Big Green: Geothermal vs geoexchange

[David Cardill]

See below:


----- Original Message ----- 
From: <grahame at bsc-worldwide.com>
To: <biggreen at biggreen.org>
Sent: Tuesday, October 28, 2008 11:05 AM
Subject: Re: Big Green: Geothermal vs geoexchange


> Fellow Big Greeners;
> 
> I have been following the discussion on defining whether the term should
> be geothermal heat pumps, ground source heat pumps or geo-exchange heat
> pumps.
> 
> My concern is whether there should be any of these heat pumps,
> particularly when we are discussing sustainable solutions.  There have
> been geo-exchange heat pump systems in Pennsylvania since the 1960's and
> today they are being installed in PA as if they are a relatively new
> technology.
> 
> This is proof positive that the geothermal heat pump consortium has done a
> stellar job of marketing geothermal heat pumps as a great system to
> install.  They should be made an honorary member of K Street in DC.
> 
> The problem is water-to-air geothermal heat pumps, as most people have
> been discussing, have three strikes against them:
> 
> 1. They make a building move toward being an all-electric building when we
> need to move in the opposite direction for a sustainable building,
> minimizing the electric use.

What do you mean by opposite to electric? Eletric has an opposite?
Rather than electrically driven heating systems, what do we have for an
alternative? What are you suggesting we use then? Don't say something is no 
good, without offering us an alternative.

 
> 2. Water to air heat pump units, as most people are discussing, tend to
> have a geo-exchange water loop piped around the building and standard air
> conditioning style heat pump units fed from the poorly designed water
> loop.  There is refrigerant in each heat pump unit so there is refrigerant
> all around the building.  The heat pump units are often inside the
> building in a corridor or false ceiling, often next to an occupied room of
> children when installed in schools.  This is not an environmentally
> sensitive solution for most people or parents, even if the refrigerant is
> the new, more non-toxic formula.

Who designed the water loop? And, why was it poorly designed?
... and no, the refrigerant never leaves the unit. We average 2.6
refrigerators per household in this country, and I don't remember you
ever saying anything about that. And, for decades now, all refrigerants 
have been non-toxic. Where do you get your information? Are you fear 
mongering here?
And, what air conditioning systems have you ever used on a building?
Your website says that you do whole building designs and maintenance of
electrical/mechanical systems, and I find it impossible to believe that
you haven't worked with existing air sourced heat pumps all the time.
(conventional air conditioning)
Existing air sourced heat pumps typically have 3-4 times the 
refrigerant charge that the compact geo ones do, AND, they are 
plumbed into the building, AND, they loose their charge more often
than geo systems do, because unlike a geo system, your conventional
air conditioning system has half of itself mounted outside.
 
> 3.  The terminal heat pump units tend to be all-air systems that put the
> building mechanical system into dead-end position.  The system will need
> to be totally replaced by a sustainable system at a later date and at a
> greater cost for the owner.

Define what you mean by a sustainable system. Air systems are the
greatest to have in buildings. They allow for filtration, and air changes. 
And, again, what is this sustainable system you keep referencing  ???

 
> If a building has a plan to move toward a sustainable future, it will not
> include geo-anything heat pumps.

OK, well do not just slam a system without offering a suitable
replacement.
What is it that you do that is more sustainable than a geo system?
Answer the question please.

 
> While geo-exchange water provides an excellent source of cooling and
> warming when connected to more innovative and sustainable mechanical
> systems, heat pumps are a tried and tested system that has proved to be a
> poor solution.

Can we see some of these test results? Who tried it? Where and when have
they ever been proven to be a poor solution? There are millions of them
installed already, and in every case, the owners love them. If you have
data that shows otherwise, can we see it?

 
> Grahame E. Maisey, P.E.
> Chief Engineer
> 
> Building Services Consultants, Inc.
> Total Quality Commissioning and Energy Master Planning
> POBox 176
> Wyncote, PA 19095
> T: 215.886.6464  F:215.886.1804
> www.bsc-worldwide.com
> 
> 
> 
David Cardill
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