Solar
thermal differs from solar PV in that instead of producing electricity,
we are producing hot water. Our two panel solar package is a great
supplement for domestic hot water needs. Additional panels can be
added to supplement a hot water heating system such as radiant or
hydro air. The two main types of solar thermal systems on the market
are drain back systems and glycol systems. These two systems produce
about the same amount of hot water, they are just applied to different
applications.
We recently installed the largest solar thermal installation on
the island. Twenty 4x8’ solar hot water panels were installed
at a private residence to heat the pool, produce domestic hot water,
and supplement the radiant heating system. We expect this system
will produce approximately 93,000,000 BTUs per year.
There is a $2,000.00 tax credit for the installation of solar hot
water panels. We have the necessary MA plumbing licenses to install
a solar hot water system in accordance with local authorities and
our products are SRCC rated; this is necessary to receive the above
mentioned tax credit. |
| Drain back systems
only fill the solar panels when there is enough solar energy to
produce hot water. This benefits the system in two ways. First,
the system will not freeze and become damaged in cold weather. Second,
a big concern of solar hot water systems is over production in the
summer. If you do not use the hot water that is produced (such as
during a vacation in the summer) you will produce an enormous amount
of hot water at super hot temperatures. This can set off safety
valves and damage the system. A drain back system eliminates these
problems by draining the collectors if the temperature of the stored
hot water rises above a safe level. |
Glycol systems protect
themselves from freezing through the use of food grade propylene
glycol. glycol systems work well, but overproduction of hot water
will break down the glycol and make this product corrosive. Overproduction
is handled in two ways. Some solar panel manufacturers have louvers
on the panels that open to create air flow when the glycol gets
too hot. The second way that glycol panels protect themselves is
through the control system. Control packages are available that
will trend production and predict when the system will overheat.
The system will then run at night to cool down the glycol by radiating
solar energy from the collectors back into the atmosphere. |
