Passive Heating [i]and[/i] Cooling
 

I commented recently that ultrawhite paint and biochar could "save the planet". Here it is paired with Vanta Black and powered by a wax motor.
2199 Heating And Cooling Without Power - Wax Motors And Paint
It looks like it comes down to the weatherability of the coatings and reliability of the hinged flaps.

Nice find and a brilliant idea Freebeard.

The Paper:
https://www.cell.com/device/pdf/S266...23)00304-6.pdf
"...it reduces the energy consumption for
cooling by 3.13 X and heating by 2.63 X..."

That's a lot!
Going to be difficult to combine with low weight and 'aero' on a car, but on a house..!

I do wonder how they get the heat trough the white tile when the black tile's down on top of it. Any air caught between them will act as an insulator..

I thought that was the area needing improvement too. But because the flaps up would shade the main surface.

The three elements need to be rearranged. I haven't figure that out.

It's sad, but Robert Murray-Smith lost his wife eleven days go and hasn't posted since.