This page explains refrigerant vapour pressure in an enclosed container: liquid evaporates until an equilibrium forms between vapour and liquid — the physical basis for Volkswagen Golf Mk7 refrigerant circuit pressure readings.
| In an enclosed container that is not completely full,
refrigerant evaporates as vapour at the surface in a quantity
sufficient to form an equilibrium between vapour and liquid.
This equilibrium develops under pressure and is often called
vapour pressure. The vapour pressure is temperature-dependant
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| Physical properties of R134a |
| Because the vapour pressure curves of R134a and other
refrigerants are in part very similar, unique identification on
the basis of pressure alone is not possible. |
| The air conditioner compressor used for R134a is lubricated
with special synthetic refrigerator oils, such as PAG oils (polyalkylene
glycol oils). |
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Questions & answers
Vapour pressure — Volkswagen Golf Mk7
How does R134a vapour pressure work?
In a partially filled container, refrigerant evaporates at the surface. The vapour pressure increases with temperature. Above a critical point, the liquid and gas phases merge.
Refrigerant R134a is currently available under the following
trade designations:
H-FKW 134a
SUVA 134a
...
In its pure state, refrigerant R134a is chemically stable
and does not attack iron or aluminium.
However, impurities such as chlorine compounds in th ...
