Once we've defined an installation area by importing an XML model, using trace-over aerial imagery, or drawing an abstract roof face (and cleaning up the boundaries), it's time to actually design our PV system. In this tutorial, we'll show you how to:

  • Select a module
  • Select an inverter
  • Select a racking system
  • Adjust the panel layout
  • Adjust setbacks
  • Adjust roof priority
  • Size strings/branches

Building Your PV System

Click on Build System to start the design process.

Once we've opened the system building menu, we have a number of options to get started.

Select a Module

Click on the field where it says "Type a solar panel and select" to begin our panel selection process. Begin to type out the name of a manufacturer or model of module you want to use, add a power rating, and the panel list will automatically narrow down to something that fits our search criteria. Simply click on whatever piece of equipment you'd like to use.

Note: even after you've narrowed down the search list, you can still scroll through the results and select whichever panel is the most appropriate for your needs.

Select an Inverter

Just like we did with the module, we can just click on the field that says "Type an Inverter name and select" in order to make our inverter selection. Usually I will start with the manufacturer, and the rating I am looking for, but I can also search by inverter type as well (e.g. MultiMPPT, Micro, String).

Again, we can search through the list by scrolling, or narrow it down further by typing more details about our selection.

Note: Want to add more than one inverter to a design? Check out this tutorial.

Select a Racking System 

Next, let's select the rail system we'll be using to mount your array. You can select generic racking, although we highly recommend that you choose a fully supported racking system. This will help the app accurately space the modules in the array, calculate the weight of the array, and allow you to automatically generate data sheets and certification documents for the racking components in a later step. Selecting a fully supported racking system is also necessary for generating an Attachment and Details page when we generate our Permit Package later.

Note: If the racking system you use is not listed in our database, please contact the manufacturer and let them know you'd like their product in SolarDesignTool! Check out the FAQ article for more information.

At this point, we can make selections on our branch/string size, but I like to make sure that the layout style and setbacks are to my liking first. 

Adjusting the Panel Layout

To adjust the Panel layout, click on the "Racking" option and then click on "Layout Strategy" to view different layout options. Don't worry if the array isn't exactly where you envisioned it; you can (re)arrange modules and move the array with more precision at a later step.

Adjusting Setbacks

Click on "Setbacks" and enter the value (in feet or inches) you would like for each roof edge.

Adjusting Roof Priority

One more element worth noting in the system builder is that we can sort installation areas in the order we would like them to be filled, by dragging them higher, or lower in the queue of Array Layout areas. Installation areas higher in the queue will be filled in before those lower in the queue.

Finally, we can select our string/branch size. 

Sizing Strings/Branches

For this particular system, all we have to do is select how many panels we want in our string and select it from the branch menu.

Note: when we are adding strings to an installation area, the system builder automatically populates the area starting at the top row, and fills it in from left to right. If we want to adjust where these panels fill in, we can do this from the Array Editor (accessible after we save our system). 

Once we've sized out our first branch, we can add an additional branch, add an additional inverter, or just save our system. 

Note: If we do want to add a second branch, and we want to ensure that each branch is placed on a separate installation area, we can use the Lock/Unlock feature to make this easier. Locked roofs cannot have additional panels placed on them, Unlocked Roofs can.

Next Steps

Next, you may want to (re)arrange modules to fine-tune the array layout. Then, we'll want to specify the mechanical & balance of system components being used. After that, we'll be able to generate and download permitting documents, including system datasheets, concept designs, and permit packages.

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