Re: [TRNSYS-users] Type164a : Compressed Gas Reservoir

[David BRADLEY <d.bradley@tess-inc.com>]

Ghady

  The initial pressure issue is one that was fixed in later TRNSYS versions. Once you modify the FORTRAN then yes, you have to rebuild the TRNdll.dll. the FORTRAN code is just a set of text files. These are read, processed and turned into a DLL by the FORTRAN compiler. Only the DLL is accessed when TRNSYS actually runs.

  Instructions for how to rebuild the TRNDll are contained in the 07-Programmer's Guide (in the ..\TrnsysXX\Documentation folder)

  There is no restriction in the code that limits the tank volume to 1m3. A change to the proforma should be sufficient. Once you modify the proforma and save the changes, however, your changes will not be reflected in your project until you select the Type164 in your project, right click on it and select "replace" from the context menu. Find the modified proforma in the proforma directory and the new limit will take effect. As a side note, I am not clear what you mean when you "it does not work." Are you getting an error when you run the simulation or are you still unable to enter a value less than 1m3.

kind regards,

 David

On 04/13/2018 07:12, Ghady Dib via TRNSYS-users wrote:

Hello,

I am modeling a 2 stages of air compressors with 2 compressed air reservoirs (Type164). And I have two questions regarding:

1)      Initial pressure of the Reservoir (Type164):

If we double click on type 164, we have access to the parameters, inputs and outputs. In my project, I want to fix the pressure of the reservoir (Pgas) to 1 bar. So I fixed PMAX=50bar (Para (2)) and PLEV_INI=0.02 (Input (4)) in order to P_INI = PLEV_INI*PMAX*1E5 equals 1 bar.

When I run the project, and I plot the result, I have at t=0 PGAS equals to zero (Pression.out).

It’s a bit confusing to initialize the pressure because there is a way_1 to fix P_ini (described above) and another way_2 to set initial output values (in my case, PGAS is OUT(2)). To be on safe side I put in the FORTRAN code (!set initial output value) OUT(2)=P_INI (And even with this, it does not work). So what way to take in order to initialize the pressure? Way 1 or 2 or both?

 

If I modify the FORTRAN (in order to set the initial output values), should I regenerate the Type164? And then rebuild new library? Or no need (just save)? If yes can you tell me step by step the process to rebuild the library, because I did it once not correctly (rebuild the library) and I damaged all the other types.

 

 

2)      Volume of the Reservoir (Type164):

By default the minimum volume of the reservoir is 1 m³. In order to change the interval (min, max) of the volume I did the following steps:

Right click on the type à Proforma à Variables à change the min for parameter 3 (VOL). Then click OK and close the Proforma after saving the changes. By this, the Type 164 is changed in the library also.

Problem: It does not work with the modified reservoir. In fact I repeated the same project [compressor and a reservoir (VOL=1 m³), where the system worked]. So I guess the steps to change the VOL interval are not correct.

Thank you for help

--

Ghady DIB

Doctorant

Laboratoire CETHIL UMR 5008
Groupe Energétique des Systèmes Thermiques et Frigorifiques (ESTF)

Département Génie Energétique et Environnement

INSA Lyon
France

Tel:+ (33) 6 33 52 96 74

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David BRADLEY
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Thermal Energy Systems Specialists, LLC
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