Blue or green solar thermal collector?

[Chiel555]

Hello, i have a question;
The most solar thermal collectors i have seen have a black adsorber; this adsorbs the visible part of the electromagnetic spectrum; that's why they are black right?
is het possible to have an adsorber painted green or blue which still adsorbs a reasonable amount of the electromagnetic spectrum ( i mean the full electromagnetic spectrum: visible and non visible )? ;
it will reflect the green or blue light( because that's the reason it looks green or blue) so it will adsorb less of the visible part electromagnetic spectrum than a black adsorber;
but maybe it will adsorb some lightwaves from the non visible part of the electromagnetic spectrum better than a black adsorber; so that in total it might adsorb more or less the same light energy as a black adsorber

 

[berkeman]

Is there a reason you want this solar collector to be blue or green versus black? Almost certainly it will not be as efficient.

Also, are you using the term "adsorption" on purpose? It seems like you should be using "absorption" for the heat transfer: https://chembam.com/definitions/adsorption-vs-absorption/

 

[Rive]

this adsorbs the visible part of the electromagnetic spectrum; that's why they are black right?

Nobody said that it'll absorb only the visible spectrum.
Actually, usually it's absorbing quite an amount of IR (thermal) radiation too.
(And UV too, but that's not much - not much coming through the atmosphere anyway.)

but maybe it will adsorb some lightwaves from the non visible part

Google up 'selective solar coating'.

Ps.: the key point is actually not the absorption - it's usually above 90%. It's the low temperature radiation, what makes the difference for these solar paints...