[TRNSYS-users] Exterior wall against ground

Mon Apr 16 04:56:47 PDT 2007

Thanks a lot for your help!

Mit freundlichen Grüssen / Kind regards 

Daniel Büchele
Dipl. Ing. Gebäudeklimatik- / Technik 
Projektleiter  

Helbling Holding AG
Hohlstrasse 614
CH-8048 Zürich
Telefon +41 44 438 18 64
Mobile  +41 79 641 44 03
Telefax +41 44 438 18 10
mailto:daniel.buechele at helbling.ch <http://www.helbling.ch <http://www.helbling.ch/> > 

________________________________

Von: David Bradley [mailto:bradley at tess-inc.com] 
Gesendet: Freitag, 13. April 2007 20:09
An: aa1 at brighton.ac.uk; Büchele Daniel (Helbling Beratung + Bauplanung); trnsys-users at engr.wisc.edu
Betreff: RE: [TRNSYS-users] Exterior wall against ground

Abdullahi,
  You are correct that you should integrate with respect to depth and calcuate the average. There is no simple way to do that directly in Type77/501 at the moment. It is an interesting idea for future versions. As a simple alternative, you can use the Kasuda depth for the middle of the below grade section of the wall although it is not quite as correct.
Cheers,
 David

At 12:27 4/13/2007, aa1 at brighton.ac.uk wrote:

	David/Daniel,

	My only concern with the use of Kasuda correlation (in the form used in type 77 &Type 501) for vertical surfaces like a basement wall, is the fact that these components will only give the soil temperature at a single vertical point (say depth Z,Z1,Z2 .....at any given time). If your wall is very deep, say 1-2m deep, what you need is probably the average temperature of a vertical profile ranging between depth Z1 and Z2. 

	The way to go about this is to integrate the Kasuda expression with respect to depth (Z1 to Z2). My question to David is whether this is achievable with Type77/501? If not perhaps Daniel might want to look at the following document on how to integrate the Labs/kasuda correlations. 

	Labs, K. 1989. Earth Coupling. Passive Cooling. J. Cook. Cambridge Massachusetts, The MIT Press: 197-346.

	Abdullahi

	School of the Environment
	University of Brighton
	Cockcroft Building
	Lewes Rd.
	Brighton
	BN2 4GJ

	Tel: +44 01273 643455

	-----Original Message-----
	From: David Bradley [ mailto:bradley at tess-inc.com <mailto:bradley at tess-inc.com> ] 
	Sent: 13 April 2007 17:38
	To: Büchele Daniel (Helbling Beratung + Bauplanung); trnsys-users at engr.wisc.edu
	Subject: Re: [TRNSYS-users] Exterior wall against ground

	Daniel,
	  Arie's response is quite correct. Additionally, if you do not want to use the annual ambient temperature as your boundary wall temperature, you can use the temperature of undisturbed ground as calculated by the Kasuda correlation from Type77. This makes the ground temperature a function of depth and time of year. Like with Arie's response, it assumes that the ground is an infinite source / sink and that energy transferred from the building through the wall to the ground does not affect the ground temperature in the long term. We have written a few basement models recently that do account for the change in the ground temperature due to energy transfer through the wall but they assume four basement walls and a floor. If you only have one wall below grade then you might be best off using Arie's method either with the annual average ground temperature or with Type77.
	Cheers,
	 David

	At 12:48 4/12/2007, Helbling Beratung + Bauplanung wrote:

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	Hello everybody 

	Can anyone, tell me whats the best way to simulate a external wall against the ground. 
	How can I define the ground ?? 

	Thanks in advance 

	Mit freundlichen Grüssen / Kind regards 

	Daniel Büchele
	Dipl. Ing. Gebäudeklimatik- / Technik 
	Projektleiter 

	Helbling Holding AG
	Hohlstrasse 614
	CH-8048 Zürich
	Telefon +41 44 438 18 64
	Mobile  +41 79 641 44 03
	Telefax +41 44 438 18 10
	mailto:daniel.buechele at helbling.ch < http://www.helbling.ch <http://www.helbling.ch/>  > 

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Thermal Energy System Specialists (TESS), LLC 
David BRADLEY                           2916 Marketplace Drive - Suite 104 
Partner                                        Madison, WI 53719 
Phone: (608) 274-2577 USA 
Fax: (608) 278-1475 
E-mail: bradley at tess-inc.com 
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