Ed Davies Posted November 30, 2018 Share Posted November 30, 2018 We've had previous discussion of using PV panels in roof as a replacement for tiles or slates but I wondering about using them on a wall in place of the cladding. Currently the wall is JJI timber I-beam studs and dwangs (noggins) with 9mm OSB3 over. Next calm days, if ever, I'll put Protect TF200 Thermo breathable membrane over that with staples and 38x12 counter battens. According the planning permission I was going to put a site-built low yield solar thermal collector over those (deliberately didn't specify whether that meant warm air or warm water - hadn't decided then) but with the price of PV coming down I was having second thoughts about that even at the time the PP application went in and now I'm pretty sure that extra PV (beyond the planned ~6 kW PV and 6 or 8 evacuated-tube solar thermal panels on the roof) would be a better bet. I'm assuming this will be easy to organize as a non-material change to the planning permission, together with a couple of other tweaks found along the way. The wall in question faces a bit north of east compared with the main roof which is a bit east of due south; the idea is that the extra PV might well pick up early morning sun before sea-air has clouded out the main roof. Probably pretty useless in deepest winter, when the sun's way south all the time it's up, but a helpful addition in the shoulder months. @ProDave might well have a source of cheap panels which would be good for this application, the main issue being getting them to the Highlands economically. Anyway, what I'm wondering about is the mechanics of using the panels as cladding, particularly sealing between them. Though the wall would be exposed to driving rain the glass-fibre in-roof trays seem like overkill for this application, not least because the trays are about as expensive as the panels. What I'm thinking is a second layer of membrane immediately behind the panels (over the counter-battens and battens) then Compriband between the panels and between them and the infill T&G timber cladding in the corners of the wall. Maybe something a bit stiffer which wouldn't be affected by wind so much? Thoughts? Link to comment Share on other sites More sharing options...
PeterW Posted November 30, 2018 Share Posted November 30, 2018 I would use an EDPM roof membrane below them and it should be fine. It’s UV stable and pretty cheap, fixing through it is a standard detail so wouldn’t cause any issues. Link to comment Share on other sites More sharing options...
the_r_sole Posted November 30, 2018 Share Posted November 30, 2018 (edited) . Edited September 26, 2019 by the_r_sole Link to comment Share on other sites More sharing options...
Jeremy Harris Posted November 30, 2018 Share Posted November 30, 2018 Depends how cheaply you can get the panels, I would guess. The fixings for our in-roof panels are T shaped clamps screwed down between the panels, so each clamp secures two panels. I haven't measured the gap, but would guess that it's around 20mm, so similar to that used on some forms of vertical timber cladding. The newer design of GSE T clamps are shown on this page: http://www.windandsun.co.uk/products/PV-Mounting-Structures/GSE-Integration-Roof-Integrated#9033 , but the older design we have looks neater, IMHO, as it used aluminium extrusions for the T clamps. The Easy Roof Evolution T clamps are similar to the older GSE ones, but are designed to only fit their saddle brackets that are secured through the trays on either side. Might be able to be adapted to fit without the trays, though. Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 30, 2018 Share Posted November 30, 2018 You could just cut short lengths of thick walled nylon tube, say 12mm in diameter, and use stainless screws and rubber faced washers to hold the panels on. Near sermless, but 20mm isn’t the end of the world imo. Good idea tbh, as long as the wall ‘pays for itself’ which it should do compared to just cladding. Those used panels posted by @ProDave iirc seems a good solution. If you exceed the DNO permissible limit then dump into DC immersions. Can’t recall if you’re off grid @Ed Davies? Link to comment Share on other sites More sharing options...
Ed Davies Posted November 30, 2018 Author Share Posted November 30, 2018 (edited) 56 minutes ago, PeterW said: I would use an EDPM roof membrane below them Excellent idea, thanks. 34 minutes ago, the_r_sole said: seems like an expensive way to clad a building? Yes, 40% more expensive than timber cladding (per m²) but generates some electricity. PV panels £38.80/m², 155 W/m²; timber cladding £27.85/m², 0 W/m² so that's £0.07/W ? Edited November 30, 2018 by Ed Davies 2 Link to comment Share on other sites More sharing options...
