Solar Water Heaters
Solar water heaters are nothing new. Using the sun
to heat water is something that dates back to the 1800s. What's
new these days is how solar water heaters look and function. Solar
water heaters use panels that are generally installed flat against
the roof of the house and resemble a skylight. The solar water heater
tanks, however, reside elsewhere.
Solar water heaters can drastically reduce utility bills in a
home whether they supply all of the hot water or a portion of it.
There are many things that determine what kinds of solar water
heaters may be needed for a particular residence. The geographic
location where the house is, the design of the heater system, collector
orientation and collector size all need to be considered when selecting
solar water heaters.
A solar water heating system usually has the same components including
a storage tank, a system collector (this absorbs the solar energy),
a back-up energy source (such as gas or electric) and a pump and
controls (if the system is a forced circulation system.)
The two main types of solar water heaters are passive and forced
air. A passive solar water heater system consists of a heater connected
to or lying above the system collector. These can have an integrated
collector storage (ICS) system, also called batch heaters, where
the H2O is stored and heated inside the collector.
These solar water heater systems can only be used in warmer climates
as they cannot stand up to freezing temperatures. The other type
of passive solar water heater system requires the liquid to flow
naturally through the collector to the storage tank as the H2O is
warmed in the collector.
The most common type of solar water heater is a forced circulation
system. This requires a pump and the pump moves the liquid from
the storage tank to the collector.
Most solar collectors are made up of a black copper plate that
has tubes attached to the absorber plates. As the sun's energy falls
on the absorber plate, it is transferred to the H2O in the tubes,
therefore heating it. The absorber plate is covered with a plastic
coating and insulation to prevent any heat from escaping.
Solar water heater systems that are integrated do not have separate
parts but are one unit. These types of systems combine the function
of storage and absorbing the solar energy. Another type of solar
heaters are evacuated tube collectors.
These are more complicated than flat plate collectors but produce
much higher temperatures. These solar water heaters are made up
of multiple tubes that contain a heat pipe. The heat pipe absorbs
the energy and transfers it to the liquid. The tubes are emptied
through a vacuum. This causes for a drastic reduction in heat lost
from H2O.
All types of solar water heaters should come equipped with a back-up
heating system. This is a system that will use gas or electricity
to heat the liquid, in case the solar heating system is out of use
for a period of time.
Because the energy is coming from the sun, utility bills are much
lower in any home fitted with solar water heaters, whatever type
that may be. Initially it is more costly to have solar water heaters
installed but the benefits will be reaped for many, many years to
come. Solar water heaters are used for domestic use, to heat pools
as well as for space heating needs and their popularity is growing
every day.
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