Abstract: A heat source unit and a refrigeration cycle apparatus that are able to reduce damage to a connection pipe when a refrigerant containing at least 1,2-difluoroethylene is used are provided. An outdoor unit (20) that is connected via a liquid-side connection pipe (6) and a gas-side connection pipe (5) to an indoor unit (30) including an indoor heat exchanger (31) and that is a component of an air conditioner (1) includes a compressor (21) and an outdoor heat exchanger (23). A refrigerant containing at least 1,2-difluoroethylene is used as a refrigerant. A design pressure of the outdoor unit (20) is lower than 1.5 times a design pressure of each of the liquid-side connection pipe (6) and the gas-side connection pipe (5).

Abstract: A refrigeration cycle apparatus capable of keeping a LCCP low when a heat cycle is performed using a sufficiently small-GWP refrigerant, and a method of determining a refrigerant enclosure amount in the refrigeration cycle apparatus are provided. An outdoor unit (20) including a compressor (21) and an outdoor heat exchanger (23), an indoor unit (30) including an indoor heat exchanger (31), and a refrigerant pipe (5, 6) that connects the outdoor unit (20) and the indoor unit (30) to each other are provided. A refrigerant containing at least 1,2-difluoroethylene is enclosed in a refrigerant circuit (10) that is constituted by connecting the compressor (21), the outdoor heat exchanger (23), and the indoor heat exchanger (31) to one another. An enclosure amount of the refrigerant in the refrigerant circuit (10) per 1 kW of refrigeration capacity satisfies a condition of 160 g or more and 560 g or less.

Abstract: A refrigeration cycle apparatus that is able to reduce the amount of refrigerant used while reducing a pressure loss in the case where a refrigerant containing at least 1,2-difluoroethylene is used is provided. In an air conditioner (1) including a refrigerant circuit (10), including a compressor (21), an outdoor heat exchanger (23), an outdoor expansion valve (24), and an indoor heat exchanger (31), and a refrigerant containing at least 1,2-difluoroethylene and sealed in the refrigerant circuit (10), the outdoor heat exchanger (23) has a heat transfer tube (23b) of which a pipe diameter is greater than or equal to 6.35 mm and less than 10.0 mm.

Abstract: A control unit (19) that controls the operation of a refrigerant circuit (10) executes pump down operation in which a non-azeotropic refrigerant mixture is collected into a portion of the refrigerant circuit (10) within an outdoor unit (2), executes compositional ratio determination in which the compositional ratio of the non-azeotropic refrigerant mixture is determined based on the pressure and temperature of the non-azeotropic refrigerant mixture collected into the outdoor unit (2) by the pump down operation, and generates an alert when the compositional ratio of the non-azeotropic refrigerant mixture determined by the compositional ratio determination is outside an acceptable proportion range of a hydrofluorocarbon having the property of undergoing a disproportionation reaction.

Abstract: A refrigeration apparatus includes a refrigerant circuit including: a compressor, a radiator, an expansion mechanism, and an evaporator that are connected. The refrigerant circuit encloses a refrigerant that contains a fluorinated hydrocarbon that causes a disproportionation reaction. The refrigerant circuit further includes: a discharged refrigerant recovery receiver that is branch-connected to a path between a discharge side of the compressor and a gas side of the radiator through a discharged refrigerant branch pipe; and a discharged refrigerant relief mechanism that is disposed in the discharged refrigerant branch pipe and that connects discharge side of the compressor with the discharged refrigerant recovery receiver when the refrigerant on the discharge side of the compressor satisfies a predetermined condition.

Abstract: A refrigeration apparatus includes a multistage compression mechanism, a heat-source-side main heat exchanger, at least one heat-source-side sub heat exchanger, a usage-side heat exchanger, a switching mechanism, an expansion mechanism and a refrigerant piping group. The refrigerant piping group connects the multistage compression mechanism, the switching mechanism, the heat-source-side main heat exchanger, the heat-source-side sub heat exchanger, the expansion mechanism and the usage-side heat exchanger so that during the heating operation, the heat-source-side main heat exchanger and the heat-source-side sub heat exchanger are connected in series.

Abstract: A refrigeration apparatus includes a multistage compression mechanism, switching mechanisms, intercoolers, oil separators, and a control unit. The multistage compression mechanism has one high-stage-side compression mechanism and a plurality of low-stage-side compression mechanisms connected in series. The switching mechanisms are connected to blow-out pipes of the low-stage-side compression mechanisms. The switching mechanisms switch between cooling and heating operation cycles. The intercoolers cool refrigerant blown out from the low-stage-side compression mechanisms during the cooling cycle. The oil separators are disposed between the switching mechanisms and the intercoolers. The oil separators separate lubricating oil from refrigerant blown out from the low-stage-side compression mechanisms during the cooling cycle. The control unit controls the multi-stage compression mechanism and the switching mechanisms.

Abstract: A refrigeration apparatus includes a multistage compression mechanism, a heat-source-side main heat exchanger, at least one heat-source-side sub heat exchanger, a usage-side heat exchanger, a switching mechanism, an expansion mechanism and a refrigerant piping group. The refrigerant piping group connects the multistage compression mechanism, the switching mechanism, the heat-source-side main heat exchanger, the heat-source-side sub heat exchanger, the expansion mechanism and the usage-side heat exchanger so that during the heating operation, the heat-source-side main heat exchanger and the heat-source-side sub heat exchanger are connected in series.

Abstract: A refrigeration apparatus includes a multistage compression mechanism, switching mechanisms, intercoolers, oil separators, and a control unit. The multistage compression mechanism has one high-stage-side compression mechanism and a plurality of low-stage-side compression mechanisms connected in series. The switching mechanisms are connected to blow-out pipes of the low-stage-side compression mechanisms. The switching mechanisms switch between cooling and heating operation cycles. The intercoolers cool refrigerant blown out from the low-stage-side compression mechanisms during the cooling cycle. The oil separators are disposed between the switching mechanisms and the intercoolers. The oil separators separate lubricating oil from refrigerant blown out from the low-stage-side compression mechanisms during the cooling cycle. The control unit controls the multi-stage compression mechanism and the switching mechanisms.

Abstract: In an outdoor unit, first through third intermediate heat exchangers and an outdoor heat exchanger are disposed to stand along an air inlet of an outdoor casing, and the outdoor heat exchanger is located above the first through third intermediate heat exchangers.

Abstract: In a refrigerant circuit (5) of an air conditioner (1), a single-stage compression refrigeration cycle is performed. In the refrigerant circuit (5), a second heat exchanger (40) is provided downstream a first heat exchanger (30). In the first heat exchanger (30), high-pressure refrigerant of a high-pressure flow path (31) is cooled by exchanging heat with first intermediate-pressure refrigerant of an intermediate-pressure flow path (32). First intermediate-pressure gas refrigerant generated in the first heat exchanger (30) is supplied to a first compression mechanism (71). Second intermediate-pressure refrigerant having a pressure lower than that of the first intermediate-pressure refrigerant is supplied to an intermediate-pressure flow path (42) of the second heat exchanger (40). In the second heat exchanger (40), high-pressure refrigerant of a high-pressure flow path (41) is further cooled by exchanging heat with the second intermediate-pressure refrigerant of the intermediate-pressure flow path (42).