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Re: underground structures

Hi Maurizio,
  Certainly the modeling assumption that you have made by connecting your basement to the ground temperature model is a common one. It has two shortcomings, however. First, the energy transferred from the basement has no effect upon the ground temperature of the soil surrounding the basement. Second, the Kasuda correlation, however (on which Type501 is based) provides the ground temperature as a function of depth and time for undisturbed soil when in fact the ground underneath a slab or outside the basement walls has been disturbed. Where the six models that Jeff Thornton developed differ from your assumption is that they define a region of disturbed soil between the basement walls / slab and the undisturbed ground temperature given by the Kasuda correlation. The size of the region is user defined and so may be as large or as small as you like. In this region, the model computes the heat transfer between the basement, the undisturbed ground far away from the building and the surface air conditions. I hope that clarifies a bit.
Cheers,
  David
 

At 03:39 PM 3/5/2004 +0000, you wrote:
Hi Beatriz! Hi David!
 
Probably I don't understand the question... I'm simulating a building with an underground cellar simply using type56 multizone model. In PREBID in fact is possible to define walls with boundary condition; the userdefined temperature of the boundary allows to create an input of type 56 to link with the outputs of type501 ground temperature model (with calculates Tsoil(z,t) according to the ASHRAE). In this way simulation looks like run with good results.
 
Kind regards
 
Maurizio Sorce
Department of Energy and Environmental Research (DREAM)
Università degli Studi di Palermo
----- Original Message -----
From: David Bradley
To: trnsys@xxxxxxxxxxxxxxxxxxx
Sent: Thursday, March 04, 2004 3:23 PM
Subject: Re: underground structures

Beatriz,
  My apologies for delaying so long in answering you. There are a number of ways that you can handle ground coupling in TRNSYS, some built into the program and others as separate models. We developed a set of six ground coupling models to which I think you are referring. In all cases, the models define the slab (or slab and walls in the case of the basement model) and define a 3D volume of soil surrounding the slab. This so called "near field" is divided up into nodes and extends away from and below the slab or basement. Because the user is asked to define the size of the nodes, the near field can be as large or as small as you would like. Beyond the near field is the "far field." The models assume that the far field soil is not affected by heat transfer from the near field but that the near field may be influenced by the conditions in the far field. Essentially the far field is an infinite energy source/sink. The models all perform a 3D conduction problem to balance energy in the near field at each time step.

The six models are broken down into three pairs of models. The first pair of models is for simple slab on grade. The second pair is for slab in grade (soil surrounds the perimeter of the slab) and allows the user to define any number of fluid filled pipes that may travel through the slab or through the surrounding near field. The user also defines the path that the pipes follow. The third pair of models is for basement modeling in which there is not only a slab but also four walls.

Within each pair of models, one is designed to interface with the Type56 building model and one is designed to interface with simplified zone models that do not contain the concept of a boundary wall, which do not perform internal radiation exchange calculations but which do provide the user with a zone air temperature. I will send you a second email with a document that contains the General Description for each of the six models (I don't want to annoy everyone with the document). If anyone else would like a copy, please let me know and I will be happy to send it.

Kind regards,
  David

  

At 11:09 AM 3/2/2004 +0100, you wrote:

Dear TRNSYS users:
 
I am a PhD student at the Bioclimatic Architecture at CIEMAT, Spain. Now I am studying the thermal behaviour of underground wine cellars in Spain and I would like to simulate these buildings in TRNSYS.
 
I have seen that there is a Basement Model (Type 56 Mode) which could be valuable for my research. I would be very grateful if you could send me more information about this module, as well as any other module or information related to earth-sheltered or underground structures.
 
In addition I would be interested in get information about the module: Slab on Grade (Type 56 mode) and (Simple Zone Mode) in order to simulate above ground buildings.
 
Thank you in advance, Beatriz.
 
-----------------------------
Beatriz Porcar Laynez
Bioclimatic Architecture Program
Renewable Energy Department
CIEMAT
mailto: beatriz.porcar@xxxxxxxxx
Phone: (+34) 913466344
---------------------
 
****************************************************************************************
Thermal Energy System Specialists (TESS)
David BRADLEY                           2916 Marketplace Drive - Suite 104
Partner                                        Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley@xxxxxxxxxxxx
Web Pages:  http://www.tess-inc.com    and      http://www.trnsys.com

"Providing software solutions for today's energy engineering projects"
****************************************************************************************

****************************************************************************************
Thermal Energy System Specialists (TESS)
David BRADLEY                           2916 Marketplace Drive - Suite 104
Partner                                        Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley@xxxxxxxxxxxx
Web Pages:  http://www.tess-inc.com     and      http://www.trnsys.com

"Providing software solutions for today's energy engineering projects"
****************************************************************************************