JP2013108735A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle device improving refrigeration efficiency, while properly recovering oil content flowing to a refrigeration circuit.SOLUTION: The refrigeration cycle device includes a refrigerant circuit 10 which is formed by sequentially connecting, with refrigerant pipes 16: an evaporator 11; a compression mechanism 12 for sucking and compressing refrigerant evaporated by the evaporator 11; a heat radiator 13 dissipating heat from the refrigerant compressed by the compression mechanism 12; a branching mechanism 14 for branching the refrigerant from which heat has been dissipated by the heat radiator 13, into two flows, decompressing one refrigerant by a refrigerant decompressor 144, and causing an intermediate cooler 145 to cool the other refrigerant by using evaporation action of the decompressed refrigerant; and an expansion mechanism 15 for adiabatically expanding the refrigerant cooled by the intermediate cooler 145 and supplying it to the evaporator 11. The refrigerant cycle device further includes an oil separating mechanism 17 that causes an oil separator 171 to separate oil content contained in the refrigerant compressed by the compression mechanism 12, decompresses the separated oil content by an auxiliary decompressor 173, and cools the refrigerant whose heat has been dissipated by the heat radiator 13, with the decompressed oil content.

Description

  The present invention relates to a refrigeration cycle apparatus.

  2. Description of the Related Art Conventionally, a refrigeration cycle apparatus applied to a showcase, a vending machine or the like that employs a two-stage compression / single-stage expansion refrigeration cycle using carbon dioxide as a refrigerant is known. Such a refrigeration cycle apparatus has a refrigerant circuit in which carbon dioxide is enclosed. The refrigerant circuit includes an evaporator, a compression mechanism, a radiator, a diversion mechanism, and an expansion mechanism as refrigerant piping. Are connected in sequence.

  An evaporator is a heat exchanger that cools ambient air by evaporating supplied refrigerant. The compression mechanism includes a first compressor that sucks and compresses the refrigerant evaporated by the evaporator, an intermediate heat exchanger that dissipates the refrigerant compressed by the first compressor, and a refrigerant that dissipates heat by the intermediate heat exchanger And a second compressor for compressing.

  The radiator is a heat exchanger that heats ambient air by dissipating the refrigerant compressed by the compression mechanism. The diversion mechanism diverts the refrigerant radiated by the radiator into a refrigerant that passes through the first refrigerant flow path and a refrigerant that passes through the second refrigerant flow path, and depressurizes the refrigerant that passes through the first refrigerant flow path. The refrigerant passing through the second refrigerant flow path is cooled by the intermediate cooler by the evaporation action of the refrigerant reduced in pressure by the decompressor. The expansion mechanism adiabatically expands the refrigerant cooled by the intermediate cooler in the flow dividing mechanism and sends it to the evaporator.

  In such a refrigeration cycle device, the enthalpy at the inlet of the evaporator is reduced by cooling the refrigerant passing through the second refrigerant flow path to the refrigerant passing through the first refrigerant flow path in the intermediate cooler in the flow dividing mechanism, Thereby, a freezing performance coefficient can be increased.

  Then, in order to collect the oil component that has flowed out into the refrigerant circuit, the oil component is separated from the refrigerant that has radiated heat by the radiator with the oil separator, and the oil component passes through the first refrigerant flow path together with the refrigerant that has been divided by the flow divider. And returned to the compression mechanism (see, for example, Patent Document 1).

JP 2008-249209 A

  By the way, in the refrigeration cycle apparatus proposed in Patent Document 1 described above, since the oil component is separated from the refrigerant radiated by the radiator, the refrigerant (carbon dioxide) that is in a supercritical state in the pipe of the radiator. Oil components dissolved or mixed in are supplied. Therefore, the heat exchange between the refrigerant and the ambient air in the radiator is hindered by the oil component, resulting in a decrease in the heat exchange performance in the radiator and the refrigeration efficiency.

  In view of the above circumstances, an object of the present invention is to provide a refrigeration cycle apparatus capable of improving the refrigeration efficiency while appropriately collecting the oil component flowing out to the refrigerant circuit.

  In order to achieve the above object, a refrigeration cycle apparatus according to claim 1 of the present invention includes an evaporator that evaporates supplied refrigerant, a compression mechanism that sucks and compresses refrigerant evaporated in the evaporator, and A heat radiator that radiates the refrigerant compressed by the compression mechanism and a refrigerant radiated by the heat radiator are divided into two, and one of the divided refrigerant is depressurized by the refrigerant depressurizer, and depressurized by this refrigerant depressurizer. Refrigerant piping includes a flow dividing mechanism that cools the other refrigerant divided by the evaporation of the refrigerant with an intermediate cooler, and an expansion mechanism that adiabatically expands the refrigerant cooled by the intermediate cooler in the flow dividing mechanism and sends the refrigerant to the evaporator. In the refrigeration cycle apparatus having a refrigerant circuit configured to be sequentially connected to each other, an oil component contained in the refrigerant compressed by the compression mechanism is separated by an oil separator, and the separated oil component is supplemented by an auxiliary pressure reducer. Reducing the pressure, characterized by the oil component was depressurized further comprising an oil separation mechanism for cooling the refrigerant radiated by the radiator. Here, the “oil component” separated by the oil separation mechanism includes not only the lubricating oil but also a refrigerant mixed with the lubricating oil.

  The refrigeration cycle apparatus according to claim 2 of the present invention is the refrigeration cycle apparatus according to claim 1, wherein the oil separation mechanism is disposed in a refrigerant pipe extending from the compression mechanism to the radiator and is compressed by the compression mechanism. An oil separator that separates the oil component contained in the refrigerant, an oil separation passage that guides the oil component separated by the oil separator to the compression mechanism, and the oil separation passage. An auxiliary pressure reducer that depressurizes the oil component that passes through the oil separation flow path, and a supercooler that cools the other refrigerant divided by the flow dividing mechanism by the oil component reduced in pressure by the auxiliary pressure reducer. It is characterized by that.

