Volkswagen Polo Service & Repair Manual: 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. |
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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 ref ...
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 ref ...
Other materials:
General Information
WARNING
Risk of injury.
Read and follow the Safety Precautions when working
with batteries. Refer to
→ Chapter „Warnings and Safety Precautions“.
...
Using a mobile telephone in the vehicle without a connection to the external
aerial
First read and observe the introductory information
and safety warningsBoth during telephone calls and in standby mode, mobile
telephones transmit and receive radio waves, which may also be termed "high-frequency
energy". Current scientific literature warns us that radio waves can be harmful
...
Overview - Cigarette Lighter -U1-
Caution
Using force to remove cigarette lighter sockets
without illumination can result in damage to the
mounting sleeve retainers.
The Cigarette Lighter Release Tool -T40148- can o ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information