The installed nominal power (STC) is directly proportionnal to the collector area:
Pnom [kWp] = Coll. Area [m2] * Effic at STC [%] / 100
Now the Utilization Factor
UF (= Acoll / Aground), which is the inverse of the Ground Coverage Ratio
(GCR), is calculated according to:
File comment: Utilization Factor
Sheds_Definition_Calcul.png [ 9.24 KiB | Viewed 7615 times ]
We can notice that the more relevant parameter is the collector tilt: with 30° tilt you can install only 40-50% of the available ground area, when with 4° or less you can install more than 80% of your ground area.
This is very weakly dependent on your limit angle.
File comment: UF as function of collector tilt
Sheds_Utilization_Ratio.png [ 7.52 KiB | Viewed 7615 times ]
Therefore when the area is limited, you are always advised to put your collectors as horizontal as possible (with the only limit of the soiling problems).
Moreover, this results in much simpler support's mechanics, less wind sensitivity, lower weight, etc.
This allows also to define higher shed's width, i.e. more strings in the width of the shed. This drastically limits the electrical shadings losses.
In most cases, taking the shading effects into account, the overall energy loss will be less than 2-3% with respect to 20-30° sheds.