The Effect of Water Evaporation in Automotive Windshield Defrosting

Water evaporation during windshield defrosting is investigated paying particular attention to the effects of air humidity and wind speed. During the defrosting process, the ice layer on the windshield begins to melt as the temperature of the defrost air increases. Results have shown that the iceturned-water can evaporate depending upon the ambient air humidity level and the wind speed. Water evaporation takes the heat otherwise available for melting, thereby delaying the ice melting process. It is found that at low wind speeds the effect of air humidity in delaying the ice-melting is minimal. However, at high wind speeds, (>10 m/s) water evaporation can take enough heat away from melting, thereby significantly reducing the ice removal rate. In relation to this, driver safety concerns associated with the reduction of ice melting rate are discussed.