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In Victoria, on a North facing unshaded roof, it is possible for the sun to
provide up to 89% of a household's hot water needs. In the summer the sun
will produce almost all the hot water you will need. However, in winter
where there is not quite enough heat in the sun and length in the day, it is
necessary to boost the temperature in the cylinder from say 35 degrees up to
60 degrees using Gas, Electricity or Fire.
Orientation
Solar hot water systems work most effectively where the panels are pointing
within 35 degrees of True North (which is approximately 12 degrees west of
what your compass shows). If none of your roof points within 35 degrees of
North then you can orientate the collector panels to North using a frame, or
you can use higher efficiency panels and face them to the West (please note
you may sacrifice part of your government rebate by doing this).
Close-coupled systems
These are systems where the water cylinder is on the roof above the
collector panels so that it is the heat of the sun that causes the heat from
the collector panels to rise and transfer to the water in the cylinder
(horizontal). This is called thermo siphon. There are no moving parts in
these systems, which means there is nothing to go wrong.
Split (or Forced) systems
These are systems where the panels are on your roof and the cylinder
(Vertical) is on the ground. These systems require sensors, a pump and a
controller (to tell the pump when to switch on when the sensor in the
collector panels shows a higher temperature than the sensor in the water
cylinder). These systems are more expensive than close-coupled systems, but
are appropriate where the visual impact of the tank on the roof is a
concern. Highly efficient evacuated tubes are available for this configuration.
Retro-fits
Where a household has a gas hot water service (storage or instantaneous),
which is less than 6 years old, it is often possible to use a solar hot
water system as a pre-heater to your existing water heater, which boosts the
temperature in the winter. In the case of an existing electric water
storage cylinder it is possible to adapt your water cylinder by securing
collector panels to your roof and adding a pump with a controller to convert
it to a solar hot water system
Heat pumps
If you do not have a North facing roof OR your house is in a heritage
overlay area and the front roof points North OR your roof is shaded then a
heat pump may be your best option for using nature's energy. These systems
extract heat energy from the atmosphere and use a (non CFC) refrigerant gas
to heat the water via an evaporator and coil wrapped around the water
cylinder. It works on the same principle as a refrigerator. The
electricity used to drive these systems is 1/4 to 1/3 of the power needed by
conventional electric or gas water heaters and they operate effectively in
all weather conditions.
Rebates
Please visit our page on Rebates to find out what the current options are for
making the switch to solar energy.
Come and see examples of these systems at Insolar's showroom at 441
Flemington Road in North Melbourne
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