 described in Embodiment 1, can suppress the influence of the disproportionation reaction in the refrigeration cycle when the disproportionation reaction of the refrigerant occurs.

[0142] That is, the air conditioning device 2 includes a compressor 200, a heat exchanger 13 as a heat source side heat exchanger, heat exchangers 11a, 11b as a utilization side heat exchanger, and an expansion mechanism. The air conditioning device 2 includes four-way valves 21, 22 and a control device 20, and the four-way valves 21, 22 switch between a heating operation state in which the heat exchangers 11a, 11b work as condensers and a cooling operation state in which the heat exchanger 13 works as a condenser. The air conditioning device 2 uses a working medium containing ethylene fluoroolefin as a refrigerant. When the control device 20 detects that the pressure of the working medium of the high-pressure part including the compressor 200 and the condenser has risen to a threshold value in the heating operation state, the four-way valves 21, 22 are controlled to switch from the heating operation state to the cooling operation state.

[0143] Thus, the air conditioner 2 achieves low GWP by using a working medium containing ethylene fluoroolefin. In addition, when a disproportionation reaction of the refrigerant is likely to occur, or when it is inferred that a disproportionation reaction has occurred, the air conditioner 2 switches from a heating operation state to a cooling operation state to narrow the area HP where the high-pressure refrigerant flows. Thus, the area where the pressure of the refrigerant rises sharply due to the disproportionation reaction can be limited, thereby suppressing the influence of the disproportionation reaction.

[0144] The expansion mechanism of the air conditioning device 2 includes an expansion valve 14 or expansion valves 12a, 12b arranged at the outlet of the condenser. The control device 20 controls the expansion valves 12a, 12b, 14. When the control device 20 detects that the pressure of the working medium of the high-pressure part of the air conditioning device 2 has risen to a threshold value or more, it causes any one of the expansion valves 12a, 12b, 14 to move in the closing direction to a first opening degree, and then, when the pressure of the working medium of the high-pressure part stops rising, it causes the expansion valve to move in the closing direction to a second opening degree. The second opening degree is, for example, a fully closed state. The high-pressure part includes, for example, a compressor 100 and a condenser.

[0145] Thus, when a disproportionation reaction of the refrigerant is likely to have occurred or when it is estimated that a disproportionation reaction has occurred, the pressure rise accompanying the disproportionation reaction can be suppressed. Furthermore, after the pressure rise of the high-pressure portion stops, the valve is closed to the second opening degree, so that the propagation of the disproportionation reaction can be more reliably suppressed.

[0146] The air conditioning device 2 has a pipe 42 through which the compressor 200 discharges the compressed refrigerant, and a safety valve 60 that releases the pressure when the pressure in the pipe 42 becomes equal to or higher than a set pressure.

[0147] Thus, when the pressure in the pipe 42 suddenly increases due to the occurrence of the disproportionation reaction, the pressure in the pipe 42 can be released, and the influence of the disproportionation reaction can be reduced.

[0148] In the air conditioning device 2, the compressor 200 is a two-stage compressor including: a suction port 104 for sucking a working medium, a first compressor 100A for compressing the working medium sucked from the suction port 104, and a second compressor 100B for compressing the working medium compressed by the first compressor 100A. The air conditioning device 2 has an injection portion 202 for supplying the working medium between the first compressor 100A and the second compressor 100B.

[0149] Thus, the air conditioning device 2 can achieve low GWP by using the working medium containing ethylene fluoroolefin. In addition, the refrigerant is supplied to the connecting pipe 201 between the first compressor 100A and the second compressor 100B through the injection unit 202, so that the temperature of the discharged refrigerant of the compressor 200 is reduced, thereby realizing a structure in which the disproportionation reaction of ethylene fluoroolefin is difficult to occur. Therefore, the disproportionation reaction when using a refrigerant with a low GWP can be suppressed.

[0150] Furthermore, the air conditioner 2 can suppress the compression ratios of the first compressor 100A and the second compressor 100B by using the two-stage compressor 200. Therefore, compression loss can be reduced and the load on the motor of the compressor 200 can be reduced, and the temperature rise of the motor can be suppressed.

