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More
Info on Solar and Radiant Heating:
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Please
note that the answers given are abbreviated in order to be
"short and to the point". The answers are meant to provide a starting
point towards further understanding. Further research into these
questions is encouraged, or feel free to call CCE. Some books may be
referenced elsewhere in this webpage for further information.
What's all of this hype about "radiant floor" heat?
Radiant panel heating refers generally to heat tubing (PEX) laid down
in a poured concrete/gypcrete floor, usually during new construction.
Since the entire floor surface is the "heating element", your feet feel
very comfortable, which makes the rest of you feel good! Also, much
lower temperature water can be used to heat the home, which offers two
further advantages: It works wonderfully with solar heat systems, and
it takes advantage of the high efficiency provided by the newer, more
efficient modulating/condensing boilers, by operating them in their low
temperature (most efficient) range.
I am renovating the house. I'd like to upgrade to
radiant
heating, but I don't want to redo my floor to add radiant. What are my
options?
These are a few options to consider:
1. You can add a radiant ceiling (pex stapled to ceiling and covered
with gypsum wallboard.
2. You can create a radiant wall panel (pex under wallboard).
3. European-style panel radiators - these are attractive, low profile
radiators that perform well and look great (see pix in "System
Portfolio" link above).
Will I need a boiler in
the house to provide backup heat in case the
sun doesn't shine?
In almost all cases, yes. Typically, a modulating/condensing boiler is
used for backup. When heat in the solar storage tank is depleted, the
radiant (typically) system will automatically switch over to the boiler
to provide the balance of floor heat necessary to satisfy the home
heating load. The modulating/condensing boiler will only come on when
the sun can't keep up with the load (mostly in December/January, and
decreasing in the "skirt" winter months). Generally, from March thru
early October, most of the heat (home heat and domestic hot water) will
be provided by the solar system. When it is called upon, the mod/con
boiler, which is designed to operate in it's "sweet spot" for
efficiency, will use much less fuel than a typical "traditional"
boiler.
How reliable are the new mod/con boilers?
Initially, when they came out over ten years ago, they had some
problems, but those "early adoption" problems have been eliminated by
the manufacturers. Mod/con boilers have become the mainstay of modern
hydronic heating systems, are a mature and very reliable product. They
have many more programming features than the older generation of
boilers. These features provide additional efficiency improvements in
addition to their inherently higher burner efficiency. Daily
temperature offsets, outdoor, room, and slab temperature sensors, smart
circulator controls, etc., ensure significant fuel and electricity
savings. Since these boilers are more sopisticated, they should be
periodically checked by a trained technician to ensure that they are
operating in an optimal state. Checks are recommended every one, two or
three years. If desired, the homeowner can perform the simpler checks
(system pressure, observing system temperatures, checking some system
parameters) using the LCD readout, thus cutting down on the need for
technician servicing.
My heating system not only uses a lot of fuel, but my
electric bills are also high. How can I cut down on electricity usage
on the heating system?
The largest electricity users on a heating system are the various
circulators used to move the heating fluid around to where it's needed.
A typical heating system in our area runs for about 3500 (+ or-) hours
per year. Assuming that you have two circulators running, and they use
an average of 200W, that translates to 700kW hrs of electricity.
Assuming 10 cents/kW hr, that's $75/yr, just for running the
circulators. The newer style ECM circulators, recently introduced from
Europe, and used by CCE, use much less power for the same flow rate.
Replacing the older circulators with ECM style circulators, the same
calculation would be 20W x 3500hrs = 75kW hrs => $7.50/year, which
is one tenth the electricity charge when compared to the older
circulator style that is used most commonly in today's hydronic
systems! Many systems in larger homes have even more circulators, and
therefore the elctricity usage is even higher than used in the above
example.
Should I use glycol in my heating system pipes?
The answer to this question depends on how well insulated the house is
in the area where heating system pipes are located. If there is little
chance of freezing, then it's much better NOT to run glycol for the
following reasons:
1. Glycol is more viscous, and requires more power from the system
circulators. This translates to larger circulators, and higher
electrical usage.
2. Water is the most efficient heat transfer substance. Using glycol
drops heat transfer efficiency by about 10% (so you have to pump the
fluid thru the system a little harder, adding that much more to
electricity usage).
3. Any fluid losses in the system need to be replaced with a glycol
mixture, which requires a bit more complexity (glycol makeup system or
site visit by a heating tech). A pure water based system can have a
simpler water makeup valve to make up for such losses.
Despite the above caveats, glycol is needed as an insurance against
freezing in many situations. Consult a heating expert when trying to
decide! |