Shadow length.csv

Dear all,
i wanted to implement below formula
http://www.mysolarpannels.com/optimu...-solar-panels/

Can determining shadow length how to calculate new elevation angle. Usually Shadow will be influence 7AM-10AM and evening 4pm-6PM.I have attached excel sheet for reference

x=1200 mm
when manually measure distance spacing between 2 panel is 3200mm=Lmin
ω-modules angle is conv_angle in excel sheet which will be +ve in morning and -ve on evening

question is to determine Lmin and ω-modules angle.