How does SolarAPP+ address "bifacial" module design considerations?

Check the module datasheet for the Cell type, either it is Monocrystalline or Bifacial

Find the Short Circuit Current: "Isc (A)" under Standard Test Conditions. In this case, it is 10.74 amps

First you have the high irradiance factor of 1.25 [NEC 690.8(A)(1)(a)(1)] that you apply to the output ISC of the module.

10.74 * 1.25 = 13.425 (This would be the last step if you were working with a Monocrystal Module)

For a bifacial module, determine if the module will be mounted flush to the roof surface or tilted up. Bifacial modules can produce energy from the backside of the module based on the tilt angle and roof materials. SolarAPP+ will apply the following factors to Module short circuit current:

• Flush mount 1.05 i.e. increase modules short circuit current by 5%
• Tilt mount 1.30 i.e. increase modules short circuit current by 30%

Next, multiply module short circuit current with high irradiance factor by 1.3 to get your max Isc Amps in an extreme weather event for a bifacial module.

13.425 * 1.3 = 17.4525