Based on China National Standard-Number Designation and Safety Classification of Refrigerants
refrigerant for the cascade water-to-water heat pump were selected according to principles of environmental-friendly
safety and thermodynamic cycle performances. Different refrigerant combinations for high- and low-temperature cycles in the cascade heat pump were calculated and compared. Results show that combinations of R245fa/R134a
R245fa/R420A
R245fa/R413A
R245ca/R420A are better for the cascade heat pump. It also shows that
considering easy access and economy of refrigerants