[TRNSYS-users] Energy balance for one zone

Wed Feb 1 03:26:43 PST 2006

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.
>
>_______________________________________________
>TRNSYS-users mailing list
>TRNSYS-users at engr.wisc.edu
>https://www.cae.wisc.edu/mailman/listinfo/trnsys-users

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