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Re: Special Controller


Working on a solar hot water system, I have the project to manage the back-up use according to some external & evolutive conditions (solar irradiation, load profile of the last days & hours, atmospheric pressure...). A special algorithm (fuzzy logic) will be used with several equations, using values from the inputs (instantenous and older), to preventively start & stop the back up. I would like to know whether a good idea is to model this controller with TRNSYS 15 using the TYPE 66 and the EES solver or to use any other way such as the "Delayed inputs controller" (taken from HVAC library (TESS)) ???

Jeff Thornton asnwered your message on the Bldg-Sim list. Here is his reply:

> While you could use the TRNSYS/EES connection and/or the TESS delayed
> input controller, I would strongly recommend that you write your own
> component to model your fuzzy controller.  It's easy to add your own
> models to TRNSYS and in this way the controller does EXACTLY what you
> need it to do. You could pass in the solar radiation, load profile,
> atmospheric pressure, and store any values you need from previous
> timesteps for your algorithm.  Refer to the source code of relevant
> components for hints and ideas on your model.
> Good luck,
> Jeff

I completely agree with Jeff that writing your own component will give you much more flexibility than trying to combine equations with existing Types.
Concerning the use of Type 66 and EES, please keep in mind that it will slow down your simulation. This is usually only justified if you take advantage of advanced EES capabilities (e.g. solver or thermodynamic properties).
If you need complex fuzzy logic algorithms and you are a Matlab user, you could also use the Matlab connection Type (available on the TRNSYS website). The same warning applies, though: it will make your simulation slower than a "pure" Fortran Type.
If you go for the Fortran Type, you could start from Type 93 (input value recall) so you don't have to "re-invent" the part that stores the input values at previous timestep(s).

Kind regards,

Michaël Kummert

-- _________________________________________________________

Michaël Kummert

Solar Energy Laboratory - University of Wisconsin-Madison
1303 Engr Res Bldg, 1500 Engineering Drive
Madison, WI 53706

Tel: +1 (608) 263-1589
Fax: +1 (608) 262-8464
E-mail: kummert@xxxxxxxxxxxxx

SEL Web Site: http://sel.me.wisc.edu
TRNSYS Web Site: http://sel.me.wisc.edu/trnsys