Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...
Air conditioner with refrigerant R134a - Edition 11.2018
⇒ “2.6.1 Physical properties of refrigerant R134a”, page 10
⇒ “2.6.2 Critical point”, page 10
⇒ “2.6.3 Environmental aspects of refrigerant R134a”,
page 10
2.6.1
Physical properties of refrigerant R134a
Chemical formula
Chemical designation
Boiling point at 1 bar
Solidification point
Critical temperature
Critical pressure
CH2F–CF3 or CF3–CH2F
Tetrafluoroethane
-26.5 °C
-101.6 °C
100.6 °C
40.56 bar (absolute)
2.6.2
Critical point
The critical point (critical temperature and critical pressure) is the
point 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 both liquid and gas are present in the vessel, the pres‐
sure is governed by ambient temperature ⇒ page 8 “Vapour
pressure table”.
Note
Different types of refrigerant must never be mixed. The refrigerant
specified for the respective air conditioning system must be used
exclusively.
2.6.3
Environmental aspects of refrigerant
R134a
♦ R134a is a fluorocarbon and contains no chlorine.
♦ R134a has a shorter atmospheric lifespan than refrigerant
R12.
♦ R134a does not damage the ozone layer; the ozone-depleting
potential is zero.
♦ The global warming potential (GWP) of R134a is approx. 1400
(GWP of carbon dioxide = 1). To reduce the impact of refrig‐
erant R134a on global warming, the European Commission
has ruled that vehicles with air conditioners using refrigerant
with a GWP higher than 150 may no longer be made available
on the market from 1 January 2017 onwards. Air conditioners
in vehicles which were made available on the market before
31 December 2016 may be filled and operated with refrigerant
R134a until further notice.
♦ The global warming effect of R134a is ten times less than that
of refrigerant R12.
10
Rep. gr.87 - Air conditioning system
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