Copyright © 2014
Ikhwezi Solar (Pty) Ltd, Novatherm CC, Solar Assist (Pty) Ltd
5
6.3
Tilt angle
In respect of the optimum angle of inclination for a solar collector, the rule
of thumb provides that the latitude of the location is taken and then 10°
added thereto. Therefore, a location with latitude of 25° would indicate an
optimum collector tilt angle of 35°.
The angle of inclination, however, is also flexible and minimal loss of
performance occurs by installing at lower or higher angles of inclination.
The NovaSun collector can be installed as low as 10°. Below this, however,
the thermo-siphon process does not function effectively. Also, angles lower
than this would result in build-up of dust, as it is not able to be washed
away effectively by rainfall.
It must also be noted that installation angles over 30° will require additional
strapping to secure the geyser and collector during and after installation, as
at this angle the system will tend to move downward. Consideration should
be given to a split installation in these circumstances.
6.4
Water supply / delivery
The location of the installation should give as efficient a supply of hot water
to all areas of the residence as possible. If not possible, the system should
be placed as close to its main point of usage (e.g. master bathroom).
Discuss this with the client and confirm their understanding and
requirements.
6.5
Roof structural integrity
The area chosen for installation must be structurally capable of handling the
loading. Check load weights of applicable system and ensure that the weight
can be borne by the roof structure. Specialist advice should be sought if
required.
The system should be placed, such that the tank spans at least three main
trusses. It is good practice to brace all truss work that supports the
installation.
Strengthen rafters (or timbers or other structures) used for supporting the
panel and tank, for example by adding noggins between rafters or adding
thicker timbers alongside them or cross bracing them or adding additional
supporting struts to the truss to spread the additional load to a load bearing
point. Where ever possible the system should be installed over a supporting
wall of the building (i.e. on a truss resting on a supporting load bearing
wall). Never install a system on a roof with damaged or rotting timbers.
To prevent cracking of certain fibre cement and metal roof sheeting, a flat
mounting frame designed to spread the load of the geyser and its contents
should be designed by suitably qualified personnel and installed below the
geyser. Ensure that the roof covering material is structurally sound to
receive the weight of the system. In the case of a split system installation a
wooden frame should be constructed which raises the tank above the level
of the collectors. Care should be taken in the design and construction of this
frame so as to ensure it meets all relevant standards.
7.
Mounting methods
7.1
Selection of appropriate mounting method
Please note that it is the installer’s responsibility to ensure that the means of
fixing the system to the roof such that it results in a safe and functional
installation.
The methods suggested are generic and will not necessarily be suitable in all
situations.
7.2
System mounting methods
7.2.1Suggested
method 1
- General purpose installation brackets
The image below depicts a typical bracketing system which could be used
with NovaSun solar hot water systems. This type of bracketing system is
suitable for tiled or corrugated roof structures with a pitch of less than 30
degrees. Typical kits would include the following pieces:
A (2 pieces) – Tank Cradle Bracket
B (2 pieces) – Collector Clamp
C (2 pieces) – Straps (not included*)
D (2 pieces) – Collector Hanger Bracket**
*Straps are not included as lengths required will differ from installation to installation.
These should be aluminium or stainless steel.
**Please note that two hanger brackets are required per collector. The 300 litre
system using two collectors require 4 hanger brackets (two per collector).
Please note that points of contact between the collector frame and mounting
brackets and between tank and mounting brackets are buffered by a foam
lining to prevent issues surrounding galvanic corrosion.
The installer must install the system in such a fashion to prevent long term
degradation of system materials through galvanic reaction.
7.2.2Suggested
method 2
- Alternate installation brackets
As an alternative to the first bracketing system, straps could be used.
Collectors could be secured directly to the roof structure, at each of the four
corners of the collector, by means of aluminium strapping.
The straps should be securely fixed to the underside of the aluminium
collector frame using aluminium speed screws. The straps can then be
passed under the tiling and secured around the nearest truss and/or purlin.
In respect of the geyser, strapping can be hooped around the geyser, on
either end of the cylinder, using strap clamps available with commercially
available strapping systems, leaving enough length to pass the tail pieces
under the tiles and secured around the appropriate roof woodwork.
As indicated above the installer must install the system in such a manner so
as to prevent galvanic corrosion between system components and the
mounting brackets and/or straps.
