20 degree roof, panels and snow.

I have a warehouse tent I plan to convert to a lightweight building. The frame is 50mm/2in galvanised pipe (2mm/0.080in) thick. It is definitely not strong enough to handle any serious snow load. But snow simply slid down the roof.

I initially planned corrugated steel so snow would continue to slide, but now that panels are so cheap I'm considering making the roof out of them. However I worry frames will stop snow from sliding and TTE whole thing will collapse when there is 10in plus of snow.

Does anyone have any experience with panels right next to eachother at such shallow angle?

Luk88 said:

Does anyone have any experience with panels right next to eachother at such shallow angle?

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YUP!
I tilt my panels from 30 degrees (summer) to 72 degrees (winter)
I can tell you, if my panels are at 30 degrees and we get snow, it will not slide off, unless the temps come up enough to form a layer of water.
Even the 72-degree angle for winter can collect a couple inches (50-60mm) of snow before it will slid off if the conditions are just right - like wet snow followed by cold night.

I think your concerns are valid. When deciding whether to put panels on my 5:12 pitch roof (~23deg) or a ground mount, I paid attention to how long after a storm the snow remained up there. After a fairly big storm (~1m of snow) it took about 10 days to clear, and about 3 days after a 24cm snow storm. Of course it will depend on the weather after the storm, but based on these observations at my place, I opt'ed for a ground mount.

The glass of the panels will make for a smoother surface to enable snow sliding. And if you think you will be there to manually remove the snow that will help too. But it seems likely that at some point the structure will need to deal with some snow load; possibly often depending upon your weather.

Luk88 said:

The frame is 50mm/2in galvanised pipe (2mm/0.080in) thick. It is definitely not strong enough to handle any serious snow load.

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Another option would be to reinforce the structure frame with extra material to increase it's bending resistance, and carry the desired total load.

I find the glass surface of a PV panel allows snow to slide, but the aluminum frames stick up just enough to catch the snow and resist sliding. Often it seems wet snow will stick an build up on the aluminum, creating a dam that holds snow behind it from sliding well, especially where multiple rows of PV panels are set row upon row together.

I think I'll stick to corrugated steel for that structure. Reinforcing it would cost a lot. Thank you for your answers.

I already have a ground mounted array and I'm in a process of building another, but at current prices I'm thinking where else can I put some panels.

Luk88 said:

I have a warehouse tent I plan to convert to a lightweight building. The frame is 50mm/2in galvanised pipe (2mm/0.080in) thick. It is definitely not strong enough to handle any serious snow load. But snow simply slid down the roof.

I initially planned corrugated steel so snow would continue to slide, but now that panels are so cheap I'm considering making the roof out of them. However I worry frames will stop snow from sliding and TTE whole thing will collapse when there is 10in plus of snow.

Does anyone have any experience with panels right next to eachother at such shallow angle?

Click to expand...

For places where winter snow and minimal direct winter sun are an issue, vertical bifacial panels (solar fence) with south facing fronts will outperform tilted panels. They will self-clear of snow and collect light on both sides on overcast & cloudy days. In clear weather, they will produce less power than ideally tilted panels but by having a morning and afternoon production peak they effectively reduce the mid-day peak when combined with tilted panels and extend the production hours. If you have snow, use bifacial panels.

Gold Country Russ said:

For places where winter snow and minimal direct winter sun are an issue, vertical bifacial panels (solar fence) with south facing fronts will outperform tilted panels. They will self-clear of snow and collect light on both sides on overcast & cloudy days. In clear weather, they will produce less power than ideally tilted panels but by having a morning and afternoon production peak they effectively reduce the mid-day peak when combined with tilted panels and extend the production hours. If you have snow, use bifacial panels.

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Sadly I haven't got any unshaded south-north facing fencing unless I want to put fencing in a middle...

I've spent quite a bit recently buying bifacial panels for a "typical" ground mounted array so if there are more panels they will be cheap second hand ones (or the cheapest new ones).

Half of my property is unfenced so I'm looking for a "panel fence", but that half has good sky view on north-east and south-west.

Does anyone have any experience with the soil being actively farmed right next to their solar panel fence?

I'm especially concerned about small stones being thrown by machinery (tiling etc).

The neighbour over the south-west is farming, this (especially manure being thrown about a meter from the boundary on my side) is somewhat discouraging to put a panel fence there. I'd probably have to set it back 2m or so which is not ideal.

Then there are trees on the unfenced part of my property. I left them there intentionally as I like the kind of "secluded woodland" feel it produced. But this year I have to make a very hard decision. Either I cut all of them or I'll not be able to cut them anymore significantly lowering the value of that land.

Therefore a law written to protect trees is essentially forcing me to cut them all or else. Ironic.

Search online for "agrivoltaics" to see examples of solar fences and canopies for farming and ranching. By fencing I mean that they look like a fence but frequently are used in rows allowing agriculture between the rows.

Ultimately you need to make choices, as we all do. Cutting trees or not, roof mounting or ground-mount, fence lines or out in the middle of an open area. Tough choices often. Most of us will take the "low hanging fruit" first, easy and low cost area for the first PV panels, then less convenient locations - ie long wire runs to access PV potential area.
All we can do is offer you suggestions, then it will be up to you to choose.
In my own set up, I lose a lot of early morning sun due to a zone of big trees along the East side of the property, because if I cut these, my neighbour's trucking business will be wide open to my space, and I decided I would live with losing some early morning sun in exchange for better sound barrier effect of that wooded area. We all gotta make choices, for better or worse. Up to you.

I have ground mount 30deg panels in Chicago metro so we get a lot of snow. It's not just the snowfall, it's the sudden temp changes. If we get a heavy wet snow and a cold front comes in, that snow can be there for weeks because it turns to ice on the panels. So I have to get out there before it gets cold and clear them. If it's just a normal snow without temp changes, the panels will clear themselves in a day or two. I plan to add my next panels mounted vertically on the barn wall so they'll always stay clear.