Quote:
Originally Posted by freebeard
Nor sure why they call it passive, when there're pumps and circulating fluids.
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You know about the difference between an air-cooled engine and a water-cooled engine. Both have cooling fins somewhere, but which needs a water pump and why?
The same thing with the panels. The idea is to move the heat towards the panels from around the inside of a building and also to have a way to control it (you probably don't want a chilling effect during the middle of winter).
But if temperature control weren't a requirement, then you could just put this material on the roof as the roofing material, so to speak. The bottom line is that it radiates more heat than it assorbs, making it cooler than ambient temperature by as much as 15 degrees. Most materials don't do that, most either assorb a lot of heat from the light from the Sun or they reflect most of that heat without being able to radiate heat.
It's like the valve covers on a VW air-cooled engine. Black valve covers are usually preffered because black tends to radiate more heat (infrared). But reportedly VW would sell air-cooled engines with chrome valve covers in artic areas to help hold heat in.
But this material both reflects and radiates at the same time. It would be nice if they could design a material like this for engines so we could have nice chrome looking engines that also radiate heat as if they were painted black.