Viessmann Vitosol 200-T SP2A Technical Data Manual page 7

Design Information
Vitosol 200-T, SP2A Technical Data
Installation on Flat Roofs
(continued)
Determining the collector row clearance z
At sunrise and sunset (when the sun is very low),
shading cannot be avoided when collectors are arranged
behind one another. To keep the reduction in yield within
acceptable parameters, observe specific row clearances
(dimension z). When the sun is at its highest on the
shortest day of the year (21.12), the rows at the back
should be free of shading. The angle of the sun  (at
midday) on 21.12. must be used to calculate
the row clearance.
Example:
Toronto is approximately located on latitude 43° north.
In the northern hemisphere, this value is calculated as
follows:
Angle  = 90° - 23.5° - latitude
= 90 - 23.5 - 43 =23.5
h = 2241 mm
 = 45°
 = 23.5°
z = sin (180°– (+))
sin 
h
z = 2241 mm · sin (180° – 68.5°)
sin 23.5°
z = 205.9 in. (5229 mm)
z = Distance between collector rows
h = Collector height (for dimensions see "Specification"
for the relevant collector)
 = Angle of collector inclination
 = Angle of the sun
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