4.1 Selecting the Site
4 Installation
4.1.1 Azimuth. Angle of orientation, with respect to south (0º)
This should be as close as possible to Due South (0º) in the Northern Hemisphere, or Due
North (90º) in the Southern Hemisphere, for maximum solar irradiataion. However, sometimes
it's better to deviate from optimal azimuth to avoid shading.
4.1.2 Inclination. Angle of pitch (for serpentine installation on the roof)
On a pitched roof, the angle of the collectors is usually fixed. However the serpentine system is
more suited to flat roofs making it possible to choose collector inclination.
Optimal inclination to generate maximum solar gain is a function of latitude, but also of the use
and performance of the solar system through the year. A steeper pitch angle will receive more
solar energy in winter months; though average solar irradiation/m2/day would be higher if
inclination is the same as lattitude. A solar pumping system for example would require
inclination for maximum solar gain during summer (latitude – 20 to 23º); to cope with peak
demand for pumping.
For year-round household demand a solar serpentine system should be installed for maximum
Winter solar irradiance. Following the advice of Jaume Domingo, a pioneering Catalan solar
engineer, in Equador and tropical zones, with a similar irradiation through the year, its
reasonable to match inclination to latitude. In Xela, Guatemala, a template zone with lower
Winter irradiance, the inclination should be latitude + (20 to 23º) 35º.
4.1.3 Shading
!!Select a shade free site for the solar collectors.
The performance of the SSWH depends on maximum exposure to solar radiation. The solar
array should not have tall buildings, trees or hills positioned in front of them (to the North in the
S. Hemisphere or South in the N. Hemisphere). This is also true for protrusions from the roof.
Even shading objects to the East or West can have an effect, as during the day the sun will
move from East through Southeast (or Northeast in the Southern Hemisphere) through South
then through Southwest to West.
4.1.4 Position of the Solar Installation relative to the shower
Flow to the shower depends on the pressure drop from the hot water tank. In the pipe between
the tank and the shower, straight vertical drops improve flow (although long runs should be
insulated to prevent heat loss.) Minimise horizontal „dead-legs‟ which will restrict flow.
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