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Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017
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♦ For the air conditioning system, only approved refrigerant with
the requisite level of purity may be used
⇒ “6.2.16 Analysis of refrigerant R1234yf”, page 24 .
♦ R1234yf refrigerant is a halogenated hydrocarbon compound
with the chemical designation “2,3,3,3-tetrafluoroprop-1-ene”
which boils at -29.4°C at a vapour pressure of “1 bar” (equiv‐
alent to ambient pressure).
6.2.2
Potential risks with R1234yf refrigerant
♦ The refrigerant is flammable with ambient air in a certain mix‐
ture ratio
⇒ “6.2.3 Physical and chemical properties of R1234yf refrig‐
erant”, page 20 and
⇒ “6.2.13 Flammability / decomposition of R1234yf refriger‐
ant”, page 23 .
♦ Rapid vaporisation of the liquid can cause freezing injuries
♦ High vapour concentrations can cause headaches, dizziness,
drowsiness and nausea and even loss of consciousness.
6.2.3
Physical and chemical properties of
R1234yf refrigerant
The following is a list of the main properties and safety information
for R1234yf refrigerant. The complete details can be found in the
respective safety data sheets on the ⇒ VW / Audi ServiceNet .
Chemical formula
CF3CF=CH2
Chemical designation
2,3,3,3-tetrafluoroprop-1-ene,
HFO-1234yf
Boiling point at 1 bar
Solidification point
Critical temperature
Critical pressure
-29.4 °C
-152.2 °C
94.7 °C
32.82 bar (positive pressure)
33.82 bar (absolute pressure)
Self-combustion temperature 405°C at 1.02 bar (absolute
pressure)
Flammability
Flammable gas
♦ Lower explosion threshold
6.2% (volume)
♦ Upper explosion threshold
12.3% (volume)
Form
Colour
Odour
Compressed, liquefied gas
Colourless
Weak odour
6.2.4
Critical point
The critical point (critical temperature and critical pressure)
means the point above which there is no longer a surface of sep‐
aration 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
contained within a pressure vessel exhibit a liquid phase and a
gas phase, i.e. 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
⇒ “6.1.3 Vapour pressure table for refrigerant”, page 17 .
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Rep. gr.00 - Technical data
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