Refrigerant
Also known as: refrigerant gas, freon
Short definitionThe substance that circulates inside the refrigeration circuit. It picks up the heat of the room as it evaporates in the evaporator and gives it up outside as it turns back to liquid in the condenser.
Customers often ask “which gas is in it”; this is what they mean. At low pressure the refrigerant boils while cold, and once compressed it liquefies while hot. That is how the heat of a 0 °C room ends up in 40 °C outdoor air. Refrigerants are named with the letter R and a number. Freon is a brand name that came to be used for every synthetic gas.
In a quotation the refrigerant is chosen by three things: room temperature, the F-gas rules and the safety class. R449A, or formerly R404A, is common in freezer rooms, R134a and R513A in chill rooms. High-GWP HFCs are being phased out. Propane is flammable, CO₂ runs at very high pressure and ammonia is toxic; all three have next to no climate impact. Each refrigerant has its own pressure–temperature table.