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:
Brush Grinder Set -VAS6776
Definition:
Brush Grinder Set -VAS6776-
Product Description:
The device is used to clean surfaces and remove corrosion in
hard to reach areas. For example, it is suitable for joints,
grooves, ...
Tires, Dismounting, Run-Flat Tires and Ultra High Performance Tires
Only trained personnel can perform the assembly work on
run-flat tires and ultra high performance tires.
If equipped check the tire pressure monitoring sensor with
the vehicle diagnostic tester and if necessary replace.
...
Battery, Charging
Requirements
WARNING
Batteries that have a light yellow visual indicator
do not have to be tested or charged. Jump starting must
not be used!
There is a risk ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information