Solar heat works by absorbing the sun's
radiation and converting this to heat energy. The concept of
air movement, called natural convection, is an integral part
of all successful solar heating installations. If a solar
heating system works with natural convection, hot air rising
and cold air falling, then the result in comfort level can
exceed expectations.
Solar heating can be used to heat the
space in your home or to heat the water in your plumbing
system. There are many benefits to incorporating a solar
heating system into your home's design:
- Solar heat is environmentally
friendly.
- Solar heat does not pollute or
produce greenhouse gases.
- Solar heating helps conserve the
earth's energy resources.
- Solar heat is the best choice for
people with allergy problems and chemical sensitivities.
- Solar heating is stable in price.
Once you have bought it, you are protected from inflation
and the political/economic surprises that come with other
fuels.
There are two basic types of solar
heating systems: passive solar heating and active solar
heating.
Passive Solar Heating
A passive solar heating design does not
actually include any sort of mechanical heating device.
Rather, passive solar heating functions by incorporating
building features that absorb heat and then release it slowly
to maintain the temperature within the home. These building
features, often referred to as thermal mass, may include large
windows, stone flooring, and brick walls.
For passive solar energy to be utilized
effectively there must also be a means for the heated air to
circulate throughout the home. The natural circulation of air
is usually enough as long as doors are left open throughout
the home, however, sometimes fans are also incorporated into
the design to facilitate this.
While these may sound like relatively
simple measures, passive solar heating features can reduce
heating bills by almost 50 percent. And, in many cases,
especially if you're working with a builder who is familiar
with the processes of passive solar heating, building a
passive solar home may cost the same as building a
conventional home.
Active Solar Heating
Active solar heating is similar to
passive solar heating, but it is a much more involved process
and generates much more heat than passive systems do. Active
solar heating relies strongly on three components: a solar
collector to absorb the solar energy, a solar storage system,
and a heat transfer system to disperse the heat to the
appropriate places in your home.
Active heating systems can be divided
into two categories: air systems and liquid systems. The
differences in the heating systems are in the way the solar
energy accumulates in the solar collector. Liquid systems use
a liquid to collect the energy in the solar collector; whereas
air systems absorb the energy through the air.
Since solar collectors are normally
installed on the roof of the building being heated, it is best
to place the hot air outlet in the ceiling to shorten the duct
run. A system installed in this manner mixes the air in a
building like a ceiling fan in addition to supplying solar
heat.
The downside of an active solar system
is that the initial installation costs are much higher, since
in most cases you will also need to install a traditional
heating system for the times when the solar heating can't
work–many cloudy days in a row, for example. Active solar
heating systems can be expected to supply between 40 and 80
percent of your home's heating, depending on the size of the
system you have installed as well as the climate where you
live. However, in the long term you will reap the benefits
(and break even) through significant savings on utility bills.
