Volkswagen Polo Service & Repair Manual: Critical Point

Volkswagen Polo Service & Repair Manual / Refrrigerant R134a Servicing / A/C System, General Information / Refrigerant R134a / 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.

Refrigerant R134a Physical Data

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 ...

Refrigerant R134a Environmental Information

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:

Battery Charger -VAS5900- Maintenance Charging
Note If the battery is discharged by an electrical consumer during maintenance charging, the Battery Charger -VAS5900- automatically supplies the appropriate charge. Maintenance charging can be performed without time ...

Two-Part Filler
Definition: Two-Part Filler -LLS MAX 202 M2-, medium gray Edition 03/2013 Product Description The Two-Part Filler -LLS MAX 202 M2-, (medium gray) is a high-quality two-part H ...

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. ...