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:
Tires with Rim Protector
The tire industry produces tires with rim protector for
light alloy wheels (rim protector). The rim protector prevents
damage to the light alloy wheels caused by contact with curbs.
Using tires with rim protector on steel wheels with wheel
...
Checklist
Never carry out any work on the engine or in the engine compartment
if you are not familiar with the requisite procedures and general safety requirements,
or if you only have access to incorrect operating equipment, service fluids,
and unsuitable tools . The work should be carried ou ...
Using a child seat on the front passenger seat
Fig. 63 On the sun visor on the passenger
side: airbag sticker
First read and observe the introductory information
and safety warnings
Not all countries allow you to transport children on the front passenger seat.
Not every child seat is suitable for use on the front passenger seat. Volkswa ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information