Abstract: A refrigerant circuit includes a compressor, a high-pressure side heat exchanger, a decompressor, and a low-pressure side heat exchanger, which are annularly interconnected by a refrigerant pipe, and is configured to circulate refrigerant. The refrigerant circuit performs an oil recovery operation based on an operation history of the compressor during a normal operation of the refrigerant circuit and an amount of oil in the compressor detected by an oil depletion sensor.

Abstract: A refrigeration cycle apparatus includes a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, a flow path switching valve, a first expansion valve, a second expansion valve, a third expansion valve, a refrigerant container, a first check valve, and a second check valve. The flow path switching valve switches a circulation direction of a non-azeotropic refrigerant mixture between a first circulation direction and a second circulation direction. A first port of the third expansion valve communicates with the refrigerant container through the third heat exchanger. A second port of the third expansion valve communicates through the first check valve with a first flow path between the first heat exchanger and the first expansion valve, and communicates through the second check valve with a second flow path between the second heat exchanger and the second expansion valve.

Abstract: An electrolytic cell capable of simply electrolyzing carbon dioxide into carbon monoxide and oxygen with low activation energy, and an electrolytic device. The carbon dioxide electrolytic cell includes a cathode, an anode, and a solid electrolyte having oxide ion conductivity. The cathode is the following (A) or (B); (A) a metal and a first mayenite-type compound are included therein or (B) a metal and a second mayenite-type compound are included therein, said second mayenite type compound including a mayenite type compound having electron conductivity.

Abstract: An air conditioning apparatus includes: a refrigerant circuit that includes a compressor, an outdoor heat exchanger, an indoor heat exchanger, and a pressure reducing device, and that is configured to circulate refrigerant; a plurality of sensors configured to detect a state of the refrigerant circuit; and a controller configured to control the refrigerant circuit based on detection results of the plurality of sensors, and the controller is configured to compare a determination value that is obtained based on a detection value of a sensor selected from the plurality of sensors, with a threshold value that is obtained based on a detection value of a sensor selected from the plurality of sensors, and determine, based on a comparison result, whether or not a reference amount of refrigerating machine oil is stored in the compressor.

Abstract: A heat exchanger includes a heat transfer tube. The heat transfer tube includes a first tube portion, and second tube portions connected in parallel with each other with respect to the first tube portion. The first tube portion has a first inner circumferential surface, and first grooves recessed relative to the first inner circumferential surface and arranged side by side in a circumferential direction of the heat transfer tube. The second tube portions each have a second inner circumferential surface, and a plurality of second grooves recessed relative to the second inner circumferential surface and arranged side by side in the circumferential direction. The first grooves are less than the second grooves in one or more of a number of grooves, a depth of each groove, and a lead angle of each groove.

Abstract: A refrigeration cycle apparatus includes a flow path switching apparatus. In a first operation mode, the flow path switching apparatus is configured to cause a second port and a second refrigerant port of a second heat exchanger to communicate with a suction port of a compressor via a four-way valve. In a second operation mode, the flow path switching apparatus is configured to cause the second port to communicate with the second refrigerant port of the second heat exchanger without the second port and the second refrigerant port of the second heat exchanger communicating with the suction port of the compressor, and cause a discharge port of the compressor to communicate with a first refrigerant port of the second heat exchanger via the four-way valve.

Abstract: A refrigeration cycle apparatus comprises: a compressor; a first heat exchanger; a second heat exchanger; a first decompressing apparatus; an oil separator; a first circulation pathway in which a refrigerant circulates in an order of the compressor, the first heat exchanger, the oil separator, the first decompressing apparatus, and the second heat exchanger; an oil-returned pathway connecting between the oil separator and a suction side of the compressor; a second decompressing apparatus provided in the oil-returned pathway; and a controller configured to control the first decompressing apparatus and the second decompressing apparatus. The controller is configured to set an operation mode to an oil collection mode by adjusting a degree of decompression of the first decompressing apparatus and a degree of decompression of the second decompressing apparatus when the refrigerant and a refrigerating machine oil flowing in the first circulation pathway are separated in the oil separator.

Abstract: A controller is configured to: execute control for prohibiting an operating frequency of a compressor from increasing when a stop frequency of the compressor exceeds a prescribed value and when a degree of superheat of the refrigerant output from the compressor is lower than a set value after start of an operation of the compressor, the stop frequency being a frequency at which the compressor stops when the degree of superheat is lower than the set value; and permit the operating frequency of the compressor to increase when the stop frequency is equal to or less than the prescribed value.

Abstract: An air conditioner is a refrigeration cycle apparatus in which incompatible oil is employed as refrigerating machine oil, and includes a compressor to compress refrigerant, a first heat exchanger to condense the refrigerant output from the compressor, a pressure reducing device to reduce a pressure of the refrigerant output from the first heat exchanger, and a second heat exchanger to evaporate the refrigerant output from the pressure reducing device and output the resultant refrigerant to the compressor. The second heat exchanger includes a heat transfer tube having a groove formed on an inner surface of the heat transfer tube. The groove of the heat transfer tube is formed such that an inner surface area of the heat transfer tube on a downstream side of the heat transfer tube is smaller than an inner surface area on an upstream side of the heat transfer tuber.

Abstract: A refrigeration cycle apparatus includes: a refrigerant circuit configured to circulate refrigerant; and a controller configured to control the refrigerant circuit. The refrigerant circuit includes a compressor, a first heat exchanger, a first expansion device, a second expansion device, a third expansion device, a second heat exchanger, and a cooler configured to cool a substrate of the controller. In a first path of the refrigerant circuit, the compressor, the first heat exchanger, the first expansion device, the second expansion device, and the second heat exchanger are connected in order of the compressor, the first heat exchanger, the first expansion device, the second expansion device, and the second heat exchanger.

