RE170 (Dimethyl Ether) and ternary mixtures (R744 / RE170 / R600) as alternatives to R290 for refrigeration and heat pump applications

Abstract

This study explores the potential of dimethyl ether (RE170) and ternary mixtures (R744/RE170/R600) as alternatives to R290 in refrigeration and heat pump applications. A thermodynamic analysis using Refprop v.10 was conducted to determine optimal compositions, followed by an experimental evaluation in a single-stage vapor compression cycle with a variable speed compressor. Results indicate that RE170 and its mixtures provide superior energy efficiency compared to R290, with maximum COP improvements of 29.8 % (refrigeration) and 17.99 % (heat pump), albeit with reduced cooling and heating capacities. Experimental tests show that RE170 is the best candidate for substitution, as it avoids temperature glide and maintains higher heat transfer coefficients. These findings suggest that RE170 and its optimized mixtures could enhance system efficiency, provided adequate system modifications are implemented.