Paint Question

Ned Bulken

Member
Messages
5,529
Location
Lakeport NY and/or the nearest hotel
OK gang, Question for you... I'm going to be attacking my solar project tomorrow. I'm putting up approximately 120sf of passive solar panels and I'm going to be painting the panels to increase my solar gain. I'm thinking of painting the panels a Dark Green so they'll better match the roof and look better during the summer months when I won't need the max solar gain that black would bring.

Dark GREEN

vs...


Black

just to give you an idea of the tonal difference I'm thinking of. If I can find that color relatively cheap, should I go with that, or flat black?
 
Dark colors in general will give a similar effect to black.

There is a spectrum from white to black and the colors gradually change as you pass from white and move towards the black.

Each of the individual red, blue, green will also have a gradual change from white to black,

Take the Green start with white and gradually mix in colors until it is so dark that it looks black - at that point is will be indistinguishable from the black and also perform the same way.

Traditionally, flat black, is the color of choice because it absorbs the most heat energy, but in reality any dark color that gets close to black is going to be close.

The closer to black it is - the better.

Also - the further from black that it is the less the performance.

For me - if I am going to build a purpose driven product - I am going to follow the purpose driven rules - so my vote is flat black - not gloss or satin - FLAT.
 
I have thought about solar panels on the roof of my house and my roof is green (metal) too, but didn't think about green paint for the panels.... I would put the panels on the back side of the roof and since my house backs up to a hill in the back and no neighbors for miles, not a concern too much on looks. This will probably never happen, but it's still a thought in the back of my head.
 
flat black it is, no sense in going for less than what you can get otherwise. i once read about some kids that wanted to heat their warming shack in the back yard (the dad had flooded a skating rink for them), and wanted to do it on the cheap. so they rigged a box, with an interior large enough for a dozen pop cans spaced about 2" apart, painted the whole inside of the box flat black, cans as well, had a framed glass panel for the top. they had rigged a 4" opening on the one side, and used dryer ducting from that to an opening in the side of the shack, and had a small battery powered fan to bring in the hot air. worked out pretty good for them.
 
I could give a rip about what the neighbors to either side think. I'm looking more for my own aesthetic than anything else. As for the solar project, Carol that's exactly where I've done my research. I'm going to be doing a vertical thermosyphon wall on the south end of the shop. I'm going around the doorway, as well as the right half of the doorway which is already closed in and will work well as a solar panel. I'm going to do this in stages, first will be the frame, with dark paint (I'm still leaning towards dark green, though if flat black is cheaper, I'll get that) on the field. I'll use black screen material to increase gain. I"ve got some plastic sheeting to enclose the panels, and will upgrade with ribbed clear plastic later as the budget allows. I'm looking to get a boost during the day, which, happily is when I have free time. I'm going to rearrange the shop, bringing the turning gear up near the south wall (it is in the north at the moment) so that when I have heat, I'll be able to enjoy it to the fullest.
 
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