Air conditioner

Patent metadata

Field	Value
Publication number	US-11199337-B2
Application number	US-201816955332-A
Country	US
Kind code	B2
Filing date	Apr 9, 2018
Priority date	Apr 9, 2018
Publication date	Dec 14, 2021
Grant date	Dec 14, 2021

Abstract

An air conditioner that includes a refrigerant circuit connecting a plurality of indoor heat exchangers in parallel and is able to complete collection of refrigerant to the side of an outdoor heat exchanger in a shorter time when the refrigerant has leaked at any indoor heat exchanger is provided. Thus, in the air conditioner according to the present invention, when refrigerant leak is detected by a refrigerant leak sensor provided in an indoor unit and refrigerant leak is not detected by a refrigerant leak sensor provided in an indoor unit, an indoor LEV and a cutoff valve are closed to isolate an indoor heat exchanger of the indoor unit from the refrigerant circuit in a refrigerant pump-down operation. When refrigerant leak is detected by the refrigerant leak sensor and refrigerant leak is not detected by the refrigerant leak sensor, an indoor LEV and a cutoff valve are closed.

First claim

The invention claimed is:

1. An air conditioner comprising:
a refrigerant circuit connecting a first indoor heat exchanger, a second indoor heat exchanger and an outdoor heat exchanger by a refrigerant pipe in which refrigerant is enclosed, the first indoor heat exchanger and the second indoor heat exchanger connected in parallel, the outdoor heat exchanger connected in series to the first indoor heat exchanger and the second indoor heat exchanger, the refrigerant circuit having a compressor, an accumulator and a four-way valve, the compressor, the accumulator and the four-way valve connected between the first and second indoor heat exchangers and the outdoor heat exchanger;
a first indoor unit casing housing the first indoor heat exchanger;
a second indoor unit casing housing the second indoor heat exchanger;
a first leak detector configured to detect a leak of the refrigerant inside the first indoor unit;
a second leak detector configured to detect a leak of the refrigerant inside the second indoor unit;
a first isolator configured to isolate the first indoor heat exchanger from the refrigerant circuit;
a second isolator configured to isolate the second indoor heat exchanger from the refrigerant circuit;
a controller configured to, when at least one of the first leak detector and the second leak detector detects the leak of the refrigerant, operate the compressor while the four-way valve is set to a cooling direction to perform a pump-down operation in which the refrigerant is collected to a side of the outdoor heat exchanger, and
a pressure sensor configured to detect pressure of the refrigerant in the refrigerant pipe on the side of the outdoor heat exchanger,
the controller configured
to isolate the second indoor heat exchanger from the refrigerant circuit by the second isolator in the pump-down operation when the first leak detector detects the leak of the refrigerant and the second leak detector does not detect the leak of the refrigerant,
to isolate the first indoor heat exchanger from the refrigerant circuit by the first isolator in the pump-down operation when the second leak detector detects the leak of the refrigerant and the first leak detector does not detect the leak of the refrigerant,
to end the pump-down operation when the pressure of the refrigerant in the refrigerant pipe on the side of the outdoor heat exchanger has become equal to or lower than a pressure set in advance, and
to operate the compressor while the four-way valve is set to a heating direction when a time set in advance has elapsed since the pump-down operation is started but the pressure of the refrigerant in the refrigerant pipe on the side of the outdoor heat exchanger has not become equal to or lower than the pressure set in advance.

2. The air conditioner according to claim 1 , wherein
when the first leak detector detects leak of the refrigerant and the second leak detector does not detect leak of the refrigerant, the controller connects the second indoor heat exchanger to the refrigerant circuit and isolates the first indoor heat exchanger from the refrigerant circuit by the first isolator after the pump-down operation and then resumes circulation of the refrigerant, and
when the second leak detector detects leak of the refrigerant and the first leak detector does not detect leak of the refrigerant, the controller connects the first indoor heat exchanger to the refrigerant circuit and isolates the second indoor heat exchanger from the refrigerant circuit by the second isolator after the pump-down operation and then resumes circulation of the refrigerant.

Assignees

• Mitsubishi Electric Corp

Inventors

• Kawashima Mitsuru
• Ishimura Katsuhiro

Classifications

• F25B2400/19

  Pumping down refrigerant from one part of the cycle to another part of the cycle, e.g. when the cycle is changed from cooling to heating, or before a defrost cycle is started · CPC title

• F24F11/36 Primary

  to leakage of heat-exchange fluid · CPC title

• F25B13/00

  Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) · CPC title

• F25B2600/0251

  with on-off operation · CPC title

• F25B2700/1933

  Suction pressures · CPC title