US 12,215,905 B2
Air conditioning apparatus
Yu Hirosaki, Kanagawa (JP); Tokihiko Ando, Kanagawa (JP); Shintaro Sanada, Kanagawa (JP); Koya Aoki, Kanagawa (JP); and Tatsuro Yamazaki, Kanagawa (JP)
Assigned to FUJITSU GENERAL LIMITED, Kanagawa (JP)
Appl. No. 17/441,906
Filed by FUJITSU GENERAL LIMITED, Kanagawa (JP)
PCT Filed Mar. 24, 2020, PCT No. PCT/JP2020/013164
§ 371(c)(1), (2) Date Sep. 22, 2021,
PCT Pub. No. WO2020/196565, PCT Pub. Date Oct. 1, 2020.
Claims priority of application No. 2019-058393 (JP), filed on Mar. 26, 2019.
Prior Publication US 2022/0146165 A1, May 12, 2022
Int. Cl. F25B 49/02 (2006.01); F25B 13/00 (2006.01)
CPC F25B 49/02 (2013.01) [F25B 13/00 (2013.01); F25B 2313/0314 (2013.01); F25B 2313/0315 (2013.01); F25B 2600/2513 (2013.01); F25B 2700/1931 (2013.01); F25B 2700/1933 (2013.01)] 6 Claims
OG exemplary drawing
 
1. An air conditioning apparatus comprising:
a refrigerant circuit in which a compressor, a channel switching valve, an indoor heat exchanger, a first expansion valve, a liquid pipe, a second expansion valve, and an outdoor heat exchanger are connected in series; and
a controller, including at least a processor and a memory, configured to perform switching control of the channel switching valve and to perform degree-of-opening control of the first expansion valve and the second expansion valve, wherein
the controller is configured to:
switch the channel switching valve such that a refrigerant flows through in the order of the indoor heat exchanger, the first expansion valve, the liquid pipe, the second expansion valve, and the outdoor heat exchanger at the time of a heating operation,
calculate a degree-of-dryness of the refrigerant flowing into the outdoor heat exchanger at the time of the heating operation based on a condensation temperature detected by an indoor heat exchange temperature sensor at the time of the heating operation, an evaporation temperature detected by an outdoor heat exchange temperature sensor at the time of the heating operation, and a condenser outlet temperature detected by an indoor-side refrigerant temperature sensor at the time of the heating operation,
perform, at the time of the heating operation, when the degree-of-dryness is less than or equal to a threshold that is determined in advance, a normal mode of controlling the first expansion valve such that the refrigerant flowing inside the liquid pipe is in a gas-liquid two phase state and controlling the second expansion valve such that the degree of opening of the second expansion valve is equal to a predetermined degree of opening, and
perform an inhibition mode of inhibiting, when the degree-of-dryness exceeds the threshold, control that is performed in the direction of decreasing the degree of opening of the first expansion valve.