The influence of working fluids on the performance of a cooling system is crucial and the properties of working fluids depend on the contribution sum of the different groups. Therefore

it is essential to analyze the group contribution of working fluids on system performance

which is an important guide for a suitable working fluid match. In this study

the group contribution method was used in the actual cycle of a liquid pump-driven free cooling loop according to the arrangement and combination of the molecular groups of 15 working fluids. The physical properties of the working fluids were investigated using REFPROP when the evaporation temperature was 25 ℃

the condensation temperature was 15 ℃

and the mass flow rate was 2 700 m3/h. The actual cycle of the liquid pump-driven free cooling loop is used to calculate the refrigeration capacity and energy efficiency ratio. The results show that when the working fluid is separated by a monoatomic group

the larger the number of C and H atoms

the greater the cooling capacity. When the working medium is separated by a polyatomic group

the greater the number of H atoms in the polyatomic group composed of the two atoms of C and H

the greater the amount of cooling.