in design builder, there is "cells in series "and "active area" in the one diode model of the photovoltaic generator what's the meaning of them? does the 'cells in series" means that'' there are xx (numbers) of single modules in series " ? and if I want to put them in parallel, is there any options? what is the 'active area"? for a certain sized window, when I choose different kinds of photovoltaic solar cell like ASE300-DFG/50 or BPsolar 275, the active area is not the same. and if I change the window size, the active area is not change. is the "active area" which means the for every module, the active area is xx (m^2)?