  The refrigeration cycle apparatus according to a third aspect of the present invention is the refrigeration cycle apparatus according to the first aspect, wherein the oil separation mechanism is disposed in a refrigerant pipe extending from the compression mechanism to the radiator and is compressed by the compression mechanism. An oil separator that separates the oil component contained in the refrigerant, an oil separation passage that guides the oil component separated by the oil separator to the compression mechanism, and the oil separation passage. An auxiliary pressure reducer that depressurizes the oil component that passes through the oil separation flow path, and a supercooler that cools the refrigerant that passes through the refrigerant pipe extending from the radiator to the flow dividing mechanism by the oil component reduced in pressure by the auxiliary pressure reducer. It is characterized by comprising.

  Moreover, the refrigeration cycle apparatus according to claim 4 of the present invention is the refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the oil separation mechanism is separated by the oil separator toward the auxiliary pressure reducer. An oil cooler that dissipates heat from the oil component passing therethrough is provided.

  The refrigeration cycle apparatus according to claim 5 of the present invention is characterized in that, in any one of claims 1 to 4 described above, the refrigerant is carbon dioxide.

  According to the present invention, since the oil separation mechanism separates the oil component contained in the refrigerant compressed by the compression mechanism by the oil separator, the oil component can be suppressed from being supplied to the radiator. It is possible to avoid a decrease in the heat exchange performance. In addition, the oil component separated by the oil separator is decompressed by the auxiliary decompressor, and the refrigerant dissipated by the radiator is cooled by the decompressed oil component, so the cooling effect of the intermediate cooler is also combined. Thus, the enthalpy of the refrigerant reaching the expansion mechanism can be sufficiently reduced. The amount of change in enthalpy in the evaporator can be sufficiently increased, and the refrigeration performance coefficient can be improved. Therefore, it is possible to improve the refrigeration efficiency while appropriately collecting the oil component flowing out to the refrigerant circuit.

FIG. 1 is a schematic diagram showing a refrigeration cycle apparatus according to Embodiment 1 of the present invention. FIG. 2 is a Ph diagram (Mollier diagram) of the refrigerant circuit in the refrigeration cycle apparatus shown in FIG. FIG. 3 is a schematic diagram showing a refrigeration cycle apparatus according to Embodiment 2 of the present invention. FIG. 4 is a Ph diagram (Mollier diagram) of the refrigerant circuit in the refrigeration cycle apparatus shown in FIG. 3. FIG. 5 is a schematic diagram showing a refrigeration cycle apparatus according to Embodiment 3 of the present invention. 6 is a Ph diagram (Mollier diagram) of a refrigerant circuit in the refrigeration cycle apparatus shown in FIG.

  Exemplary embodiments of a refrigeration cycle apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings.

<Embodiment 1>
FIG. 1 is a schematic diagram showing a refrigeration cycle apparatus according to Embodiment 1 of the present invention. The refrigeration cycle apparatus exemplified here is applied to a showcase or the like, and cools the internal atmosphere of a container to be cooled, and has a refrigerant circuit 10 in which a refrigerant (for example, carbon dioxide) is enclosed. Yes.

  The refrigerant circuit 10 circulates the refrigerant, and is configured by sequentially connecting an evaporator 11, a compression mechanism 12, a radiator 13, a branching mechanism 14, and an expansion mechanism 15 through a refrigerant pipe 16.

  The evaporator 11 is a heat exchanger that is disposed in the storage and cools the internal atmosphere of the storage by evaporating the supplied refrigerant.

  The compression mechanism 12 is disposed outside the storage, and is configured by sequentially connecting a first compressor 121, an intermediate heat exchanger 122, and a second compressor 123 through a compressed refrigerant channel 124. It is. The first compressor 121 sucks and compresses the refrigerant evaporated in the evaporator 11. The intermediate heat exchanger 122 radiates and cools the refrigerant compressed by the first compressor 121. The second compressor 123 sucks and compresses the refrigerant radiated by the intermediate heat exchanger 122.

  The heat radiator 13 is disposed outside the housing similarly to the compression mechanism 12, and dissipates heat by exchanging heat between the refrigerant compressed by the compression mechanism 12, that is, the refrigerant compressed by the second compressor 123, with ambient air. Heat exchanger. The radiator 13 has a pipe through which the refrigerant passes separated from the pipe in the intermediate heat exchanger 122, but the fins penetrating these pipes are shared so that the intermediate heat It is integrated with the exchanger 122.

  Similar to the compression mechanism 12 and the radiator 13, the flow dividing mechanism 14 is disposed outside the storage, and includes a flow divider 141, a refrigerant decompressor 144, and an intermediate cooler 145. The flow divider 141 divides the refrigerant radiated by the radiator 13 into two, sends one of the divided refrigerant to the first refrigerant flow path 142, and sends the other refrigerant to the second refrigerant flow path 143. Is. Here, the first refrigerant flow path 142 has one end connected to the flow divider 141 and the other end connected to the compressed refrigerant flow path 124 via the merger 146, and is divided and sent by the flow divider 141. One refrigerant is passed through the compressed refrigerant channel 124. The second refrigerant flow path 143 has one end connected to the flow divider 141 and the other end connected to the refrigerant pipe 16 connected to the expansion mechanism 15. The other refrigerant flow path 143 is divided and sent by the flow divider 141. The refrigerant is passed through the expansion mechanism 15.

  The refrigerant pressure reducer 144 is disposed in the first refrigerant flow path 142, and is constituted by, for example, an expansion valve whose opening degree (pressure reduction amount) can be adjusted. The refrigerant decompressor 144 decompresses and expands the refrigerant passing through the first refrigerant flow path 142.

