Performance of throttle-cycle coolers operating with mixed refrigerants designed for industrial applications in a temperature range 110 to 190 K

The efficiency of coolers designed to provide refrigeration for industrial equipment is discussed. Experience accumulated during more than twenty years of manufacturing shows that multistage auto-cascade coolers provide high refrigeration performance along with rapid cool down and defrost. Both single-stage and two-stage throttle cycles have been analyzed. Comparative data on the performance of the cycles are obtained with a computer model that includes an equation of state to calculate thermodynamic properties of mixed refrigerants. Both flammable argon-hydrocarbon- and nonflammable argon-hydrofluorocarbon-based mixed refrigerants have been considered. Non-flammable environmentally friendly mixed refrigerants include commercially available components. The experimental data were obtained for coolers based on a single-stage compressor. The tested systems provided refrigeration capacity from 500 to 3600 W depending on the compressor displacement volume. A Carnot efficiency coefficient as high as 0.21 was achieved. This corresponds to the efficiency of conventional freezers operating at temperatures above 230 K.