3.14. Freeze protection
Freeze protection must be implemented in any regions that experience freezing conditions at any time
throughout the year.
a) For areas with temperature not falling below –5
o
C / 23
o
F, simple low temp controller based freeze protection may
be used. (i.e. Pump circulates if the manifold temperature approaches freezing). If possible, backup protection in
the form of uninterrupted power supply (UPS) or drip valve (which opens to allow water to dribble out if power
supply is cut) should also be installed. It is also important that the tank is heated at least once daily (to the bottom)
to ensure there is heat to keep the solar loop from freezing.
b) For areas with temperatures below –5
o
C / 23
o
F, a closed loop filled with an anti-freeze mix can be used to provide
freeze protection. Please refer to propylene glycol manufacturer’s specifications about the temperature ranges the
liquid can withstand. See also 1.4 regarding water quality requirements. Anti-freeze liquids are normally required to
be potable water grade; please check with local regulations. The other option for cold temperatures is a drain back
systems whereby the collector drains empty of water each time the pump stops circulating.
c) Evacuated tubes are not susceptible to damage in cold weather, and Apricus heat pipes are protected against
damage that could result from the freezing of the water inside.
d) Apricus does not warrant the solar collector against freeze related damage.
3.15. Wind Loading
a) When installing the collector, wind loading must be considered.
b) The standard frame, and frames kits are all designed to withstand wind speeds of up to 208km/h / 130mph
without damage for installation angle of 45
o
and less. This wind speed corresponds to the mid range of Category 2
cyclones (US Saffir-Simpson Scale). For higher wind speeds additional frame components, lower installation angle
and reinforcement of roof attachment may be required. Collector mounting in high wind regions (>208km/h /
130mph) should be reviewed, and where required, approved in writing by a qualified engineer.
c) Refer to section 4 for specific roof attachment details for various frame options.
3.16. Snow Load
a) In areas prone to heavy snow falls the solar collectors should ideally be installed at an angle of 50
o
or greater to
help promote snow sliding off the tubes. In addition it is advisable to raise the front of the collector frame 15-20cm
off the roof surface as this allows snow to sit beneath the collector and also more easily blow away from under the
collector. See the picture to the right.
A front track extension (#FR-SS-FTEXT) can be used for this purpose.
b) The solar collectors are able to withstand a maximum snow loading of 300kg/m
2
/ 60lbs/ft
2
. Refer to local
regulations regarding snow loading guidelines.
3.17. Hail Resistance
a) Apricus glass evacuated tubes are able to withstand impact from hail up to 25mm /1” in diameter.
b) In areas prone to large hail (>
∅
20mm /
∅
3/4”) it is recommended to install at an angle of 40
o
or greater to provide
optimum protection.
c) The solar collector can still function properly with one or more broken tubes, however a reduction in heat output
will result (depending upon how many tubes are broken). A broken tube should be replaced by authorised persons
only. Please refer to section 8.3 for more details on tube replacement.
3.18. Lightning
It is advisable to earth/ground the copper circulation loop of the collector to avoid lightning related damage, or
electrical safety issues.
Apricus Solar Collector Installation and Operation Manual - International Edition
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2013 – Apricus Solar Co., Ltd A11-01.1.1-PB-V16 Page 8 of 27
