[TRNSYS-users] air Density in TRNBuild

Thu Nov 3 01:47:03 PDT 2011

Dear TRNSYS-Users,

if you use Type 56 without TRNflow, a constant value for the air density
is used as written in PROPERTIES.

If you use TRNFLOW, the air density is temperature depended including
the calculated mass flows.

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: Mohamed Ayman [mailto:ayman.mohamed at aalto.fi] 
Gesendet: Mittwoch, 2. November 2011 12:19
An: 王洋; trnsys-users at cae.wisc.edu
Betreff: Re: [TRNSYS-users] air Density in TRNBuild

Hi Wang

The air density changes with temperature in Trnbuild.

Best Regards

Ayman Mohamed

From: trnsys-users-bounces at cae.wisc.edu
[mailto:trnsys-users-bounces at cae.wisc.edu] On Behalf Of ??
Sent: Wednesday, November 02, 2011 1:14 PM
To: trnsys-users at cae.wisc.edu
Subject: [TRNSYS-users] air Density in TRNBuild

Dear all,

    Which experts can tell me a question about air density?

    In TRNbuild  PROPERTIES about air density 1.2 kg/m^3: Is it a
initial value? If outdoor temperature changes in TrnFlow, this air
density value will change as the teperature or it is a constant?

   Thanks!

    wang

2011/11/1 <trnsys-users-request at cae.wisc.edu>

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Today's Topics:

  1. Re: Information (David BRADLEY)

---------- 已转发邮件 ----------
From: David BRADLEY <d.bradley at tess-inc.com>
To: "Adriana Gómez Aldana" <adrigomezaldana at gmail.com>
Date: Tue, 01 Nov 2011 11:35:52 -0500
Subject: Re: [TRNSYS-users] Information

Adriana,
  I had thought that I sent a response about this. In case it did not
get to you, here it is again:

...
  It would help to know a bit more about the configuration of your
system: what are you drying, is the material in a big lump, is it spread
out on shelves, is it moving, does it occupy most of the available space
in the chamber or a comparatively small part of the space, etc.)

  I think you could probably use the Type56 multi-zone building model
for the drying chamber itself. 

  I would guess that you would need to write a new model for the
material that you are drying. If the material is quite spread-out then
this might be easily enough characterized by a first-order differential
equation and you even might be able to use Tess Type693. Type693 is
intended to model a thermal lumped capacitance that heats and cools
according to a first-order differential equation but I imagine that
pricipals are basically the same whether you are talking about thermal
capacitance or moisture capacitance. 

  If the product is not spread out, if important moisture gradients
develop within it as it dries, or if its drying process is exothermic
(like it is for compost) then I think you would need to write your own
model or collaborate with someone who could write the model for you. In
order to write the model you would need to have access to a FORTRAN
compiler such as Intel Visual Fortran v11.x

  Once you have the model of the drying substance, you would connect its
moisture loss to a moisture gain input of the building (drying chamber)
model.

Kind regards,
 David

On 10/30/2011 20:45, Adriana Gómez Aldana wrote: 

Good Morning,

I am a TRNSYS user since it is one of the tools for my phD thesis.
Currently, I am working in a solar drying problem and I would like to
know if there is a special module to simulate the drying chamber. If it
is possible to acquire this module, I would be very thankful if you can
explain me how is the procedure to access it. 

Thanks for your attention,

Adriana Gómez

phD Student - Engineering Department

Universidad de los Andes

Bogotá, Colombia

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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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