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:
Maximum permitted trailer weights
First read and observe the introductory information
and safety warnings
All data in the official vehicle documents take precedence over these data. All
data in this manual apply to the basic model. The vehicle data sticker in the service
schedule and the official vehicle documents show which ...
Wear Spots
A wear spot is a flat spot on the tread of the tires that
can be caused by extreme braking maneuvers on subsurface such as
asphalt.
At the same time a tire during the braking maneuver is
rubbed at selective points which ...
Introduction
This chapter contains information on the following subjects:
→ Opening and closing the electric panorama sliding/tilting glass roof
→ Electric panorama sliding/tilting glass roof – function
→ Roll-back function of the electric panorama sliding/tilting glass roof
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