Designing Your System and Permitting:
Your system design will consist of PV modules (solar panels), module support structure (racking), DC – AC inverter, wiring and shut offs.
Modules:
How many modules your system will require is based upon your AC annual energy needs. Sizing your system; space for the solar panels and your energy needs are the main constraints when it comes to the PV Modules. Once you find the models that you think will be a good fit and you have your measurements on where you want to place the modules you can get a good idea on how many panels can fit in the space allotted. Knowing how many modules can be installed you then can add up the DC output. For instance if you can fit 15 modules and each module has an output of 345 watts then you will have 15 x 345 watts = 5175 watts or 5.175 kW system. With your AC output, tilt and azimuth you can now input those numbers into PV Watts – https://pvwatts.nrel.gov/ and see what your AC output will be for your location. This will give you an idea on what to expect from your system.
Racking systems:
The next step is to look into the racking systems that will secure your modules. You will want to make sure you pick a system that meets your buildings codes, compatible with your modules and your roof type or structure.
We recommend Iron Ridge racking. They are easy to install and very robust. In the Racking section we will go over installation for Iron Ridge racking. We also carry their product.
AC/DC inverter:
As discussed earlier there are two main types of inverters. String inverters and micro inverters. Now is the time to decide what will meet your budget and your design layout. If you have some concern with shading, microinverters may be the way to go or you could opt for a string inverter with multiple inputs or DC optimizers to help with different shading and tilt/angle of different strings.
We recommend Enphase microinverters. They are very easy to install and also reliable. Just make sure you are matching up the Watts and cell rating of the microinverter to what cell your solar panels are. An example is if you got the Mission Solar Panel 345W 60 cell you will want to pair it with the Enphase IQ7A-72-US 366W. That inverter is good for 60 and 72 solar panels up to 366W.
Things you will want to gather to start your system design and permit packet:
Asmuth – Compass direction of arrays
Slope – Slope of roof
Building codes – how close you can put panels to roof edge, ridge and other obstacles like vents or chimneys.
What type of roofing material is your roof made of – i.e. Shingles, corrugated Metal, wood shake, slate.
Deck sheathing type – Check what type of decking you have on your roof. Typical decking is OSB or plywood. Also while you’re up in the attic check the thickness of the roofing materials. i.e. 15/32” OSB or 11/32” plywood.
Construction Type – Another thing to check while up in the attic is what type of construction is holding up the roof. i.e Manufactured truss, rafters, beams and purlins, vaulted beams.
Truss Top-Chord Dimensions – You will need to get the dimensions of the top truss. i.e. 1.5” x 3.5”
Truss Spacing (O.C., in inches) – You will also need to get the spacing between your trusses. i.e. 24” o.c.
If you would like help with the design process and permitting please reach out to us: info@ware.energy. Full service design and permitting typically costs $250. We will need you to gather key information listed above for the install. Permitting is probable is biggest pain of the process.
If you want to go the permitting route on your own, typically you will need the following:
To be continued...