  The intercooler 145 passes through the first refrigerant channel 142 and the refrigerant (one refrigerant) decompressed by the refrigerant decompressor 144 and the refrigerant (the other refrigerant) that passes through the second refrigerant channel 143. It is a heat exchanger that exchanges heat. That is, the intermediate cooler 145 cools the refrigerant passing through the second refrigerant flow path 143 by the evaporation action of the refrigerant depressurized by the refrigerant depressurizer 144.

  The expansion mechanism 15 is disposed outside the storage. The expansion mechanism 15 is constituted by, for example, an expansion valve, a capillary tube, or the like, and is supplied by a refrigerant pipe 16 connected in a manner communicating with its own inlet, that is, an intermediate cooler 145 in the flow dividing mechanism 14. The cooled refrigerant is decompressed to adiabatically expand to a gas-liquid two-phase state (low-pressure refrigerant), and is sent to the evaporator 11.

  The refrigerant circuit 10 having such a configuration has an oil separation mechanism 17 in addition to the above configuration. The oil separation mechanism 17 includes an oil separator 171, an oil separation channel 172, an auxiliary pressure reducer 173, and a supercooler 174.

  The oil separator 171 is disposed in the refrigerant pipe 16 extending from the compression mechanism 12 to the radiator 13. The oil separator 171 separates an oil component (lubricant and refrigerant mixed with the lubricant) contained in the refrigerant compressed by the compression mechanism 12, that is, dissolves or mixes into the refrigerant from a refrigerant in a supercritical state. It separates the combined oil components.

  The oil separation channel 172 is a channel for guiding the oil component separated by the oil separator 171 to a predetermined oil reservoir of the compression mechanism 12.

  The auxiliary decompressor 173 is disposed in the oil separation channel 172. The auxiliary pressure reducer 173 depressurizes the oil component that passes through the oil separation channel 172. More specifically, the auxiliary pressure reducer 173 can cool the refrigerant radiated by the radiator 13 by the reduced oil component. The oil component is decompressed.

  The subcooler 174 exchanges heat to exchange heat between the oil component that has passed through the oil separation channel 172 and has been decompressed by the auxiliary decompressor 173, and the refrigerant (the other refrigerant) that has passed through the second refrigerant channel 143. It is a vessel. That is, the supercooler 174 cools the refrigerant passing through the second refrigerant flow path 143 by the oil component decompressed by the auxiliary decompressor 173.

  In the refrigeration cycle apparatus of the first embodiment having the configuration described above, the refrigerant circulates in the refrigerant circuit 10 as described below, thereby cooling the internal atmosphere of the container in which the evaporator 11 is disposed. can do. Here, FIG. 2 is a Ph diagram (Mollier diagram) of the refrigerant circuit in the refrigeration cycle apparatus shown in FIG. 1 and will be described using this Ph diagram.

  The refrigerant sucked into the compression mechanism 12 is compressed by the first compressor 121, passes through the compressed refrigerant flow path 124, and is discharged to the intermediate heat exchanger 122 (a → b process). The refrigerant discharged to the intermediate heat exchanger 122 is radiated and cooled by exchanging heat with ambient air (b → c process). The refrigerant cooled by the intermediate heat exchanger 122 is sucked and compressed by the second compressor 123 through the compressed refrigerant flow path 124, and discharged in a high-temperature and high-pressure supercritical state (step c → d). In the refrigerant discharged in such a supercritical state, the lubricating oil of the first compressor 121 and the second compressor 123 constituting the compression mechanism 12 is dissolved or mixed.

  The refrigerant discharged from the compression mechanism 12 is separated into oil components by the oil separator 171. The separated oil component passes through the oil separation channel 172 and is decompressed by the auxiliary decompressor 173. The oil component decompressed by the auxiliary decompressor 173 passes through the oil separation flow path 172 and is guided to a predetermined oil reservoir of the compression mechanism 12 via the supercooler 174.

  By the way, the refrigerant from which the oil component has been separated by the oil separator 171 passes through the refrigerant pipe 16 and is sent to the radiator 13. The refrigerant sent to the radiator 13 is cooled by releasing heat by exchanging heat with ambient air (d → e process). The refrigerant cooled by the radiator 13 passes through the refrigerant pipe 16 and passes through the first refrigerant flow path 142 in the flow divider 141 constituting the flow dividing mechanism 14, and the second refrigerant flow path. The refrigerant is diverted to the refrigerant passing through 143 (the other refrigerant).

  The refrigerant passing through the first refrigerant flow path 142 is depressurized by the refrigerant depressurizer 144 (e → f process), then reaches the merger 146 via the intermediate cooler 145, and merges with the compressed refrigerant flow path 124. Then, it is sucked into the second compressor 123 (process of f → c).

  The refrigerant passing through the second refrigerant flow path 143 is cooled by exchanging heat with the oil component passing through the oil separation flow path 172 in the subcooler 174 (e → e ′ process). The refrigerant cooled to the oil component then reaches the intermediate cooler 145 and is further cooled by the evaporating action of the refrigerant passing through the first refrigerant flow path 142 decompressed by the refrigerant decompressor 144 in the intermediate cooler 145. (E ′ → g process).

  The refrigerant cooled in the intermediate cooler 145 in this way reaches the expansion mechanism 15 through the refrigerant pipe 16, is decompressed by the expansion mechanism 15 and adiabatically expands, and is supplied to the evaporator 11 through the refrigerant pipe 16 (g → The process of h). The refrigerant supplied to the evaporator 11 exchanges heat with the internal atmosphere of the storage and evaporates to cool the internal atmosphere of the storage (h → a process). Thereby, the goods stored in the storage can be cooled.

  The refrigerant evaporated in the evaporator 11 reaches the compression mechanism 12 by being sucked by the first compressor 121 constituting the compression mechanism 12 and repeats circulation in the refrigerant circuit 10.

