Novasun 150L Instruction & Installation Manual - page 15
Copyright © 2014
Ikhwezi Solar (Pty) Ltd, Novatherm CC, Solar Assist (Pty) Ltd
14
Once you get used to the system and its
optimum performance pattern, you may
eventually completely switch the electrical
backup off, particularly in summer months.
An additional benefit of this is that it is the
fastest way to reduce the system’s payback
period.
Savings can be further maximised by using
hot water in the evening rather than in the
morning, maximising the free energy
harvested during the day.
Additional tips to enhance savings include:
To further optimise energy and hot water
savings, install aerated shower heads and
aerators in taps to reduce hot water
consumption.
Insulate hot water piping to minimise heat
losses.
Showering generally uses less water than
bathing.
For health reasons your hot water system
should provide water at 55ºC, but not much
warmer than that. Do not set your
thermostat backup temperature control for
temperatures in excess of this.
If shading of collectors is experienced
between 9am and 3pm then corrective
action should be taken. Annually prune or
cut trees that shade the system.
Partial shading by chimneys, TV antennas,
roof erected fixtures, etc. on buildings
during these hours is acceptable provided
that it does not exceed 10% of the area.
Shading from newly erected buildings
should be checked and if system
performance is affected, relocation of the
system may be necessary.
13.3
Over-night temperature stabilisation
Over-night temperature stabilisation is the
reduction in water temperature, as the hot
water at the top of the storage cylinder
transfers some of its heat to the cooler
water in the lower section of the cylinder.
This effect is often perceived as heat loss,
but is actually the redistribution of stored
heat more evenly over the entire contents
of the storage tank. This may make it
necessary to use the electric element to
raise the water in the top section of the
cylinder back to an acceptable temperature.
Over-night temperature stabilisation is most
evident in the morning if the time clock is
left off overnight.
13.4
High water temperature
Your solar water heater will generate hot
water quickly and efficiently. Under normal
family use, it will operate between 60ºC
and 70ºC. However, the temperature can
exceed this and under certain
circumstances may be as high as 75ºC. This
can occur during prolonged periods of
direct sunlight and particularly in summer
or long periods of reduced water usage.
Extreme care should be taken in these
circumstances.
Although every system is fitted with a
mixing valve that regulates temperature at
points of water use, check the water
temperature before use, such as when
entering a shower or filling a bath or basin,
to ensure it is suitable for the application
and will not cause scalding. It is required by
SANS regulations, that a temperature
limiting device / mixing valve be fitted to
the system. This will limit the water
temperature to 50°C at the point of use.
The risk of scalding will be reduced, but
water should always be tested prior to use
to prevent injury in the case of a tempering
valve failure.
13.5
Periods of reduced usage or holidays