[TRNSYS-users] Data Reader interpolation question

[David BRADLEY]

George,
  I would think that if you are getting negative values in the 
interpolation of data that is always positive, there might be an 
incorrect setting as to the nature of the data. Type9 asks you to 
specify various things about your data. For example: whether or not 
there is a line of initial values at the beginning of the data file, 
whether the values in your data file are instantaneous values at the end 
of the data interval or whether they are average values over the 
interval, and whether or not you want the values to be interpolated. The 
Type9 "mode" can also have an impact. I often play around with these 
values until the outputs that Type9 are producing (plotted with Type65) 
match up with the data that is going in.

  One "cheap and dirty" fix would be to put Type9's outputs through an 
equation as follows:

posVals = MAX(0.,Type9Output)

but officially, you did not hear me suggest that... :-)

best,
  David


On 12/12/2011 09:54, George Kyriakarakos wrote:
>
> Dearall,
>
> I have some hourly electrical consumption data (unit is kW). I want to 
> do some simulations with low timestep (eg.0.05) in order to check a 
> controllerI have designed. When I try that at some timesteps I get 
> negative values of load, because of big changesin the datafrom one 
> hour to the other. I understand why this happens, but of course I 
> cannot use this. Is there any way using standard types to interpolate 
> data keeping in mind that the result ought to be positive? Of course I 
> can write a new type, but I would rather not go down that road.
>
> Thanks in advance,
>
> George
>
> -------------------------------------------------------------------
>
> George Kyriakarakos, Agricultural Engineer
>
> MSc Energy Systems & Renewable Energy Sources
>
> Agricultural University of Athens,
>
> Dept. of Natural Resources and Agricultural Engineering
>
> Iera odos street, 75, Athens 11855, Greece
>
> Tel. +30.210.5294046 (direct), Fax: +30.210.5294023
>
> Mobile +30.6942.046895
>
> e-mail: <___gk at aua.gr_<mailto:gk at aua.gr>>
>
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>
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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
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d.bradley at tess-inc.com

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