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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
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.
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?!
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.