Semi-empirical and environmental assessment of the low GWP refrigerant HCFO-1224yd(Z) to replace HFC-245fa in high temperature heat pumps

Abstract

This paper investigates a promising low-GWP refrigerant, HCFO-1224yd(Z), as an environmentally friendly replacement for HFC-245fa in high temperature heat pumps (HTHPs). First, the thermophysical properties of both fluids were analysed, and a single-stage cycle with Internal Heat Exchanger (IHX) was modelled. Then, a semi-empirical drop-in test replacement was assessed. The low-temperature reservoir was fixed at 80 °C, whereas the high-temperature reservoir was varied from 110 to 140 °C to cover a wide range of industrial applications. The theoretical and semi-empirical results illustrate that HCFO-1224yd(Z) heat- ing capacity becomes around 8.9% lower than HFC-245fa. However, the higher suction density of HCFO- 1224yd(Z) compared to the reference fluid can compensate for this effect, reducing the compressor power consumption. Hence, HCFO-1224yd(Z) presents a COP increase up to 4.5% compared to the reference fluid. At high-temperature reservoir of 140 °C, HCFO-1224yd(Z) shows a COP of 2.33, whereas HFC-245fa only reaches 2.23. The carbon footprint assessment illustrates a significant equivalent CO 2,eq emissions reduc- tion down to 90%, depending on the country (carbon emission factor). Therefore, HCFO-1224yd(Z) can be used as an alternative to HFC-245fa in HTHP systems due to its beneficial operating, energetic and environmental characteristics.