Abstract: The invention concerns a refrigerating fluid cycle comprising the standard compressor, condenser, liquid/gas separating reservoir, expansion device and evaporator. The invention is characterized in that a pre-expansion device is placed between the condenser and the reservoir, so as to reduce the fluid pressure until it reaches its saturation vapor pressure. The reservoir can thus contain a variable amount of liquid to compensate the fluid losses in the cycle by maintaining the sub-cooling temperature constant thereby enabling the heat load to be absorbed by the condenser.