Hydrofluoroolefins

In the light of the worldwide phase-down of high GWP refrigerants, Dave Richards, UK head of sales at refrigerant supplier Climalife, looks at the various options available for HVAC chillers.

In both technical and non-technical literature, fluorine-containing (HFC) refrigerants are increasingly referred to as ‘chemical’ or ‘synthetic’ refrigerants in contrast to the so-called ‘natural’ refrigerants. Generally ‘chemical’ is now seen by some as being ‘bad’ and is contrasted with ‘natural’, which implies ‘good’.

The ban on the use of R134a in mobile air-conditioning systems within the EU has triggered a series of research projects. Apart from the CO₂ technology (page 35), new refrigerants with very low GWP values and similar thermodynamic properties as R134a have been developed.

In this project, two newly developed refrigerants, R1234yf and R1234ze have been studied as promising drop-in replacements for the common high global warming potential refrigerants. In view of that, thermodynamic and transport properties of new refrigerants were obtained by RefProp version 7.01 to study and compare their cycle performances with current refrigerants.