Performance Assessment of Low Global Warming Potential Working Fluids R1233zd (E) and R1224yd(Z) for Low Pressure Centrifugal Chiller Applications

With the ever-increasing societal demands to control the climate change, various policy and regulatory actions are coming out to reduce or restrict refrigerants with non-zero ozone depletion potential (ODP) and high global warming potential (GWP). For low pressure centrifugal chiller applications, R123 with non-zero ODP and R245fa with high GWP, will be phased out. For the current study, the performance of R1233zd(E) and newly developed R1224yd(Z) were evaluated in view of replacement for R123 and R245fa for two-stage centrifugal chiller applications. The system-level thermal performance, component-level heat transfer performance/sizing, and life time environmental performance are investigated at a fixed cooling capacity of 500 t (1750 kW). Both fluids have an equivalent COP. R245fa and R1224yd(Z) can achieve a volume capacity 60% higher than that of R123, while that of R1233zd(E) is 40% higher. R245fa and R1233zd(E) can achieve a mass flow rate $$\sim 10$$ % lower than that of R123, and R1224yd(Z) displays a mass flow rate $$\sim 5$$ % higher than that of R123. R1233zd(E) and R1224yd(Z) demonstrate an evaporator shell side heat transfer coefficient 19% and 16% higher, respectively, as compared with R123. R1233zd(E) has a condenser shell side heat transfer performance 32% higher than that of R123, and those of R245fa and R1224yd(Z) are $$\sim 24$$ % higher. R1233zd(E) and R1224yd(Z) exhibit compressor impeller diameters 17.8% and 19.7% less, respectively, as compared with R123. Both R1233zd(E) and R1224yd(Z) can exhibit a $$\sim 10$$ % life cycle emission reduction as compared with R245fa. To sum up, R1233zd(E) and R1224yd(Z) can be good candidates to replace R123, and R1224yd suits better than R1233zd(E) to replace R245fa for centrifugal chiller systems, which is due to its heat transfer area close to that of R245fa and smaller compressor modifications. It is anticipated that the current study can be beneficial for the chiller community to maintain the maximum sustainability and economic benefits.