Refrigerating system and purification method for the same

The present invention provides a refrigerating system, including: a refrigerating loop, including a compressor, a condenser, a throttling element, and an evaporator that are connected in sequence through a pipeline; and a purification loop, connected to the refrigerating loop and configured to separate a pressure maintaining gas in the refrigerating loop; wherein the refrigerating loop is connected into the purification loop from the top of the condenser or the top of the compressor. The present invention further provides a purification method for a refrigerating system, including: in a first time period, performing S1: charging, into the refrigerating system, a refrigerant that satisfies a designed refrigerating capacity; and S2: charging a pressure maintaining gas into the refrigerating system, so that pressure in the refrigerating system is higher than atmospheric pressure; and in a second time period, performing S3: separating and discharging the pressure maintaining gas in the refrigerating system.