[TRNSYS-users] monthly input for convection coefficients in a 5 year run

simge andolsun simgeandolsun at gmail.com
Wed Nov 2 12:13:46 PDT 2011


Dear TRNSYS users,

I would like to input monthly inside/outside convection coefficients
to a building I modeled in TRNSYS. I am willing to make a 5 year run
to make sure that the slab-on-grade heat transfer converges between
run years. I tried using the Equation tool to input the convection
coefficients and entered the convection coefficients using the
following two ways:

Hi_Floor=2.42*(GE(TIME,0)*LE(TIME,744))+2.32*(GE(TIME,745)*LE(TIME,1416))+2.10*(GE(TIME,1417)*LE(TIME,2160))+1.72*(GE(TIME,2161)*LE(TIME,2880))+0.92*(GE(TIME,2881)*LE(TIME,3624))+2.61*(GE(TIME,3625)*LE(TIME,4344))+2.76*(GE(TIME,4345)*LE(TIME,5088))+1.70*(GE(TIME,5089)*LE(TIME,5832))+1.53*(GE(TIME,5833)*LE(TIME,6552))+1.99*(GE(TIME,6553)*LE(TIME,7296))+2.27*(GE(TIME,7297)*LE(TIME,8016))+2.40*(GE(TIME,8017)*LE(TIME,8760))+2.42*(GT(TIME,8760)*LE(TIME,9504))+…

Hi_Floor=2.42*(GE(TIME,0)*LE(TIME,744))or(GT(TIME,8760)*LE(TIME,9504))or(GT(TIME,17520)*LE(TIME,18264))or(GT(TIME,26280)*LE(TIME,27024))or(GT(TIME,35040)*LE(TIME,35784))+2.32*(GE(TIME,745)*LE(TIME,1416))or(GE(TIME,9505)*LE(TIME,10176))or(GE(TIME,18265)*LE(TIME,18936))or(GE(TIME,27025)*LE(TIME,27696))or(GE(TIME,35785)*LE(TIME,36456))+
...


Both of my trials above ended up giving the same error, which says
"Unmatched parentheses in a function. The TRNSYS processor has found
an unmatched parenthesis (the number of left parentheses does not
equal to the number of right parentheses). This error can be caused by
missing brackets in a [unit, output] expression." I checked the number
of parentheses in the equations I entered and they seemed to be
correct. Then, I ran the same building just for 2 years by limiting
the convection coefficient inputs for two years, and this time TRNSYS
did not report any error and ran without any problem. This made me
think that, may be, the Equation tool has a limit for the number of
parenthesis that can be entered. If so, I will need another method to
enter the monthly convection coefficients into my model to be able to
run it for 5 years. Would you please let me know which other method
can I use for this purpose?

Thanks in advance for your help,
Best regards,
Simge



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