[TRNSYS-users] Heat Exchanger with Constant Effectiveness

[Michel Bernier]

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 at 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 at tess-inc.com
>Web: www.tess-inc.com
>
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