Theoretical Global Warming Impact Evaluation of Medium and High Temperature Heat Pumps Using Low GWP Refrigerants

Abstract

This study provides a global warming impact analysis of environmentally friendly refrigerants used as replacements for R134a and R245fa. R290, R1234yf, R1234ze(E), R513A and R450A are considered as refrigerants to replace R134a in medium temperature applications. For R245fa, there are five alternative refrigerants, R1224yd(Z), R600, R1336mzz(Z), R1233zd(E) and R1234ze(Z), which are selected for high-temperature applications. The analysis is done considering the emission factors in Brazil, Sweden, Canada and Poland. In Sweden and Brazil, the total equivalent warming impact per heating capacity of R134a is higher than its alternative refrigerants in medium temperature application, although R134a exhibits a higher coefficient of performance than its alternatives. In high-temperature applications, R1336mzz(Z) has the lowest total equivalent warming impact per heating capacity due to its higher coefficient of performance than other tested refrigerants. The highest total equivalent warming impact per heating capacity belongs to R245fa in all countries except in Poland, where R600 exhibits a higher value due to its lower coefficient of performance and the relatively higher emission factor in Poland compared to other selected countries. These results revealed that in addition to the global warming potential, the emission factor associated with the sources of electricity generation has a crucial impact on indirect emissions.

Energy and Environmental Performance Comparison of Heat Pump Systems Working with Alternative Refrigerants

“…In addition, several results on fluids alternative to R410A have been obtained by numerical simulations [20][21][22][23][24][25]. In particular, Yu et al [20] performed a theoretical screening of refrigerant mixtures subjected to a multiparameter optimization process consisting of GWP, flammability and thermodynamic parameters; starting from 12 pure refrigerants, the screening identified several mixtures fulfilling all the restrictions, which were promising to be used in applications with a GWP limit below 150.…”

“…In particular, Yu et al [20] performed a theoretical screening of refrigerant mixtures subjected to a multiparameter optimization process consisting of GWP, flammability and thermodynamic parameters; starting from 12 pure refrigerants, the screening identified several mixtures fulfilling all the restrictions, which were promising to be used in applications with a GWP limit below 150. Ghanbarpour et al [21] provided a global-warming impact analysis of environmentally friendly refrigerants used as replacements for R-134a and R-245fa in medium-and high-temperature heat pumps by considering the emission factors of different countries. The results revealed that in addition to the GWP, the emission factor associated with the sources of electricity generation has a crucial impact on indirect emissions determining whether it is beneficial to employ alternative refrigerants in the heat pump systems.…”