From: kyleh@oakhill.sps.mot.com (Kyle Harper)
Subject: Re: Ground-source Heat Pumps
Organization: Motorola Inc., Austin, Texas
Date: Wed, 6 Jan 1993 17:20:11 GMT

captain@tigger.cc.utexas.edu (Bran Muffin) writes:

>Kyle Harper (kyleh@oakhill.sps.mot.com) wrote:
>: We are about to build a house and have been researching the idea of installing
>: a ground source (aka, "water-source", or "water-to-air") heat pump system. I
>: am interested in opinions and feedback from anyone who has used them,
>: particularly in the central Texas area. Specific interest is the following:
>: 
>: 1) *Actual* energy savings as compared with conventional heat pumps and gas
>: 	(please include square footage, insulation values, etc., if possible) 
>: 2) Recommendations (or warnings) of specific heat pump manufacturers and 
>: 	installers
>: 3) Opinions, testimonials, disappointments, do's and dont's, flames
>: 


>I used to live in Houston, and we had just such a system.  It was really 
>flakey, and the horrifying thing about it is that when the freon leaks
>out, it doesn't just go up & kill some ozone, it goes into the GROUNDWATER!
>It may not kill you, but it will find its way into someone's well water,
>or even Barton Springs! and that's not good.  

That's a very good point.
Hmmm, I'm not sure what type of system you had in Houston; perhaps they have
improved on the system design since then ...
The type of ground source heat pump we are hearing about has NO freon running
outside the central air enclosure unit in the closet/attic. (In fact,
there is no compressor outside the house.) There is a pipe "loop" that leaves
this unit, is buried in the ground for the specified length and depth for the
size of the house, and returns to the unit.  In this loop circulates a water and
*non-toxic, environmentally safe* antifreeze solution that serves as the heat
exchange medium with the ground.  This is a closed loop system that does not
have direct contact with ground or surface (i.e., drinking) water. There is no
Freon in the loop. However, there is the usual risk of freon leaking out
of the unit in the closet/attic (same as any other air conditioning system).
Actually, there is probably less chance of damage and a freon leak than in a
conventional air conditioner compressor system; there is no compressor
unit outside the house, hence less stress on the freon lines due to exposure to
extreme weather.
One thing I have noticed is that every manufacturer we've talked with repeatedly
mentions their "25 year warranty" on the ground loop plumbing and the fact that
they do not use environmentally toxic solutions in the loop. Perhaps at one
time they had problems with ground loop plumbing integrity and/or toxic
chemical leaks, and have since changed the designs.

>Check into some of the modern AC units, and read all of the home builder's
>magazines you can get your hands on.  There are some very effecient units
>out there that pose less of an environment risk than a groundwater system.
>Good luck!

>|The opinions expressed above are merely the result of chaotic synapse firings|
>|Electrics and electronics work on smoke. If you let the smoke       -   O    |
>|out, they stop working.   --   Fight AIDS.  Play safe.                |      |
>|captain@ccwf.cc.utexas.edu  (Brian Murfin)  DoD# 0690  nt650gt     \_^___/   |

-- 
Kyle Harper
Motorola, Inc.
Austin, Texas
inet address: kyleh@oakhill.sps.mot.com
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