Best paint for solar heat absorbtion?

[trx]

Hi, first-time poster. I hope this is the right area for this topic. It looks like this is the place to find smart people to give me good answers (I haven't seen any good forums dedicated to DIY solar heaters).

Ok, I'm going to start building a solar air heater and I'd like to pick the best paint to use on the collector. I know flat black is the way to go but is there some paints that perform better than others when absorbing solar heat? When testing different designs I used cheap flat black spray paint but still had some shine to it, plus I know it probably won't handle high temps. I know there's high temp flat black paint for grills, engines and exhaust but I have no idea how they perform at absorbing solar heat. I know manufactured collectors use better performing special coatings but they aren't really an option for the DIYer's as they aren't paints. Hopefully I can get some input here to save me some effort and/or guessing. Thanks.

Chad Urvig
Elk River, MN

 

[Astronuc]

I know there's high temp flat black paint for grills, engines and exhaust

I would think such paints are acceptable. I don't imagine that black solar collectors will operate at such high temperatures. If the solar collect is heating water at 1 atm (14.7 psia), then the temperature would be at most slightly above the saturation temp of 212°F (100°C).