"window screen style"
Someone, somewhere, tested multiple versions or multiple ideas. University kid in India maybe?
'Furnace Filter style' worked best.
I either lost his link, or it disappeared, but he had a decent pdf up somewhere.
Maybe one of the other GM still has a link? (*cough cough bruce cough*)
My micro-mini-nano experiments with distilling water proved what the pdf said.
Cheapie furnace filters, 3 layers deep was the best bang-for-the-buck. 4 layer was a little better output. Over a few $$$ in places not as poor as where this guy was, I'd opt for the 4th layer. Flat black spray paint. Simple.
I have pics somewhere, but expect that SD card is a long way from here at the moment. I can TRY to dig them up in old emails if anyone is interested.
G-