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:
Crimping Pliers with Insert
The Crimping Pliers without Insert -VAS1978/1- with Crimping
Pliers - Insert 2 -VAS1978/2- is a component of the Wiring
Harness Repair Set -VAS1978- and is used to crimp the connector
during the wiring harness repair.
...
Comfort
Being comfortable while driving leads to better
concentration and safe driving. Air conditioning makes drivers
and passengers more comfortable when temperatures or humidity
are high. While opening the windows or sunroof or increasing the
air flow can mak ...
Headlight range control, instrument and switch lighting
Fig. 69 Next to the steering wheel: control
for instrument and switch lighting ① and headlight range control ②
First read and observe the introductory information
and safety warnings
① Instrument and switch lighting
When the headlights are switched on, the brightness of the instrument ...
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Refrigerant R134a Physical Data
Refrigerant R134a Environmental Information