Solar System Design Guide
6020 457 - 01
12
Inclination of the receiver surface
The yield of a solar thermal system varies depending
on the inclination and orientation of the collector area.
If the collector installation surface is angled, the angle
of incidence changes, as does the irradiance, and
consequently the amount of energy. This is greatest
when the radiation hits the collector installation surface at
right angles. In our latitudes, this case never arises relative
to the horizontal. Consequently, the inclination of the
receiver surface can optimize the yield. In North America,
a collector installation surface oriented facing South and
angled 35° receives approximately 12% more energy
when compared with a horizontal position.
A common rule of thumb is used when designing a
solar DHW heating system to optimize the year round
production of energy:
Collector inclination = latitude of location.
For combination DHW + space heating supplement
systems, the collectors should be installed at a steeper
angle of inclination to take advantage of lower winter sun
angles and to more effectively shed snow. The rule of
thumb to optimize combination systems:
Collector inclination = latitude of lo15°.
Avoid shading of the collector installation surface
Looking at the installation of a collector facing south,
we recommend that the area between south-east and
south-west is kept free of shading (at an angle towards
the horizon of up to 20°). It should be noted that the
solar system is to operate for longer than 20 years, and
that during this time, for example, trees would grow
substantially.
Avoid Shading of the Receiver Surface
Principles
Orientation of the Receiver Surface
Optimum alignment and inclination
The solar collector provides the highest solar yield over an
annual average when facing due South with an inclination
of approximately 30° to 45° from the horizontal plane.
However, the installation of a solar heating system is
still viable even when the installation deviates quite
significantly from the above (+/- 45° of due South
alignment or with an inclination of 25° to 55° from
the horizontal plane). Greater deviations, for example,
for installation on walls, can be compensated for by a
correspondingly larger collector area.
Solar Energy Yield
a
100%
d
65%
g
80%
j
50%
b
95%
e
70%
h
80%
k
90%
c
95%
f
65%
i
50%
Inclination of the Receiver Surface
Collector Inclination Angles:
Summer biased installation = latitude of location -15°
Optimum, year round performance = latitude of location
Winter biased installation = latitude of lo15°
