A refrigerant is a fluid used within a refrigeration or cooling system to transfer heat. The refrigerant is circulated and absorbs heat at low temperatures and pressures and transfers this heat at high temperatures and pressures. Refrigerants are typically man-made fluorocarbon compounds but there are natural refrigerants including Ammonia, CO2, hydrocarbons, water and air. Within an air conditioning unit, the term ‘refrigerant charge’ is also used. This is the amount of refrigerant, measured in Kg within the cooling system.