The air conditioning system of vehicles (Mobile Air Conditioning) is going through an important evolution in order to satisfy the European regulation 2006/40/EC about the greenhouse effect of gases. This directive has forced the car maker (that will be the first company involved in this passage) to adopt refrigerant fluids with low Global Warming Potential, GWP < 150, starting from 2011 for new models of motor vehicles.
It has been initially evaluated the effect of the CO2 or R-744 (GWP = 1) in substitution of the current fluid R-134a (with GWP = 1430), solution abandoned very soon due to the fact that it could not be used like a “drop in” in the actual standard systems because it means the redesign of all components and, in particular, the high pressure levels of the refrigerant cycle (around 100 bars), with consequent increment of costs for the car maker equal to 200 € approximately.
In parallel to the R-744 analysis it has been evaluated the new generation refrigerant fluid HFO-1234yf produced by Honeywell - DuPont, declared similar to the R-134a. The advantage of this fluid is that it does not imply the redesign of the whole air conditioning system but the adoption of some solution only due to its lower molecular dimension respect to the R-134a.
This new refrigerant fluid has the same exercise pressure levels respect to the R-134a but a lower cycle efficiency.
Nowadays several car maker (FGA is included) have declared the adoption of the refrigerant fluid HFO-1234yf in substitution of the current R-134a for new vehicles.
The current job has been given a contribution to the project of the refrigerant recharging machine for HFO-1234yf produced by Luvata Italy s.r.l. (already manufacturer of these recharging machine with R-134a). The study has become necessary to evaluate the risk assessment in spite of the weak flammable property of the new refrigerant.
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