a method for operating a refrigeration system in order to perform temperature control of a closed volume is disclosed . the refrigeration system comprising a compressor , a condenser , an expansion device and an evaporator connected in series in a refrigerant flow path . the refrigeration system further comprises one or more fans arranged to cause a flow of air across the evaporator . the compressor is controlled by switching the compressor on or off in accordance with a measured temperature , t sup , of air which has passed across the evaporator and is being supplied to the closed volume , and in order to achieve a set point temperature , t set , in the closed volume . during this a compressor switching pattern is determined . temperature fluctuations inside the closed volume are minimised , and energy is conserved .