New-Generation Refrigerants: Performance Analysis, AI-Driven Prediction, Thermodynamic Modelling, and Environmental Transition

The accelerating phase-down of hydrofluorocarbons (HFCs) under the Kigali Amendment to the Montreal Protocol has intensified global research into low-global-warming-potential (GWP) refrigerants that can meet the dual imperatives of environmental sustainability and thermodynamic efficiency. This paper presents a comprehensive review of emerging refrigerant classes — including hydrofluoroolefins (HFOs), hydrochlorofluoroolefins (HCFOs), natural refrigerants (CO₂, ammonia, hydrocarbons), and novel blends — evaluating their thermophysical properties, cycle performance, safety classifications, and compatibility with existing vapor-compression infrastructure. A comparative thermodynamic analysis is conducted using the coefficient of performance (COP), volumetric refrigerating capacity, and exergy efficiency as primary benchmarks. Special attention is given to HFO- 1234yf, HFO-1234ze(E), and R-290 (propane) as front-runner replacements in residential, commercial, and automotive refrigeration sectors. The study further examines regulatory frameworks, material compatibility challenges, lubricant interactions, and the economic feasibility of retrofit and drop-in solutions. Findings indicate that while no single refrigerant universally replicates the performance of incumbent HFCs, optimized low-GWP blends and CO₂-based trans critical systems demonstrate strong potential across a broad range of applications. This work aims to inform engineers, policymakers, and manufacturers in navigating the ongoing refrigerant transition toward a climate-responsible cooling industry.