[TRNSYS-users] building type 56: performance based on time-step

[hotline]

Dear Axel,
 
the reason for this behaviour is the TIMEBASE definition required for
the TRANSFER FUNCTION CALCULATION.
If you decrease the TIMEBASE in the TRNBUILD -> PROJECT - > OUTPUT
window then these steps get away.
But you have to consider that the TIMEBASE has to be 1,2,... times of
the simulation time step and it can be that after changing the value
you get an error message that the coefficients for certain walls
couldn't be generated. Then you'll have to increase the timebase again.
It is always recommended to keep the Timebase as close as possible to
the simulation time step.
Best regards

Christian 

 

TRANSSOLAR Software Team

hotline at transsolar.com

 

www.trnsys.de

Transsolar KlimaEngineering - Technologien für energieeffizientes Bauen
und Nutzerkomfort in Gebäuden                                    

Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart /
Amtsgericht Stuttgart - HRB 23347 / UsSt.-Id: DE152272639

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

 

  _____  

Von: Axel.Oliva at ise.fraunhofer.de [mailto:Axel.Oliva at ise.fraunhofer.de] 
Gesendet: Mittwoch, 20. April 2011 12:27
An: trnsys-users at cae.wisc.edu
Betreff: [TRNSYS-users] building type 56: performance based on time-step


Dear TRNSYS users, 

the building type 56 is used to generate a load profile regarding to a
constant room temperature. I experienced a different behavior of cooling
and heating demand based on the time-step selected. It seems that the
building type is extrapolating its performance within one hour, when
such a smaller time-step is selected - and correction its state, based
on one hour calculations. 

All input values like irradiation on all surfaces contribute as a
continuous function. Details are shown in the attached .pdf file. The
same issue appears in TRNSYS versions of 16 and 17. 

The same issue has already been discussed without detailed answering:
https://mailman.cae.wisc.edu/pipermail/trnsys-users/2008/003893.html 


Tanks for help 
best regards, 

Axel Oliva 
-- 
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Dipl.-Ing. Axel Oliva
Division Solar Thermal and Optics
Fraunhofer Institute for Solar Energy Systems ISE
Heidenhofstrasse 2, 79110 Freiburg, Germany
Phone:+49(0)761/4588-5698 Fax:+49(0)761/4588-9950
axel.oliva at ise.fraunhofer.de
http://www.ise.fraunhofer.de
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