Abstract: A refrigeration cycle apparatus includes a refrigerant circuit in which refrigerant circulates in the order of a compressor, an oil separator, a first heat exchanger, a decompressing apparatus, and a second heat exchanger and returns to the compressor. The refrigeration cycle apparatus further includes: an oil reservoir that stores refrigeration oil; a first pipe that connects the oil separator and the oil reservoir, the first pipe sends the refrigeration oil separated by the oil separator to the oil reservoir; a second pipe that connects the oil reservoir and a suction side of the compressor; 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 heater that heats the refrigeration oil separated by the oil separator.

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 connected by a refrigerant pipe, and is configured to circulate refrigerant. The refrigerant circuit is configured to perform an oil recovery operation based on an operation history of the compressor during a normal operation of the refrigerant circuit and a property of the refrigerant circuit. The property of the refrigerant circuit includes at least one selected from the group of a length of the refrigerant pipe, a height difference of the refrigerant pipe, and an outside air temperature.

Abstract: An oil separator includes a separation container. The separation container has a side surface portion to which an inlet pipe is attached. The separation container has an upper surface portion to which an outlet pipe is attached. An oil reservoir is provided in a lower portion of the separation container. The separation container has a lower surface portion to which an oil return pipe is attached. The separation container has an inner wall surface provided with a liquid passage section. The liquid passage section is provided with a groove. The groove is disposed to extend in a direction of gravity toward the oil reservoir. The groove is formed to be gradually increased in depth from an upper portion of the groove toward a lower portion thereof.

Abstract: A heat exchanger includes a heat transfer tube. The heat transfer tube includes a first tube portion, and a plurality of 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 a plurality of 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 plurality of 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 plurality of first grooves are less than the plurality of second grooves in at least one of a number of grooves, a depth of each groove, and a lead angle of each groove.

Abstract: An oil separation device includes a container, an inlet pipe, an outlet pipe, an oil return pipe, and an oil return regulating valve. The container includes a separation chamber, a storage chamber, and a partition portion. The oil return regulating valve is connected to the oil return pipe. The partition portion is configured to allow the refrigeration oil separated from the fluid mixture to flow from the separation chamber to the storage chamber. The oil return regulating valve is configured to regulate the quantity of refrigeration oil that is returned from the storage chamber to the compressor.

Abstract: A refrigeration cycle apparatus includes a plurality of outdoor units. Each of the plurality of outdoor units includes an outdoor heat exchanger, a compressor, and a sensor to detect the quantity of refrigeration oil in the outdoor unit. A controller has a first operation mode in which a part of the plurality of outdoor units is operated and another outdoor unit is stopped; and a second operation mode in which all of the plurality of outdoor units are operated. In the first operation mode, when the operating time of an operating outdoor unit exceeds a prescribed time and the quantity of refrigeration oil in the compressor of the operating outdoor unit is equal to or larger than a prescribed quantity, the controller stops the operating outdoor unit and makes a switch to bring a stopped outdoor unit of the plurality of outdoor units into operation.

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: An oil separator includes a capturing member inside a main body container, which includes a first capturing member portion arranged on a side closer to an inflow pipe and a second capturing member portion being arranged on a side closer to an outflow pipe and having a porosity smaller than that of the first capturing member portion. Therefore, a driving force is generated by the capturing member having the different porosities. Through the driving force, a force of gravity, and a capillary phenomenon, oil inside the main body container is transported to an oil return pipe to prevent re-scattering of the oil, thereby being capable of suppressing reduction in oil separation efficiency. At the same time, oil return efficiency to the compressor is improved.

Abstract: A refrigeration cycle apparatus includes a compressor, first and second heat exchangers, an expansion valve, a four-way valve, and a controller. The four-way valve is configured to switch a direction of flow of the refrigerant between a first direction and a second direction. The controller is configured to control the four-way valve to switch an operation from a defrosting operation in which the refrigerant flows in the second direction, to a heating operation in which the refrigerant flows in the first direction, to perform a heating preparation control for increasing a degree of superheat of the refrigerant output to the compressor from the second heat exchanger, and thereafter to start the heating operation.

