[TRNSYS-users] Changing the role of a standard component

[Diego A. Arias]

Hi Papia,

I just thought of a way of doing this without a Fortran compiler.  You 
can use a Type22-Feedback controller, to find the right input that 
minimizes the error between a set point and a measured signal.  In this 
case, your set point is the heat transfer rate that you want (from 
Type14), and the measured signal is the result from Type91 (actual heat 
transfer rate).  The control signal from Type22 can be used to modulate 
(for our purposes, calculate) the mass flow rate that will yield the 
heat transfer rate that minimizes the error.

I am attaching an example project.  The example is very simple. I do not 
know if in a more complex simulation it may become more difficult to 
follow this strategy.  I will appreciate any comments. 

Best regards,

Diego




David Bradley wrote:
> Papia,
>   Type91 calculates the heat transfer rate across the heat exchanger 
> based on the conditions (temperature and flow rate) at the inlets and 
> on the effectiveness specified by the user. The place you need to 
> start is with the 05-Mathematical Description manual to resolve the 
> equations that Type91 uses so that the heat exchange rate is known and 
> some other variable (outlet temperature of one side of the HX for 
> example) is unknown. As Diego and I mentioned in our previous emails, 
> you would then need a Fortran compiler in order to write a new 
> component for TRNSYS.
> Kind regards,
>  David
>
>
> At 20:32 3/25/2007, papia sultana wrote:
>> Dear Diego,
>> Thanx for your interest.
>> In my problem, I am using 'type 14 h' to read a variable cooling load 
>> (let's
>> say within 0 to 24 hr). Next, I am linking this to a 'type 91' HE 
>> through an
>> appropriate equation 'equa' (needed to convert the unit). For the HE of
>> 'type 91', I would like to link the 'cooling load' in terms of 'heat
>> transfer rate' in the input list. So that new input list could be: heat
>> transfer rate, hot side flow rate, cold side inlet temp, cold side flow
>> rate. The output list may remain same or could cut down one/ two. My 
>> point
>> is, how could I modify the component 'type 91' to cop with variable 
>> load?
>>
>> best regards
>> Papia
>>
>>
>>
>>
>> >From: "Diego A. Arias" <daarias at wisc.edu>
>> >To: papia sultana <papia_s at hotmail.com>
>> >CC: trnsys-users at engr.wisc.edu
>> >Subject: Re: [TRNSYS-users]  Changing the role of a standard component
>> >Date: Fri, 23 Mar 2007 09:35:30 -0500
>> >
>> >Dear Papia,
>> >
>> >Changing a component is more than changing the proforma.  You need to
>> >change the mathematical formulation, which is done in a Fortran 
>> compiler.
>> >If you need to modify a standard component, please feel free to send 
>> me a
>> >more detailed description of what you need and I may be able to help 
>> you.
>> >Best regards,
>> >
>> >Diego
>> >
>> >
>> >papia sultana wrote:
>> >>Dear TRNSYS users,
>> >>
>> >>I have just started to use TRNSYS for centralized cooling system 
>> and I am
>> >>just a novice. I would like to know If I change any of the output 
>> variable
>> >>to an input variable or vice-versa to a component, do I need to 
>> generate
>> >>new component?  If not, I am not able to change any of the variable
>> >>properties from the Proforma dialogue box even after saving the 
>> changes?
>> >>
>> >>btw I will highly appreciate If any body like to share a basic central
>> >>cooling model with me.
>> >>
>> >>Best regards
>> >>Papia
>> >>
>> >>
>> >
>> >
>> >--
>> >Diego A. Arias
>> >TRNSYS Coordinator
>> >Solar Energy Laboratory
>> >University of Wisconsin - Madison
>> >1500 Engineering Drive
>> >Madison, WI 53706
>>
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>
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-- 
Diego A. Arias
TRNSYS Coordinator
Solar Energy Laboratory
University of Wisconsin - Madison
1500 Engineering Drive
Madison, WI 53706
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