Agriculture Reference
In-Depth Information
S-2, 10 a.m.
S-3, 2 p.m.
12 a.m.
S-4, 4 p.m.
S-1, 8 a.m.
C
East
West
A
B
12 a.m.
S-2 and S-3,10 a.m. and 2 p.m.
C
S-1 and S-4, 8 a.m. and 4 p.m.
B'
A'
North
South
Fig. 4.21.
Distribution of shadows created by the gutter (C) through the day in two greenhouses with
east-west orientation (bottom, A'B') and north-south (top, AB). The sun's elevation is shown between
8 a.m. and 4 p.m. (solar time) on the 21 December (latitude 37°N). The shadows are distributed more
uniformly in the north-south oriented greenhouse.
SR
SR
SR
North
a
a
a
h
SR
Fig. 4.22.
In a multi-span greenhouse oriented east-west, if the roof angle of the north side (a) is greater
than the angle of the elevation of the Sun (
h
) shadows are produced (shown as grey shading) as one
span casts a shadow over the adjacent span. In a single-span greenhouse these shadows are not
produced. SR, Solar rays.
