Black vs Silver panels?

[nwdiver]

Black panels seem to be popular and sell for a premium.

Esthetics aside, my gut tells me that black panels will absorb more sunlight and run warmer than silver panels, so could be less desirable. But if they are more effective at changing light into electricity, then they could be more desirable.

Have you seen data either way?

Thank you.

I tried to find 320w 60 cell panels with silver frames. Looks like Residential panels only come in black now.

[Mike90250]

I think all frames are anodized, and that's why only specific sets of hardware are rated to pierce the hard anodized finish. And from my experience with powder coating, it's only good for a couple years before the UV cooks the plastic and it crazes and starts peeling off. Sheltered, it lasts a long time, on a PV frame or rack I'd guess 5 years tops.

[J.P.M.]

This is very interesting and helpful. Thank you all.

This proves one thing about solar power: no matter what aspect you delve into, there are so many details.

Just like most applied technologies, you can go as deep as you want. But unlike pure science, the knowledge depth of most applied technology is often limited by economics and application.

[bob-n]

This is very interesting and helpful. Thank you all.

I just did some quick web searching. There are a few articles claiming that indeed black panels are less effecient (is that the right word) than "normal". Reading about black panels also links to many discussions about poly vs mono, but that's another topic. It's hard to separate claims for black panels from claims for mono panels.

Silicon will naturally oxidize, just like aluminum, and is protected by intentionally grown and/or deposited oxide. The interesting difference is that silicon dioxide (or silicon nitride) will have a different color depending on thickness, due to the wavelengths of light at different colors. I haven't yet found how they make some cells intentionally appear blacker than others.

I also found that both black anodized frames and black powder-coated frames are used, depending on the manufacturer. I also read that all black anodized coatings fade when exposed to long-term sunlight,

This proves one thing about solar power: no matter what aspect you delve into, there are so many details.

[J.P.M.]

How is the black coating applied to an aluminum frame, and will it actually
last over 2 decades? Bruce Roe

Depends on the coating, how it's applied and, for one set of considerations, how fit the coating is for prolonged exposure to the elements, including solar radiation.
Spray painting with rustoleum on unprimed and unoxidized aluminum most likely has a lower probability of lasting as long as the useful production life of a PV panel.

My guess is most colored frames are painted - e.g., see LG product hype - but it's possible to have the anodized aluminum colored during the anodizing process. Don't know how common that is, if at all, for PV framing applications. FWIW, some types of anodizing make some types of aluminum more brittle. That may/may not be a consideration for PV framing applications. Powder coating may also be an option, which, for all I know, may be common.

I'd also guess packaging and handling during erection would also be a consideration with respect to surface durability.

[bcroe]

How is the black coating applied to an aluminum frame, and will it actually
last over 2 decades? Bruce Roe

[J.P.M.]

I seem to recall looking at mfg. data sheets that showed STC efficiencies for all black panels being slightly lower than identical panels that are not all black. That will make them less efficient and less productive and so less cost effective, but not necessarily less desireable

Since the published/claimed penalty in STC efficiency I've seen is of the order of ~ 0.4 to 0.5% or so, and most folks are clueless about what that may mean, I suspect, esthetic considerations will sell more product than efficiency.

If you're a peddler, put aesthetics aside at your peril. It's easier for a peddler to leverage customer vanity than explain anything involving math. The probability of closing a sale is also higher using vanity than rubbing a customers nose in their math phobia.

On efficiencies: I remember seeing Sunpower data sheets that had that 0.5 % lower STC efficiencies or so (21.0 vs. 21.5 STC eff. or so) for all black panels w/monolithic frontsides vs silver frames and busbars on front, but I have no independent data to confirm that. Data sheets seem to play with numbers a bit and some mfg. processes/procedures and testing protocol do change slightly with time, but (21.5-21.0)/21.5 seems like a believable % increase in a panel's temp. diff. with the environment ( w/bottomline temp. increase maybe ~ 3-5 C. or so difference, black to silver) when operating at close to STC conditions.

From a mfg./production standpoint, I can't see where two otherwise identical panels except for color and/or maybe if the wiring is moved from the frontside to the backside of the panel would mandate different cell characteristics. I'd also think black vs. white backsheets on the all black panels don't do much to lower the equilibrium temp. of a panel (but probably not a lot +/-, at least for a roof mount), s, my $$'s are on cells in either panel being identical. If some of that is a correct description of how the game is run, "blacker" panels will be less effective or less effective at changing sunlight into electricity, but they may be more marketable due to appearance, and customer vanity is an easy thing to take advantage of.

From a scientific standpoint, while there may be some mitigating factors that may need consideration(s), thermal radiation basics, etc. will confirm that objects with greater absorbance of solar radiation (things that are more "black " will get hotter than objects with lower absorbance of solar radiation.

There are no white solar thermal panels for a reason.

[solarix]

Yep, Black panels are not as productive, but they look so much better and sell better (black is beautiful). Around here, the local city officials have mandated black frame solar panels only. You'll notice that in the high-efficiency panels (the ones on the bleeding edge of efficiency bragging rights), they are all aluminum framed.

[bob-n]

Black panels seem to be popular and sell for a premium.

Esthetics aside, my gut tells me that black panels will absorb more sunlight and run warmer than silver panels, so could be less desirable. But if they are more effective at changing light into electricity, then they could be more desirable.

Have you seen data either way?

Thank you.