DIY 5kW Patio Shade Structure in Phoenix

miscrmsmiscrms Registered Users Posts: 15 ✭✭
Hello all,

I'm looking at installing a roughly 5kW grid-tied system on our new (to us) home in Phoenix. The house itself has a sloped roof, but is E/W facing and also suffers from a lot of shading. The only spot that's really sunny year round is the patio on the north west corner of the house, so I'm thinking the best plan might be to build a free standing mount that would double as a shade structure over the patio.

My main concern is what the requirements are for this structure to remain eligible for the utility incentives and tax credits. IE does it have to be permitted, and if so does it have to be built by a contractor and if so does it have to be certified by an engineer etc. All that is starting to sound expensive, and I'm trying to preserve as much of the budget as possible for the actual equipment ;) In general I'm trying to keep costs to a minimum with as much DIY as possible. This is my first solar install, but I've been obsessively reading and planning for years :D Fortunately I do have a good friend who has worked as an installer and do have an EE degree myself, so hopefully between the two of us we can manage most of it, save the final hookup. Hopefully we can find an electrician who's willing to hook it all up and sign off on the system.

Right now I'm looking at 2x12 strings of the Canadian Solar CSP6-230-P panels feeding into a Sunny Boy 6000. Sunny Design seems happy with that arrangement at least. The structure would be roughly 20x20' probably starting at 10' (to be clear of shading from roof obstacles) with a ~12 degree south facing slope. Most likely would be timber framed, with unistrut used for the mounting rails. Hoping to get that all done for ~$15-17k. I'm currently looking at about $11,500 for all the equipment.

Any comments or suggestions would be most welcome :)

Rob Smith,
Phoenix

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    Welcome to the forum, Rob.

    This is one of those instances where you really have to consult with the local authorities as to what they require both in terms of the structure and the electrical hook-up. There's lots of smart folk here who can help you figure out how to meet those requirements, but until you know what they actually are you're just guessing.

    At a glance, the panels seem a bit undersized for a 6kW inverter - but maybe that's all you could fit? Or the string calculation lands on one of those awkward panel fractions which requires reducing to the nearest round number? Usually in a hot climate you might go for a bit more array than the inverter rating due to decreased output from hot panels.

    But that's just speculation. There's some good GT experts here who can help you get the system "dialed in" just right. :D
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    you do realize that the pvs would need to face south from that north west corner? it may be advisable to call up a professional to get your site evaluated. if he agrees it's a viable site then you can quibble over pricing. there is much for you to learn if you wish to do any of this on your own and it's possible the installer may allow you to do some of the work supervised by him to give you a discount.
  • FrxddyFrxddy Solar Expert Posts: 113 ✭✭✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    You said "My main concern is what the requirements are for this structure to remain eligible for the utility incentives and tax credits."

    I'd start with phone calls...one to each place that offers credits or rebates. The Federal one you can get if you do it yourself, but any and all others may depend on several local factors. I had to pass on my state rebate. While it's legal to "have it inspected", I could not find one authorized person in my state that would come and inspect my system so I could get the rebate. So, check that too. Just because it CAN be done, doesn't mean you can get it done.

    Even though I did not get that rebate I still saved many thousands by doing it myself under the guidance of a master electrician. So, do your research & best of luck to you.
  • miscrmsmiscrms Registered Users Posts: 15 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    Thanks for the comments everyone!

    I had done my own "site evaluation" using an iphone app called sun scout. Its actually designed for photographers, so they can see exactly where in the image the sun will be at any particular time on any particular day. I went through and did a month by month projection of what time the sun would clear and descend behind the surrounding trees. I then used that info to "mask off" the hourly production tables from pvwatts for each month. Based on that data, I estimate the annual production loss due to shading to only be about 3-4%.

    I later had the folks from one of the larger installers in town come out to do a site evaluation, as they weren't willing to bid the job based on aerial photos due to the shading issues. After taking all the measurements, they were happy that the NW corner patio was a viable site. Unfortunately their bid was not viable for my wallet ;)

    The 24 panel array is sized mostly on available area, but partially on cost as well. Sunny design puts it as just oversized for the SB5000, but certainly a bit undersized for the SB6000. As the price difference is only ~$300 I though I might as well go with the 6000. Maybe the 5000 would be fine, but I was concerned it would clip/limit under peak conditions and lose some production. Maybe this is not really a concern due to the panel temperature affects.

    Sunny Design puts the array peak power output at 5.52kW, I assume this is corrected for angle, temperature etc? While the max DC Power for the 5000 is shown as 5.3kW SD is still reporting 100% usability factor, so I guess that means its still converting it all. Array voltage range is estimated at 303-495 V, which seems like a decent match to the inverters peak tracking range of 250-480V.

