A refrigeration cycle device includes a heat source, a first use unit, a second use unit, a first connection flow path, and a second connection flow path. The heat source has a compressor and a heat-source side heat exchanger. The first use unit is separated from the heat source unit and has a first use-side heat exchanger. The second use unit is separated from the heat source unit and has a second use-side heat exchanger. The first connection flow path connects the heat source unit to the first and the second use units and causes a first refrigerant to flow. The second connection flow path connects the heat source unit to the first and the second use units and causes a second refrigerant to flow. A specific enthalpy of the second refrigerant is smaller than a specific enthalpy of the first refrigerant.

A cooling system uses P-traps to address the oil return issues that result from a vertical separation between a compressor and a heat exchanger. Generally, the vertical piping that carries the refrigerant from the compressor to the heat exchanger includes P-traps installed at various heights to capture oil in the refrigerant and to prevent that oil from flowing back to the compressor. T-connections are coupled to the P-traps to allow the oil to drain out of the P-traps. The oil may then be collected and returned to the compressor.

A method for operating a refrigeration system for a motor vehicle. The method includes setting an operating mode of the refrigeration system having active primary line and inactive secondary line or having active secondary line and inactive primary line; detecting the pressure in the inactive line; and activating and extraction of refrigerant from the inactive line into the active line by lowering the pressure in the active line to a value below the pressure in the inactive line and by opening the relevant valve device.

A refrigerant pipe of a refrigeration apparatus includes: a first pipe, made of stainless steel, through which a refrigerant flows; a joint pipe, made of a material different from stainless steel, disposed on an outer peripheral surface of the first pipe; and a second pipe, having a diameter smaller than a diameter of the first pipe, connected to the outer peripheral surface of the first pipe via the joint pipe. A surface of the second pipe at which the second pipe is connected to the joint pipe is made of a material identical to the material of the joint pipe.

A heat exchanger includes heat exchanger cores connected to a distributor. The inside of the distributor is divided into refrigerant flow paths, allowing the refrigerant to flow from one of the refrigerant flow paths to another one of the refrigerant flow paths. The heat transfer tubes of one of the heat exchanger cores disposed on a windward side of a flow of the air fed to the heat exchanger are connected to at least one of the refrigerant flow paths disposed in the distributor on an upstream side of a flow of the refrigerant. The heat transfer tubes of one of the heat exchanger cores disposed on a leeward side of the flow of the air fed to the heat exchanger are connected to at least one of the refrigerant flow paths disposed in the distributor on a downstream side of the flow of the refrigerant.

A refrigerant distributor branches refrigerant flowing in a refrigerant circuit into three, and includes a first bifurcate flow divider including a first pipe portion forming one inflow port, a second pipe portion and a third pipe portion forming two outflow ports communicating with the inflow port of the first pipe portion, and a second bifurcate flow divider including a fourth pipe portion forming one inflow port, and a fifth pipe portion and a sixth pipe portion forming two outflow ports communicating with the inflow port of the fourth pipe portion. The outflow port of the third pipe portion and the inflow port of the fourth pipe portion communicate with each other, and an angle θ formed by a first plane passing through the first bifurcate flow divider and a second plane passing through the second bifurcate flow divider is between 60 and 120 degrees.

A refrigerant distributor branches refrigerant flowing in a refrigerant circuit into three, and includes a first bifurcate flow divider including a first pipe portion forming one inflow port, a second pipe portion and a third pipe portion forming two outflow ports communicating with the inflow port of the first pipe portion, and a second bifurcate flow divider including a fourth pipe portion forming one inflow port, and a fifth pipe portion and a sixth pipe portion forming two outflow ports communicating with the inflow port of the fourth pipe portion. The outflow port of the third pipe portion and the inflow port of the fourth pipe portion communicate with each other, and an angle θ formed by a first plane passing through the first bifurcate flow divider and a second plane passing through the second bifurcate flow divider is between 60 and 120 degrees.

A refrigeration cycle device includes a compressor configured to compress and discharge a refrigerant containing oil, a refrigerant radiator configured to heat the ventilation air using the refrigerant discharged from the compressor as a heat source during a room interior heating, a refrigerant decompression unit configured to decompress the refrigerant having passed through the refrigerant radiator, an evaporator configured to evaporate the refrigerant and to function as a heat absorber during the room interior heating; and a controller configured to control the refrigerant decompression unit and to perform a fluctuation operation at least during the room interior heating. In the fluctuation operation, a throttle opening degree of the refrigerant decompression unit is changed such that a refrigerant state on a refrigerant outlet side of the evaporator is alternately changed to a superheated state having a superheat degree and a wet state containing the wet vapor.

Provided is an air conditioning apparatus. The air conditioning apparatus includes a heat exchanger in which the refrigerant and the water are heat-exchanged with each other, a high-pressure guide tube extending from a high-pressure gas tube of an outdoor unit so as to be connected to one side of the heat exchanger, a low-pressure guide tube extending from a low-pressure gas tube of the outdoor unit so as to be combined with the high-pressure guide tube, a liquid guide tube extending from a liquid tube of the outdoor unit so as to be connected to the other side of the heat exchanger, a bypass tube configured to connect a bypass branch point of the high-pressure gas tube to a bypass combination point of the liquid guide tube to bypass a high-pressure refrigerant existing in the high-pressure tube to the liquid guide tube, and a bypass valve installed in the bypass tube.

In a refrigerant circuit of an air conditioning device, an upper heat source side heat exchanger having a large heat load and a lower heat source side heat exchanger having a small heat load are connected in parallel between an expansion device and a suction side of a compressor. Additionally, the refrigerant circuit of the air conditioning device is provided with a branch circuit configured to distribute refrigerant to each of the upper heat source side heat exchanger and the lower heat source side heat exchanger, and the branch circuit is configured to supply the upper heat source side heat exchanger with refrigerant of lower quality than that of the refrigerant supplied to the lower heat source side heat exchanger.