Refrigerants are crucial for cooling things down, but with a focus on environmental impact, new types are being explored. Scientists are looking into various refrigerants, including some newer ones like HFOs with unique carbon bonds and traditional ones like ammonia and carbon dioxide. Even though older HFC refrigerants are on the decline, they are still being used. The choice of refrigerant is influenced by both environmental concerns and how well it works in a cooling system. Different refrigerants have different properties that affect how well they work in a cooling cycle. Designers need to balance these factors when choosing a refrigerant for a system to make sure it runs efficiently.