What factors influence refrigerant selection for HVAC systems?

Refrigerant selection depends on thermodynamic properties (boiling point, latent heat, pressure-temperature relationship), environmental factors (ODP-ozone depletion potential, GWP-global warming potential), safety (toxicity, flammability), compatibility with materials, cost, and regulations. R-134a and R-410A are common in air conditioning, while R-290 (propane) and R-744 (CO2) are gaining popularity as eco-friendly alternatives. The phase-down of HFCs under Kigali Amendment is driving adoption of low-GWP refrigerants.