The Three Main Methods of Designing a Rooftop Solar System

During the sales and planning phases of a residential rooftop solar project, different methods are used to determine how to arrange the solar modules on a rooftop. We will talk about three methods that solar professionals often use during this phase.

The Three Main Methods of Designing a Rooftop Solar System

Article by | Eagle View

What are solar panel designs used for?

After a to sell was made, a solar design, also known as “final design”, is done during the planning phase to produce technical drawings or the “set of plans” for a project. These drawings are used to provide information on equipment selection, installation rules and permit requirements.

What are the three types of solar design methods?

The three types of solar panel design methods are three-dimensional (3D), two-dimensional (2D) projected views, and two-dimensional overlays.

Design of three-dimensional (3D) solar panels

Certainly the most accurate in my opinion, 3D solar design methods rely on 3D models of structures, whether obtained from a third party or modeled by the user from field measurements, to perform installation of solar modules. The solar module representations themselves are aligned and placed over the 3D model, essentially creating a project-scale digital twin in CAD. This methodology eliminates potential errors when adjusting the size of the solar modules to account for roof pitch, but requires a level of spatial capability on the part of the designer to operate in a 3D environment. Because this method produces a digital twin of the structure, AutoCAD can generate many different views of the project to include in the blueprint set, such as a holistic top-down view, 2D projected views, or even 3D renderings.

Isometric view of a three-dimensional (3D) solar panel design


Supported CAD software: AutoCAD, SketchUp and other popular CAD programs

Suggested CAD software: AutoCAD

Suggested EagleView CAD deliverable: standard DXF file

Be careful: when aligning module representations to the roof facet, make sure that the modules do not float above the 3D roof facet, as this could lead to accuracy errors.

Advantage: Speed, Accuracy, Consistency

Tip: To quickly and accurately place solar modules on a 3D roof facet, AutoCAD’s “Align” command is a unique feature that will move and rotate the solar modules in 3D space.

Two-dimensional (2D) projected view solar panel design

As the most traditional method of solar design, 2D projected view solar design originated when the most common practice for obtaining roof measurements was to send a technician to the roof with a tape measure. These technicians usually provided perimeter measurements to the designer of each facet so that it could be redrawn in AutoCAD. While this method works great for converting field measurements to a solar panel layout, some third-party measurement vendors do not provide CAD files in this format and additionally it can be difficult to get a holistic view. downward from the structure (when setting up the location of each 2D roof facet to mimic the structure of the subject, the roof facets themselves do not match on each edge, much like laying a flat orange peel on a table).

Isometric view of a two-dimensional (2D) solar panel design


Supported CAD software: AutoCAD, SketchUp and other popular CAD programs

Suggested CAD software: AutoCAD or AutoCAD LT

Suggested EagleView CAD deliverable: DXF file with 2D projected view

Be careful when forcing each roof facet projection together to get an overall top-down view of the solar design, as roof geometries and their accuracy can be compromised.

Advantage: User and software can operate only in 2D environment

Tip: Instead of forcing 2D roof projections together to get a holistic view of the structure from the top-down perspective, EagleView’s new DXF file includes both a 3D model of the structure as well as 2D roof projections so the designer can leverage either 3D or 2D overlay methods to achieve the desired holistic plan view result while being able to include 2D facet views in the plan set.

Two-Dimensional (2D) Overlays: The Hybrid Solar Design Method

Finally, the solar design technique of a 2D overlay could be considered a hybrid of true 3D design and the traditional 2D projection method. I believe this methodology has gained popularity among solar designers lately due to software limitations or the lack of professional CAD techniques developed since the days when draftsmen drew by hand. Regardless of how it originated, this methodology can work well but requires the proper checks and balances in the designer’s process to ensure accurate results.

Isometric view of a solar panel design using a two-dimensional (2D) hybrid overlay.


Supported CAD software: AutoCAD, SketchUp and other popular CAD programs

Suggested CAD software: AutoCAD or AutoCAD LT

Suggested EagleView CAD deliverable: standard DXF file

Be careful: when adjusting the size of the solar module to account for the pitched distance from the roof.

Advantage: Minimal CAD training is required for the solar designer to perform a solar module layout, as they are essentially drawing the view they want to see in the blueprint set

Tip: While EagleView provides a 3D model in the standard DXF file, a 2D overlay can be done directly on the model from the top-down view, or the 3D model can be flattened in AutoCAD using the “Flatten” command (although I don’t recommend the practice of flattening as you will lose the slanted linear measurements we provide and layout accuracy may be compromised)

Which solar panel design method should you use?

The best design methodology for your organization depends on your CAD software and the technical capability of the individual designer. EagleView recommends 3D solar design methods because of the speed, accuracy, and consistency they provide, but 2D methods can work as long as the proper checks and balances are built into the designer’s processes to ensure accurate designs. that can be installed on the roof in question. . Whichever method your organization uses, EagleView can provide a CAD deliverable that will undoubtedly improve efficiency and accuracy.

The content and opinions of this article are those of the author and do not necessarily represent the views of AltEnergyMag

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