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Dear David,
certainly the
modeling assumption that you have described is more detailed of mine.
However I'm using type501ground temperature model; it works satisfactoryly if I assume an amplitude
of the surface temperature function throughout the year (parameter 3) of
8,8°C (disequal to the amplitude of the annual air temperature for the given
location (16,2°C in Palermo); I accept this assumpion only for the
mean surface temperature (parameter 1), in which case TRNSYS reference manual
suggests to use the average annual air temperature
(18,4°C)).
Thaks a
lot
Maurizio
Sorce
Department of
Energy and Environmental Research (DREAM)
Università degli Studi di
Palermo
----- Original Message -----
Sent: Monday, March 08, 2004 7:15
PM
Subject: 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"
****************************************************************************************
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