Keep snow off solar panels!

[alex@aspenlog]

I am researching starting a new company selling solar panels in Utah, and very quickly realized that there is nothing developed to keep snow off of the panels in winter. I have since started development of a simple device to do just that, but wanted to get some feedback before starting production. How big a problem is keeping snow off of the panels?

[halfcrazy]

tell us more about your device? there may be something in the works for snow melting but we will see. i am curius about your device does it melt it or sweep it or what?

[Brock]

In our last house I never had an issue. I wasn't thinking about wind where we are now. I mounted the panels on a south facing roof, but the house continues further south of the garage. So to the west of our panels I have the east facing house roof, the panels sort of start in that valley and continue further east. The problem is the snow blows from the Northwest and drops in the southeast corner of that part of the roof, right where I have the panels.

After our first big snow storm (11 inches with a lot of wind) the panels in the corner were buried by more than 3 feet of snow. I had to put a harness on and go shovel out the panels, quite a pain. The garage roof 10 feet to the east was windswept and clear. I do have mounts all the way across but started in the valley, right where all the snow stuck.

Our panels are tilted enough so snow can slide off, but not if there is no place for the snow to slide to. I would think in most cases design and location would rule out snow coverage, but sometimes it can’t be avoided.

Oh now I keep our pool brush right there and can pull the snow away from the bottom side of the panels so they can self clear, needless to say next summer the panels are moving 10 feet east.

[alex@aspenlog]

Melts. From what I understand once light begins to hit the panel they heat up and pretty much takes over from there. My device just starts the process. It works like a defroster for your car winow

[Solar Guppy]

Latitudes that have snow require the panels be at a steep pitch for proper operation ( Sun angle is very low in the horizon and require 45 to 60 degree pitch on the panels ). Panels self-shed the snow

[halfcrazy]

well i am fairly north here in maine and my panels do not self shed i wish they did. but the snow melt idea is being thrown around and seems like a good one. on my array as soon as it gets started it will slide rite off.

[alex@aspenlog]

will covering the panels with another thin layer of plexiglas reduce light absorption?

[icarus]

A little sweep as needed, and within an hour or so in sun they melt off. The worst is warm snow (not an oxymoron!) on cold panels, that freezes to a thick crust at the bottom of the snow. That takes a bit to melt off, but normal snow melts pretty quickly.

A simple idea is some frost-tex type heat tape around the edges of each panels. Controlled by a switch rather than a t-stat, they draw under 3 watts/foot, only when they are on. You could also carefully run a string of frost-tex across a panel, making sure you don't shade individual cells. The tiny amount of heat would allow the panels to melt off even faster if getting on a roof to sweep them is out of the question.

Tony

PS. My panels are near the ridge. The problem is that the panels may slide, but the roof below the doesn't, so that even when I sweep them, I have to shovel out below them a couple of times a winter to clear the build up of snow below the bottom edges of the panels.

[BB.]

Yes... But you can confirm that for yourself...

Take any silicon solar cell/panel and connect it to a amp meter. The output current of a shorted silicon solar cell is pretty much proportional to the amount of light energy it receives.

The ratio of the two readings (behind plastic, no plastic; both in the same sun) will give you the answer.

-Bill

[icarus]

will covering the panels with another thin layer of plexiglas reduce light absorption?

The short answer is yes to some extent, but the question is, why would you want to do this? Plexiglas, and most plastics will yellow in the sun over time, and will reduce transmittance significantly over time.

I can't think of why adding a layer of plexiglass would aid in melting the panels.

Tony