Spanish Researchers Identify New Mixtures as Propane Alternatives

Study Evaluates Dimethyl Ether and Mixtures as Alternatives to R290.

Researchers from Jaume I University in Spain have conducted a study evaluating dimethyl ether (RE170) and its ternary mixtures with CO2 (R744) and butane (R600) as potential substitutes for propane (R290) in refrigeration and heat pump systems.

The study included both theoretical modeling and laboratory experiments. Using thermodynamic analysis with Refprop v.10, the team identified promising refrigerant compositions. These were then tested on a single-stage vapor compression cycle with a variable-speed compressor.

Results showed that pure RE170 and selected mixtures achieved higher energy efficiency than R290, with the best configurations improving the coefficient of performance (COP) by up to 29.8% for refrigeration and 17.99% for heat pump use. However, all alternatives had lower cooling and heating capacities compared to R290, meaning they are not suitable as direct drop-in replacements without system modifications.

RE170 stood out due to its stable thermodynamic properties, no temperature glide, and high heat transfer performance. Mixtures with CO2 and R600 also showed promising efficiency results, especially when optimized to balance pressure, volume, and heat capacity.

The authors conclude that RE170 and certain optimized blends could offer efficient and environmentally friendly alternatives to R290 in new system designs.

The research was led by Daniel Calleja-Anta, Manel Martínez-Ángeles, and Rodrigo Llopis from the Thermal Engineering Group at Jaume I University.

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