Comparing Reflection and Temperature

Basic test setup, on insulating material, a piece of paper, a piece of special material, next to it the roof deck.

Check the main page

If the sun beats down on cities in a heat wave, you’d think there’s little you can do. But you can definitely reduce the heat, simply by reflecting light back into space. Its like having bright clouds overhead, the travel time of the light is just a bit longer. Like with clouds whatever is underneath does not recieve the solar radiation. Because the atmosphere is transparent to specific IR radiation it really leaves the planet, it does not warm up anything.

Above you see three materials, paper, special PTFE and plastic roof deck, and their temperatures under direct sunlight. The special PTFE is the coolest, still not the coolest possible temperature but cool enough to endure. White TiO paint will not cool like this meterial does, but I will test it. The trick is to radiate IR in the right frequency band as well. Most white paints don’t. You can see if they do by measuring their efficacy in the shade. If your paint is cooler than other paints in the shade it radiates IR in a different range.

The temperature difference can be quite large already I wonder if one can build an energy source out of a device that is actually shedding energy away from Earth?