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).

 

[oswaler]

I would recommend using a high-temperature, flat black paint specifically designed for solar heat absorption. This type of paint is typically used for solar collector panels and has been tested and proven to have high solar heat absorption rates. It is also designed to withstand high temperatures and is more durable than regular flat black paint. Additionally, you may want to consider using a primer or base coat specifically designed for solar heat absorption before applying the flat black paint to further enhance its performance. I would also suggest doing some research on different brands and their performance in terms of solar heat absorption to find the best one for your specific needs. Lastly, it is always a good idea to consult with a professional or do some testing to ensure the best results for your DIY solar heater project.