[TRNSYS-users] minmassflowrate

Marion Hiller hiller at transsolar.com
Thu Jun 21 00:14:22 PDT 2012


 

Michael,

 

The min. mass flow rate calcualted by TRNbuild may differ from the
calculated during the simulation

If there it switches from turblent to laminar flow. However, this isn’t
your problem.

 

I had a quick look at your file

When I open your file  b17 I get an error message for surface 15 (the
one with active layer): 

 



 

 

The adjacent surface numbers of surface 12 and 15 are wrong!!

 

ZONE Z02

RADIATIONMODE

 BEAM=STANDARD : DIFFUSE=STANDARD : LONGWAVE=STANDARD : GEOMODE=MANUAL

AIRNODE Z02

WALL  =IW01       : SURF= 11 : AREA=     40.66 : INTERNAL

WALL  =ID01       : SURF= 12 : AREA=     44.87 : ADJACENT=Z02 :
ADJ_SURF=5 : FRONT : INTEMP = INPUT 1*Z02_TABS_TETA_SW : MFLOW = INPUT
1*Z02_TABS_MASSFLOW : NLOOP = 6 : MFLOWMIN = 15

WALL  =ID02       : SURF= 13 : AREA=      5.09 : BOUNDARY=IDENTICAL

WALL  =ID03       : SURF= 14 : AREA=     12.69 : BOUNDARY=0

WALL  =ID01       : SURF= 15 : AREA=     44.87 : ADJACENT=Z02 :
ADJ_SURF=1 : BACK : INTEMP = INPUT 1*Z02_TABS_TETA_SW : MFLOW = INPUT
1*Z02_TABS_MASSFLOW : NLOOP = 6 : MFLOWMIN = 15

WALL  =ID05       : SURF= 16 : AREA=     12.69 : BOUNDARY=IDENTICAL

 

I assume you edit the file manually. 

If I delete the wrong ADJ_SURF, and I reopen it TRNbuild it assigns the
the correct numbers.

 

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 

 

 

 

-----Ursprüngliche Nachricht-----
Von: Michael Döbele [mailto:michael.doebele at hochschule-bc.de] 
Gesendet: Montag, 18. Juni 2012 23:25
An: trnsys-users at engr.wisc.edu
Betreff: [TRNSYS-users] minmassflowrate

 

Dear TRNSSYS User,

 

i am trying to run an active layer with an specific massflow rate of 15 

kg/h m² (absolute value 654.15 kg/h). TRNBuild calculates a minimum 

allowed massflow rate of 10.25 kg/h. (446 kg/h) ....so far so good.

But when I set this massflow rate in TRNSYS Studio via Input to the 

wanted 654.15 kg/h  I get following error

 

"specific fluid mass flow of active layer in surface 2 below minimum

value of16.26/m2h, increase the minimum mass flow rate or use

autosegmentation feature of TRNBuild for subdividing the surface."

 

This is a really strange behavior. The massflow criteria varies and 

seems to depend on the inlet temperature.. I also tried autosegmentation


- I didn´t help, I got the same error message.

Please help me out here..

 

Thank you

 

Michael Döbele

 

 


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