Natural
Energy SystemsNatural
Energy SystemsWhat size will the panels be?
We will size your collector according to your hot water requirements but as
a general guideline for a household of up to 4 people a recommended minimum
would be 4 sq.metres of high efficiency flat plate collector or 3 sq.metres
(30 tubes) of evacuated heat pipe collector. A general rule is to allow 1 sq.metre
per person per 50 litres (or 10 galls.) of stored water; with an added 1sq.metre
per extra person for larger households.
For commercial installations we will calculate collector size according to design
temperature, hot water usage and storage capacity required.
Where will the panels be positioned?
In an ideal world your panels should face South at an inclination of approximately
45° from the horizontal. You are usually governed however by the pitch of
your existing roof so it is comforting to know that BS 5918(1989) states that
for a collector facing anywhere between SE & SW and tilted from the horizontal
between 5° and 60° the annual solar energy supplied will be at least
90% of the optimum amount. Panels may also be fixed to a flat roof or wall,
for which we can supply suitable frames. More important is ensuring that panels
are not overshadowed by trees or other buildings etc. particularly at midday
as this can significantly lower performance.
How does it work?
The collector heats the solar storage cylinder (either twin coil or preheat)
by means of a pump operated by a temperature differential controller. When there
is sufficient heat to be gained either by direct radiation (approx. 40%) or
more usually diffused radiation (approx. 60%) then the controller will switch
on the pump transferring the heat (hot water) from the collector/manifold to
the solar storage cylinder. When the temperature of the collector and store
are approximately equal the pump will switch off allowing the collector to re-heat
before repeating the cycle. The system is fully automatic in operation and virtually
maintenance free, requiring only a change of antifreeze at 5 yearly intervals.
Boiling is prevented by careful sizing of the collector area - to storage cylinder
ratio and freezing is prevented by the addition of a non toxic antifreeze/corrosion
proofer mix to the collector system water. Systems are usually based upon a
design temperature of 60°C. and comply with BS 5918(1989).
Where will the solar hot water cylinder be positioned?
Wherever possible we will install a foam lagged, twin coil, indirect, copper
solar cylinder to replace your existing hot water cylinder with minor modifications
to the pipework to enable your existing boiler to operate as normal on the top
coil while the bottom coil is connected to the solar collector giving a preheat
facility all year round with the full cylinder capacity available as a solar
store when the weather is favourable. This system generally gives increased
solar store capacity and eliminates potential problems with siting a second,
separate solar preheat cylinder, installing a valve (usually motorised) to give
direct sun-to-tap hot water and, if the preheat cylinder is located in the loft
having to raise the cold water storage cistern. However should a separate preheat
cylinder be required due to lack of airing cupboard space etc. then it will
be situated as close as reasonably possible to the existing cylinder. The work
involved in changing your existing cylinder for the solar twin coil cylinder
is basically straightforward.
How much will I save?
A correctly designed and installed solar system will realistically provide 50%-65%
of your annual hot water requirements. The subsequent cash savings together
with the long life and minimal running costs will, in most cases, more than
justify the investment in a solar hot water system.
How long will it last?
With a life expectancy of 20 years plus for an evacuated heat pipe collector
and 30 years for a flat plate collector, once installed, with tried and tested
materials, which are in everyday use in the heating trade, your investment in
a solar system should be more than repaid before the system is halfway through
its useful life.
How long will it take to install?
Your solar system will usually be installed in approximately 4 days and will
cause minimal disruption to your house. Most of the inside work takes place
in the loft and even if your hot water cylinder is changed this is generally
completed in one day to ensure you are not inconvenienced any more than absolutely
necessary.
Finally, what guarantee do I have?
Because we use only first class solar collectors and tried and tested products
which are well established in the heating and plumbing trade all materials and
labour supplied by us are guaranteed for a period of FIVE YEARS from the date
of completion of installation.