[TRNSYS-users] Ventilation network solver

[Marion Hiller]

Hannes,

 

I had a very quick look at your project only. 

Without knowing the aim of the simulation, your project looks quite
complicated to me because you divided the church into many airnodes. 

Is this really necessary? Do you expect different temperatures for each
airnode? 

 

For thermal modelling I assume that three to four airnodes would be
enough. Using more airnodes increase 

the complexity significant as well as the input and control effort
without necessarily an increase in accuracy.

In addition, I wonder if you really need a detailed distribution model
for direct radiation. I assume that GEOSURF 

yield to a good result. 

 

For evaluating air flow in large volumes you need  CFD rather than a
network flow tool like TRNFlow. 

The resulting stratification really depends on local airstreams raising
/falling and you need a discretisation of the volume. 

I doubt that TRNFlow gives you the exoected result.

In addition, the CFD would be able to show you how many thermal airnodes
are really required. 

 

I really recommend beginning with a simple model. If the simple model
works fine you may become 

more detailed and verify that add adding detail really increases the
accuracy of your model.

 

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: Hannes Oppeel [mailto:hoppeel at hotmail.com] 
Gesendet: Freitag, 20. April 2012 10:24
An: trnsys-users at cae.wisc.edu
Betreff: [TRNSYS-users] Ventilation network solver

 

Hi all

 

I'm having a problem with trnflow in the church I'm currently modeling:
whenever I switch on trnflow I get a range check error.

When I take a look in the listfile it says:

 

 

 ***** WARNING ***** UNIT 14 TYPE 56, TIME =   5.000E+00

 COMIS MESSAGE  ***** ERROR *****   

 Ventilation network solver reached maximum number of Jacobian
factorizations.

 Increase &-PR-CONTrol Miter, or adjust the network.

  

  VENTILATION NETWORK SOLVER REPORTS ERROR

  

 There were too many iterations.

 The maximum allowed (see *CIF &-PR-CONTrol) is:          50

 

Any ideas what the problem could be, or how I can change the maximum
alowed iterations?

 

Please help! It's urgent!

 

Hannes Oppeel


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