Researchers Daniel Calleja-Anta, Katja Klinar, Urban Tomc and Andrej Kitanovski have conducted a thermodynamic screening of 29,271 refrigerant compositions for micro-scale vapour compression refrigeration and heat pump systems. The study evaluated pure refrigerants and binary and ternary mixtures, using COP and volumetric cooling or heating capacity as key performance criteria.
The screening covered 11 pure refrigerants, 1,045 binary mixtures and 28,215 ternary mixtures. Thermodynamic properties were calculated with NIST REFPROP 10.0, while the TOPSIS multi-criteria method was used to balance COP and volumetric capacity. The base evaluation assigned a weight of 0.7 to COP and 0.3 to volumetric cooling or heating capacity.
The analysis considered micro domestic and light commercial refrigeration, beverage coolers, personal cooling and electronics cooling, as well as reversible heat pumps for electric vehicle cabin and battery thermal management. Four screening scenarios addressed high performance, theoretical A1 safety classification, low-pressure operation and combined low-pressure/non-flammable constraints.
The researchers found no significant thermodynamic advantage from ternary mixtures compared with simpler binary blends. For maximum performance, the study recommends R1270 and R290/RE170 (60/40)%, while R1234yf/R1224yd(Z) (72/28)% was identified for safety-critical A1 applications.
For natural, low-pressure operation, the selected mixtures include RE170/R600 (65/35)% and R600/R1270 (28/72)%. Under combined constraints, the study identifies R1234ze(E)/R1233zd(E) (72/28)% and R1234ze(E)/R1224yd(Z) (68/32)% as candidates for micro-scale vapour compression systems.
