Solar
panels usually are of two broad-based types – Solar
panels with photovoltaic cells that generate electricity
and those that are used for heating. We are here to
discuss the latter type which have several sub-groups
that all cater to heating water. With a view to heating
water using solar energy, a collector is attached to the
roof of a building or on a wall facing the sun. The
working fluid is either driven by natural convection as
in a case of ‘passive system’ or is pumped into it as in
an ‘active system’.
Also,
the collector could be made of glass-topped insulated
box with a flat solar absorber made of sheet metal
attached to copper tubing and painted black or a set of
metal tubes set within a near vacuum
container.
An
‘active system’ solar water heating arrangement would
pump cold water onto a collector to be heated that flows
back to the collection tank for use later on. This type
of collector provides enough hot water for an entire
family for several years.
Sometimes,
heat is stored in a hot water tank whose volume must be
larger with solar
heating
system to allow excess for inclement weather conditions
as also for the simple reason that the optimum
temperature for the absorber is always lower than a
typical immersion heater or a combination
heater.
Here
are a few types of solar heating
panels
1)
Evacuated-tube
solar water heating panels are recommended for cold
climates. They have parallel rows of transparent glass
tubing, each provided with outer tube and a metal
absorber tube attached to fins or a set of metal tubes
surrounded by an evacuated (near vacuum) glass cylinder.
Often before the solar energy is absorbed, a parabolic
mirror is put into use to concentrate rays of the sun on
the tube.
2)
Integral
collector-storage solar water heating panels are good
for locations where the weather is moderate to warm.
These include several black-painted tanks or tubes
within insulated and glazed box. Here the water
initially passes through the solar collectors in the
solar panel that pre-heats the water. It is then allowed
to pass into the conventional backup water heater, thus
providing a good source of hot water. The progressive
Tube passive system, incidentally, is the most cost
efficient water heater.
3)
Unglazed
collector panels are ideal for pools and are suggested
for locations that have above-freezing climates. Instead
of glass (glazed) coverings, these are usually made of
heavy-duty PVC or rubber treated with UV protecting
material to extend the life of the panel. Unglazed
collectors are more cost effective than glazed
ones.
Home
solar panels or commercial solar panels, there are many
advantages of both. You can save on your electricity
bills and this is eco-friendly as well. But before you
can go solar you need to know a few things – where to
set up a system, how to install it, how to wire it,
where to get parts and batteries from cheaply, and
finally the safety precautions.
