Quote:
Originally Posted by miket
Otto what is the emissivity of white plastic?
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Dunno, but white is less emissive and less absorptive than black, but much more reflective, so stays cooler in sun. On a sunny day, put your hand on the roofs of various colored cars, and feel that white is coolest. White stays in a narrower temperature range than black, for less thermal stress. That's why German sailplanes are required, by law, to be white--materials last longer with less solar or UV degradation.
Maybe, driving across Death Valley in July in your car with white belly pan, the white would reflect more heat energy back to the road, helping keep your car cooler, getting an extra 1/1,000 mpg since the AC does not need to work quite so hard. That's a stretch, I know. Sorry.
I like white for belly pans because if stuff drips off, say, a radiator hose or oil pan, the drips are easier to see on white. Also, crawling under the car or looking down into the engine bay it is typically too dark to see very well, and white would reflect light better so I can see better. That's just me, though. Overall, probably a chocolate vs. vanilla debate.
When I do my old Ford van belly pan, it will be whatever color politician's sign I can most easily "borrow."
