Patent ID: 7856836

Claim:
A refrigerating air conditioning system provided with a refrigerant circuit including a compressor, an indoor heat exchanger, a first pressure reducing device, an outdoor heat exchanger, and a switching device for switching a direction of a refrigerant flow between heating and cooling modes for supplying heat from the indoor heat exchanger, wherein: refrigerant temperature detection means of the outdoor heat exchanger and outdoor air temperature detection means are provided for determining if an amount of frost formed on the outdoor heat exchanger is less than or equal to a predetermined value; two types of defrosting inhibition time values τ 1 and τ 3 are allowed to be set in accordance with a correspondence to a plurality of ranges of a previous defrosting time τ 2 for continuously performing heating operation; and a defrosting operation is performed by controlling the defrosting inhibition time values τ 1 and τ 3 to be longer, when an amount of the frost formed on the outdoor heat exchanger is determined to be less than or equal to the predetermined value, than the defrosting inhibition time values τ 1 and τ 3 when the amount of the frost formed on the outdoor heat exchanger is determined to be greater than the predetermined value.