From GridLAB-D Wiki
orientation_azimuth – Facing direction of the panel
Synopsis
module generators; class solar { double orientation_azimuth[deg]; } object solar { orientation_azimuth value; }
Remarks
orientation_azimuth is used for calculating the solar insulation when the panel orientation type is FIXED.
orientation_azimuth is referenced on the normal cardinal coordinate scheme (0 = N, 90 = E, 180 = S, 270 = W).
Default
By default, orientation_azimuth = 180, which means the panel is facing towards the Equator.