Experimental investigation of the performance of a low-temperature refrigeration cycle using R170/R290 and R1150/R600a mixtures.

Nowadays, the interest and use of hydrocarbons (HCs) and their mixtures is increasing due to its minimum environmental impact and high performance. The use of zeotropic HC mixtures in a compression-based system is still a topic of research, especially in single-compressor auto-cascade cycles, where it offers important advantages in terms of total system cost and maintenance.
This study presents an experimental investigation of pull-down and steady-state performance of an ultra-low temperature freezer device. The experimental set-up is based on a modified auto-cascade refrigeration cycle (ARC) using capillary tubes as a throttling device. Natural binary mixtures R170/R290 and R1150/R600a at different compositions are employed as working fluids and are evaluated during the pull-down and steady- state operation for different low-stage evaporating temperatures ranging from -90°C to -20°C. Measured dynamic parameters are discussed, especially in terms of power consumption and discharge temperature.