  In the refrigeration cycle apparatus according to the first embodiment as described above, the oil component separated by the oil separator 171 is decompressed by the auxiliary decompressor 173, and the second refrigerant flow path 143 is defined by the subcooler 174. Since the passing refrigerant is cooled (e → e ′ process), the enthalpy of the refrigerant reaching the expansion mechanism 15 can be sufficiently reduced in combination with the cooling effect in the intermediate cooler 145. That is, the enthalpy of the refrigerant reaching the expansion mechanism 15 can be reduced even when compared with the conventional refrigeration cycle apparatus indicated by the chain line in FIG.

  Thereby, the amount of change in enthalpy in the process of h → a can be sufficiently increased, and the refrigeration coefficient of performance defined by the following formula (1) can be improved.

Formula (1)
Freezing performance coefficient = (h (a) −h (h)) / ((h (b) −h (a)) + (h (d) −h (c)))
Here, h (a), h (b), h (c), h (d), and h (h) are specific enthalpies at symbols a, b, c, d, and h in FIG. 1, respectively.

  Further, in the refrigeration cycle apparatus, since the oil component is separated by the oil separator 171 from the refrigerant discharged from the compression mechanism 12 and supplied to the radiator 13, the oil component is supplied to the radiator 13. Can be suppressed. Thereby, the fall of the heat exchange performance in the heat radiator 13 can be avoided.

  Therefore, according to the refrigeration cycle apparatus of the first embodiment, the refrigeration coefficient of performance can be improved, and the oil component is separated from the refrigerant discharged from the compression mechanism 12 by the oil separator 171 to remove the oil component. Since it can collect | recover and the fall of the heat exchange performance in the heat radiator 13 can be avoided, the improvement of refrigeration efficiency can be aimed at, collect | recovering the oil components which flow into the refrigerant circuit 10 appropriately.

<Embodiment 2>
FIG. 3 is a schematic diagram showing a refrigeration cycle apparatus according to Embodiment 2 of the present invention. The refrigeration cycle apparatus exemplified here is applied to a showcase or the like, and cools the internal atmosphere of a container to be cooled, and has a refrigerant circuit 20 in which a refrigerant (for example, carbon dioxide) is enclosed. Yes.

  The refrigerant circuit 20 circulates the refrigerant, and is configured by sequentially connecting an evaporator 21, a compression mechanism 22, a radiator 23, a branching mechanism 24, and an expansion mechanism 25 through a refrigerant pipe 26.

  The evaporator 21 is a heat exchanger that is disposed in the storage and cools the internal atmosphere of the storage by evaporating the supplied refrigerant.

  The compression mechanism 22 is disposed outside the storage, and is configured by sequentially connecting a first compressor 221, an intermediate heat exchanger 222, and a second compressor 223 through a compressed refrigerant flow path 224. It is. The first compressor 221 sucks and compresses the refrigerant evaporated in the evaporator 21. The intermediate heat exchanger 222 cools the refrigerant compressed by the first compressor 221 by releasing heat. The second compressor 223 sucks and compresses the refrigerant radiated by the intermediate heat exchanger 222.

  The heat radiator 23 is disposed outside the housing similarly to the compression mechanism 22 and dissipates heat by exchanging heat between the refrigerant compressed by the compression mechanism 22, that is, the refrigerant compressed by the second compressor 223, with the ambient air. Heat exchanger. In the radiator 23, the pipe through which the refrigerant passes is separated from the pipe in the intermediate heat exchanger 222, but the fins penetrating these pipes are shared, so that the intermediate heat It is integrated with the exchanger 222.

  Similar to the compression mechanism 22 and the radiator 23, the shunt mechanism 24 is disposed outside the storage, and includes a shunt 241, a refrigerant decompressor 244, and an intermediate cooler 245. The flow divider 241 divides the refrigerant radiated by the radiator 23 into two, sends one of the divided refrigerant to the first refrigerant channel 242 and sends the other refrigerant to the second refrigerant channel 243. Is. Here, one end of the first refrigerant flow path 242 is connected to the flow divider 241, and the other end is connected to the compressed refrigerant flow path 224 via the merger 246, and the first refrigerant flow path 242 is divided and sent by the flow divider 241. One refrigerant is passed through the compressed refrigerant channel 224. The second refrigerant flow path 243 has one end connected to the flow divider 241 and the other end connected to the refrigerant pipe 26 connected to the expansion mechanism 25. The other refrigerant flow path 243 is divided and sent by the flow divider 241. The refrigerant is passed through the expansion mechanism 25.

  The refrigerant pressure reducer 244 is disposed in the first refrigerant flow path 242 and is constituted by, for example, an expansion valve whose opening degree (pressure reduction amount) can be adjusted. The refrigerant decompressor 244 decompresses and expands the refrigerant passing through the first refrigerant flow path 242.

  The intermediate cooler 245 passes through the first refrigerant flow path 242 and the refrigerant (one refrigerant) decompressed by the refrigerant decompressor 244 and the refrigerant (the other refrigerant) that passes through the second refrigerant flow path 243. It is a heat exchanger that exchanges heat. That is, the intermediate cooler 245 cools the refrigerant passing through the second refrigerant flow path 243 by the evaporation action of the refrigerant depressurized by the refrigerant depressurizer 244.

  The expansion mechanism 25 is disposed outside the container. The expansion mechanism 25 is constituted by, for example, an expansion valve, a capillary tube, or the like, and is supplied by a refrigerant pipe 26 connected in a manner communicating with its own inlet, that is, an intermediate cooler 245 in the flow dividing mechanism 24. The cooled refrigerant is depressurized and adiabatically expanded to form a gas-liquid two-phase state (low-pressure refrigerant) and sent to the evaporator 21.

