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

[David BRADLEY]

I would recommend using a Type14 forcing function for your convection 
coefficient algorithm. It takes 2 parameters per point; the time at 
which the value occurs, and the value itself.
Kind regards,
  David


On 11/2/2011 14:13, simge andolsun wrote:
> 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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>
>

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
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