Volkswagen Golf Service & Repair Manual: Refrigerant R134a
| Air conditioners in vehicles use the evaporation and
condensation process. The system contains a liquid with a low
boiling point, called the refrigerant. |
| The refrigerant used is tetrafluoroethane R134a, which boils
at -26.5°C with vapour pressure of 1 bar. |
|
| Physical data of refrigerant R134a |
|
|
|
| Chemical formula |
CH2F–CF3 or CF3–CH2F |
| Chemical designation |
Tetrafluoroethane |
| Boiling point at 1 bar |
-26.5°C |
| Freezing point |
-101.6°C |
| Critical temperature |
100.6°C |
| Critical pressure |
40.56 bar (technical) pressure
equates to 39.5 bar (standard) pressure |
| Critical point (critical temperature and critical pressure)
means the point above which there is no longer a surface of
separation between liquid and gas. |
| Above its critical point, a substance is always gaseous. |
| At temperatures below the critical point, all types of
refrigerant contained within a pressure tank exhibit a liquid
phase and a gas phase, so that there is a gas cushion above the
liquid. |
| As long as there is gas in the pressure vessel alongside the
liquid, the pressure depends directly on the ambient temperature
→ Chapter. |
 Note
| Different types of refrigerants must not be mixed with each
other. Only refrigerants specified for the respective air
conditioning system may be used. |
|
|
|
| Environmental aspects of refrigerant
R134a |
| R134a is a fluorocarbon and contains no chlorine. |
| R134a has a shorter atmospheric persistence than refrigerant
R12. |
| R134a does not damage the ozone layer, the potential to
reduce the amount of ozone is zero. |
| The Global Warming Potential (GWP) of R134a lies by
approx. 1430 (the GWP for carbon dioxide lies by 1). |
| The contribution of R134a to the greenhouse effect is less
by a factor of 10 than that of refrigerant R12. |
|
|
|
The vapour pressure table for each refrigerant is published
in the literature for refrigeration engineers. This table shows
the vapour pressure exerted on the liquid ...
Other materials:
Removing and installing high-level brake light, Golf
Special tools and workshop equipment
required
Plastic wedge -T10039/1-
Removing:
–
Switch off ignition and all electrical loads, and pull out
...
Measuring axial play of camshaft
Special tools and workshop equipment
required
Universal dial gauge bracket -VW 387-
Dial gau ...
Texture additive
Designation:
Fine texture additive -ALN 775 108-
Issued 04.2013
Product description
The fine texture additive -ALN 775 108- is designed to be
added to 2-pack HS top coats. Th ...
© 2016-2026 Copyright www.vwgolf.org
Vapour pressure table for refrigerant R134a