  The refrigerant circuit 20 having such a configuration has an oil separation mechanism 27 in addition to the above configuration. The oil separation mechanism 27 includes an oil separator 271, an oil separation channel 272, an auxiliary decompressor 273, and a supercooler 274.

  The oil separator 271 is disposed in the refrigerant pipe 26 extending from the compression mechanism 22 to the radiator 23. The oil separator 271 separates oil components (lubricating oil and refrigerant mixed with the lubricating oil) contained in the refrigerant compressed by the compression mechanism 22, that is, dissolves or mixes into the refrigerant from the refrigerant in a supercritical state. It separates the combined oil components.

  The oil separation channel 272 is a channel for guiding the oil component separated by the oil separator 271 to a predetermined oil reservoir of the compression mechanism 22.

  The auxiliary decompressor 273 is disposed in the oil separation channel 272. The auxiliary decompressor 273 decompresses the oil component that passes through the oil separation channel 272. More specifically, the auxiliary decompressor 273 can cool the refrigerant that has been radiated by the radiator 23 by the decompressed oil component. The oil component is decompressed.

  The subcooler 274 passes through the oil separation channel 272 and the oil component decompressed by the auxiliary decompressor 273 and the refrigerant that radiates heat from the radiator 23 and passes through the refrigerant pipe 26 toward the flow divider 241. It is a heat exchanger that exchanges heat. That is, the subcooler 274 cools the refrigerant that has radiated heat from the radiator 23 by the oil component depressurized by the auxiliary decompressor 273.

  In the refrigeration cycle apparatus of the second embodiment having the above-described configuration, the refrigerant circulates in the refrigerant circuit 20 as described below, thereby cooling the internal atmosphere of the container in which the evaporator 21 is disposed. can do. Here, FIG. 4 is a Ph diagram (Mollier diagram) of the refrigerant circuit in the refrigeration cycle apparatus shown in FIG. 3 and will be described with reference to the Ph diagram.

  The refrigerant sucked by the compression mechanism 22 is compressed by the first compressor 221, passes through the compressed refrigerant flow path 224, and is discharged to the intermediate heat exchanger 222 (i → j process). The refrigerant discharged to the intermediate heat exchanger 222 is cooled by releasing heat by exchanging heat with ambient air (process of j → k). The refrigerant cooled by the intermediate heat exchanger 222 is sucked and compressed by the second compressor 223 through the compressed refrigerant flow path 224, and is discharged in a high-temperature and high-pressure supercritical state (process of k → m). In the refrigerant discharged in such a supercritical state, the lubricating oil of the first compressor 221 and the second compressor 223 constituting the compression mechanism 22 is dissolved or mixed.

  The refrigerant discharged from the compression mechanism 22 is separated into oil components by the oil separator 271. The separated oil component passes through the oil separation channel 272 and is decompressed by the auxiliary decompressor 273. The oil component decompressed by the auxiliary decompressor 273 passes through the oil separation channel 272 and is guided to a predetermined oil reservoir of the compression mechanism 22 via the supercooler 274.

  Incidentally, the refrigerant from which the oil component has been separated by the oil separator 271 passes through the refrigerant pipe 26 and is sent to the radiator 23. The refrigerant sent to the radiator 23 is cooled by releasing heat by exchanging heat with ambient air (process of m → n).

  The refrigerant cooled by the radiator 23 is cooled by exchanging heat with the oil component passing through the oil separation channel 272 in the subcooler 274 (process of n → n ′). The refrigerant cooled to the oil component passes through the refrigerant pipe 26 and passes through the first refrigerant flow path 242 in the flow divider 241 constituting the flow dividing mechanism 24, and the second refrigerant flow path 243. To the refrigerant passing through (the other refrigerant).

  The refrigerant passing through the first refrigerant flow path 242 is depressurized by the refrigerant depressurizer 244 (the process of n ′ → o), and then reaches the merger 246 via the intermediate cooler 245 and enters the compressed refrigerant flow path 224. It merges and is sucked into the second compressor 223 (process of o → k).

  The refrigerant passing through the second refrigerant flow path 243 then reaches the intermediate cooler 245, and the refrigerant evaporates through the first refrigerant flow path 242 decompressed by the refrigerant depressurizer 244 in the intermediate cooler 245. Is further cooled (process of n ′ → p).

  The refrigerant thus cooled by the intermediate cooler 245 reaches the expansion mechanism 25 through the refrigerant pipe 26, is decompressed by the expansion mechanism 25 and adiabatically expands, and is supplied to the evaporator 21 through the refrigerant pipe 26 (p). → The process of q). The refrigerant supplied to the evaporator 21 exchanges heat with the internal atmosphere of the storage and evaporates to cool the internal atmosphere of the storage (process of q → i). Thereby, the goods stored in the storage can be cooled.

  The refrigerant evaporated in the evaporator 21 is sucked into the first compressor 221 constituting the compression mechanism 22 to reach the compression mechanism 22 and repeats circulation in the refrigerant circuit 20.

  In the refrigeration cycle apparatus according to the second embodiment as described above, the oil component separated by the oil separator 271 is decompressed by the auxiliary decompressor 273 and the refrigerant radiated by the radiator 23 by the subcooler 274. Is cooled (in the process of n → n ′), the cooling effect in the intercooler 245 can be combined to sufficiently reduce the enthalpy of the refrigerant reaching the expansion mechanism 25. That is, the enthalpy of the refrigerant reaching the expansion mechanism 25 can be reduced even when compared with the conventional refrigeration cycle apparatus indicated by the chain line in FIG.

  Thereby, the amount of change in enthalpy in the process of q → i can be sufficiently increased, and the refrigeration coefficient of performance defined by the following equation (2) can be improved.

