Comment by rwmj
2 days ago
I'm now wondering if painting a roof white is better than covering the same roof with solar panels and using that to drive air conditioning (in the house). My intuition is that painting it white must be vastly more environmentally friendly, although it probably doesn't reduce the temperature very much compared to aircon.
There are certain materials that aren't just white but also specifically radiate heavily in IR bands that the atmosphere is particularly transparent to and so can actually stay sub-ambient temperature while in sunlight. See, for example, https://onlinelibrary.wiley.com/doi/full/10.1002/eom2.12284
But adding conventional AC is never going to cool down the world.
AC doesn't make it cool it merely transfers the heat to the outside in an energy efficient manor. The emerging tech is special coatings that convert heat to an infrared frequency that easily escapes the Earth's atmosphere.
Most manors aren’t very energy efficient. Take Downton Abbey for example.
Thank you!
man·ner /ˈmanər/ noun 1. a way in which a thing is done or happens.
It's worth factoring in that solar panels also provide solar insulation to the roof by effectively shading it, ie the sun shines on the panels and there is an air gap between the panels and your roof.
In cooler climates, you are now taking a hit on heating costs. That now blocked Winter sun would have provided some amount of free warmth.
If it's that cold, you probably have a fair amount of roof insulation anyway that's preventing heat absorbed by your roof from being conducted to the conditioned space.
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Does the house already have AC or not? And are you talking about indoor temperature or outdoor temperature? Also many places are cold. Running AC would make it worse.