Comprehensive thermodynamic screening of low-GWP refrigerant mixtures for micro-scale vapour compression refrigerators and heat pumps
As the demand for high-performance micro and power electronics grows, micro-scale vapour compression refrigeration (VCR) systems and heat pumps (VCHP) have emerged as critical technologies for active heating and cooling. However, the progressive phase-down of hydrofluorocarbon refrigerants under international environmental regulations, necessitates the identification of low-global warming potential alternatives specifically optimized for the unique constraints of small-scale hardware, such as limited compressor displacement and low refrigerant charge.
This study presents a comprehensive and systematic thermodynamic screening of approximately 30,000 refrigerant compositions, including pure fluids, binary, and ternary mixtures, specifically aimed at three key application scenarios: domestic and commercial micro-appliances, personal cooling systems for hostile environments, and reversible heat pumps for electric vehicle cabin and battery management. Using a multi-criteria decision-making approach based on the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method to maximize simultaneously coefficient of performance and volumetric heating and cooling capacity, optimal candidates were identified across four practical scenarios: high-performance, safety-critical – low-flammability (A1), low-pressure, and a combined low-pressure/non-flammable scenario.
Findings demonstrate that added complexity in ternary mixtures offer no significant thermodynamic advantage over simpler binary blends for micro-scale applications. Final recommendations for next-generation micro-VCR/VCHP systems include: R1270 and R290/RE170 (60/40)% for maximum performance; R1234yf/R1224yd(Z) (72/28)% for safety-critical (A1) applications; RE170/R600 (65/35)% and R600/R1270 (28/72)% for natural, low-pressure operation; and R1234ze(E)/R1233zd(E) (72/28)% or R1234ze(E)/R1224yd(Z) (68/32)% for combined constraints. This study establishes a structured roadmap to navigate the complex landscape of sustainable refrigerant selection in the micro-VCR/VCHP domain.
Link: https://doi.org/10.1016/j.applthermaleng.2026.132282
