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How your solar hot water
system works
Depending on your system configuration, solar energy is
collected by either one to three flat panel collectors or
one to three evacuated tube collectors and used to heat
water inside the collector. This water (when hot enough) is
circulated using a pump inside a solar controller which is
fixed to the storage tank located on the ground. If there is
solar gain, the solar controller will circulate water from inside
the storage tank, through the collector(s) and back to the
tank. Depending on your system, the storage tank capacity
may be 270L, 340L or 450L.
Your solar hot water system is also boosted by one of
two methods of heating (depending on your system
configuration) to ensure it delivers hot water all year round
and also to kill any bacteria (including Legionella) originating
in your water supply. The two methods of boosting your
solar hot water system are as follows:
Electric boosted
If your system is electric boosted, your storage tank will
have an electric element inside it that will ensure the water
inside your tank is at least 60°C when power is available to
the element. If the water temperature inside the tank is kept
above this level by the solar collector(s) then the element
will not need to operate. The boosting element may be
connected to a continuous or an off peak power supply. It
is designed to be installed on extended off peak which is
available up to 18 hours of the day compared to the standard
off peak available only 8 hours. If standard off peak is
supplied to the premises, it is recommended to contact your
electrical supplier and get it changed to extended off peak
to ensure the correct performance of the hot water system.
Gas boosted
If your system is gas boosted, a gas continuous flow water
heater will be installed on the outlet piping of the storage
tank. The gas continuous flow water heater monitors the
temperature of the water (when passing through it) and if it
is less than 55°C, will start up and boost the temperature of
the water to an acceptable level using the minimum amount
of gas required. If however the temperature of the water
passing through the unit is above 55°C, it will not need
to operate, minimising your gas consumption. For more
detailed information about the gas continuous flow water
heater please see the user manual supplied with it.
Solar availability and limitations
Since the collector takes its energy directly from the sun,
it is limited by the weather conditions and the amount of
solar radiation available. During winter months the hours of
sunlight are shorter and the sun is lower in the sky, the further
you are from the equator the greater this effect will be. What
this means is that the solar radiation produced by the sun
during the day will not last as long or hit the collectors at the
optimum angle and as such their efficiency will be reduced.
The recommended direction for the collector panels to face
is true north (in the southern hemisphere) however this may
not be possible in all situations due to the availability of roof
space or the exact direction in which the roof faces. Facing
the collector panels in a direction other than true north will
reduce their efficiency.
The amount of solar radiation that the collectors receive may
also be reduced by cloud cover or pollution in your area.
Freeze protection
The solar collectors and pump controller system have been
approved to level two frost protection and can therefore
withstand frosty conditions.
The anti-freeze protection system works by circulating
warmer water from the tank through the collectors when it
detects the collector is at risk of freezing. This protection
is built into the software of the solar controller and as such
there is no need for monitoring or intervention. However,
power will need to be applied to the solar hot water system
at all times in order for the anti-freeze protection system to
operate. If the system is to be without power for an extended
period of time and frost damage conditions are possible,
please drain the entire solar hot water system of water to
prevent damage.
If your system is gas boosted, please see the user manual
supplied with the gas continuous flow unit for its own level
of frost protection and methods of draining during frosty
conditions.
Solar controller operation
The primary task of the solar controller is to control
the operation of the circulating water pump in order to
optimise solar energy collection. This function is performed
by measuring the temperature difference between the
collectors and the storage tank. When the temperature
difference exceeds 10°C the pump is activated and water
circulates from inside the storage tank, through the collectors
and back to the tank.
The secondary task of the solar controller is to stop solar
energy collection when the tank is already full of hot water.
This is referred to as no-load protection and the pump will
not operate if the temperature of the water going to the
collectors exceeds 72°C. At such a temperature in the base
of the storage tank, the water temperature at the top of the
tank is expected to be even higher.
The third task of the solar controller is to prevent water
inside your solar hot water system from freezing during frosty
conditions and damaging the components. This operation
works by circulating warm water from your storage tank to
the collectors and back to your tank. It is important to ensure
that power is always available to the solar controller in order
for the freeze protection operation to occur.
During these entire operations the green LED marked
"SOLAR" will remain on, indicating that the solar controller is
operating correctly.
The temperature settings for the solar hot water system are
factory pre-set to ensure optimum energy efficiency whilst
providing Legionella bacteria protection. The temperature
settings are therefore not adjustable by the customer
or installer.
Kelvinator solar hot water systems how your solar hot water system works 7
SOLAR
ATTENTION
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