DIY Install plans, specs and permits - Plans, Engineering and System Questions

[bryankloos]

Hi guys,
I'm in the beginning stages of planning a DIY install of a 16-20kW system for my home. I'm very handy and willing to take on most of the work. I need a new roof so I will hire that portion out and probably have the roofer install the racking.
Most other work will be done by me.
I am curious where most people go for detailed plans to submit for the building inspector and the POCO applications? How much detail does the inspector require, in what format and at what point do I need to get an engineer in to look at my roof structure?

I'm contemplating the 16.7 or 20.1 kW solar edge with suniva 335 grid tie packages available online. Are these packages good options for a DIY system?

More questions to come.

Thanks guys.

Bryan

[foo1bar]

Hi guys,
I'm in the beginning stages of planning a DIY install of a 16-20kW system for my home.

Do you really need that large of an array?
Most solar installs around here are 3-5kW. My DIY job was on the large side at 8.96kW. (pool pump uses a fair amount of energy)

If you haven't already looked at http://pvwatts.nrel.gov/ you should do that.
If you haven't already learned exactly how your POCO will credit you for power you generate, you should do that too.
And I'd measure the roof and where it has vents, etc - then draw in panels on top of it to see how things fit. (20kW of panels is a lot of panel area)

I did my own plans - but there were places I saw that would have drawn them for me for ~$300.
My permit dept had a nice "This is an example of what we want to see in a permit application" handout. I had to make a bunch of changes because their example was different type of system - but all in all it wasn't too difficult. But they didn't require engineer stamped drawings if I spaced the feet every 4' or less. And <10kW systems was I think lower requirements (no need for POCO to look at transformer capacity or such)

I'd stop by the permit office and tell them you're considering it -and ask if they have an example of one done recently.
If I were you I'd probably tell them that I was still investigating just what size I needed, and such - that I wasn't sure if it'd be 10kW or more.

There's one guy that posts here regularly that has a very large ground-mount system - he's using electric for heat pump in a place that gets decent snow as well as electric for lots of other stuff (cooking, etc) So it's possible you need a large system - it's just that systems like his are fairly unusual.

[foo1bar]

Are these packages good options for a DIY system?

IMO the packages are just a starting point for being modified to suit your design.
They're half marketing tool IMO.
You figure out how many panels you need and of what size, what inverter you want, what racking you want, what feet you want.
And if that is actually a match to a "kit" on one of the vendors I'll be really really surprised.
BUT you look at the components of the kit, email/message the vendor saying "I want kit blah but remove items A, B, and C, and add X, Y, and Z - can you write me up a quote?"

I started with a "kit" created by renvu's kit creator - but I modified things for my order (added extra feet, and changed the rail lengths/quantity).
I think I went through 3 iterations with them as I did more planning/searching - for example I added an extra panel and IIRC I went from 275W to 280W (or maybe it was 285W to 280W?)
In any case, since I was ordering ~$15K of items from them they had no problem with doing order revisions and were helpful in pointing out things that they saw as inconsistencies (ex. I had two different types of grounding lugs - but that was on purpose)

[FNG AZ]

I started out by asking the AHJ what they required and what code they are enforcing. 2011? 2014? Etc...

I used a program called e draw max pro to do my drawings and asked some questions here along the way. My poco also has examples of electrical and site plans available on line. Yours may as well.

See if your poco has a solar interconnect department and ask them what a self installer needs to do to get interconnected.

[bryankloos]

Thanks Guys.
I'm averaging about 18,000-20,000 kWh over the course of a year, and my roof is E-W orientation. I've used PVWatts and get about 20,000kWh with a system sized at 16K given 169 azimuth, 28 degree roof with premium panels. I'm not sure about 14% loss, but that was the default... I have some high trees in the rear of the house which will limit some late day sun. They may come down, but that is TBD.

I was planning on talking to the inspector and asking if they have a template. I did ask briefly and he said I'm clear to pull permits as long as I can supply the appropriate drawings, specs, etc etc.

I guess this should be my first step, as I will know for sure what he needs/wants for the permit.

[J.P.M.]

