The performance of a vapor compression cycle with nanoparticles additives in the working fluid was investigated theoretically. In the present study four different nano materials with R143-a refrigerant were investigated. The performance of the cycle was studied for different condensation and evaporation temperature. By using enthalpy which is obtained through nanorefrigerant density, a model is developed to investigate the performance parameter of the cycle. The model was validated using two of the data given in the literature. The results showed that the coefficient of performance is increased by using nanomaterials additives compared to the pure refrigerant and the maximum value was obtained for R143-a/CuO mixture