Panel Mounting on Pole Barn In Snowy area with Metal Roof

SteveA

in my other thread i'm asking about the PV system. I wanted to break this into it's own thread.

Our barn is being built in an off grid location where 12-20" snowfalls are common. We've seen a couple 30+" heavy snows in less than 48" in the last few years. The roof will be the standard (cheap) galvalum corregated metal roof. The eave height of the barn will be 12 feet. I'm concerned about panel mounting. the site will be unmanned (to a degree) though people will come and go especially after a snow event as we are grooming snowmobile trails out of this building.

My original plan had been to mount the panels near the eaves so we could clear them with a roof rake if necessary (plan to mount them near vertical during the winter) but my concern is the snow letting go from the roof and wiping out the panels. The roof will be HUGE (4/12 pitch on a 40x60 barn) and could send large amounts of snow off the side in one swoop. Perhaps if i mount them on 15 standoffs with a tilt kit?

I want the roof for security reasons but possible an eave mount on the wall could work. Panel cost is now to the point where theft isn't as big a deal for my 2 or 3 kyo 215's.

As always we are trying to do this cheap. any thoughts or suggestions? I suppose a pole could work though i'd prefer not to.

niel

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

if you are saying there's a roof above the pvs that could avalanche to the pvs then that's not a good place for them. you only have a few pvs so why not try a pole mount away from the possible hazards?

Cariboocoot

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

The pole mount is a good idea indeed.

For what it's worth, mine are at the peak of the roof so no snow can cascade down on to them. They are also at an angle sufficient to keep them free of any significant snow build-up.

In Great Lakes country the snowfall can be huge in a very short time (I used to live there) and anything short of vertical could get covered by lake effect. An adjustable tilt pole mounting might be just the ticket there.

vtmaps

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

Cariboocoot wrote: »

The pole mount is a good idea indeed.
<snip>
anything short of vertical could get covered by lake effect. An adjustable tilt pole mounting might be just the ticket there.

Are you referring to a side-of-pole mount? I assume so because I've never seen a top-of-pole mount that could go vertical. Is there such a thing?

--vtMaps

Cariboocoot

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

vtmaps wrote: »

Are you referring to a side-of-pole mount? I assume so because I've never seen a top-of-pole mount that could go vertical. Is there such a thing?

--vtMaps

It's all in how you fab it.
With the mid of the array at the top of the pole you get an even weight balance on the pivot which makes angle changing easier.
With the top of the array at the top of the pole all the weight hangs down which makes it more stable against wind.

Oh no; I'm not going to start doing structural engineering for free too!

peakbagger

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

Attachment not found.

My pole mount could go vertical before I wired it. I actually used that to my advantage when I installed the panels. I would install a few panels with the frame facing frontwards and then flip it over so it was facing backwards and install more panels on the top row. It saved a lot of staging and having to climb up on it. Currently the lowest connection point for the unistrut sets the array at 30 degrees. I can still set it vertical by removing some stops but it would stress the wiring. With some creativity, I could set it up with a loop in the right place and it could go vertical even when wired. It does occasionally holds snow but once the sun comes out it usually slips off. I run a snow blower in front of it on occasion when the snow builds up, so for an unattended install, I would definitely build it higher which requires larger columns.

This array is in northern NH, we may not get lake effect but the town has the next to highest snow load in NH (the town next door is the highest).

vtmaps

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

peakbagger wrote: »

My pole mount could go vertical before I wired it. I actually used that to my advantage when I installed the panels. I would install a few panels with the frame facing frontwards and then flip it over so it was facing backwards and install more panels on the top row.

Is yours a custom design, or is it a commercially available mount? My DPW top-of-pole mount does not go vertical and I would like to know of one that does.

--vtMaps

SteveA

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

sounds like my optimum setup will be to mount my 2 or 3 40" wide panels in landscape on the south wall of the barn (12 feet high) and then tip them out for the summer (when our power requirements are lower). We'll have a 12" overhang on that side but if i go down far enough they should be fine(?) and still high enough to be sort of secure. Will probably cost less too.

inetdog

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

Cariboocoot wrote: »

Oh no; I'm not going to start doing structural engineering for free too!

The Errors and Omissions insurance alone would bankrupt you. :-)

peakbagger

Re: Panel Mounting on Pole Barn In Snowy area with Metal Roof

vtmaps wrote: »

Is yours a custom design, or is it a commercially available mount? My DPW top-of-pole mount does not go vertical and I would like to know of one that does.

--vtMaps

My setup is custom design, based on unistrut and two rectangular steel tubes for the posts. The array has been substantially increased in size up to 2 KW (10 evergreen 215 panels) since the photo was taken. The movable section pivots around a 3/4" diameter shaft running between the tubes. This does impose rotational load on the tubes when the wind is blowing. The tubes are supported independently from the base so in order to restore torsional stiffness to the system I have horizontal braces that bolt onto the tubes up high which limit how low I can go for tilt angle. If I remove the braces and disconnect the wiring it will drop right down into vertical. I also limit the travel to vertical as the panel naturally wants to drop down to vertical when I am adjusting the tilt and I really dont want to get between the array and pole when its swinging down.

It wouldnt be that hard to build a similar design for a much larger array replacing the unistrut with some beefier box section tube. I had considered setting up for horizontal and vertical tracking, but unlike VT, the rebate structure in NH is installed KW versus FIT. The tracking arrays made in Hinesburg are impressive but definitely overkill for my installs