Thanks Guys.
I'm averaging about 18,000-20,000 kWh over the course of a year, and my roof is E-W orientation. I've used PVWatts and get about 20,000kWh with a system sized at 16K given 169 azimuth, 28 degree roof with premium panels. I'm not sure about 14% loss, but that was the default... I have some high trees in the rear of the house which will limit some late day sun. They may come down, but that is TBD.

I was planning on talking to the inspector and asking if they have a template. I did ask briefly and he said I'm clear to pull permits as long as I can supply the appropriate drawings, specs, etc etc.

I guess this should be my first step, as I will know for sure what he needs/wants for the permit.

NOMB or care/concern, but you've either got a huge and/or leaky house, or you heat with electricity, or all of the above and more.

If part of your reason for PV is to save the most $$ for minimum expense, I'd suggest a different 1st step might be to get a handle on your loads with an energy audit and reduce them. That's always less expensive, less hassle and more cost effective than solar.

After that, figure out how you are charged for electricity and see if other tariffs are available and if changing to one of them will save $$.

In spite of what peddlers will tell you, many times it is not cost effective to replace an entire electric load with PV power. Taking a bit of time to find out why that may be true can often save of $$.

As for the system loss parameter in PVWatts, if you head to the help screens for info and then look at the loss calculator pull down you can get a more informed estimate for system losses. Note that the 14% default already has 3% shading loss in it. A better number MAY be ~ 8-10%, but that # is all over the board.

[bryankloos]

No worries, I'm not offended!
I have a 3400 sq foot house, central AC with 2 condensors and air handlers, 2 full size fridges, and 2 freezers converted to fridges to work as kegerators, and an in ground swimming pool.
I have over 70 BR30 pot lights in the house (all changed to Cree LEDs) and many other lighting fixtures.
I heat with wood mostly (offset with oil) and use some fans to move the heat around. My low months are 1100 kWh and my high summer months are 2700 kWh. I've had an energy audit and was told that given the house, I'm doing pretty well. I need to replace my windows, but that's a $60K bill.

I'm buying a new pool pump this year, which will save me about 1400kWh over the season, and at some point when the AC craps out, I'll replace that with more efficient units.

I've recently installed the Neurio energy monitor, and know that I run about 270 watts in the middle of the night (steady draw from vampire sources, cable boxes etc etc).

Short of the AC and the fridges, I'm running out of room to drastically lower the consumption. More insulation and windows would help.... I may sprayfoam the attic and make that a conditioned space. Time will tell....

[foo1bar]

2 freezers converted to fridges to work as kegerators,

Have you checked the seals on those?
If the seals are worn, replacing them could pay for itself pretty quickly.

Also, I'd look at replacing the kegerators with a "walk-in" refrigerator room. IIRC I read a blog a few years ago by someone who turned their under-stairs closet into a kegerator room. It let them keep a lot more refrigerated and they were able to insulate it and seal it really well.

[J.P.M.]

Also, I'd look at replacing the kegerators with a "walk-in" refrigerator room.

You need that much storage space for beer you must be keeping the breweries on three shifts. Hats off to you.

[foo1bar]

You need that much storage space for beer you must be keeping the breweries on three shifts. Hats off to you.

Or if you're doing your own brewing, at least you're helping support prices for the hops growers.

[bryankloos]

I'm a pretty serious homebrewer. One chest freezer is the kegerator and the other is used for controlling fermentation temps. I probably brew up 100 gallons per year, most of which my friends drink. Its a fun hobby.

[J.P.M.]

I'm a pretty serious homebrewer. One chest freezer is the kegerator and the other is used for controlling fermentation temps. I probably brew up 100 gallons per year, most of which my friends drink. Its a fun hobby.

I had responsible charge for the mechanical design for a bunch of stuff for Anheuser-Busch a long time ago, including the de-alcohollizers for O'Doul's Amber. They later switched to reverse osmosis, starting, I believe with the L.A. plant.

I designed the equipment for a living. I drank with my friends. Both were fun most of the time.

[ktran1]

You can go to website of SMA http://www.sunnydesignweb.com/sdweb/#/Home to size solar string inverter calculation. Some inverters allow MAX DC input at 600V