[TRNSYS-users] Boundary wall

[Marion Hiller]

Dear Ayman,

 

do you mean the 4th input of Type 56 TSGRD?

 

This temperature input is used for longwave radiation exchange of an
external surfaces with the environment. 

The environment is divided into 2 parts 

- the sky presented by a sky temperature TSKY and the view factor to the
sky FSKY and

- the “non-sky” part called ground presented by a ground temperature
TSGRD and the view factor 1-FSKY.

 

If the building is surrounded by other buildings the walls doesn’t “see”
the ground that much but the other buildings.

In this case TSGRD should represent the surface temperature of the other
buildings.

 

Best,

 

Marion

 

 

 

 

Dipl.-Ing. Marion Hiller 
TRANSSOLAR: KlimaEngineering - Technologien für energieeffizientes Bauen
und Nutzerkomfort in Gebäude 
Munich - New York - Stuttgart + 49.711.67976.0 

Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart 
Amtsgericht Stuttgart - HRB 23347, Steuernummer 99073/00911, USt-IdNr.:
DE152272639

Geschäftsführer: Dipl.Ing. Matthias Schuler, Dipl.Ing. Thomas Auer,
Dipl.Phys. Stefan Holst, Prof. Dipl.-Ing. Bleicher 

 

 

  _____  

Von: Ayman Sarwa [mailto:aymaneldakhl at yahoo.com] 
Gesendet: Samstag, 6. August 2011 12:20
An: David BRADLEY; trnsys-users at cae.wisc.edu
Betreff: Re: [TRNSYS-users] Boundary wall

 

Thanks David 

 

But , what is the importance or function of Tground as an Input in Type
56 ?

 

   ------

   Best Regadrs

   Eng. Ayman  Mohamed

    

  _____  

From: David BRADLEY <d.bradley at tess-inc.com>
To: Ayman Sarwa <aymaneldakhl at yahoo.com>
Cc: "trnsys-users at cae.wisc.edu" <trnsys-users at cae.wisc.edu>
Sent: Friday, August 5, 2011 10:44 PM
Subject: Re: [TRNSYS-users] Boundary wall

Ayman,
  I am not sure that I follow quite what you are doing. If your floor is
defined as a BOUNDARY and the back side temperature is set to identical
then that defines an air temperature on the other side of the floor as
being identical to the air temperature of your zone. You can't then
define the back side temperature as a ground temperature; that would
doubly define the temperature on the other side of the floor. 

Best,
 David

On 8/5/2011 09:50, Ayman Sarwa wrote: 

I am simulating single zone by Trnbuild and Trnsys 17, I define the
floor as boundary and select boundary as identical when I read  the
energy from inside surf. of floor conv.  to air and longwave radiation
to other surfaces = NTYPE19 the QCOMI of floor, and Temp. of inside
floor, I note that, 

for all cases when I define the ground Temp i.e Input of type 56 by type
77 (ground temp ) or by const value , the QCOMI always keeps +ve while T
sur_in < T zone, i.e the energy transfer from air zone to floor  , but
QCOMI  must be -ve, Why ?

Any one can help me to Know what is happen ?

thanks

------

Best Regadrs

Eng. Ayman  Mohamed

 

 
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA
 
P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com
 
http://www.tess-inc.com
http://www.trnsys.com

 


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