Abstract: Reverse cycle defrost mode for defrosting by heating transformation for the cooling mode, when the compressor stop, four-way valve reversing, frost during the evaporator absorbs a lot of calories to defrost, cause indoor temperature fluctuation and the temperature drop is larger, less comfortable experience. Also exist in the process of defrosting larger compression, low evaporation temperature, frequent compressor start cause oil level lower reliability problems. This paper presents a new intelligent frost model that hot gas defrosting, defrosting period remains heating mode. Electronic expansion valve fully open, in order to realize the system within the throttling element "slight throttling", the effect of using the compressor discharge of high temperature gaseous refrigerant in the evaporator to condenser defrosting. Without any increase in production costs, on the basis of realization of defrost during continuous heating, improve heating comfort and reliability.

Key words: Comfort and energy saving, Continuous heating, Positive defrosting