Formula (2)
Freezing performance coefficient = (h (i) −h (q)) / ((h (j) −h (i)) + (h (m) −h (k)))
Here, h (i), h (j), h (k), h (m), and h (q) are specific enthalpies at symbols i, j, k, m, and q in FIG.

  Further, in the refrigeration cycle apparatus, since the oil component is separated by the oil separator 271 from the refrigerant discharged from the compression mechanism 22 and supplied to the radiator 23, the oil component is supplied to the radiator 23. Can be suppressed. Thereby, the fall of the heat exchange performance in the heat radiator 23 can be avoided.

  Therefore, according to the refrigeration cycle apparatus according to the second embodiment, the refrigeration performance coefficient can be improved, and the oil component is separated from the refrigerant discharged from the compression mechanism 22 by the oil separator 271 to remove the oil component. Since it can collect | recover and the fall of the heat exchange performance in the heat radiator 23 can be avoided, the improvement of refrigeration efficiency can be aimed at, collect | recovering the oil components which flow into the refrigerant circuit 20 appropriately.

<Embodiment 3>
FIG. 5 is a schematic diagram showing a refrigeration cycle apparatus according to Embodiment 3 of the present invention. The refrigeration cycle apparatus exemplified here is applied to a showcase or the like, and cools the internal atmosphere of a container to be cooled, and has a refrigerant circuit 30 in which a refrigerant (for example, carbon dioxide) is enclosed. Yes.

  The refrigerant circuit 30 circulates the refrigerant, and is configured by sequentially connecting an evaporator 31, a compression mechanism 32, a radiator 33, a flow dividing mechanism 34, and an expansion mechanism 35 through a refrigerant pipe 36.

  The evaporator 31 is a heat exchanger that is disposed in the storage and cools the internal atmosphere of the storage by evaporating the supplied refrigerant.

  The compression mechanism 32 is disposed outside the storage, and is configured by sequentially connecting a first compressor 321, an intermediate heat exchanger 322, and a second compressor 323 through a compressed refrigerant channel 324. It is. The first compressor 321 sucks and compresses the refrigerant evaporated in the evaporator 31. The intermediate heat exchanger 322 radiates and cools the refrigerant compressed by the first compressor 321. The second compressor 323 sucks and compresses the refrigerant radiated by the intermediate heat exchanger 322.

  The heat radiator 33 is disposed outside the housing similarly to the compression mechanism 32, and dissipates heat by exchanging heat between the refrigerant compressed by the compression mechanism 32, that is, the refrigerant compressed by the second compressor 323, with the ambient air. Heat exchanger. In the radiator 33, the pipe through which the refrigerant passes is separated from the pipe in the intermediate heat exchanger 322, but the fins penetrating the pipes are shared so that the intermediate heat It is integrated with the exchanger 322.

  Similar to the compression mechanism 32 and the heat radiator 33, the flow dividing mechanism 34 is disposed outside the container, and includes a flow divider 341, a refrigerant decompressor 344, and an intermediate cooler 345. The flow divider 341 divides the refrigerant radiated by the radiator 33 into two, sends one of the divided refrigerant to the first refrigerant channel 342, and sends the other refrigerant to the second refrigerant channel 343. Is. Here, the first refrigerant flow path 342 has one end connected to the flow divider 341 and the other end connected to the compressed refrigerant flow path 324 via the merger 346, and is divided and sent by the flow divider 341. One refrigerant is passed through the compressed refrigerant flow path 324. The second refrigerant flow path 343 has one end connected to the flow divider 341 and the other end connected to the refrigerant pipe 36 connected to the expansion mechanism 35. The other refrigerant flow path 343 is divided and sent by the flow divider 341. The refrigerant is passed through the expansion mechanism 35.

  The refrigerant pressure reducer 344 is disposed in the first refrigerant flow path 342, and is constituted by, for example, an expansion valve whose opening degree (pressure reduction amount) can be adjusted. The refrigerant decompressor 344 decompresses and expands the refrigerant passing through the first refrigerant flow path 342.

  The intermediate cooler 345 passes the first refrigerant flow path 342 and the refrigerant (one refrigerant) decompressed by the refrigerant decompressor 344 and the refrigerant (the other refrigerant) that passes the second refrigerant flow path 343. It is a heat exchanger that exchanges heat. That is, the intermediate cooler 345 cools the refrigerant passing through the second refrigerant flow path 343 by the evaporation action of the refrigerant depressurized by the refrigerant depressurizer 344.

  The expansion mechanism 35 is disposed outside the storage. The expansion mechanism 35 is constituted by, for example, an expansion valve, a capillary tube, or the like, and is supplied by a refrigerant pipe 36 connected in a manner communicating with its own inlet, that is, an intermediate cooler 345 in the flow dividing mechanism 34. The cooled refrigerant is decompressed and adiabatically expanded to form a gas-liquid two-phase state (low-pressure refrigerant) and sent to the evaporator 31.

  The refrigerant circuit 30 having such a configuration has an oil separation mechanism 37 in addition to the above configuration. The oil separation mechanism 37 includes an oil separator 371, an oil separation channel 372, an oil cooler 373, an auxiliary decompressor 374, and a supercooler 375.

  The oil separator 371 is disposed in the refrigerant pipe 36 extending from the compression mechanism 32 to the radiator 33. The oil separator 371 separates an oil component (lubricating oil and a refrigerant mixed with the lubricating oil) contained in the refrigerant compressed by the compression mechanism 32, that is, dissolves or mixes the refrigerant in a supercritical state with the refrigerant. It separates the combined oil components.

  The oil separation channel 372 is a channel for guiding the oil component separated by the oil separator 371 to a predetermined oil reservoir of the compression mechanism 32.

  The oil cooler 373 is disposed in the oil separation channel 372. The oil cooler 373 is a heat exchanger that cools the oil component passing through the oil separation flow path 372 by dissipating heat by exchanging heat with ambient air. In the oil cooler 373, pipes through which oil components pass are separated from the pipes in the intermediate heat exchanger 322 and the radiator 33, but fins penetrating through these pipes are shared. Therefore, the intermediate heat exchanger 322 and the radiator 33 are integrated.

