What are the main constraints imposed by the phase-down of HFCs on vapor-compression equipment?

The phase-down of HFCs will require trade-offs among cost, efficiency, and safety in vapor-compression equipment. This is because alternative refrigerants may have different thermodynamic properties, toxicity, and flammability, which can impact equipment design, operation, and maintenance. Additionally, the phase-down may lead to increased costs, reduced efficiency, and new safety risks, making it essential to explore alternative space-conditioning technologies.