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Re: [TRNSYS-users] Energy balance for one zone

Dear Hector,

You can read below the communication between Diego and me about this subject. I hope this helps.

Kind regards,
Christophe.


Dear Diego,
 
Thanks for your help, I appreciate.
I?m afraid there is a mistake in your proposal : I don?t think QSOLGAIN is equal to QTABSI + QTABSO. I?ve done some simulations and compared values of energy_zone.bal with direct outputs : at any time I find that QSOLGAIN = QTSABS (NTYPE 75) and not at all QTABSI + QTABSO. It seems logical for me : QTABSI and QTABSO are total radiation absorbed at all inside/outside surf. of zone (includes solar gains, radiative heat, internal radiative gains and wallgains) (see volume 6, part 2, page 96). It doesn?t correspond to solar gains?don't you agree ?
 
I will adopt your proposal to obtain the energy balance of my building but it is not perfectly satisfying. In my job, more and more projects use dynamic simulation of building. It is very interesting because, thanks to dynamic simulation, we learn a lot of things about thermal behaviour of buildings. But we have to be sure of our simulation results. In thermal simulations, it is always satisfying to verify that energy balance is OK. It is a good indicator of coherence of results. That?s why I think it may be very useful to have access to QTRANS in direct outputs. Don?t you think it can be included in the next version of TRNSYS 16 ?
 
An other suggestion : it may be very useful for TRNSYS Users to have access to scientific papers about studies using TRNSYS (I know there exist a lot of papers about scientific studies using dynamic simulation, especially in solar energy?). Reading these papers can be very reassuring concerning validations of models, useful concerning limits of models, etc.
 
I think many TRNSYS Users don?t have the time to search these kind of papers in the web. Don?t you think it can be possible to have access to these papers or links to site where they can be found, in your SEL Website ?
 
Best regards,
Christophe.

At 17:04 09/11/2005, Diego A. Arias wrote:
Dear Christophe:

The energy balance on a zone is given by:
BAL_ENERGY = -DQAIRdt + QHEAT - QCOOL + QINF + QVENT + QCOUP + QTRANS + QGINT + QWGAIN + QSOLGAIN
BAL_ENERGY should be always 0.

You can get many of these values using the optional outputs (NTYPES):
DQAIRdt --> DQAIR (NTYPE8)
QHEAT --> QHEAT (NTYPE30)
QCOOL--> QCOOL (NTYPE31)
QINF   --> QINF (NTYPE4)
QVENT --> QVENT (NTYPE5)
QCOUP --> QCOUP(NTYPE6)
QGINT -->  QGCONV(NTYPE7) + QGRAD(NTYPE13)
QWGAIN --> QTWG (NTYPE76)
QSOLGAIN --> QTABSI (NTYPE14) + QTABSO(NTYPE15)

The only variable that is not given as an optional output is QTRANS. But, as you have all of the other variables, it can be calculated from the energy balance.
Please let me know if this helps.
Best regards,

Diego


Enertech wrote:

Dear Diego,

Thanks for your solution. Even if it isn't the most cleanest solution, I don't really care. But I think the most simplest solution would be to obtain the same energy balance that in the file energy_zone.bal, with direct outputs (see the second part of my email). I found the equivalent output of QSOLGAIN : this is QTSABS (NTYPE75, see volume 6, part 2, page 98), but I don't know how to obtain the equivalent output (or combination of outputs) of QTRANS. Do you have an idea ?

Kind Regards,

Christophe

At 17:07 08/11/2005, Diego A. Arias wrote:

Dear Christophe:

Unfortunately, the renaming of the output files only occurs in files that have the same file name as the input file.

An alternative could be to take advantage of the possibility that TRNSYS can be run from the command line.  If you type 'TRNExe.exe 
Input.dck', TRNSYS will start and execute the input file Input.dck 
This alternative allows you to run batch files.  For example, you can have in your batch file:

"C:\Program Files\Trnsys16\Exe\TRNExe.exe" "C:\Program Files\Trnsys16\MyProjects\input1.dck" /N
"C:\Program Files\Trnsys16\Exe\TRNExe.exe" "C:\Program Files\Trnsys16\MyProjects\input2.dck" /N

In this case, TRNSYS will start and run input1.dck, close, open again and run input2.dck.  The command /N tells TRNSYS not to display the dialog box at the end of the simulation.

This may not be the cleanest solution, since you will have to create the input files by hand, but I do not know of another way to work out this problem.
Please let me know if you need additional information of how to implement this.
Best regards,

Diego

Enertech wrote:

Dear TRNSYS Users,

In a building simulation study, I want to do a batch simulation by changing automatically several parameters. So, I would like to use TRNEDIT and a parametric table. My problem is that the file I want to use,"Energy_zone.bal", is overwritten at each simulation and that I don't know how to increment this file name.

I know that the output file must have the same name that the *.trd file to be incremented but I don't know how to change the name of energy_zone.bal.
As a solution, I'm trying to recalculate the data contained in the file "energy_zone.bal" with direct outputs of the *.bui file, but I don't know how to calculate QTRANS and QSOLGAIN (see volume 6 part 2, page 103), these variables are not direct outputs.
So, what do you think I should do ?

Thanks a lot for your help.
Christophe
e<At 13:32 24/01/2006, Héctor Montoya wrote:
Hello Trnsys users.

 I'm checking the energy balance in my project, but is impossible to
 get QTRANS as an ouput in  TRNbuild. Is there any possibility to get
 this value? Besides energy balance for one zone equal zero.

 Thanks.

 Héctor Montoya M.
 Alumno de Magíster en Ingeniería Mecánica
 Universidad de Concepción
 Concepción - Chile.

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