Experimental validation of RE170 / R600 (Dimethyl Ether / Butane) mixture as a superior refrigerant compared to R600a (Isobutane)

Isobutane (R600a) is the most used refrigerant for low-capacity refrigeration systems, as it combines excellent environmental properties and offers good energy performance. A real possibility to increase the efficiency of these systems is using new refrigerant mixtures offering energy improvements (being compatible with existing systems). This work, from an experimental perspective, proposes mixtures of dimethyl ether and butane (RE170/R600) as potential drop-in refrigerants of R600a systems. For a given operating condition, the energy performance of RE170/R600 mixtures with maximum proportion of 27.5 % of RE170 has been tested using a water-to-water single-stage compression cycle, measuring COP increments from 10.1 to 17.6 % in relation to R600a. Then, the blend RE170/R600 (15/85 %), considered as the potential drop-in fluid of R600a, has been tested in a wide range of operating conditions, concluding that it offers the same cooling capacity than R600a but with COP increments from 12.6 % to 17.6 %.