Ground mount solar rack?

Hypoxic

Active member
Jun 19, 2016
25
Ontario, Canada
I plan to build a ground mount rack for my solar panels. I've seen a few different ways of building the rack and I'm not sure which would be best. There is the fully covered rack that the panels sit on top of and then there is an open slat type rack that the panels sit on top of. The slat type would be cheaper to build but the fully covered plywood type would be more sturdy. Which type would provide the best heating performance?
 

CJadamec

TFP Expert
Apr 29, 2016
2,269
Quaker Hill, CT
I've got the same project planned for whenever spring manages to make its way to my area. Im planning on a 2x6 frame with 2x6 slats probably 16" on center. You may have issues long term with plywood delamination from moisture. The pile of 2x6's I have left from a deck I took down has influenced my design a bit tho. I don't think there is any justification for the added cost of plywood.
 

domct203

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Jun 3, 2015
3,959
CT
I've got the same project planned for whenever spring manages to make its way to my area. Im planning on a 2x6 frame with 2x6 slats probably 16" on center. You may have issues long term with plywood delamination from moisture. The pile of 2x6's I have left from a deck I took down has influenced my design a bit tho. I don't think there is any justification for the added cost of plywood.
That's pretty much how I built mine, all treated lumber.

I chose to top it with treated plywood, and painted it flat black. I wanted to reduce as much heat loss as possible from wind, as well as add to the heat by painting the rack deck black. I remove the solar panels & store them inside for winter, and wrap the whole rack with a tarp for winter.

IMG_9683.jpg
 

pooldv

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Aug 10, 2012
25,178
FL panhandle
That's a nice looking solar set up! I agree that there will be some gains from blocking the wind from behind and painting the deck black. Pressure treated CDX plywood should hold up pretty well. I would actually use an opaque, black stain rather than paint. It is easier to recoat in a few years than paint is. Opaque stain is great for all outdoor wood projects. :thumleft:
 

pooldv

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Aug 10, 2012
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Yes, I think that pvc pipes would absorb a fair amount more heat than white pvc would reflect.
 

sandract

Member
Jul 9, 2014
10
Danbury, Connecticut
I am ready to build some type of rack for solar panels. I had laid them on the ground, but they got damaged within a week. My pool was much warmer even though they were facing north. I have seen some that were made using pvc rather than wood. Wondering if that is study enough? I am planning on bringing the panels in for the winter. Does anyone have plans or pictures that they are willing to share. Looking for something that I can easily build and not too expensive for materials.
 

CJadamec

TFP Expert
Apr 29, 2016
2,269
Quaker Hill, CT
You would need a lot of fittings and pipe to make a frame with enough support for the panels. Not that it can't be done but it probably won't be that much cheaper than a wooden frame. I just finished getting my panels mounted and it looks a lot like the ones that dom did just maybe not as neatly done. Surface temp of that plywood gets HOT in the full sun I've seen it up over 160F. I'm really impressed with how much heat those panels put into the pool.
 

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mas985

TFP Expert
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May 3, 2007
12,382
Pleasanton, CA
Surface temp of that plywood gets HOT in the full sun I've seen it up over 160F.
That means that it is not conducting to the panels very well. If it was conducting to the panels it would be just as cool as the panels. Wood is a terrible conductor of heat so most likely it is not adding much heat to the panels and most is being radiated away. Now if the surface was a metal, then it would probably conduct much better, be cooler and add to the panel heat.
 

CJadamec

TFP Expert
Apr 29, 2016
2,269
Quaker Hill, CT
Wasn't really expecting the wood to conduct heat into the panels much the same as an asphalt shingle will have about the same conductive properties if installed on a roof. The surface of the panels themselves is not much warmer than the pool water.

Not sure you get any significant conductive gains by adding a layer of metal to grab the heat in the space between the panels.
 

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