No, results specific to solar panel orientation. Math is not trivial at all, but the results are intuitive: roughly, point the panel in the direction which, in mean, is in the direction of the sun. So tilted towards the equator, at the same angle as your latitude.

http://www.nrel.gov/rredc/pvwatts/changing_parameters.html#t...

"The default value is a tilt angle equal to the station's latitude. This normally maximizes annual energy production. Increasing the tilt angle favors energy production in the winter, and decreasing the tilt angle favors energy production in the summer."

(Couldn't find a clear proof of this (under any modelling assumptions), sorry.)

A unique optimum isn't really necessary here (I shouldn't have required it!)