Two solar technologies compared
Solar Water Heating systems take the power of the sun
and use it to directly heat water. There are broadly
two types of rooftop solar collectors in use in the
UK. These are known as 'flat plate collectors' and 'evacuated
tubes'. Both systems are suitable for installation throughout
most of the United Kingdom, because it is not the outside
temperature, but the sunlight that heats the water.
To help you decide on which of the two systems to adopt,
we have prepared this short introduction.
Rooftop solar water heater differences
Where a south-facing roof is available, a solar collector
can be mounted. The first obvious difference when deciding
on flat plate vs evacuated tubes is the comparative
size of the units. A flat plate system will typically
need to be 30% larger than one containing evacuated
tubes in order to heat an equivalent quantity of water.
However, as the name implies, a flat plate collector
generally has a lower profile than the tubes. Tubes
are also significantly heavier than flat plate collectors.
Knowing whether your roof is structurally up to the
job is an important consideration when deciding on flat
plate vs evacuated tubes.
Comparing the efficiency of flat plate vs evacuated
tubes
Evacuated tube systems are typically more efficient
at heating water (hence they can be smaller as noted
earlier). Flate plate collectors deliver water at lower
temperatures. However this is not always a disadvantage.
Some parts of evacuated tube systems can reach several
hundred degrees centigrade and much of that energy may
dissipate and be wasted if the pipe bore, pump speed
and distance to holding tank are not properly considered.
Oversized evacuated tubes can deliver too much hot water
which is in itself wasteful.
Comparing the cost of flat plate vs evacuated tubes
Flate plate systems are typically cheaper and easier
to install. Ensure your installers do the mathematics
to work out whether short term savings or log term gains
are best for both the environment and your pocket.
The ultimate cost of flat plate vs evacuated tubes
will vary according to the size, position and heat efficiency
of the house itself.
To discuss your solar water heating needs Call us
on 0800 619 1262
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