[0151] In addition, when the control device 20 detects that the pressure of the working medium in the high-pressure part has risen to above the threshold value in the heating operation state of the air-conditioning device 2, the four-way valves 21 and 22 are controlled to switch from the heating operation state to the cooling operation state. Thus, when it is inferred that a disproportionation reaction has occurred in the high-pressure part in the heating operation state, the area where the high-pressure refrigerant flows can be limited by switching to the cooling operation state. Thus, the transmission of the disproportionation reaction can be suppressed. In addition, in the cooling operation state, the high-pressure refrigerant does not flow through the heat exchangers 11a and 11b as the utilization side heat exchangers, so the influence of the disproportionation reaction can be avoided from affecting the conditioned space.

[0152] In addition, the air conditioning device 2 includes a pipe 43 that allows the working medium to flow from the gas-liquid separator 15 into the injection portion 202. The air conditioning device 2 includes a valve 16 that opens and closes the pipe 43 and a control device 20 that controls the valve 16. The control device 20 controls the valve 16 to open when the temperature of the compressor 200 satisfies a preset condition.

[0153] Thus, when the temperature of the compressor 200 satisfies a preset condition, the pressure of the refrigerant in the gas-liquid separator 15 can be reduced by extracting the refrigerant from the gas-liquid separator 15 via the pipe 43, and the refrigerant can be expanded in the gas-liquid separator 15. Therefore, the gas-liquid separator 15 can function as an intercooler, and the expansion valve 14 and the gas-liquid separator 15 form a two-stage (two-stage) expansion stroke. Thus, in the case where a state in which a disproportionation reaction is likely to occur occurs in the compressor 200, the state can be eliminated. In addition, in the case where it is inferred that a disproportionation reaction has occurred in the compressor 200, the disproportionation reaction can be suppressed or stopped.

[0154] (Implementation 3)

[0155] Figure 6 It is a diagram showing the configuration of an air-conditioning apparatus 1A according to Embodiment 3. Figure 6 The air-conditioning apparatus 1A shown is an example of a refrigeration circuit to which the present invention is applied.

[0156] The air conditioning device 1A is in reference to Figure 1 to Figure 4 The described air conditioning apparatus 1 is provided with a configuration of a pipe 55 and a valve 56. The configuration of each portion other than the pipe 55 and the valve 56 is common to the configuration described in Embodiment 1, and thus the same reference numerals are given and the description thereof is omitted.

[0157] The pipe 55 is a refrigerant pipe connecting the pipe 48 and the pipe 41. The pipe 55 is provided with a valve 56. The valve 56 is, for example, composed of a solenoid valve, and is opened and closed under the control of the control device 10. The valve 56 may also be composed of a solenoid valve. In this case, the control device 10 can control the opening and closing of the valve 56 and can also adjust the opening degree of the valve 56. The pipe 55 corresponds to an example of a motor cooling circuit, and the valve 56 corresponds to an example of a motor cooling valve.

[0158] In the state where the valve 56 is opened, the refrigerant flows from the pipe 48 to the pipe 41 in the pipe 55. The refrigerant flowing in the pipe 55 is the liquid refrigerant flowing from the gas-liquid separator 15 to the pipe 48. The refrigerant reaches the suction port 104 through the pipe 41 and is supplied to the interior of the container 102.

[0159] Therefore, when the valve 56 is open, liquid refrigerant is supplied to the motor 110 from the suction port 104. The refrigerant cools the motor 110 in the process of being sucked into the compression mechanism 120 through the suction port 104. The pipe 55 may be directly connected to the container 102 that accommodates the motor 110. In this case, the temperature of the motor 110 can also be lowered by supplying liquid refrigerant from the pipe 55 to the container 102. In particular, if Figure 2 As shown, by adopting a structure in which the refrigerant sucked from the suction port 104 passes through the air gap between the stator 111 and the rotor 112, the electric motor 110 can be cooled more effectively.

