In this study, for double-effect absorption cooling systems, a computer simulation which is based on mass, material and heat balance equations for each part of the system is described. Thermodynamic design data are investigated for the water-lithium bromide-lithium thiocyanate mixture and a comparative study of the water-LiBr-LiSCN mixture with the water-LiBr pair and the water-LiCl pair is given. The influences of component temperatures on the cooling coefficients of performance have been investigated to obtain optimum operating condition. It is found that the cooling COP is higher for water-LiBr-LiSCN mixture than for the water-LiBr pair or for the water-LiCl pair, and the flow ratio of water-LiBr-LiSCN mixture is not higher than that of the water-LiBr pair.