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Re: [TRNSYS-users] TRNSYS-users Digest, Vol 96, Issue 29



Martin,
 I am afraid I don't know where you might get that source code. From time to time, users are kind enough to package up components that they have written and we add them to the TRNLib resource online. I am not familiar, though, with the Type177 that you mention.
Kind regards,
 David


On 12/23/2012 05:47, Martin Ssembatya wrote:
Hey David, i saw that there is a Type 177 that was used by IEA - SHC task 25. This model is freely available at www.eta.tu-berlin.de, however the author at this site doesn't give the source code of the model. I realized that one of the four options under this type was specifically developed for Yazaki model WFC 10, the exact chiller model i am simulating. He suggests that we can get the source code from from www.iea-shc-task25.com, but i checked this source and it so happened that source code link is nolonger available since 2009. Could you be having an idea of how i can get this source code??? thanks

Best regards
Martin 

On Wed, Dec 19, 2012 at 8:34 PM, <trnsys-users-request@cae.wisc.edu> wrote:
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Today's Topics:

   1. Re: Yazaki chiller unit model (David BRADLEY)
   2. Re: Defining transparent wall (David BRADLEY)
   3. Re: building simulation (David BRADLEY)


---------- Forwarded message ----------
From: David BRADLEY <d.bradley@tess-inc.com>
To: Martin Ssembatya <mssembatya@gmail.com>
Cc: trnsys-users@cae.wisc.edu
Date: Wed, 19 Dec 2012 11:05:01 -0600
Subject: Re: [TRNSYS-users] Yazaki chiller unit model
Martin,
  I would recommend that you make a very simple project where the chiller is subject to a known constant load with known constant outdoor conditions. Hook up a Type65 online plotter to the chiller and take a look at its performance under these known conditions; once the model looks up the performance data in the data file, its computations are really quite simplistic. You can verify them by hand using the documentation in the 04-Mathematical Reference. This will give you some confidence in your model.

  One of the issues that often occurs in modeling absorption chillers is that if you compute a building load and pass it directly to the chiller then the chiller spends a lot of its time running at a very very low part load. In reality, a chiller can't operate much below 20% capacity so you have to make sure that this is reflected in the data file. The data file should have near zero capacity and near zero fraction of design energy input below about 20% PLR (part load ratio). At one time, I think there was an error in the Type107 example data file that showed too large a capacity at very low PLR. The more correct way to model the system would be to place the chiller on its own primary loop and to place the load on a secondary loop. The loops can be separated by a thermal storage tank whose volume is equal to the volume of the primary and secondary loops. The chiller operates to keep the primary loop cold and the secondary loop draws off only as much as it needs to meet the load.
Kind regards,
 David



On 12/19/2012 01:51, Martin Ssembatya wrote:
Hello there,
 
I have been modelling a solar ooling system that uses one of the YAazaki chiller models. I used type 107 for the modelling of the absorption chiller partly because i did not have satisfactory chiller performance data from the manufacturer to model the chiller unit, but alos because i did not have enough time and compiling language to create my own model for this chiller. But on using type 107 for this purpose, i am not getting satifactory results from my simulation i.e. the chilling energy is always too low compared to the rated capacity of the chiller regardless of the season of the year, including summer periods with high insolation values. Is there any one who could have created a TRNSYS model for any Yazaki absorption chiller unit? If yes, can you kindly help me with that model you created and to use it in my simulation and see its effect on results. I will be very grateful. 
 
Best regards
Martin


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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley@tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com


---------- Forwarded message ----------
From: David BRADLEY <d.bradley@tess-inc.com>
To: Martin Ssembatya <mssembatya@gmail.com>
Cc: trnsys-users@cae.wisc.edu
Date: Wed, 19 Dec 2012 11:14:23 -0600
Subject: Re: [TRNSYS-users] Defining transparent wall
Martin,
  A few years back, I was faced with modeling some greenhouses that were covered by a plastic film. I ended up modeling them as a window in Type56 and worked a lot in LBNL's WINDOW5 software to create a glazing system that represented the plastic film. The process was no different from creating any other new window for TRNBuild/Type56. I wasn't entirely happy with the solution in part because of the diffusion of the incoming solar caused by the plastic. However, it was the best I could do at the time and the results were  defensible. At the time, I also looked for (and found) some models of actual greenhouses that people had developed. None of them suited the project very well but that might be a good avenue to pursue as well.
Kind regards,
 David