[0160] In the air conditioning apparatus 1A, the control device 10 performs the above-mentioned opening and closing control of the valve 16 and Figure 4 Controls shown.

[0161] Furthermore, the control device 10 controls the valve 56 to open when the temperature of the compressor 100 satisfies a preset condition. The preset condition is, for example, a threshold value of the temperature of the compressor 100. Specifically, it is the temperature of the compressor 100 or the temperature of the refrigerant discharged from the compression mechanism 120. The control device 10 opens the valve 56 when the temperature of the motor 110 or the temperature of the refrigerant discharged from the compression mechanism 120 exceeds a threshold value. By opening the valve 56, the control device 10 can supply liquid refrigerant to the motor 110 to reduce the temperature of the motor 110. Thus, the motor 110 can be cooled to suppress the disproportionation reaction.

[0162] Thus, the air conditioning apparatus 1A of Embodiment 3 includes: the pipe 55 for allowing the liquid working medium to flow into the container 102 of the compressor 100 through the pipe 41, the valve 56 for opening and closing the pipe 55, and the control device 10 for controlling the valve 56. The control device 10 controls the valve 56 to open when the temperature of the compressor 100 satisfies a preset condition.

[0163] Thus, the liquid refrigerant can be used to cool the motor 110. For example, when the motor 110 reaches a high temperature and is in a state where a disproportionation reaction of the refrigerant is likely to occur, or when it is estimated that a disproportionation reaction of the refrigerant has occurred, the motor 110 can be cooled. Therefore, the disproportionation reaction of the refrigerant can be suppressed or stopped.

[0164] (Implementation 4)

[0165] Figure 7 It is a diagram showing the configuration of an air-conditioning apparatus 2A according to Embodiment 4. Figure 7 The illustrated air-conditioning apparatus 2A is an example of a refrigeration circuit to which the present invention is applied.

[0166] The air conditioner 2A is in reference to Figure 5 The described air conditioning device 2 is provided with piping 57, valve 58, and valve 59. The configuration of each part other than piping 57, valve 58, and valve 59 is the same as that described in Embodiment 2, and thus the same reference numerals are given and the description thereof is omitted.

[0167] One end of the pipe 57 is connected to the pipe 48, and the liquid refrigerant flows from the gas-liquid separator 15 to the pipe 57. The pipe 57 is divided into two branches at the branch portion 205. The pipe 57 is connected to the connecting pipe 201 at the connecting portion 203, and is connected to the pipe 41 at the connecting portion 204. A valve 58 is provided between the branch portion 205 and the connecting portion 203, and a valve 59 is provided between the branch portion 205 and the connecting portion 204.

[0168] The valve 58 and the valve 59 are each constituted by, for example, an electromagnetic valve, and are opened and closed according to the control of the control device 20. The valves 58 and 59 may also be constituted by electromagnetic valves. In this case, the control device 20 can control the opening and closing of the valves 58 and 59 and can also adjust the opening degree of each of the valves 58 and 59. The pipe 57 corresponds to an example of a motor cooling circuit, and the valves 58 and 59 correspond to an example of a motor cooling valve.

[0169] When the valve 58 is opened, the liquid refrigerant stored in the gas-liquid separator 15 flows to the connecting pipe 201 through the pipe 57. The refrigerant is sucked into the second compressor 100B and vaporizes inside the second compressor 100B, thereby cooling the second compressor 100B.

[0170] With valve 59 opened, liquid refrigerant stored in gas-liquid separator 15 flows into pipe 41 through pipe 57. This refrigerant is sucked into first compressor 100A and vaporizes inside first compressor 100A, thereby cooling first compressor 100A.

[0171] In the air conditioning device 2A, as described in the second embodiment, the control device 20 performs the above-mentioned opening and closing control of the valve 16 and Figure 4 Controls shown.

