Understanding Active Solar Heating
Active solar heating relies on mechanical devices to carry out
the steps of collecting, storing and moving the sun’s heat throughout
a home. Solar collectors absorb and collect the sun’s radiation
and heat pumps, exchangers and fans transfer and circulate the
heat that’s been collected and converted. Such a system typically
incorporates storage tanks to ensure there’s plenty of heat available
during times when the sun doesn’t shine.
When it comes to active solar heating systems, there are two
basic types and they are so named because of the medium used for
heat absorption. One is a liquid active solar heating system and
the other is an air system. Liquid is the more common of the two.
Understanding how active solar heating works
It all starts when sunlight falls on an active solar heating
collector such as a rooftop collector. A rooftop collector resembles
a glass-covered box with dark-colored plates made from metal inside.
These dark metal plates absorb the sun and convert it into heat.
The heat that’s been converted is then used to heat air or water
(depending on the system) as it flows through the collector. Pumps
or fans and a series of pipes or ducts move warmed air or water
throughout the home’s interior.
Intricate controls ensure the active solar heating system continuously
maintains the desired interior temperature. Sensors, signals and
a thermostat are constantly at work monitoring and evaluating
different aspects of the system. When the temperature in the collectors
and the storage unit vary by a certain amount, pumps or fans for
circulating heat are called into duty.
A liquid active solar heating system consists of hydronic collectors,
pumps, pipes, controls, a heat exchanger and a large tank for
storage. Storage tanks can either be located in a basement or
outside. Besides water, some liquid systems use antifreeze or
methyl alcohol to keep water from freezing.
An air active solar heating system includes collectors, ducts,
fans, and controls. This type of system stores heat in bins made
from rock that can be located underneath, outside, or inside the
home.
US
DOE on Active Solar Heating
Bob
Vilas on Active Solar Heating
Active solar heating points to consider
Besides the obvious benefits of using a renewable and clean energy
source, an active solar heating system can be designed to heat
just a few rooms rather than the entire house. Doing so is less
expensive because design and installation are simpler. But such
a set-up typically doesn’t incorporate a storage unit therefore
it’s primarily used only for heating during the day.
Although active solar heating is capable of producing quite a
bit of heat, it still isn’t always capable of meeting 100% of
a home’s heating needs. If you’re considering active solar heating
for your home, you may need a back-up heating system. Note that
there are some municipalities in which a back-up is required by
law.
So before going any further with plans to incorporate active
solar heating, it makes sense to consult with an expert to determine:
which is better, air or water active solar heating; new or retrofit
requirements; and costs versus potential savings.
