Kenneth wrote:
On Sat, 08 Dec 2007 09:22:52 -0600, dpb
wrote:

Kenneth wrote:
...

So, on the days with setback, the mean KWH/DD was 1.06. On
the days with no setback, that mean was 1.36.

The resulting savings are approximately 22%.

I do remain baffled by the reasons the geothermal folks
(installers, designers, sellers) seem to be consistent in
suggesting that such setbacks are not of value.
As at least one other poster noted, they're concerned w/ other factors
that aren't applicable in your case (primarily dominated by the use of
resistance electric heat in many/most systems)...

There are others including the potential freezeup, etc., that are
possible but imo they're mostly cya kinds of responses. Did you try the
Water Furnace people directly or contact the Okla State or some of the
other resources for other input?

Howdy,

The CYA analysis makes sense to me, but as you probably
know, there is no real "freeze up" danger at all. These
systems simply turn themselves off is the incoming water is
too cold.

The problem I've normally seen is on the once-through water exchange
systems (which is also what I think I recall being mentioned in one of
the earlier postings of a problem--whether it was yours or another I
don't recall) is the freezeup of the outlet when systems aren't running.
My opinion remains as I noted there is that if that's a problem for a
given system, it will be so whether there's a setback or not unless the
system is so undersized as to run continuously; hence my assessment of
that as a response as being in the "CYA" category.

Also, as you may know "Water Furnace" is a brand name. Our
equipment is ClimateMaster.

Yes, I had thought that was who you had said earlier...I don't know
ClimateMaster; had a Water Furnace system earlier and was pretty
impressed w/ their factory rep service/technical support.

I have communicated about all this at some length with the
ClimateMaster folks, with the geo folks from my electric
utility, and with the installer of the equipment. They all
have said "no setback" is best.

I think again all of those folks are addressing the general case still
rather than the specifics of a given installation and are still using
the answer that is easiest for them. It would be interesting if could
get to one of the actual research facilities that might address a
specific system rather than the general consumer response. If you were
still interested in pursuing it from that standpoint I'd again suggest
ORNL, TVA R&D (not power) or OSU might be more likely to answer a real
question.

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