US 11,885,548 B2
Refrigeration cycle apparatus that injects refrigerant into compressor during low load operation
Toshiki Imanishi, Tokyo (JP); and Kohei Tatsuwaki, Tokyo (JP)
Assigned to Mitsubishi Electric Corporation, Tokyo (JP)
Appl. No. 17/288,093
Filed by MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
PCT Filed Jan. 7, 2019, PCT No. PCT/JP2019/000058
§ 371(c)(1), (2) Date Apr. 23, 2021,
PCT Pub. No. WO2020/144728, PCT Pub. Date Jul. 16, 2020.
Prior Publication US 2021/0372680 A1, Dec. 2, 2021
Int. Cl. F25B 41/42 (2021.01); F25B 41/31 (2021.01); F25B 49/02 (2006.01); F25B 41/20 (2021.01); F25B 1/04 (2006.01)
CPC F25B 49/027 (2013.01) [F25B 1/04 (2013.01); F25B 41/20 (2021.01); F25B 41/31 (2021.01); F25B 41/42 (2021.01); F25B 49/022 (2013.01); F25B 2400/0409 (2013.01); F25B 2400/13 (2013.01); F25B 2500/16 (2013.01); F25B 2600/025 (2013.01); F25B 2600/0253 (2013.01); F25B 2600/2509 (2013.01); F25B 2600/2513 (2013.01); F25B 2700/171 (2013.01); F25B 2700/21163 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A refrigeration cycle apparatus comprising:
a refrigeration cycle circuit in which a compressor, a condenser, a first expansion valve, and an evaporator are connected by refrigerant pipes;
an injection pipe having a refrigerant inflow side end and a refrigerant outflow side end, the refrigerant inflow side end being connected between the condenser and the first expansion valve, the refrigerant outflow side end being connected to a suction side of the compressor;
a second expansion valve provided at the injection pipe; and
a controller configured to control a rotation speed of the compressor and an opening degree of the second expansion valve,
wherein the controller is configured to
determine whether the rotation speed of the compressor is at or below a specified low load rotation speed,
in response to the rotation speed of the compressor being determined to be at or below the specified low load rotation speed, perform a low load operation during which the rotation speed is maintained at the specified low load rotation speed and the controller controls the second expansion valve to open to cause refrigerant to flow through the injection pipe to the suction side of the compressor, to reduce a heat-exchange capability of the evaporator.