Re: [TRNSYS-users] Heat Exchanger with Constant Effectiveness

[Michel Bernier <michel.bernier@polymtl.ca>]

Hi,

Jeff is right. You shouldn't be using a regular heat exchanger
model to model a canadian well. The DST model is also
excellent to model vertical ground heat exchangers.
However, I don't think it will help you as most
often canadian wells are placed horizontally and form
so called "earth-tubes".  If that is the case then
you may want to look at the air-to-soil heat exchanger
(type 460) from TRANSSOLAR.

Hope this helps,

Michel

***************************************
Michel Bernier ing., Ph.D.
Professeur
Departement de genie mecanique
Ecole Polytechnique de Montreal
Case Postale 6079, Succ. "Centre-Ville"
Montreal, Quebec Canada
H3C 3A7
Tél: (514) 340-4711 ext: 4381
Fax: (514) 340-5917
e-mail:michel.bernier@polymtl.ca
***************************************

At 01:47 PM 11/06/2008, Jeff Thornton wrote:
> <I want simulate a building (type 56)Â  refreshes by a Canadian well in
> using Heat Exchanger. If we used Heat Exchanger with Constant
> Effectiveness (type 91) like heat exchanger in the soil. The type 91
> requires to fix the value of each flow fluid, or the soil is not a fluid
> which poses a problem. why we can resolved this problem? NB: I don't have
> TESS library i have just standard library.>
>
> Trying to model a ground heat exchanger in anything other than a model
> dedicated to ground heat exchange will very likely fail.  Using Type 91
> will not work as it does not account for the capacitance of the soil and
> long-term heat build up affects - which can be significant.  The ground
> heat exchanger model in the TESS libraries (DST from University of Lund
> Sweden) is an excellent model and has been calibrated (with great results)
> against several long and short-term data sets.  My strong recommendation
> is to purchase the DST model from a TRNSYS distributor and not try and
> "trick the system" by using a lesser model.
>
> Jeff
>
>
> Jeff Thornton
> President - TESS, LLC
>
> 2916 Marketplace Drive - Suite 104
> Madison WI 53719 USA
>
> Phone: 608-274-2577
> Fax: 608-278-1475
> E-mail: thornton@tess-inc.com
> Web: www.tess-inc.com
>
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