Module Orientation Strategies for Array Layouts

SolarNexus can automatically layout your PV Modules into an array within each area you define on the Site (most typically a roof plane). This article describes the various module orientation strategies that you can use for automated array layouts. Example layouts are shown below to illustrate how each strategy affects the layouts for some common roof array cases.

Because PV modules have a long edge and short edge, the orientation of modules (portrait or landscape) plays a primary role in their layout and is the primary attribute you can control. The alignment of modules from row to row (aligned in a grid or offset) is also very important and is the second attribute you can control.

There are several considerations to make when choosing a module orientation strategy for your layouts, including:

• shape of the area
• size of the area with respect to desired generation capacity (i.e. how critical is it to fit the maximum modules)
• edge setback restrictions
• presence of obstructions
• customer's array appearance preferences
• your installation preferences

NOTE: SolarNexus auto-layout feature automatically includes a 1" intermodule spacing between rows and columns of modules.

 

Supported Module Orientation Strategies

The "module orientation" field allows you select which strategy to use in the layout of each array.

Portrait / Landscape

 

This is by far the most common layout strategy, and portrait is far more common than landscape. It is characterized by strictly aligning rows of modules into aligned columns. A very effective strategy in most cases.

Portrait Optimized with Landscape

This is the basic Portrait grid layout with a possible addition. The software will check to see if there is sufficient space for an additional row of modules to fit in landscape in the available space. If it can, one will be added, if not the array will simply look as a portrait gird style.

 

Portrait / Landscape - Half Offset

Using the half offset option tells the software to offset each row by 50% from the rows above and below it. It maintains an attractive, and symmetrical layout, especially good for maximizing modules on symmetrical triangular roof faces. If the roof face shape allows it, a half offset strategy adds one additional module to each row as you proceed up the triangle when compared to a grid layout.

 

Portrait / Landscape - Optimal Offset

The optimal offset option tells the software to fit as many modules as possible in the area, giving the permission to offset each row to any extent such that an another module is added. Use this option for areas with obstructions for which you've created restrictions AND you and the customer are OK with a potentially irregular looking array. If the software cannot fit any more modules that in a standard grid strategy, then it will return a standard grid layout of the selected portrait or landscape orientation. Note that a high percentage of cases will result in a standard grid orientation rather than including any irregular offsets.

 

Example - Hip Roof, 2 Adjacent Arrays

The following example shows a hip roof with southwest and southeast faces where we've determined will be used for arrays. We believe that we need to maximize the number of modules because the customer's use is relatively high compared to his roof size. The southwest roof has a chimney and a pair of plumbing vents we need to avoid. Our permitting jurisdiction requires a 3 foot setback from all roof ridges, as well as a 3 foot access path from the eave to the ridge between each array, so we will apply an 18" setback to the "hip" edge.

The following images show how the array layouts resulting from use of the available module orientation strategies.

1) Portrait

Both Southwest and Southeast arrays below are laid out using the Portrait strategy. All modules are placed in a grid format - where rows and columns are strictly aligned. The southwest array fills in around the restricted areas drawn, as well as respecting the 3 foot setback from the ridge, and 18 inches from the hip. The southeast array is also at least 18 inches from the hip.

Total modules = 17 (SW: 8, SE: 9).

 

2) Portrait - Half Offset and Portrait Optimized with Landscape

The image below shows the Southeast array as laid out using the "Portrait - Half Offset" module orientation strategy. The shape of the area including the 18 inch hip setback does not allow 4 modules in the middle row, so fewer modules can fit on this roof. The Southwest roof uses the "Portrait Optimized with Landscape." A third row of portrait modules won't fit across the top, however, a row of landscape modules will fit. Note that this strategy will ONLY add a landscape row in cases where a portrait row will not fit, but landscape will. This means that its relatively rare and becomes more rare as your module becomes more square rather than rectangular.

Total modules = 19 (SW: 11, SE: 8).

3) Portrait - Optimal Offset

The image below shows both arrays using the Optimal Offset option. In this case, neither Southwest nor Southeast array would gain additional modules in each array from any staggering of the rows. This result is very common, in most cases, using the optimal offset option will not result in a different layout. However, its worth trying out whenever you have a roof broken up by obstructions or odd shapes and both your customer and you are willing to have an installation with potentially odd row offsets.

Total modules = 17 (SW: 8, SE: 9).

 

4) Landscape

The Landscape orientation strategy was used on both arrays below, enforcing a strict grid strategy where each rows modules align into columns.

Total modules = 17 (SW: 9, SE: 8).

 

5) Landscape - Half Offset and Portrait Optimized with Landscape

The Landscape - Half Offset orientation strategy was used on the Southeast array, giving the most modules of any options thus far. The Southwest array uses the Portrait Optimized with Landscape option shown to have the most modules tried on that roof thus far. Note that setbacks continue to be respected.

Total modules = 21 (SW: 11, SE: 10)

6) Portrait - Half Offset

The image below shows both arrays using the Portrait - Half Offset option. Note the Southwest array where the lowest row is elevated a bit to allow two modules to fit in the space between restricted areas. If selecting Half Offset, half offset is applied to every row.

Total modules = 16 (SW: 8, SE: 8).

 

7) Landscape - Half Offset

The image below shows the Southwest array laid out using the Landscape - Half Offset option. Every row's modules are offset by 50% of the above and below rows. It doesn't produce an attractive, nor easy to build layout in this case. This is probably not a good application of that module orientation strategy. The Southeast array uses the half offset option as described above.

Total modules = 18 (SW: 10, SE: 8).

 

8) Landscape - Optimal Offset

The image below shows Landscape - Optimal Offset applied to the Southwest array which staggers rows of modules to attempt a best fit of the most modules possible. The Southeast array uses the half offset option as described above.

Total modules = 19 (SW: 11, SE: 8)