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Posted by Ed on August 21, 2006, 5:19 am
 
Nick,

Thanks for the clarifications.

Ed

nicksanspam@ece.villanova.edu wrote:


Posted by SJC on August 17, 2006, 6:22 pm
 
It seems to me that they did not have propane furnaces nor heat pumps in 1891
either.
So it sounds like the constraints are what is visible. Now you need to determine
what
amount of visibility is acceptable and start from there.



Posted by Paul M. Eldridge on August 17, 2006, 9:47 pm
 While I hesitate to mention this in alt.solar.thermal, would a ground
source heat pump be another option to consider?  That way, *all* of
the equipment would be hidden out-of-view.  I'm not sure how the
initial costs would compare, but the operating costs would be modest
compared to propane and lower than those of the existing air-source
heat pump and, again, no outside propane tank(s), compressor or solar
panels/storage tank to compromise the appearance of the home.

Cheers,
Paul



either.

determine what


Posted by Ed on August 18, 2006, 4:26 am
 Paul M. Eldridge wrote:

I'm glad you brought up the idea of ground source heat pumps (GSHP).  I
have very seriously considered that approach, but have hesitated
because of the experience a friend had with his GSHP system.  About six
years ago my friend built a new log home and installed a geothermal
GSHP unit.  He used vertical boreholes and at first the system seemed
to work correctly.  The first winter caused him a lot of trouble.  The
system would not generate enough heat for his new home and the unit
frequently kicked in the desuperheater (heat strip maybe) and drove his
electric bill quite high.  He also had some serious problems with pipe
leakage in the boreholes and at the central control unit.  In short, he
was not happy.  As I recall he paid more than double what a
conventional system would have cost.  He wasn't getting the payback he
expected.

The pasture behind my house is an ideal location for GSHP lines.  I
could easily run 500' - 2000' of line in that pasture.  I'd probably
have to use trenches instead of vertical boreholes because Lovingston
Granite starts at about 8' down.  Also, where the lines would be
located is very close to the water table of an intermittent mountain
stream that is located about 200' beyond where the boreholes would be
drilled.  I'd probably be better off laying the lines on top of the
granite.

I think a GSHP retrofit using the existing ductwork would be fairly
easy and I've even considered a dual-fuel approach for both heat and
A/C. My reluctance is based on the unreliable experience of the GSHP
system that my friend had installed.  And, the work on his system was
done by pros.  Of course that was six years ago and most likely the
technology of GSHP units has improved since then.

I know that GSHP units are quiet. I could not hear the unit running in
my friend's house.  My present heat pump is a typical American Standard
unit that is about five years old.  In February, my wife refers to it
as a "cold pump."

At the moment I don't have enough data together on the solar
panels/tank thermal approach to compare to a GSHP approach.  My guess
at this point is that a GSHP retrofit would probably cost me about
$2,000 - $5,000. Excavation and trenching work would be simple,
because between myself and my neighbors we have enough backhoes, track
hoes, and dozers to do the job.  We'd just do what the GSHP contractor
needed done in terms of digging and moving dirt. If the GSHP system
would operate satisfactorily, I could justify the cost against rising
propane and electricity costs over 10 ten years. I know that some GSHP
units now have long warranties. On the other hand if the GSHP unit
required constant use of a desuperheater in the winter I would be
displeased.

I haven't prepared a budget yet for the solar panels/tank system, in
part because I have been unable to accurately size the system to meet
our hot water and heat demands.  But, my gut instincts and experience
suggest to me that I could probably install the system for about half
the cost of a GSHP system.  Operating costs of the solar panels/tanks
would be almost nil.  In essence it would also be a dual-fuel approach.
It should certainly lower by a large amount, future propane purchases.
Also, if 20% of my electricity costs are for creating hot water, then
that cost would almost disappear.  My recollection is that GSHP units
are also able to generate domestic hot water.  In fact, my friends
system was suppose to do that too, but at best it could only do a
limited amount of preheat.


Posted by Paul M. Eldridge on August 18, 2006, 5:51 am
 Hi Ed,

I'm really sorry to hear of your friend's poor experience (sadly, I've
heard of similar stories before). If I were to spend that kind of
money, needless to say, I would expect it to work properly.  I suspect
there were folks who jumped into this field without the knowledge and
hands-on experience required to do the job right.  Unfortunately, your
friend may very well have stumbled across one them; I don't know.

As with any major purchase, you must do your due diligence and proceed
carefully.  Read all of the available literature you can find so that
you'll know the right questions to ask and, just as importantly, all
the right answers.  It sounds like you're already *well* ahead of the
curve in this regard.

Interview contractors who work in your area and who are familiar with
your soil and its thermal conductivity.  Ask for several references
and follow up each one.  You're entrusting this individual with a
large sum of cash, so there must be good communication, a mutual sense
of trust and respect and complete confidence in their professional
abilities.  Examine each quote carefully to ensure there are no
unaccounted for costs nor any hidden surprises.

When properly designed and installed correctly, it's my understanding
these systems work exceedingly well and customer satisfaction is
extraordinary high.  If you do decide to go this route, I hope you can
find a contractor who is fully capable of the task and who will treat
you with honesty and respect.

Good luck with this project and with all your renovations.  It sounds
like your home is in very good hands.

Best regards,
Paul




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