How to design with bifacial panels

Summary:

This article walks you through the process of designing a project using bifacial solar panels in OpenSolar, including how to configure bifacial-specific parameters and understand their effect on system performance. You’ll also learn how bifacial gains are modeled and how to interpret them in your system summary.

What Are Bifacial Panels?

Bifacial panels generate electricity from both the front and rear sides, capturing reflected light from the ground or surrounding surfaces. This can lead to increased energy output, especially in installations with high albedo surfaces or elevated racking.

Where to Configure Bifacial Properties:

To confirm or modify bifacial characteristics for a module:

1. Navigate to:
   Control > Design & Hardware > Modules

2. Click the edit icon next to the panel you want to inspect.

3. Configure the following fields:

These parameters directly influence how OpenSolar calculates bifacial performance.

Designing with Bifacial Modules:

Once a bifacial module is included in your design:

• You will see a notification in the left-hand toolbar confirming that the design includes bifacial characteristics.

• Bifacial gains are applied automatically during simulation based on the module’s defined parameters.

Pro Tip:

To view bifacial performance impact:

1. Go to the Summary tab in the Design section.

2. Click on “System Losses” in the left sidebar.

3. Look for production gains from bifacial effect in the performance breakdown.

Notes and Modeling Considerations:

Raytracing Limitation

• Raytracing is not available when using bifacial modules.

• For shading analysis:

  • Select the panel array.

  • Open the Shading section.

  • Switch from "Auto" to one of the manual options to customize.

Tilt vs. Roof Slope:

• If tilt rack slope = roof slope, the bifacial gain will be zero, as the system mimics a flush-mount layout (with minimal rear-side exposure).

• To simulate bifacial gains in such cases:

  • Introduce a slight difference between tilt rack and roof slope values.

  • Example: For a flat 20° tilt rack on a roof with 20° slope, input 20 for slope and 19 for tilt rack.

 We are working on improving how flush-mount bifacial scenarios are modeled. In the meantime, the above workaround ensures rear-side contribution is factored in.