On 12/12/2012 02:26, Martin Ssembatya wrote:
Hello there,

I am using TRNSYS 16 to estimate the total cooling requirement of three temporally built structures. One of the structures is a tent whose vertical walls contain like 50 percent plastic transparent parts. How can i create a layer and define it to be transparent to the incoming radiation?? I know that this must be having a huge effect on the total cooling requirement. Can someone please help me with some ideas how this can be done?!

Thanks
Martin


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TRNSYS-users@cae.wisc.edu
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley@tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com


---------- Forwarded message ----------
From: David BRADLEY <d.bradley@tess-inc.com>
To: Matthias Maier <matthiasmaier90@googlemail.com>
Cc: trnsys-users@cae.wisc.edu
Date: Wed, 19 Dec 2012 11:34:53 -0600
Subject: Re: [TRNSYS-users] building simulation
Matthias,
  I think the answer would depend a lot on the complexity of the HVAC systems and on the level of detail to which you would need to model them. The most comprehensive building models that I have done are for LEED projects (proposed building, proposed mechanical system, baseline (comparison) building, baseline (comparison) HVAC system, and lots of report writing). These projects can range from 70 to 200 hours of time with most coming in around 100 to 150. Again, though, that is modeling two buildings. To model just the one proposed building, I think you would probably be in the range of 50 to 150 hours.

  Some other thoughts for you, though (which I realize you didn't request... ;-)   ). Every model, every building simulation tool that is out there is some simplification of a real process. The more assumptions the model developer builds into the model, the simpler the model is to implement but the less flexible it becomes. The fewer assumptions that the developer builds in, the more flexible the tool but the more complexity there is involved with implementing a system model. I have found it helpful to think of building energy modeling tools on a sliding scale where on one end are tools that are relatively quick to use, which have a LOT of built-in assumptions and which are therefore not very flexible. One the other end are tools that are very flexible in terms of what you can model but which are more time consuming to use. TRNSYS is definitely on the "flexible but complex" end of that scale - intentionally so. If you are trying to model a building that has some unusual features (radiant floors, natural ventilation, double skin facades, complex HVAC systems, etc.) in it then TRNSYS is a good tool to use, even though it will require more hours to implement the model. If the building has nothing but conventional envelope and systems then there is no advantage to TRNSYS (or other tools like it); you will spend an unnecessarily long time implementing the model. On the other hand, it may be quick to implement a model in another software but if the building has features that cannot be modeled by the other software, you need to change to another, more comprehensive or flexible tool.

Best,
 David




On 12/12/2012 09:30, Matthias Maier wrote:
Hi TRNSYS-users,

I am studying electrical engineering at the Technical University of Munich and currently I am writing my bachelor´s thesis at the Institute for Energy Economy and Application Technology. My subject is the comparison and assessment of various building simulation programs. Background of this thesis is the development of an automatized demand side management for commercial buildings, in case of the emergence of a dynamic electricity tariff in Germany. Therefor a whole thermal simulation of the building and it´s HVAC systems would be necessary.

One of my tasks is to estimate the costs for the implementation of a building including its HVAC systems. For this reason I selected an example building to estimate the costs for (added in the attachment). Support referred me to this user service. I would be very grateful if anyone could tell me how long it takes to implement this example building including its HVAC to TRNSYS and perform a high-resolution simulation (minute-basis) for a eperienced user. 

Thank you for your attention.

Regards,
Matthias Maier


_______________________________________________
TRNSYS-users mailing list
TRNSYS-users@cae.wisc.edu
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley@tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

_______________________________________________
TRNSYS-users mailing list
TRNSYS-users@cae.wisc.edu
https://mailman.cae.wisc.edu/listinfo/trnsys-users




_______________________________________________
TRNSYS-users mailing list
TRNSYS-users@cae.wisc.edu
https://mailman.cae.wisc.edu/listinfo/trnsys-users

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley@tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com