Understanding A2L Refrigerants for Air Conditioners
ACHR News - 3. Finding the Right Alternative Refrigerants
Tradeoff: GWP vs Flammability
GWP
New Category : A2L
To shift the balance towards being more environmentally
friendly, we must accept some degree of flammability.
Refrigerant molecules with reduced number of fluorine atoms
generally have lower GWP, but these refrigerants have a higher
proportion of hydrogen atoms
Transitioning to low-GWP refrigerants doesn't mean compromising on safety.
The leading lower-GWP candidates fall into the relatively new lower flammability
classification of A2L.
Safety Group Classification
Substance
B2L
Ammonia
R 717
A3
Propane
A2
Refrigerant Designation
Chemical Formula
R 290
A2L
1,1 Difluoroethane Difluoromethane
R 152a
R 32
C3H8
Burning Velocity (m/s)
0.39
C₂H₂F₂
0.23
CH2F2
0.067
0.072
46
16
9
19
NH3
Toxicity: A, B
Flammability: 1, 2, 2L, 3
Heat Of Combustion (MJ/kg)
Combustion Image
■ TABLE 1: Selected refrigerant examples by safety group.
B. BROODS
9.15.08
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