When choosing a solar collector, selecting the
correct size is important. To find out what size collector you need
please
click
here. Once you have determined what size collector suits your
needs, the next question is where to install it.
Deciding the Direction and Angle of
Installation
The angle and direction of installation is also
of great importance as it will effect the efficiency of the solar
collector. Naturally you want the collector to receive the maximum
amount of sunlight each day and throughout the year. As a general
rule if you are in the Northern Hemisphere then the collector should
face South and if you are in the Southern Hemisphere then the
collector should face North. See diagram below.

The angle at which you mount the collector should
roughly correspond to the latitude of your location. For
example:
- Melbourne, Australia has a latitude of 37o South - the collector should therefore face
north at a 37o angle.
- London, UK
has a latitude of 51o North - the
collector should therefore face south at a 51o angle.
You do not have to be too careful about mounting
the collector at the exact angle suggested. If your roof angle is
within 10o+/- of your desired angle
you can just mount the solar collector flush against the roof
surface. The added trouble of adjusting the collector to a precise
angle is not warranted as it will not result in a great improvement
in efficiency.
Seasonal Changes in Heat Output
How to prevent
excessive summer heat output
If you are using the solar collector for space
heating as well as hot water production, or if you just want a
larger solar contribution, you will need a system that will greatly
surpass heat requirements in the summer. Generally in the summer
heating will not be required, in contrast cooling is. Unfortunately,
at present solar cooling for domestic applications is not yet
economically viable, so what to do with the additional heat? If you
have a swimming pool or spa, the excess heat can be used to
supplement heating. Turning off the pump and letting the collector
stagnate is not ideal as high pressure and temps, and large volumes
of vented steam may result (wasted water).
If you do not have
an additional means of using the excess heat, then adjusting the
angle of the collector can help to reduce summer heat output. As can
be seen by the diagram above, the sun is low in the sky during the
winter and high in the summer. Solar smart house designs will take
advantage of this by having big North or South (depending on your
location) facing windows allowing maximum absorption of winter sun,
with large eves or veranda to block out the summer sun.
By
increasing the vertical angle of the collector by about 20o more the location's latitude (ie. 60o instead of 40o), greater winter performance will be
experienced. This is because the collector is "facing" the sun
(perpendicular - longitudinal angle). Due to the higher location of
the sun in the sky during the summer, the collector will be around
40o from perpendicular and as such
heat output will be reduced as the collector is not fully "facing"
the sun. This simple solution alone can reduce peak summer output
considerably, thus reducing problems associated with excessive
summer heat production.

The above photo shows an ideal example of an
installation angle that optimises winter, spring and autumn heat
output, while minimising summer output. The high angle not only
maximises expose to the direct winter sun, but also allows the
sunlight reflected off the snow to be absorbed. In the summer when
the sun is high overhead the exposed surface area is small,
especially with the overhanging roof which would partially shade the
collector. In areas without snow fall (and a latitude range of
30-40o) an angle lower than that
shown above would be suitable.
Please note: For the Micoe solar water heater, optimal heat pipe performance is
achieved in the angle range of 20-70o. Although your locations may have a latitude
of less than 20o, this basic
installation guideline should be adhered to. Horizontal angles of
+/- 5o are acceptable and may be
appropriate if the manifold needs to be drainable (end port models
only).