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 refrigeration cycle apparatus includes a refrigerant circuit, a fan configured to send air to a heat exchanger, and a controller. The controller is configured to switch among a first operation, a second operation, and a third operation. In the first operation, the heat exchanger is caused to act as an evaporator. In the second operation, the heat exchanger is caused to act as a radiator to defrost the heat exchanger. In the third operation that is performed after the second operation, a compressor is stopped and the fan is operated at a constant rotational speed. The controller is configured to finish the third operation and start the first operation when a physical value positively correlated with electric power supplied to the fan falls to or below a threshold value during the third operation.

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 refrigeration cycle apparatus includes a refrigerant circuit in which refrigerant circulates in the order of a compressor, an oil separator, a first heat exchanger, a decompressing apparatus, and a second heat exchanger and returns to the compressor. The refrigeration cycle apparatus further includes: an oil reservoir configured to store refrigeration oil; a first pipe and the oil reservoir, the first pipe being configured to send the refrigeration oil separated by the oil separator to the oil reservoir; a second pipe that connects the oil reservoir and a suction side of the compressor; 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 heater configured to heat the refrigeration oil separated by the oil separator.

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: An oil separator includes a separation container. The separation container has a side surface portion to which an inlet pipe is attached. The separation container has an upper surface portion to which an outlet pipe is attached. An oil reservoir is provided in a lower portion of the separation container. The separation container has a lower surface portion to which an oil return pipe is attached. The separation container has an inner wall surface provided with a liquid passage section. The liquid passage section is provided with a groove. The groove is disposed to extend in a direction of gravity toward the oil reservoir. The groove is formed to be gradually increased in depth from an upper portion of the groove toward a lower portion thereof.

Abstract: A refrigeration cycle apparatus includes: a compressor; a condenser; an expansion valve; an evaporator; and a control device. The compressor compresses refrigerant. The condenser condenses the refrigerant output from the compressor. The expansion valve decompresses the refrigerant output from the condenser. The evaporator evaporates the refrigerant output from the expansion valve for output to the compressor. In the case of stopping the compressor, the control device executes control for increasing a degree of superheat of the refrigerant output from the evaporator to the compressor, and then stops the compressor.

Abstract: An oil separation device includes a container, an inlet pipe, an outlet pipe, an oil return pipe, and an oil return regulating valve. The container includes a separation chamber, a storage chamber, and a partition portion. The oil return regulating valve is connected to the oil return pipe. The partition portion is configured to allow the refrigeration oil separated from the fluid mixture to flow from the separation chamber to the storage chamber. The oil return regulating valve is configured to regulate the quantity of refrigeration oil that is returned from the storage chamber to the compressor.

Abstract: A refrigeration cycle apparatus includes at least a compressor, a condenser, an internal heat exchanger configured to exchange heat between parts of refrigerant each having a different pressure, a refrigerant reservoir configured to store the refrigerant, a first pressure reducing device, an evaporator. The compressor, the condenser, the internal heat exchanger, the refrigerant reservoir, the first pressure reducing device, and the evaporator are sequentially connected to each other. The refrigeration cycle apparatus also includes a first pipe connecting the condenser and the refrigerant reservoir, and a second pressure reducing device provided to the first pipe between the internal heat exchanger and the refrigerant reservoir.

Abstract: A refrigeration cycle apparatus includes a plurality of outdoor units. Each of the plurality of outdoor units includes an outdoor heat exchanger, a compressor, and a sensor to detect the quantity of refrigeration oil in the outdoor unit. A controller has a first operation mode in which a part of the plurality of outdoor units is operated and another outdoor unit is stopped; and a second operation mode in which all of the plurality of outdoor units are operated. In the first operation mode, when the operating time of an operating outdoor unit exceeds a prescribed time and the quantity of refrigeration oil in the compressor of the operating outdoor unit is equal to or larger than a prescribed quantity, the controller stops the operating outdoor unit and makes a switch to bring a stopped outdoor unit of the plurality of outdoor units into operation.

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.