8400w Grid Tie System - Kit or piece it together?

[littleharbor]

There are power solar panel lifts available. May be available for rent. I believe they hold 4 or 5 panels at a time.

Solar panel lift.jpg

[Mr4btTahoe]

Lots of progress today! Only planned on getting the racking up... just got started when my brother showed up unexpectedly and wanted to stick around and help. Racking done and the first 9 panels mounted.

Racking all mounted using 3/8x3 lag bolts through the on edge roof purlins. Each mount placed at ~5'.
IMG_20180428_152659071 by acidburn02zts, on Flickr

First 3 panels set in place and squared up....
IMG_20180428_152743169 by acidburn02zts, on Flickr

IMG_20180428_152905532 by acidburn02zts, on Flickr

All excess wire tied up snugly under each panel with wire clips supporting each connector.
IMG_20180428_153722413_HDR by acidburn02zts, on Flickr

IMG_20180428_153730305_HDR by acidburn02zts, on Flickr

9 panels placed and wiring routed. This group is ready for the wiring run back to the inverter.
IMG_20180428_161629479_HDR by acidburn02zts, on Flickr

IMG_20180428_161825225 by acidburn02zts, on Flickr

Plan is to run all the conduit and such through-out the week and he's coming back next Saturday to help me place the rest of the panels. I say I really like this racking system. Once the first couple panels were set.. it went very quickly. Line 'em up.. clamp them down... route wiring. If we stay on track, that'll give me 2 weeks to get the inspector out and fix anything he may want changed prior to the POCO start-up date.

Moving right along.

[Mike90250]

Lots of progress today! Only planned on getting the racking up... just got started when my brother showed up unexpectedly and wanted to stick around and help. Racking done and the first 9 panels mounted......

Looks like a nice shady place to work at. You do have a plan for those trees?

[Mr4btTahoe]

.......always with the negativity... lol. I know you are just looking out though...

These were taken at 4 in the afternoon. This roof is in full sun from 730-8am til 330pm currently. At the time these were taken, the sun had already passed over the roof line... trees wouldn't have mattered. There is nothing shading the roof from early morning until late afternoon... not so much as a limb. I have the blisters on my shoulders to prove it. Lol.

Our area is very wooded but in the last 2 months, we've dropped nearly a dozen trees to make certain this roof face gets as much direct sun as possible. We may drop one or 2 more... however I don't believe it will be necessary.

[Mike90250]

.......always with the negativity... lol. I know you are just looking out though.......

Just being through.

[Mr4btTahoe]

Just being through.

Which I appreciate. Thanks bud.

[Mike90250]

10am - 2pm (depending on your roof orientation) are the best solar hours, less atmosphere soup for the sun to punch through.

[Mr4btTahoe]

Sounds about perfect then. I'm waiting to see how the sun tracks come summer as a few trees may cast a shadow when the sun is higher in the sky... But not sure yet. I'll take down anything that's in the way as needed though.

[NukeEngineer]

Hard to tell for sure, but those panels look pretty close to each other. I would have added at least a typical cardboard box wall width between to allow for thermal expansion, particularly if its pretty cool in your area right now.

[J.P.M.]

Hard to tell for sure, but those panels look pretty close to each other. I would have added at least a typical cardboard box wall width between to allow for thermal expansion, particularly if its pretty cool in your area right now.

Good point. The bolting might walk back & forth a bit over the racking with thermal cycling, and put some alternating and somewhat regular stresses between the frame and the glazing. But for a few panels in a row, the frames most likely have enough flexure in them to take up the differential movement and not cause the bolting to walk or come loose. Without some number crunching and a bit more thought, it is hard to speculate with any confidence.

Over a row of panels, and being in the sun and in better thermal contact with the rest of the panel than the racking is in thermal contact with the panel, the non painted panel frames as shown will get warmer than the racking, but not as warm as they would if those panel frames were a darker color. That may help things a bit, if any help is needed at all.

I've got some ideas but no proof of what the added compressive and alternating stress from too close contact (or no space) between panels might do to the integrity of a panel as f(number of panels in a row) for leak tightness over time that come down to more panels in a row with no clearance spacing = more potential for problems.

[NukeEngineer]

Good point. The bolting might walk back & forth a bit over the racking with thermal cycling, and put some alternating and somewhat regular stresses between the frame and the glazing. But for a few panels in a row, the frames most likely have enough flexure in them to take up the differential movement and not cause the bolting to walk or come loose. Without some number crunching and a bit more thought, it is hard to speculate with any confidence.

Over a row of panels, and being in the sun and in better thermal contact with the rest of the panel than the racking is in thermal contact with the panel, the non painted panel frames as shown will get warmer than the racking, but not as warm as they would if those panel frames were a darker color. That may help things a bit, if any help is needed at all.

I've got some ideas but no proof of what the added compressive and alternating stress from too close contact (or no space) between panels might do to the integrity of a panel as f(number of panels in a row) for leak tightness over time that come down to more panels in a row with no clearance spacing = more potential for problems.

Just did a quick calc and seems like an almost 2m tall aluminum frame would expand only about 0.2-0.3mm over a temp range of -10C up to 55C, so perhaps as long as there's some minimal spacing between rows, then thermal expansion probably isn't a big concern.

Horizontally, though, the total expansion is probably on the order of centimeters. But, the good news there is that since your racking is also aluminum, it will expand with your frames and not stress the panels.

[Mr4btTahoe]

Between each panel side to side is the 1/4" gap provided by the IronRidge UFO clamp.

Between rows (vertically), there is roughly 3/8"-1/2" (handle of a 3/8 ratchet... lol) between them. It doesn't look like it at all in the pictures.

Is that enough? There isn't any exact specs from the racking manufacturer on placement/spacing. It wouldn't be hard to change right now but I like the uniform look if it's enough.

[ButchDeal]

Between each panel side to side is the 1/4" gap provided by the IronRidge UFO clamp.

Between rows (vertically), there is roughly 3/8"-1/2" (handle of a 3/8 ratchet... lol) between them. It doesn't look like it at all in the pictures.

Is that enough? There isn't any exact specs from the racking manufacturer on placement/spacing.

The UFO clamp is designed to handle the expansion as well as:

ironridge does have expansion joint information on page 6:
http://files.ironridge.com/pitched-r...ion_Manual.pdf

and then on page 12 of this older manual:
http://files.ironridge.com/roofmount...esignGuide.pdf

[Mr4btTahoe]

Actually ironridge does have expansion joint information on page 6:

I must be looking at a different book then. The only thermal expansion reference I can find is for the actual rail splices (over 50').. not panel spacing.

[ButchDeal]

I must be looking at a different book then. The only thermal expansion reference I can find is for the actual rail splices (over 50').. not panel spacing.

I provided the links. the splices are for thermal expansion of the rails..