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  • heimdm
    replied
    Indiana still existing under NEC 2008 rules. Beside that I am going with Solar Edge, and I believe the optimizers handle RSD requirements.

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  • khanh dam
    replied
    make sure the shed will ONLY be used for solar purposes. NEC 2017 allows that. if you use shed for other reasons the AHJ might claim you need RSD modules on every panel which could add another $2000 for the price. storage might be allowed, but putting a tv and couch/man cave woudl probabaly not.

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  • heimdm
    replied
    Originally posted by khanh dam View Post
    I would stick build the shed. that way exact slope can be matched if you want
    The prebuilt building is around 20k (32' x 16') The stick built price I have is around 26k (26' x 16'). I am hoping in the next couple of weeks to get another stick-built quote. The stick built goes on a concrete pad. The pre-built goes on concrete but has its own floor. Because it has its own floor, I'd probably have to move the conduit so it comes through the wall instead of through the floor. If the stick-built price is close, I'll take that.

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  • khanh dam
    replied
    I would stick build the shed. that way exact slope can be matched if you want

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  • khanh dam
    replied
    Looking good! That’s going to be one huge open span under the panels

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  • heimdm
    replied
    Received stamped drawing for the structure today. Essentially there are 8 concrete pads that are 5' x 10' x 1'. They are located 18" below the surface. In this update the need for the concrete piers on top of the foundation was eliminated, which should make my concrete contractor happier. My aluminum fence runs close to some of these pads, so part of the fence might temporarily, have to come out.StructureOverview.png

    Foundation-Simple.png

    On another note, on the fence about doing a stick built shed next to the array or a pre-fab one. I found a nice pre-fab one from ezpb.com, their Austin model. The pitch would be 3/12 which is nearly identical to the array. My dimensions would be different than what is shown in the photo.
    ezfb.png

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  • khanh dam
    replied
    looks like the steel goes into the concrete foundation and sticks out of it, correct. Concrete guys have told me that the exposed steel will expand faster than the cool 60 degree ground concrete and can cause cracks around the poles? not sure if it really is an issue. maybe a thin foam wrap and then caulked on top to prevent water from getting in latter on or just diamond saw cut a control cut around each post.

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  • J.P.M.
    replied
    Originally posted by Mike90250 View Post
    Where you steel penetrates the 4" concrete pad, you need to leave an expansion space, or the microflexing of the steel and thermal effects will create a gap in an uncontrolled manner.
    I don't claim competence in reinforced concrete design but concrete and steel have coefficients of thermal expansion that are within 5 to 10 % of one another, that is, quite small. That usually makes the relative lateral or short span thermally induced axial movement quite small and so too the resulting thermally induced stresses over commonly seen temp. ranges and conditions.

    Induced stresses from usually local galvanic corrosion of the steel within the concrete (the resulting rust = iron oxide) has a greater volume than the steel) are usually a greater concern than the thermally induced stresses and can create (depending on length/thickness) a much larger tensile stress in the concrete than any thermal expansion. Most of those concerns deal with rebar, but structural members can be affected as well. Usually, a competent designer addresses those and other such concerns.

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  • heimdm
    replied
    If I am following correctly, Mike90250, there is a need to have a gap between the concrete and the base plate. Based on this schematic, I believe that is addressed.
    .baseplate.png

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  • Mike90250
    replied
    Where you steel penetrates the 4" concrete pad, you need to leave an expansion space, or the microflexing of the steel and thermal effects will create a gap in an uncontrolled manner.

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  • heimdm
    replied
    ss-prelim.png
    Received preliminary drawings/plans for the structure. The foundations are essentially a 5' x 12' x 1' pad with a 6" pier extending up, which is where the base plate and anchor will connect. The entire foundation will require just over 18 yards of concrete. My soil type has lots of limestone chunks, so a shallow foundation is preferred. At the moment the concrete anchors will be recessed. A concrete pad will be poured over the majority of the area covered by the panels. Hopefully, next week we will get finalized drawings and I can meet with my excavator/concrete contractor and get this moving forward.ss-prelim.png
    ss-foundation.png
    Last edited by heimdm; 02-14-2021, 10:17 PM.

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  • heimdm
    replied
    This week saw the arrival of 92 panels arrive by freight carrier. The panels came stacked 2 pallets high. Luckily, a local business with a skidsteer with forks was able to put all the pallets on the ground. They were kind enough not to charge. I have to pick up a pallet jack tomorrow to move them inside the garage, so we can inspect all the panels for damage. Next week, the temperatures are supposed to be near 10 degrees or less, so definitely want to have the panels in the garage for inspection.

    As far as the steel structure goes, the company that is building it is doing the design work, which hopefully will be completed in the next 2 weeks.

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  • heimdm
    replied
    Originally posted by khanh dam View Post
    sounds dumb. I put commercial sunpower panels on my picnic shelter roof. main difference is they are bigger than residential panels. Why the heck LG cares is anyone's guess.
    I spoke to a residential engineer today they said pergola rafters needed to be 2x8" steel tube with 1/8" wall spaced 40" on center to span 160" from south header to North header. OR two 2x12 wood rafters coupled together or two 2x8" with steel filch plate between the two or 2 aluminum self mating 2x10 beams. Designed for 115mph wind load and 25 degree tilt. I'm guesisng the 25 degree tilt is what makes it have to be so strong. Most pergolas are not tilted that much.
    The tilt is up to each project for sure. The guidance, I was given is a minimum of 5 degrees so that rain water does not pool on the panels. I would have desired a higher tilt, but settled at 15 at that prevents the panels on the high end from being above the raised deck on the back of the house. Our high side (north end) is about 14' above ground.

    My spacing is expected to be:
    North-South: 21'
    East-West: 22'8"

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  • khanh dam
    replied
    sounds dumb. I put commercial sunpower panels on my picnic shelter roof. main difference is they are bigger than residential panels. Why the heck LG cares is anyone's guess.
    I spoke to a residential engineer today they said pergola rafters needed to be 2x8" steel tube with 1/8" wall spaced 40" on center to span 160" from south header to North header. OR two 2x12 wood rafters coupled together or two 2x8" with steel filch plate between the two or 2 aluminum self mating 2x10 beams. Designed for 115mph wind load and 25 degree tilt. I'm guesisng the 25 degree tilt is what makes it have to be so strong. Most pergolas are not tilted that much.

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  • heimdm
    replied
    Update to yesterday setback. I ended up talking with the regional sales manager from LG for the Midwest. The deal with "commercial" Solar Panels is you can not put those on a primary residence (house). If you do ground mount or put them on a solar pergola/canopy that is perfectly. fine. LG will honor the 25/25 warranty for the product. However, they will not cover the labor cost. For the most part anytime you see LG panels and "commercial only" that is what is going on.

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