Portrait vs Landscape layout...does it matter?

[foo1bar]

So it looks like the original design is the better one?

Which do you think looks better?

I'd probably go with the 2nd option for the left roof area. (12 panels instead of 9)

And I'd want to get a good handle on what it'd really look like - actually measure the location of the vent(s).
(I used google sketchup to do my preliminary roof layout.)

[mpkelley20]

Yeah...not sure why the vent pipe is in a different location in the second drawing. Regardless, it is still there on my roof and it takes away a panel.

The price is basically the same no matter which way I go (unless of course I go with less panels). The installer has priced my system at 3.40 per watt for Solarworld 285 which is 60 cents less than the best offer I had from others. MA is super expensive for per watt charge compared to other states. I'm having MA people on here PM me because they can't get anywhere near this pricing.

So it looks like the original design is the better one?

[inetdog]

The racking design gets complicated when you try to combine landscape and portrait in one array. See how bad it actually is with the racking system that is being proposed.
The installer may not want to do it because it does not fit the input parameters of their rack design software.

[foo1bar]

Here is the second rough drawing. I am pretty sure they can fit a row horizontally along the bottom of the main roof which will get me back to 35 or 36 panels. The installer claims his first design will be the most efficient. I feel like I should trust him but I also trust people here. Which design makes more sense (assume a horizontal row at bottom of this picture). Thoughts???

The circle is to represent a plumbing vent? Or furnace vent?
Why is it in 2 different spots between the two drawings?


The left section of roof it looks like you go from 9 to 12 by changing to portrait.
Any shading issues when covering more of that roof?

In general, I'd go with
A> what looks better
B> what costs less (because of less racking needed)

[mpkelley20]

Here is the second rough drawing. I am pretty sure they can fit a row horizontally along the bottom of the main roof which will get me back to 35 or 36 panels. The installer claims his first design will be the most efficient. I feel like I should trust him but I also trust people here. Which design makes more sense (assume a horizontal row at bottom of this picture). Thoughts???

[Carl_NH]

I understand what you are saying about the garage. Not sure they can fit three panels vertically. I will ask about snow issues for the part under the panels. My roof does a bad job clearing snow without a roof rake with no panels on so I guess if we have another winter like we did, I'll have a 4 foot snow bank below where the panels are!

I am waiting on a new drawing with vertical positions. I don't think they can fit the same number though if they go all vertical. I want to say I lose about 4 panels so I would be at 32 which is a 9.1K system. Still not bad though.

I really just want to make sure that this "maximized" design is not flawed. You just pointed out one potential flaw on the smaller roof. What about the main roof?

MP,

Measure your roof dimensions! You can do this on the ground as long as you know the pitch of the roof - most in NE are 8/12 to 12/12 pitch - which is for every foot horizontal you have 8 or 10 or 12" vertical. Go in your attic and measure the peak vs 4' down and you will have the pitch.

it shows 10 portrait now in the bottom row, so the normal 39" x 65" panels will need 195" of roof to install 3 rows in portrait.

[mpkelley20]

MP,

On the garage roof snow is going to have a tough time clearing the 4-5' below the panels - I would suggest if you ran those in portrait to the edge of the roof it would shed faster and still allow for expansion later. As noted he wanted to position the garage panels to minimize shading - which should better if in portrait?

On your main roof if I recall the dimensions correctly you could fit all in portrait? When the guys did ours, they had the approved layout, but when the installers arrived they worked out the exact positioning (we have more roof space than panels) for efficiency and snow shedding.

I guess what I am saying is the good installers consider all the angles- what's below (for snow), what's least shading, and what you want!

Good luck with your installation!

Carl

I understand what you are saying about the garage. Not sure they can fit three panels vertically. I will ask about snow issues for the part under the panels. My roof does a bad job clearing snow without a roof rake with no panels on so I guess if we have another winter like we did, I'll have a 4 foot snow bank below where the panels are!

I am waiting on a new drawing with vertical positions. I don't think they can fit the same number though if they go all vertical. I want to say I lose about 4 panels so I would be at 32 which is a 9.1K system. Still not bad though.

I really just want to make sure that this "maximized" design is not flawed. You just pointed out one potential flaw on the smaller roof. What about the main roof?

[Carl_NH]

My installer is sending me a couple of options for my system. One that would allow me to expand a bit in the future (if needed) is attached. It has both portrait and landscape design. My roof is very solid with 2x8 beams (2x6 is standard in my state). Is this a design you would consider in an area that gets snow several months out of the year? My installer said this design is the most efficient of the ones he is looking at.
The cost, whether it is landscape or portrait does not change. He wanted to give me the most efficient design that leaves room for some upgrades later. He did say that landscape design on the panels is a little better in snow conditions.

One other thing, my installer is complete opposite from another installer who wanted to leave tons of space on te roof so you could walk around on it. The guy I hired obviously doesn't leave any space on the main house. His claim is that leaving parts exposed will cause those parts of the roof to detiorate quicker (albeit still 20+ years) than the part that is covered. And he said the Solarworld 285 panels are so strong that you can walk on them (I think he even said drive on them.


