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

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@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@ise.fraunhofer.de [mailto:Axel.Oliva@ise.fraunhofer.de]
Gesendet: Mittwoch, 20. April 2011 12:27
An: trnsys-users@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@ise.fraunhofer.de
http://www.ise.fraunhofer.de
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