The topic of nanofluid heat transfer is certainly of interest to the heat transfer community. Nanorefrigerants are a type of nanofluids that are mixtures of nanoparticles and pure refrigerants. This paper focuses on five different nanorefrigerants with Al2O3 nanoparticles and their pure fluids: R12, R134a, R430a, R436a, and R600a. The coefficient of performance (COP) and compressor work for various evaporation and condensation temperatures are investigated. A method is developed to estimate the performance characteristics of nanorefrigerants in the refrigerant cycles for the nonsuperheating/subcooling case and superheating/subcooling case. The enthalpy of nanorefrigerants is obtained through the density. The validation process of the proposed method was accomplished with the available data in the literature. The results indicate that COP is enhanced by adding nanoparticles to the pure refrigerant and maximum values obtained using the R600a/Al2O3 mixture.