Abstract: The refrigerant circulation direction is switched between first and second circulation directions. In the first circulation direction, the refrigerant is circulated in order of a first heat exchanger, a compressor, a second heat exchanger, and a first decompressor, and circulated in order of the first heat exchanger, the compressor, a third heat exchanger, and a second decompressor. A controller identifies a specific heat exchanger from among the second heat exchanger and the third heat exchanger. When an elapsed time from activation of the compressor is shorter than a reference time, the controller makes an opening degree of a specific decompressor that communicates with the specific heat exchanger larger than an opening degree of the decompressor that is among the first decompressor and the second decompressor and different from the specific decompressor, and sets the refrigerant circulation direction to the second circulation direction opposite to the first circulation.

Abstract: In a refrigeration cycle apparatus, a refrigerant pipe is connected to a compressor, a first heat exchanger, an expansion valve, a second heat exchanger, a heat absorber, and the compressor sequentially in this order. R290 is used as refrigerant flowing through the refrigerant pipe. The heat absorber is provided in a portion of the refrigerant pipe between the compressor and the first heat exchanger or the second heat exchanger serving as an evaporator. The heat absorber is disposed in contact with an electric component. A branch pipe is connected in parallel with the portion provided with the heat absorber in the refrigerant pipe. The branch pipe is provided with a flow rate regulating valve.

Abstract: When a controller receives an instruction for a heating operation, the controller switches an operation mode of a refrigeration cycle apparatus between a heating operation mode and an oil recovery operation mode. The heating operation mode is a mode to circulate refrigerant in a refrigerant circuit such that the refrigerant flows through a gas extension pipe in a gas phase state. The oil recovery operation mode is a mode to circulate the refrigerant in the refrigerant circuit such that the refrigerant flows in the gas extension pipe in a gas-liquid two-phase state. The direction in which the refrigerant flows in the gas extension pipe in the oil recovery operation mode is opposite to that in which the refrigerant flows in the gas extension pipe in the heating operation mode.

Abstract: A gas-liquid separation device comprises a container, an inlet tube, a liquid outlet tube, a gas outlet tube, and a swirl vane. The swirl vane is disposed in the inlet tube. A depression is provided on an inner circumferential surface of the inlet tube. The depression faces the swirl vane.

Abstract: In a refrigeration cycle apparatus, refrigerant circulates in order of a compressor, first and second heat exchangers. The refrigeration cycle apparatus has a refrigerant container, first and second switch units, and a controller. When a first condition meaning that an amount of refrigerant in liquid state stored in the refrigerant container is excessive is satisfied, the controller controls the first switch unit to guide the refrigerant from the compressor to the first heat exchanger through the refrigerant container and controls the second switch unit to guide the refrigerant from the second heat exchanger to the compressor not through the refrigerant container. When the first condition is not satisfied, the controller controls the first switch unit to guide the refrigerant from the compressor to the first heat exchanger not through the refrigerant container and controls the second switch unit to guide the refrigerant from the refrigerant container to the compressor.

Abstract: In a refrigeration cycle apparatus, refrigerant circulates successively through a compressor, a condenser, an expansion valve, and an evaporator. The refrigeration cycle apparatus includes a detection unit, a heating unit, and a controller. The detection unit is configured to detect a temperature of refrigeration oil in the compressor. The heating unit is configured to heat the refrigeration oil. The controller is configured to operate the heating unit when the temperature detected by the detection unit is lower than a pour point of the refrigeration oil, and to stop the heating by the heating unit when the temperature detected by the detection unit reaches the pour point. Preferably, the heating unit includes a heater provided on an outer side of a compressor casing and at a lower portion of a motor unit.

Abstract: An oil separator has a filter portion in a differential pressure generation mechanism configured to collect, by a differential pressure, lubricating oil that is in a form of mist included in high-pressure refrigerant that flows in a first pipe that is connected to a discharge port of a compressor and allows the collected lubricating oil to move downstream along an internal wall of the first pipe.

Abstract: Provided are a separator with improved oil separation efficiency, and a refrigeration cycle apparatus including the separator. The separator includes an inflow pipe portion, an oil storage portion, an oil return pipe portion, and an outflow pipe portion. The inflow pipe portion includes a swirling portion that defines a flow direction of refrigerant so as to swirl the refrigerant. The oil storage portion is connected to the inflow pipe portion. The oil return pipe portion is connected to a vertically lower side of the oil storage portion. The outflow pipe portion includes an opening end that faces the swirling portion. The outflow pipe portion extends from a region that faces the swirling portion to the outside of the oil storage portion. The opening end is configured such that the refrigerant discharged from the swirling portion can directly flow thereinto.

Abstract: A refrigeration cycle apparatus includes: a refrigerant circuit; an oil reservoir; a first pipe that connects the oil separator and the oil reservoir, the first pipe being configured to send the refrigeration oil separated by the oil separator to the oil reservoir; a first valve provided at the first pipe; a second pipe that connects the oil reservoir and a suction side of the compressor; a second valve provided at the second pipe; a third pipe that connects the oil reservoir and the suction side of the compressor at a position lower than a position at which the second pipe is connected to the oil reservoir; and a third valve provided at the third pipe. The first to third valves are closed in a non-operational period of the compressor.

Abstract: A refrigerant circuit includes a compressor, a high-pressure side heat exchanger, a decompressor, and a low-pressure side heat exchanger, which are annularly interconnected by a refrigerant pipe, and is configured to circulate refrigerant. The refrigerant circuit performs an oil recovery operation based on an operation history of the compressor ring a normal operation of the refrigerant circuit and an amount of oil in the compressor detected by an oil depletion sensor.