    Rob
  • SolarLurkerSolarLurker Solar Expert Posts: 122 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    I think it sounds like a nice project. Florian makes a kit to just what your propose that looks really nice, although its pricey. If your budget allows I think that the sanyo or solyundra (sp) panels work really well for projects like this.
  • miscrmsmiscrms Registered Users Posts: 15 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    Yeah, the Sanyos would be awesome, but we're looking at $1.44/W for the CS6Ps which is the only reason we're able to consider a system this big.

    Attached is an aerial photo of the property, with the rough location and size of the array.

    Rob
  • rollandelliottrollandelliott Solar Expert Posts: 834 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    ditto talk to the local codes people most of the time they are pretty cool and will accept "non engineered drawings" at least where I live, but in other areas with high winds like Florida they get more safe.
  • miscrmsmiscrms Registered Users Posts: 15 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    Here is a rough sketch of what I have in mind. Lumber sizes were chosen somewhat arbitrarily, but checking some covered patio roof code tables online they look to be in the ballpark for the spans involved. Eventually I'll have to get someone that knows what they are doing involved, but I wanted something to show to the contractors when I start getting bids. Any comments on design, layout, materials etc would be most welcome :-)
  • solar_davesolar_dave Solar Expert Posts: 2,382 ✭✭✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    Just as an FYI my neighbor in Glendale AZ tried to get code approval for a Gazebo with 4 framed box posts and because it was not an engineered stamped construction for wind load the code guys refused him, their excuse "nothing to prevent racking of the structure".

    If he had used sonotubes, rebar and concrete with a 18" deep foundation to make the corner posts up to the roof they said they would approved.

    Also you might just as well move the roof angle closer to your latitude to get more harvest, unless you want more in the summer.
  • miscrmsmiscrms Registered Users Posts: 15 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    Thanks, Dave! That's one of my big concerns, how to get the whole things to fly with the building permit folks. I'm kind of assuming I'll have to use a licensed contractor, but if I have to have the whole thing designed and certified by an engineer I'm guessing that could get pricey.
  • solar_davesolar_dave Solar Expert Posts: 2,382 ✭✭✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix
    miscrms wrote: »
    Thanks, Dave! That's one of my big concerns, how to get the whole things to fly with the building permit folks. I'm kind of assuming I'll have to use a licensed contractor, but if I have to have the whole thing designed and certified by an engineer I'm guessing that could get pricey.

    Take you sketch down to the office and see what they say. If and when they disapprove ask them what would they approve without a full blown engineering drawing. I might suggest a couple of details with galvanized strapping components as reinforcements. They will want those as a minimum. You can get them @ the local big box stores.
  • rollandelliottrollandelliott Solar Expert Posts: 834 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    what is your budget for the structure?
    www.schletter.us makes carport like structures for a few thousand with engineered drawings, and gives you instructions for building it but it is not an easy DIY task as it involves concrete, rebar, sweat etc.

    there are a couple of other carport solar makers, but they tend to cost more than schletter, one in NM, one down in Florida, etc.

    My guess is you can make it out of 80/20 aluminum
    sketch it up in googlesketch up for free and get an engineer to do a wind analysis for less, but it will take a lot of time and effort.
  • mike95490mike95490 Solar Expert Posts: 9,361 ✭✭✭✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix
    what is your budget for the structure?
    schletter.com makes carport like structures for a few thousand with engineered drawings, and gives you instructions for building it but it is not an easy DIY task as it involves concrete, rebar, sweat etc.

    That's www.schletter.us .com looks like a scumware page - no content, full of scripts....

    http://www.schletter.us/park-sol-residential.html
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • rollandelliottrollandelliott Solar Expert Posts: 834 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    also schletter's solution does not require the huge concrete blocks be above ground they can be buried and then the look of the structure is a lot less industrial looking.
  • miscrmsmiscrms Registered Users Posts: 15 ✭✭
    Re: DIY 5kW Patio Shade Structure in Phoenix

    Thanks for all the comments! I will definitely get a quote from Schletter, I had assumed they were more expensive than that. A pre-engineered kit solution would certainly solve a lot of issues. I'm also putting out requests to several companies that do aluminum and timber ramada kits. If the rack and panels are similar in weight/size to their typical roofing, or can simply be treated as "snow load" or something they may be able to offer an engineering stamp even though they were not designed for solar. At ~1500 lbs over ~400sqft thats only 3.75 lbs/sqft which seems fairly reasonable.

    I'm trying to complete the install for under $5k. If it goes much over that I may have to scale back on the array size to reduce cost. I'm an EE and have a friend who has worked on quite a few installs (though he's not himself licensed), so we're hoping to do as much as possible ourselves. Even with a pre-engineered solution we're assuming we'll need to find a building/electrical contractor who will do key parts of the construction and the final hookup to preserve tax credits and utility credits.

    Thanks everyone!
    Rob
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