Ed Davies Posted November 30, 2018 Author Share Posted November 30, 2018 6 minutes ago, Nickfromwales said: Can’t recall if you’re off grid Yes, off-grid so no DNO to worry about. Only problem will be that it's at the opposite end of the house to my main electrical stuff so I might think about “grid-tie” to my own mini-grid. 1 Link to comment Share on other sites More sharing options...
the_r_sole Posted November 30, 2018 Share Posted November 30, 2018 (edited) . Edited September 26, 2019 by the_r_sole Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 30, 2018 Share Posted November 30, 2018 2 minutes ago, the_r_sole said: Surely a north facing wall, and the bits in shade at the eaves, areas where you are walking past/have any plants etc are all going to take away the effectiveness of the panels? When you’re off grid, any power is good power Link to comment Share on other sites More sharing options...
Ed Davies Posted November 30, 2018 Author Share Posted November 30, 2018 Also, when you have very variable weather, opportunities to generate at different times of day are good. Link to comment Share on other sites More sharing options...
the_r_sole Posted November 30, 2018 Share Posted November 30, 2018 (edited) . Edited September 26, 2019 by the_r_sole Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 30, 2018 Share Posted November 30, 2018 33 minutes ago, the_r_sole said: not really, it's much more important to get the most power for the least amount of money/hassle - ground mounted arrays facing in the right direction at the right angle are going to be a better investment than cladding a building which has large ineffective collection areas. Agreed, as long as you’re allowed to fit / have the opportunity FOR a ground mounted array. My replies are tailored to the specific circumstances not general / rule of thumb. Link to comment Share on other sites More sharing options...
the_r_sole Posted November 30, 2018 Share Posted November 30, 2018 (edited) . Edited September 26, 2019 by the_r_sole Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 30, 2018 Share Posted November 30, 2018 17 minutes ago, the_r_sole said: You obviously have more background on the op than is in the thread so I'll leave you to it I only know what I’ve read in @Ed Davies‘s posts ? Link to comment Share on other sites More sharing options...
ProDave Posted November 30, 2018 Share Posted November 30, 2018 Many of you know my panels will be ground mounted. I will almost certainly be making the mounts myself. The plan is to place the panels as close as possible together. If you arrange it so the panels are portrait orientation, and the clamps are on the sides, then the top and bottom joints will touch each other. My simple thinking is just tape over the joints with something like aluminium tape. I doubt it would be a perfect seal or last that long. Perhaps some flashband cut into strips might be better? My thinking is by sealing the joints as best as I can, they will form a "roof" over the structure of the ground mount. That can then be used as simple covered storage e.g for logs awaiting processing into firewood, winter storage of garden furniture etc etc. It will no doubt morph into an odd shaped garden shed (I know there is a reason I am collecting pallets again) P.S. @Ed Davies no reply yet re the solar panels so don't bet your shirt on it just yet. Link to comment Share on other sites More sharing options...
Ed Davies Posted November 30, 2018 Author Share Posted November 30, 2018 4 hours ago, the_r_sole said: Surely a north facing wall, and the bits in shade at the eaves, areas where you are walking past/have any plants etc are all going to take away the effectiveness of the panels? It's not north facing, but faces a bit north of east, bearing 073° IIRC, so will tend to get sun early morning. In summer it'll get sun for a few hours before the main roof gets much so breakfast, etc, can come off these panels rather than cycling the batteries. It's a gable end so not much eave shading and not a place I'll walk past much. Plants will, indeed, need control around the house but about 8 metres away is the neighbour's fence. His cattle will stop much growing other than whins which don't grow that high and the ground slopes down a bit anyway. In general, I think there's a lot to be said for having PV pointing well off south to flatten the generation peak. Facing a bit round to the west for grid-connected would help with the evening consumption peak for example. As we move towards more renewables just maximizing generation becomes less of a priority compared with getting the timing right to minimise storage and transmission. 1 Link to comment Share on other sites More sharing options...
PeterW Posted November 30, 2018 Share Posted November 30, 2018 1 hour ago, ProDave said: My thinking is by sealing the joints as best as I can, they will form a "roof" over the structure of the ground mount. I would be very wary of that as you could inadvertently create a large PV kite .... with slots through the wind lift shouldn’t be as high. Link to comment Share on other sites More sharing options...
Ed Davies Posted November 30, 2018 Author Share Posted November 30, 2018 2 hours ago, ProDave said: P.S. @Ed Davies no reply yet re the solar panels so don't bet your shirt on it just yet. Yep, been thinking about doing this change (solar thermal to PV on the gable end) so worth bringing up anyway. 2 hours ago, ProDave said: My simple thinking is just tape over the joints with something like aluminium tape. I'm wondering if there are any plastic (UPVC perhaps) strips made for conservatories or greenhouses which could just clip in between the panels to just overlay the panels' frames. Probably screwed as well, of course. Link to comment Share on other sites More sharing options...
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