The article explores new refrigerants that are more environmentally friendly due to lower global warming potential. It reviews different types of refrigerants, such as HFOs, ammonia, and carbon dioxide, considering their thermodynamic properties. The goal is to help designers choose the best refrigerant for efficient cooling systems. While some old refrigerants like ammonia are making a comeback, newer options like HFOs are also being considered. The choice of refrigerant impacts how well a cooling system works. Engineers must weigh environmental concerns and thermodynamic properties when selecting a refrigerant.