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:
Checklist
Using seat belts :
Check the condition of all seat belts regularly.
Keep the seat belts clean.
Avoid allowing any foreign bodies or fluids
to get on to the seat belt or latch plate or into the slot for the seat belt
buckle.
Do not trap or damage the seat belt and
latch ...
Curtain airbags
Fig. 61 On the left-hand side of the vehicle:
location and deployment zone of the curtain airbag
First read and observe the introductory information
and safety warnings
In the interior, a curtain airbag is fitted above the doors on both the driver
and front passenger sides . The airbag loca ...
Siemens Wheel Electronics Tire Pressure Monitoring Sensor, Removing and
Installing
WARNING
If tire sealant was used, then the wheel electronics
on that particular wheel must be replaced.
The Siemens wheel electronics does not have a
microencapsulated ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information