Optimal Tilt and Azimuth

Hello Paul,

I have run a parametric analysis for two SAM models and generated somewhat surprising result for the maximum annual energy generation off of the PV system.

I expected the maximum annual generation to be generated from a PV system facing north (in the southern hemisphere), and at a tilt of roughly my latitude.

Instead, the optimal azimuth seems to be nearly 30 degrees off of north, towards the NE, while the optimal tilt is approximately my latitude. This seems to be rather far off. Have you seen this before Paul?

My hypothesis is that this is due to temperature effects on the PV cells, but I wouldn't expect it to be such a large azimuth.

energyplus.net/weather-location/southwest_pacific_wmo_region_5/AUS//AUS_QLD.Cairns.Aero.948270_RMY

Hello,

In some cases, a geographical feature like a nearby mountain range or coast can cause afternoon clouds or morning fog that would shift the optimal azimuth. For example, in the United States, the mountains just west of Boulder, Colorado cause regular afternoon clouds during the summer, which causes the optimal azimuth angle to maximize annual output of a fixed flat solar collector to be east of south. In coastal Los Angeles, California, the effect of morning fog in the hills east of the city causes the optimal azimuth angle to be west of south.

The weather file you are using is for the Cairns, Australia airport, which is at the coast, so perhaps this is a factor in your case.

Here is a link to an article on optimal tilt and azimuth angle that might be helpful:

Christensen, C.; Barker, G. (2001) Effects of Tilt and Azimuth on Annual Incident Solar Radiation for United States Locations. ( PDF 460 KB )

Best regards,
Paul.

Thanks Paul. It's good to know I am on the right track.