Air conditioning: Refrigerant

In order to remove heat from the passenger compartment a medium that has a lower evaporating temperature than air is used, because heat will always move from a hotter body to a cooler body. The medium that is used is refrigerant R134a.

R134a is a gaseous fluorocarbon. It is chlorine free and does not damage the ozone layer. However, R134a is still environmentally hazardous as it contributes to the greenhouse effect. It is therefore important that all service work is performed by trained personnel.

R134a retains its gaseous form at normal atmospheric pressure, and only condenses if it is cooled down to below -26 °C.

R134a has the following properties:

• can only be mixed with synthetic PAG oils (polyalkyline glycol) and not with mineral oils
• does not affect metals
• affects some types of plastic, so only special seals (O rings) that are intended for R134a should be used
• is not explosive
• is odorless
• is not toxic in low doses
• effectively absorbs moisture
• is not flammable
• is heavier than air in gaseous form.