Sorry for the rough drawing but I asked for this on short notice to get feedback here.

MP,

On the garage roof snow is going to have a tough time clearing the 4-5' below the panels - I would suggest if you ran those in portrait to the edge of the roof it would shed faster and still allow for expansion later. As noted he wanted to position the garage panels to minimize shading - which should better if in portrait?

On your main roof if I recall the dimensions correctly you could fit all in portrait? When the guys did ours, they had the approved layout, but when the installers arrived they worked out the exact positioning (we have more roof space than panels) for efficiency and snow shedding.

I guess what I am saying is the good installers consider all the angles- what's below (for snow), what's least shading, and what you want!

Good luck with your installation!

Carl

[mpkelley20]

Some local authorities require you to comply with the NFPA rules that require 3ft on the top and sides of the array. That may not be the case for you.
The orientation shouldn't matter for snow load.
As far as walking on the panels, although they may not show any signs of damage, excessive stress can cause micro cracks in the silicon, which will lead to lower output.

I don't think we have 3ft rules. My installer is handling the permits and stuff where he has to submit the design. That is what we are working on now as he has options. This specific design, as I mentioned, is supposedly the most efficient design based on whatever program he uses to determine output. The open area on my garage gets a bit more shade in the morning due to how the sun moves over my house so that is why he wants to leave it open (unless I want to expand). I had installers tell me they never mount horizontally so that is why I was a bit concerned. Based on this thread, the only issue is roof strength from what I gather. But from how mu roof is constructed, I don't think I have any concerns on it's durability. I just don't want to go with a design that has other issues I don't know about.

[emartin00]

Some local authorities require you to comply with the NFPA rules that require 3ft on the top and sides of the array. That may not be the case for you.
The orientation shouldn't matter for snow load.
As far as walking on the panels, although they may not show any signs of damage, excessive stress can cause micro cracks in the silicon, which will lead to lower output.

[mpkelley20]

My installer is sending me a couple of options for my system. One that would allow me to expand a bit in the future (if needed) is attached. It has both portrait and landscape design. My roof is very solid with 2x8 beams (2x6 is standard in my state). Is this a design you would consider in an area that gets snow several months out of the year? My installer said this design is the most efficient of the ones he is looking at.
The cost, whether it is landscape or portrait does not change. He wanted to give me the most efficient design that leaves room for some upgrades later. He did say that landscape design on the panels is a little better in snow conditions.

One other thing, my installer is complete opposite from another installer who wanted to leave tons of space on te roof so you could walk around on it. The guy I hired obviously doesn't leave any space on the main house. His claim is that leaving parts exposed will cause those parts of the roof to detiorate quicker (albeit still 20+ years) than the part that is covered. And he said the Solarworld 285 panels are so strong that you can walk on them (I think he even said drive on them.


Sorry for the rough drawing but I asked for this on short notice to get feedback here.

[skipro3]

No
Think about the 4 points of contact. The long side has no support and will bow in the middle. Panels are hollow and only the frame to rail contacts provide support. The length Will sway like an old horses back. I know....

[HX_Guy]

Didn't read of this, so forgive me if this has been already mentioned.

While landscape uses more rail, it supports the panel the least. You see; the landscape mount has the rails running the length and the panel can bow, only being supported on it's ends. Portrait the panels are supported more towards the middle.

Most panel mfg. will list a much lower pounds-per-square foot for loading on a landscape panel mounted with length running rails.

Wouldn't that be quite the opposite?

With panels in landscape, the rails would run parallel to the long side of the panel therefore giving it more support. A panel isn't going to bow anyway, but if it were to bow, it would bow along the 65" side, not the 40" side.

[bcroe]

I know it would be a big expense for you but I would think if the panels were elevated higher
off the ground there would more space for the snow to slide off the panels and fall onto the ground.

The next version will be another foot higher above the ground. But what I am saying, is its only 39"
down and off a panel in landscape. Its 63" in portrait and 126" when 2 are touching. Bruce Roe

[SunEagle]

When I came on the scene, PV solar was designed for SW desert operation
on rooftops. I heard little mention of clouds and snow, and a roof could better
support portrait mounted panels.

In these parts there is a lot of snow and even more clouds. With a ground
mount the support is no longer an issue. Lately the price of the panels no
longer dominates the total installation cost. After a couple winters, I would
like to minimize the time spent clearing snow (at sunrise). No increased
energy production, but less work.

Sometimes evening snow hits still warm panels and slides down a foot or
so. If it only needs to slide a foot or 2 and onto the ground, the sun may very
well do the job next day. Or, I won't have to do so much pushing. Currently the
snow here must travel 10.5 feet over a couple butted portrait panels, which will
never happen by sun power, and is quite a bit of work for me. Experiments
have been and are still running here; lets see more results after more winters.

Bruce Roe

I know it would be a big expense for you but I would think if the panels were elevated higher off the ground there would more space for the snow to slide off the panels and fall onto the ground.

Maybe a Pole mounted array might be a better option for snow country due to the height of the lowest panel being a few feet..