Air conditioner

Abstract

An air conditioner includes an outdoor fan and a refrigerant circuit having a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger connected to each other. An expansion valve refrigerant discharge control, in which the compressor is driven in a state where the outdoor fan is stopped and the expansion valve is open, is performed when a cooling start noise reduction condition that a state of refrigerant at inlet and outlet ports of the expansion valve is in a one-phase liquid state is satisfied when starting the cooling operation. An expansion valve normal switching control, in which an opening of the expansion valve is reduced and an operating frequency of the compressor is increased, is performed after the expansion valve refrigerant discharge control.

Description

TECHNICAL FIELD[0001]The present invention relates to an air conditioner, and in particular, to an air conditioner which performs a cooling operation by driving an outdoor fan and circulating refrigerant in order of a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger.BACKGROUND ART[0002]There is an air conditioner which performs a cooling operation in the background art such as shown in PTL 1 (Japanese Unexamined Patent Application Publication No. 9-133434). In detail, the air conditioner has a refrigerant circuit which is configured by connecting a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger and an outdoor fan which supplies outdoor air to the outdoor heat exchanger as a source for cooling of refrigerant which flows through the outdoor heat exchanger. Then, a cooling operation is performed in the air conditioner by driving the outdoor fan and circulating refrigerant in order of the compressor, the out...

AI Technical Summary

Benefits of technology

The invention relates to an air conditioner that can reduce noise during cooling operations. The technical effect of the patent is to suppress cavitation noise in the expansion valve when starting the cooling operation under low temperature conditions. This is achieved by controlling the expansion valve refrigerant discharge and normal switching. The invention is useful even when the expansion valve is placed in a positive cycle arrangement state.

Problems solved by technology

There is a problem in the air conditioner in the background art in terms of cavitation noise in the expansion valve during the cooling operation, and the inner diameter size of refrigerant pipes at inlet and outlet ports of the expansion valve is devised with regard to the problem of cavitation noise in the expansion valve.

However, the cavitation noise in the expansion valve most remarkably appears when starting the cooling operation under low temperature conditions such as when the outdoor temperature is low.

Then, it is not possible for the inner diameter size of the refrigerant pipes at inlet and outlet ports of the expansion valve in the air conditioner in the background art to be devised to sufficiently suppress the cavitation noise in the expansion valve when starting the cooling operation under the low temperature conditions.

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