[0172] Furthermore, the control device 20 controls the valves 58 and 59 to open when the temperature of the compressor 200 satisfies a preset condition. The preset condition is, for example, a threshold value of the temperature of the compressor 200. Specifically, it is the temperature of the motor included in the first compressor 100A and / or the motor included in the second compressor 100B, or the temperature of the discharged refrigerant of the first compressor 100A and / or the second compressor 100B. For example, when the temperature of the motor of the second compressor 100B or the temperature of the discharged refrigerant of the second compressor 100B exceeds the threshold value, the control device 20 opens the valve 58. By opening the valve 58, the control device 20 can make the second compressor 100B suck in liquid refrigerant, and reduce the temperature of the motor of the second compressor 100B and the discharged refrigerant of the second compressor 100B. In addition, for example, when the temperature of the motor of the first compressor 100A or the temperature of the discharged refrigerant of the first compressor 100A exceeds the threshold value, the control device 20 opens the valve 59. The control device 20 can open the valve 59 to allow the first compressor 100A to suck liquid refrigerant, thereby lowering the temperature of the motor of the first compressor 100A and the refrigerant discharged from the first compressor 100A. This can cool the compressor 200 to suppress or prevent the disproportionation reaction.

[0173] Thus, the air conditioning apparatus 2A of the fourth embodiment includes: the pipe 57 for allowing the liquid working medium to flow into the compressor 200 through the pipe 43, the valves 58 and 59 for opening and closing the pipe 57, and the control device 20 for controlling the valves 58 and 59. The control device 20 controls the valves 58 and 59 to open when the temperature of the compressor 200 satisfies a preset condition.

[0174] Thus, the compressor 200 can be cooled by allowing the refrigerant to flow into the compressor 200 through the pipe 43. For example, when the motor of the first compressor 100A or the second compressor 100B reaches a high temperature and becomes a state where a disproportionation reaction of the refrigerant is likely to occur, or when it is estimated that a disproportionation reaction of the refrigerant has occurred, the motor can be cooled. Therefore, the disproportionation reaction of the refrigerant can be suppressed or stopped.

[0175] (Implementation method 5)

[0176] Figure 8 This is a diagram showing the configuration of an air-conditioning apparatus 3 according to the fifth embodiment. Figure 8 The air-conditioning device 3 shown is an example of a refrigeration circuit to which the present invention is applied.

[0177] The air conditioning device 3 has the same Figure 1 to Figure 4 A portion of the common configurations of the air conditioning apparatus 1 described above are shown. These common configurations are denoted by the same reference numerals as those of Embodiment 1, and description thereof will be omitted.

[0178] The present invention is not limited to the air conditioning apparatuses 1, 1A, 2, and 2A of the above-described Embodiments 1 to 4, but can be applied to a refrigeration apparatus that can switch between cooling operation and heating operation. The air conditioning apparatus 3 corresponds to an example of such a refrigeration apparatus.

[0179] The air conditioner 3 includes: heat exchangers 11a and 11b as utilization-side heat exchangers; expansion valves 12a and 12b provided in pipes connected to the heat exchangers 11a and 11b; a heat exchanger 13 as a heat source-side heat exchanger; and an expansion valve 14 provided in a pipe 47 connected to the heat exchanger 13. In addition, the air conditioner 3 includes: a compressor 100; and a four-way valve 21 that switches the heat exchangers 11a and 11b or the heat exchanger 13 and connects to the pipe 42 on the discharge side of the compressor 100.

[0180] The air conditioning device 3 includes a control device 10A that controls the four-way valve 21. The control device 10A includes a processor such as a microcontroller, similarly to the control device 10. The control device 10A controls the air conditioning device 3 by executing a program by the processor or by the function of programmed hardware. The control device 10A controls the four-way valve 21 to switch between a cooling operation state and a heating operation state.

[0181] That is, the control device 10A connects the pipe 42 through which the high-pressure refrigerant is discharged from the compressor 100 to the pipe 46 connected to the heat exchanger 13, and connects the pipe 44 connected to the heat exchangers 11a and 11b to the pipe 41 on the suction side of the compressor 100 through the four-way valve 21. Thus, the air conditioning device 3 performs cooling operation. In the cooling operation state, the high-pressure refrigerant discharged from the compressor 100 is condensed in the heat exchanger 13 and is sent 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 and evaporates in the heat exchangers 11a and 11b, and is sucked into the compressor 100 through the pipe 41. Figure 8 1 shows the cooling operation state of the air-conditioning device 3. In the cooling operation state, the high-pressure part HP includes, for example, a compressor 100, a pipe 42 through which a high-pressure refrigerant flows, a four-way valve 21, and a heat exchanger 13.

