The effects of changing the inlet and/or outlet conditions of the suction line heat exchanger used in a refrigerating system on evaporator size, compressor power and COP of the refrigerating system have been investigated by analyzing the thermodynamics process occurring in each thermal component and by redesigning the evaporator. Decreasing the refrigerant super-heating degree at the outlet of the suction line heat exchanger can reduce the evaporator size, but it simultaneously increases the refrigerant mass flow rate and compressor power.