Solar panel rack question

[mokabb]

I have some solar panels on the way and will be placing them on a ground based rack. The array will be 30'x12'. I have seen some plans and they all seem to have an open architecture. No backing.

I would think having some black backing material would be better for the efficiency of the panels as it would insulate them to some degree, much like the roof shingles probably do on roof installs. Does it?

Pressure treated plywood to cover that area would cost ~ $400 and add construction time, considerable weight and strength.

I was wondering if anyone has tried roll roofing material over the open frame. It's about $120. Would it hold up over time just draped over the frame? I could support that with chicken wire or some such thing if it would help.

Or is all this extra stuff over-engineering and adding $$$. I would just keep it "open" if it doesn't make a difference.

Thanks.

 

[lbridges]

I have been told the roof shingles on a solar install are actually cooler due to the shade/heat absorption of the solar panels, helps cut down heat in an attic - so I don't know about the insulation factor.

However, if you are in an area with a good amount of wind, then I could see an advantage to backing (how much is ???).

 

[NWMNMom]

I agree, if there is a lot of wind there maybe? Otherwise I'm thinking a waste of resource and time - just give it the right support, configure your placement and angle to the sun and plumb it in. Our structure is built with PVC, a 2x4 lip at the bottom to keep it from sliding off since we have it at a 40 deg angle to the sun and chicken wire over the frame to support the panels.

 

[geekgranny]

I haven't check the prices lately, not since we used for roofing for my small, multi pony or multi goat or one horse barn with attached tack room, but powder coated metal roofing might be a good, lightweight, easy to work with, support for the panels. And it would be more attractive than other products. My barn was built in 88 and the roof condition is still excellent with no rusting. It is not flat but has square ridges for structural strength, unlike some of the fiberglass sheets you see (which are probably much heavier) that have curved or rolling ridges. It is very sturdy, once attached, and has held up to 70+ mph winds. My roof is colored on both sides, so it looks pretty nice inside. It is a cream color. Experts will advise on whether light or dark is better for under solar panels.

As I remember is was really easy to carry one sheet into the woods, way down the hill. I think my friend, who was living with us at the time, who built the barn, carried several sheets down at a time. His hobby was furniture building so most of the building joins, etc. are like finely crafted antique furniture. How lucky was that, and free labor. I wish it was closer to the house so I could admire it more often.

It would make a wonderful pool house but would probably cost more to have it disassembled and rebuilt than to start from scratch.

gg=alice

 

[mokabb]

Thanks for the prompt replies. There typically is not much wind on a daily basis. I repositioned our fence yesterday so the panel will be facing south. We are at about 40 latitude, so I was put the angle at 25 degrees.

I'm not sure if I will back it yet. I am sure that I won't do plywood unless someone's experience here tells me that I should absolutely do it. I haven't seen any metal roofing material locally, but will keep an eye out for it. I'm still considering some backing. If interested, take a look at the rack pics here... http://www.solarswim.net/photogallery.html , there seems to be backing on all of them. It appears to be some sort of paper or roofing material.

edit: I am building a rack based on this http://shop.solardirect.com/pdf/pool-he ... rawing.pdf

 

[Bama Rambler]

That's a good looking design on that rack. I wouldn't back it if that were the one I was building. Your panels will sag a little but it won't hurt anything at those distances.

 

[mokabb]

For those interested, I've posted a couple of pics. The pool is nice and toasty now. It easily keeps it in the 85-93 degree range. Just where my family likes it.

 

[lbridges]

That's a good looking installation!

 

[mokabb]

Thanks. It took a bit of time, but was not all that difficult once I made the plans and got the materials. If anything goes wrong, I don't have to climb up 25 ft to fix it.