[0182] When the air conditioner 3 performs heating operation under the control of the control device 10A, the high-pressure refrigerant discharged from the compressor 100 is condensed in the heat exchangers 11a and 11b and sent to the heat exchanger 13 via the expansion valve 14. The refrigerant is decompressed by the expansion valve 14, evaporates in the heat exchanger 13, and is sucked into the compressor 100 through the pipe 41. In the heating operation state of the air conditioner 3, the area HP includes the compressor 100, the pipe 42, the four-way valve 21, and the heat exchangers 11a and 11b, but they are not shown in the figure.

[0183] In this way, the air conditioning device 3 is a refrigeration device that can switch through the four-way valve 21 between cooling operation in which the heat exchanger 13 works as a condenser and heating operation in which the heat exchangers 11a and 11b work as condensers and the heat exchanger 13 works as an evaporator under the control of the control device 10A.

[0184] The air conditioning device 3 may also include one or more of a temperature sensor (not shown) for detecting the temperature of the motor 110 and a temperature sensor (not shown) for detecting the temperature of the refrigerant discharged from the compression mechanism 120. These temperature sensors are connected to the control device 10A. The control device 10A detects one or both of the temperature of the motor 110 and the temperature of the refrigerant discharged from the compression mechanism 120 by acquiring the detection value of the temperature sensor. In addition, the control device 10A may also calculate the pressure of the refrigerant discharged from the compression mechanism 120 based on the temperature of the refrigerant discharged from the compression mechanism 120. The air conditioning device 3 may also include a pressure sensor for detecting the pressure of the refrigerant discharged from the compression mechanism 120. In addition, the air conditioning device 3 may also include a heat exchanger temperature sensor (not shown) for detecting the temperature of the heat exchangers 11a, 11b and the heat exchanger 13. In this case, the control device 10A may calculate the pressure and temperature of the refrigerant discharged from the compression mechanism 120 based on the detection value of the heat exchanger temperature sensor, or may be configured not to include the above-mentioned temperature sensor.

[0185] The control device 10A executes the same operation as the control device 10. Figure 4 That is, when the control device 10A detects that the pressure of the refrigerant in the high-pressure portion HP has increased to or above the threshold value during the heating operation of the air-conditioning device 3, the control device 10A switches the air-conditioning device 3 to the cooling operation.

[0186] Thus, the air conditioning device 3 includes: a compressor 100, a heat exchanger 13 as a heat source side heat exchanger, heat exchangers 11a, 11b as a utilization side heat exchanger, and an expansion mechanism. The air conditioning device 3 includes a four-way valve 21 and a control device 10A, and the four-way valve 21 switches between a heating operation state in which the heat exchangers 11a, 11b work as condensers and a cooling operation state in which the heat exchanger 13 works as a condenser. The air conditioning device 3 uses a working medium containing ethylene fluoroolefin as a refrigerant. When the control device 10A detects that the pressure of the working medium of the high-pressure part including the compressor 100 and the condenser has risen to a threshold value in the heating operation state, the four-way valve 21 is controlled to switch from the heating operation state to the cooling operation state.

[0187] Thus, the air-conditioning device 3 can achieve low GWP by using a working medium containing ethylene fluoroolefins. In addition, when a disproportionation reaction of the refrigerant is likely to occur, or when it is inferred that a disproportionation reaction has occurred, the air-conditioning device 3 switches the air-conditioning device 3 from the heating operation state to the cooling operation state, so that the area HP where the high-pressure refrigerant flows is narrowed. Thus, the area HP where the pressure of the refrigerant rises sharply due to the disproportionation reaction can be limited, thereby suppressing the influence of the disproportionation reaction in the refrigeration cycle. For example, when the heat exchangers 11a and 11b are arranged in the conditioned space of the air-conditioning device 3 or in the vicinity thereof, the influence of the disproportionation reaction can be prevented or suppressed from spreading to the conditioned space through the control of the control device 10A.

