[TRNSYS-users] minmassflowrate

[Marion Hiller]

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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