Active solar
heating
Active solar heating systems are a novel
approach to improving the energy efficiency of your home;
compared to putting photovoltaic cells on the roof, they can be
attractive, and inconspicuous. The basic mechanism of an
active solar system is to put a solar collection surface,
usually of a dark color, with tubes that transfer the heat
transfer fluid to a storage tank. These are called active
systems because any electricity generated is used to move the
heating fluid around the system, where it can do the most
good.
Active solar heating systems are easier to retrofit into a
house, because they use much of the existing infrastructure, or
because they can be part of a remodeling job in the
attic. Important considerations in this style of solar
heating systems are the choice of the working fluid. If
you're using air, the warm air from the system heats up a bed
of rocks or clay pellets, which then re-radiate heat back into
the system after nightfall. Air-driven active solar heating systems are the
most affordable ones on the market, and the simplest ones to
install and maintain; you never have to worry about your
air-pipes freezing and bursting, for example.
Solar
heating with water as the working fluid takes advantage of
the incredible thermal capacity of water as a liquid; water is
one of the most efficient heat transfer systems around, which
is why wet clothes are a risk of hypothermia. Water
requires a pumping mechanism, which air flow systems do not,
but it's also much more efficient per unit volume of heat
transfer fluid.
One of the mechanisms used on active solar heating
sytems to make water run efficiently, and to power the pumps
needed to make them work, is a refrigerant cogeneration system,
or a small photovoltaic system (small photovoltaic systems are
also used to power fans for directing air flow in air driven
systems). The refrigerant will heat up, expand, charge a
compressor, which discharges and moves water through the system
at a faster rate than it circulates. This can also be
used to power an air conditioner, which can be a nice
benefit.
The second major advantage of a water driven system is that
it can completely replace your hot water heater system if you
have a reservoir that's large enough, and you get enough
sunlight. For homes that are built with these systems in
mind from the time the plans are drawn, you can make a
solar water heater
system that runs warm water through hose underneath a sealed
concrete floor, as part of a ground floor heating system,
with the southern facing wall painted a dark color, and used
as the primary collection point from the get go.
Active solar heating solutions are affordable,
environmentally friendly, and a good investment in the resale
value of your home; even if they won't pay for themselves in
the immediate term with reduced utility bills.
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