Gases In Regrigeration Industry
A refrigerant is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle. In most cycles it undergoes phase transitions from a liquid to a gas and back again. Many working fluids have been used for such purposes. Fluorocarbons, especially chlorofluocarbons, became commonplace in the 20th century, but they are being phased out because of theirozone depletion effects. Other common refrigerants used in various applications are ammoina, sulfur dioxide, and non-halogenated hydrocarbons such as propane.
The ideal working fluid or often called refrigerant would have favorable thermodynamic properties, be noncocorrosive to mechanical components, and be safe, including freedom from toxicity and flammability. It would not cause ozone depletion or climate change. Since different fluids have the desired traits in different degree, choice is a matter of trade-offs.
Compared to halogenated refrigerants, hydrocarbons like isobutane (R-600a) and propane (R-290) offer several advantages: low cost and widely available, zero ozone depletion potential and very low global warming potential. They also have good energy efficiency, but are flammable and can form an explosive mixture with air if a leak occurs.