[0188] The expansion mechanism includes an expansion valve 14 or expansion valves 12a, 12b arranged at the outlet of the condenser. The air conditioning device 3 includes a control device 10A that controls the expansion valves 12a, 12b, 14. When the control device 10A detects that the pressure of the working medium of the high-pressure part of the air conditioning device 3 has risen above a threshold value, it causes any one of the expansion valves 12a, 12b, 14 to move in the closing direction to a first opening degree, and then, when the pressure of the working medium of the high-pressure part stops rising, it causes the expansion valve to move in the closing direction to a second opening degree. The second opening degree is, for example, a fully closed state. The high-pressure part includes, for example, a compressor 100 and a condenser.

[0189] Thus, when a disproportionation reaction of the refrigerant is likely to have occurred or when it is estimated that a disproportionation reaction has occurred, the pressure rise accompanying the disproportionation reaction can be suppressed. Furthermore, after the pressure rise of the high-pressure portion stops, the valve is closed to the second opening degree, so that the propagation of the disproportionation reaction can be more reliably suppressed.

[0190] In the air conditioning device 3, similarly to the air conditioning device 1, a safety valve 60 may be provided in the pipe 42 through which the compressor 100 discharges the compressed refrigerant, and releases the pressure when the pressure in the pipe 42 is higher than the set pressure. In this case, when the pressure in the pipe 42 rises sharply due to the occurrence of the disproportionation reaction, the pressure in the pipe 42 can be released, and the influence of the disproportionation reaction can be reduced.

[0191] (Other embodiments)

[0192] As described above, the above-mentioned embodiments are described as examples recorded in this application. However, the technology of the present invention is not limited thereto, and can also be applied to embodiments that have been changed, replaced, added, omitted, etc. In addition, it is also possible to combine the various constituent elements described in the above-mentioned embodiments as new embodiments.

[0193] Therefore, other embodiments are exemplified below.

[0194] In the above-mentioned embodiment, as the pressure release unit provided in the piping 42, a structure using the release valve 60 also called an overflow valve is exemplified, but this is only an example. The pressure release unit may be a rupture disc (safety disc) that is broken and releases the pressure when the pressure in the piping 42 is higher than the set pressure.

[0195] The compressor 100 , the first compressor 100A, and the second compressor 100B in the above-described embodiment are not limited to scroll compressors, but may be rotary compressors or reciprocating compressors.

[0196] The structures of the various sensors included in the air conditioners 1, 1A, 2, and 2A are arbitrary. For example, the air conditioner 1 may include a temperature sensor that detects the temperature of the heat exchangers 11a, 11b, and 13, and the same is true for the air conditioners 1A, 2, and 2A. In addition, the air conditioners 1 and 1A may also include a refrigerant temperature sensor that detects the temperature of the refrigerant discharged from the compressor 100. In addition, the air conditioners 2 and 2A may also include a refrigerant temperature sensor that detects the temperature of the refrigerant discharged from the compressor 200. These sensors are appropriately connected to the control devices 10 and 20, and the control devices 10 and 20 can obtain the detection values ​​of the sensors.

[0197] (Structure supported by the above-mentioned embodiment)

[0198] The above-mentioned embodiment supports the following structure.

[0199] (Note)

[0200] (Technology 1) A refrigeration device, characterized in that it includes a compressor, a heat source side heat exchanger, a utilization side heat exchanger, an expansion mechanism, a switching valve and a control device, the switching valve being capable of switching between a heating operation state in which the utilization side heat exchanger works as a condenser and a cooling operation state in which the heat source side heat exchanger works as a condenser, the refrigeration device uses a working medium containing ethylene fluoroolefins as a refrigerant, and the control device controls the switching valve to switch from the heating operation state to the cooling operation state when it detects that the pressure of the working medium in the high-pressure part including the compressor and the condenser has risen above a threshold value in the heating operation state.

