[RE-wrenches] Spacing between ground mounted sub-arrays at 48.5 degrees N latitude

[Bob Clark]

Wrenches:

I have a customer who wants 40 solar modules on ground mounts (not poles) in an area that slopes to the ESE at 7 degrees.  Putting these modules on one ground mount assembly so that the modules are in a 0 degree slope East to West would leave the east end about 20 feet in the air.  Not acceptable as the customer wants a profile as low as possible for aesthetic reasons plus the wind can be quite strong on occasion.

So, I am trying to figure out how far apart 5, 8 module sub-arrays (landscape orientation 2 E-W by 4 N-S tilted at 35 degrees S from the horizontal) would have to be North to South and East to West so that they are low profile yet do not shade each other on the winter solstice at 48.5 degrees N latitude.  These calculations are complicated by the ground sloping to the ESE at 7 degrees.

Can anyone point to an online calculator that takes into account the slope of the ground?  Or can anyone help me with the geometry of this situation.  I have gone around in circles and thoroughly confused myself.

Thanks in advance.

Bob Clark
bclark at solar-wind.us