Volkswagen Touran Quiz
Heating, Ventilation and Air Conditioning

Refrigerant R134a

In this manual: Heating, Ventilation and Air Conditioning
General Paint Information — 130Towing Guide — 4Wheel and Tire Guide Information — 111Electrical System — 104Heating, Ventilation and Air Conditioning — 106
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Refrigerant R134a Physical Data

Vehicle air conditioning systems make use of the vaporization and condensation process. In this case, one works with a substance which boils easily, designated as refrigerant. The refrigerant employed is tetrafluoroethane R134a, which boils at -26.5 C (-15.7 F) at a vapor pressure of 1 bar (14.5 psi).
Chemical formula CH2FCF3 or CF3CH2F
Chemical designation Tetrafluoroethane
Boiling point at 1 bar (14.5 psi) -26.5 C (-15.7 F)
Solidification point -101.6 C (-150.88 F)
Critical temperature 100.6 C (213 F)
Critical pressure 40.56 bar absolute (588 psi) equals 39.5 bar pressure (573 psi)

Critical Point

Vehicle air conditioning systems make use of the vaporization and condensation process. In this case, one works with a substance which boils easily, designated as refrigerant. The refrigerant employed is tetrafluoroethane R134a, which boils at -26.5 C (-15.7 F) at a vapor pressure of 1 bar (14.5 psi). The critical point (critical temperature and critical pressure) is that above which there is no longer a boundary between liquid and gas.

A substance above its critical point is always in the gaseous state.

At temperatures below the critical point, all types of refrigerant in pressure vessels exhibit both a liquid and a gas phase, i.e. there is a layer of gas above the liquid. As long as there is still gas present in the container next to the fluid, pressure is dependent on ambient temperature. Refer to → Chapter "Refrigerant R134a Vapor Pressure Table". Note Different types of refrigerant are never to be mixed. Only the refrigerant designated for the corresponding A/C system may be used.

Refrigerant R134a Environmental Information

Vehicle air conditioning systems make use of the vaporization and condensation process. In this case, one works with a substance which boils easily, designated as refrigerant. The refrigerant employed is tetrafluoroethane R134a, which boils at -26.5 C (-15.7 F) at a vapor pressure of 1 bar (14.5 psi).

R134a is a fluorocarbon and contains no chlorine.

R134a has a shorter atmospheric life span than refrigerant R12.

R134a does not damage the ozone layer. The ozone depletion potential is zero.

The greenhouse potential of R134a (Global Warming Potential = GWP) is approximately 1430 (the GWP of carbon dioxide is 1). The global warming effect of R134a is ten times less than that of refrigerant R12.

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