Patent ID: 6012294
Filing Date: 2000-01-11
Classification: F24F,F25B

Abstract:
A method for controlling an air conditioner comprising:a refrigerating cycle including a compressor, four-way valve, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger to switch said four-way valve to reversibly switch the refrigerating cycle between a heating and a cooling operation modes;a hot gas bypass passage connecting together a refrigerant ejection port of said compressor and a refrigerant inflow port of said outdoor heat exchanger, and a shut-off valve provided in the hot gas bypass; andtemperature sensors that detect the temperatures of the refrigerant inflow and runoff port sides of said outdoor heat exchanger, wherein:when, in said heating operation mode, the temperature of the refrigerant inflow or runoff port side of said outdoor heat exchanger reaches a predetermined value or lower that requires defrosting, said shut-off valve is ""opened"" to start defrosting using the hot gas bypass defrosting method, and wherein the temperature of the refrigerant runoff port side of said outdoor heat exchanger is detected every specified time so that if the temperature change rate is less than or equal to a predetermined value, said shut-off valve is ""closed"" and said four-way valve is switched to said cooling operation mode side in order to switch to the reverse defrosting method that allows a hot gas to flow in the reverse direction from said compressor to said outdoor heat exchanger.