[0201] (Technology 2) A refrigeration device according to Technology 1, characterized in that: the expansion mechanism includes an expansion valve arranged at the outlet of the condenser, and when the control device detects that the pressure of the working medium in the high-pressure part including the compressor and the condenser has risen above a threshold value, the expansion valve is moved in the closing direction to a first opening degree, and thereafter, when the pressure rise of the working medium in the high-pressure part stops, the expansion valve is moved in the closing direction to a second opening degree.

[0202] (Technology 3) A refrigeration device according to Technology 1 or Technology 2, characterized in that a discharge pipe for discharging compressed refrigerant from the compressor has a pressure release unit for releasing pressure when the pressure in the discharge pipe is above a set pressure.

[0203] Industrial Applicability

[0204] As described above, the refrigeration device of the present invention can be used for air conditioning devices for cooling and heating the conditioned space, refrigerators with switching cooling and heating functions, refrigeration devices of freezers, refrigeration systems combining them, and other uses.

[0205] Description of Reference Numerals

[0206] 1, 1A, 2, 2A, 3 Air conditioning unit (refrigeration unit)

[0207] 10, 10A, 20 control device

[0208] 11a, 11b heat exchanger (heat exchanger on the utilization side)

[0209] 12a, 12b expansion valve

[0210] 13Heat exchanger (heat source side heat exchanger)

[0211] 14 Expansion valve

[0212] 15 Gas-liquid separator (refrigerant storage unit)

[0213] 16 valves

[0214] 20 Control device

[0215] 21, 22 four-way valve (switching valve)

[0216] 41 Piping (suction piping)

[0217] 42 piping (discharge piping)

[0218] 43 Piping (refrigerant piping)

[0219] 44, 45, 46, 47, 48, 49 piping

[0220] 55, 57 pipes (motor cooling circuit)

[0221] Valves 56, 58, 59 (motor cooling valves)

[0222] 60 Release valve (pressure relief unit)

[0223] 100, 200 compressor

[0224] 102 Containers

[0225] 103 Crankshaft

[0226] 104 Inlet (intake part)

[0227] 105 discharge pipe

[0228] 107, 108 bearings

[0229] 110 Electric Motor

[0230] 111 stator

[0231] 112 rotor

[0232] 116 drive circuit

[0233] 120 compression mechanism

[0234] 125 injection portion (refrigerant supply portion)

[0235] 100A first compressor (first compression mechanism)

[0236] 100B Second compressor (second compression mechanism)

[0237] 201 connecting pipe

[0238] 202 injection part (refrigerant supply part)

[0239] 203 connection

[0240] 204 connection

[0241] 205 branch.

Claims

1. A refrigeration device, characterized in that: The invention comprises a compressor, a heat exchanger on a heat source side, a heat exchanger on a utilization side, an expansion mechanism, a switching valve and a control device, wherein the switching valve can switch between a heating operation state in which the heat exchanger on the utilization side works as a condenser and a cooling operation state in which the heat exchanger on the heat source side works as a condenser. The refrigeration device uses a working medium containing ethylene fluoroolefin as a refrigerant. When the control device detects that the pressure of the working medium in the high-pressure portion including the compressor and the condenser has risen to or above a threshold value in the heating operation state, the control device controls the switching valve to switch from the heating operation state to the cooling operation state.

2. The refrigeration device according to claim 1, characterized in that: The expansion mechanism includes an expansion valve disposed at the outlet of the condenser. When the control device detects that the pressure of the working medium in the high-pressure part including the compressor and the condenser has risen above a threshold value, the control device moves the expansion valve in the closing direction to a first opening degree, and then, when the rise in the pressure of the working medium in the high-pressure part stops, the control device moves the expansion valve in the closing direction to a second opening degree.

3. The refrigeration device according to claim 1 or 2, characterized in that: A discharge pipe through which the compressor discharges compressed refrigerant is provided with a pressure relief unit for releasing pressure when the pressure in the discharge pipe is equal to or higher than a set pressure.

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