  The auxiliary decompressor 374 is disposed in the oil separation channel 372. The auxiliary pressure reducer 374 depressurizes the oil component that has passed through the oil separation flow path 372 and has been cooled by the oil cooler 373, and more specifically, the refrigerant in which the reduced oil component has dissipated heat by the radiator 33. The oil component is depressurized to such an extent that it can be cooled.

  The subcooler 375 exchanges heat to exchange heat between the oil component that has passed through the oil separation channel 372 and has been decompressed by the auxiliary decompressor 374, and the refrigerant (the other refrigerant) that has passed through the second refrigerant channel 343. It is a vessel. That is, the subcooler 375 cools the refrigerant passing through the second refrigerant flow path 343 with the oil component decompressed by the auxiliary decompressor 374.

  In the refrigeration cycle apparatus of the third embodiment having the above-described configuration, the refrigerant circulates in the refrigerant circuit 30 as described below, thereby cooling the internal atmosphere of the container in which the evaporator 31 is disposed. can do. Here, FIG. 6 is a Ph diagram (Mollier diagram) of the refrigerant circuit in the refrigeration cycle apparatus shown in FIG. 5 and will be described with reference to the Ph diagram.

  The refrigerant sucked by the compression mechanism 32 is compressed by the first compressor 321, passes through the compressed refrigerant flow path 324, and is discharged to the intermediate heat exchanger 322 (r → s process). The refrigerant discharged to the intermediate heat exchanger 322 is radiated and cooled by exchanging heat with ambient air (s → t process). The refrigerant cooled by the intermediate heat exchanger 322 is sucked and compressed by the second compressor 323 through the compressed refrigerant flow path 324, and discharged in a high-temperature and high-pressure supercritical state (process t → u). In the refrigerant discharged in such a supercritical state, the lubricating oil of the first compressor 321 and the second compressor 323 constituting the compression mechanism 32 is dissolved or mixed.

  The refrigerant discharged from the compression mechanism 32 is separated into oil components by the oil separator 371. The separated oil component passes through the oil separation channel 372 and is sent to the oil cooler 373. The oil component sent to the oil cooler 373 is cooled by releasing heat by exchanging heat with the ambient air. The oil component cooled by the oil cooler 373 is decompressed by the auxiliary decompressor 374. The oil component decompressed by the auxiliary decompressor 374 passes through the oil separation channel 372 and is guided to a predetermined oil reservoir of the compression mechanism 32 via the supercooler 375.

  By the way, the refrigerant from which the oil component has been separated by the oil separator 371 passes through the refrigerant pipe 36 and is sent to the radiator 33. The refrigerant sent to the radiator 33 is cooled by releasing heat by exchanging heat with ambient air (process u → v). The refrigerant cooled by the radiator 33 passes through the refrigerant pipe 36 and passes through the first refrigerant flow path 342 in the flow divider 341 constituting the flow dividing mechanism 34, and the second refrigerant flow path. The refrigerant is diverted to the refrigerant passing through H.343 (the other refrigerant).

  The refrigerant passing through the first refrigerant flow path 342 is depressurized by the refrigerant depressurizer 344 (v → w process), then reaches the merger 346 via the intermediate cooler 345, and merges with the compressed refrigerant flow path 324. Then, it is sucked into the second compressor 323 (process of w → t).

  The refrigerant passing through the second refrigerant flow path 343 is cooled by exchanging heat with the oil component passing through the oil separation flow path 372 in the subcooler 375 (process of v → v ′). The refrigerant cooled to the oil component then reaches the intermediate cooler 345 and is further cooled by the evaporating action of the refrigerant passing through the first refrigerant flow path 342 decompressed by the refrigerant decompressor 344 in the intermediate cooler 345. (V ′ → x process).

  The refrigerant thus cooled by the intermediate cooler 345 reaches the expansion mechanism 35 through the refrigerant pipe 36, is decompressed by the expansion mechanism 35 and adiabatically expands, and is supplied to the evaporator 31 through the refrigerant pipe 36 (x → y process). The refrigerant supplied to the evaporator 31 exchanges heat with the internal atmosphere of the storage box and evaporates to cool the internal atmosphere of the storage room (process of y → r). Thereby, the goods stored in the storage can be cooled.

  The refrigerant evaporated in the evaporator 31 is sucked into the first compressor 321 constituting the compression mechanism 32 to reach the compression mechanism 32 and repeats circulation in the refrigerant circuit 30.

  In the refrigeration cycle apparatus according to the third embodiment as described above, the oil component separated by the oil separator 371 is radiated and cooled by the oil cooler 373, and further depressurized by the auxiliary decompressor 374. Since the refrigerant passing through the second refrigerant flow path 343 is cooled by the subcooler 375 (process of v → v ′), the cooling effect in the intermediate cooler 345 is combined to reach the expansion mechanism 35. The enthalpy of the refrigerant can be sufficiently reduced. That is, the enthalpy of the refrigerant reaching the expansion mechanism 35 can be reduced as compared with the conventional refrigeration cycle apparatus indicated by the chain line in FIG.

  Thereby, the amount of change in enthalpy in the process of y → r can be sufficiently increased, and the refrigeration coefficient of performance defined by the following formula (3) can be improved.

Formula (3)
Freezing performance coefficient = (h (r) −h (y)) / ((h (s) −h (r)) + (h (u) −h (t)))
Here, h (r), h (s), h (t), h (u), and h (y) are specific enthalpies at symbols r, s, t, u, and y in FIG.

