Thermodynamic analysis of optimal intermediate temperatures in R134a-R410A cascade refrigeration systems and its experimental verification

► An R134a-R410A cascade system is designed for a water heating purpose. ► The new equation is established to calculate optimal intermediate temperatures. ► The three major temperatures of cascade cycle are employed as parameters. ► Experiments are also conducted to validate the result of theoretical model. ► The comparison of both results provides a fair agreement.