  In the refrigeration cycle apparatus, since the oil component is separated by the oil separator 371 from the refrigerant discharged from the compression mechanism 32 and supplied to the radiator 33, the oil component is supplied to the radiator 33. Can be suppressed. Thereby, the fall of the heat exchange performance in the heat radiator 33 can be avoided.

  Therefore, according to the refrigeration cycle apparatus of the third embodiment, the refrigeration coefficient of performance can be improved, and the oil component is separated from the refrigerant discharged from the compression mechanism 32 by the oil separator 371 to remove the oil component. Since it can collect | recover and the fall of the heat exchange performance in the heat radiator 33 can be avoided, the improvement of refrigeration efficiency can be aimed at, collect | recovering the oil components which flow into the refrigerant circuit 30 appropriately.

  Although preferred embodiments 1 to 3 of the present invention have been described above, the present invention is not limited to these and various modifications can be made.

  In the refrigeration cycle apparatus of the third embodiment described above, the oil cooler 373 is added to the refrigeration cycle apparatus of the first embodiment. However, in the present invention, an oil cooler is added to the refrigeration cycle apparatus of the second embodiment. It may be added. With such a configuration, it is possible to improve the refrigeration efficiency while properly collecting the oil component flowing out to the refrigerant circuit.

  In the above-described refrigeration cycle apparatus of the second embodiment, the supercooler 274 is separated from the radiator 23. However, in the present invention, the supercooler may be integrated with the radiator.

  As described above, the refrigeration cycle apparatus according to the present invention is useful for cooling a product to a desired temperature in, for example, a showcase.

DESCRIPTION OF SYMBOLS 10 Refrigerant circuit 11 Evaporator 12 Compression mechanism 121 1st compressor 122 Intermediate heat exchanger 123 2nd compressor 124 Compressed refrigerant flow path 13 Radiator 14 Divergence mechanism 141 Divider 142 142 1st refrigerant flow path 143 2nd refrigerant flow path 144 Refrigerant decompressor 145 Intermediate cooler 146 Merger 15 Expansion mechanism 16 Refrigerant piping 17 Oil separation mechanism 171 Oil separator 172 Oil separation flow path 173 Auxiliary decompressor 174 Subcooler 20 Refrigerant circuit 21 Evaporator 22 Compression mechanism 221 First Compressor 222 Intermediate heat exchanger 223 Second compressor 224 Compressed refrigerant flow path 23 Radiator 24 Divergence mechanism 241 Divider 242 First refrigerant flow path 243 Second refrigerant flow path 244 Refrigerant decompressor 245 Intermediate cooler 246 Merger 25 Expansion mechanism 26 Refrigerant piping 27 Oil separation mechanism 271 Oil separator 272 Oil separation flow path 273 Auxiliary reduction Compressor 274 Supercooler 30 Refrigerant circuit 31 Evaporator 32 Compression mechanism 321 First compressor 322 Intermediate heat exchanger 323 Second compressor 324 Compressed refrigerant flow path 33 Heat radiator 34 Shunt mechanism 341 Divider 342 First refrigerant flow path 343 Second refrigerant flow path 344 Refrigerant pressure reducer 345 Intermediate cooler 346 Merger 35 Expansion mechanism 36 Refrigerant piping 37 Oil separation mechanism 371 Oil separator 372 Oil separation flow path 373 Oil cooler 374 Auxiliary pressure reducer 375 Supercooler

Claims (5)

An evaporator for evaporating the supplied refrigerant;
A compression mechanism for sucking and compressing the refrigerant evaporated in the evaporator;
A radiator that dissipates heat of the refrigerant compressed by the compression mechanism;
The refrigerant radiated by the radiator is divided into two, one of the divided refrigerant is depressurized by the refrigerant depressurizer, and the other refrigerant divided by the evaporating action of the refrigerant depressurized by the refrigerant depressurizer is the intermediate cooler A shunt mechanism that is cooled by
In the refrigeration cycle apparatus including a refrigerant circuit configured by adiabatically expanding the refrigerant cooled by the intermediate cooler in the diversion mechanism and sending the refrigerant to the evaporator sequentially connected by a refrigerant pipe,
The oil component contained in the refrigerant compressed by the compression mechanism is separated by an oil separator, the separated oil component is decompressed by an auxiliary decompressor, and the refrigerant dissipated by the radiator is cooled by the decompressed oil component. A refrigeration cycle apparatus comprising an oil separation mechanism that performs the operation. The oil separation mechanism is
An oil separator that is disposed in a refrigerant pipe extending from the compression mechanism to the radiator, and that separates an oil component contained in the refrigerant compressed by the compression mechanism;
An oil separation flow path for guiding the oil component separated by the oil separator to the compression mechanism;
An auxiliary pressure reducer disposed in the oil separation channel and depressurizing an oil component passing through the oil separation channel;
The refrigeration cycle apparatus according to claim 1, further comprising: a supercooler that cools the other refrigerant divided by the diversion mechanism by the oil component depressurized by the auxiliary pressure reducer. The oil separation mechanism is
An oil separator that is disposed in a refrigerant pipe extending from the compression mechanism to the radiator, and that separates an oil component contained in the refrigerant compressed by the compression mechanism;
An oil separation flow path for guiding the oil component separated by the oil separator to the compression mechanism;
An auxiliary pressure reducer disposed in the oil separation channel and depressurizing an oil component passing through the oil separation channel;
2. A refrigeration cycle according to claim 1, further comprising: a supercooler that cools a refrigerant that passes through a refrigerant pipe extending from the radiator to the flow dividing mechanism by an oil component decompressed by the auxiliary decompressor. apparatus.   The said oil separation mechanism was equipped with the oil cooler which thermally radiates the oil component isolate | separated by the said oil separator and passing toward the said auxiliary pressure reduction device, The Claim 1 characterized by the above-mentioned. Refrigeration cycle equipment.   The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the refrigerant is carbon dioxide.

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