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There are a number of examples of coupling Modelica with building
simulation, also MatLab with building simulation:<br>
<a href="http://www.seas.upenn.edu/~cis800/software.html" eudora="autourl">
http://www.seas.upenn.edu/~cis800/software.html<br><br>
<br>
</a>At 07:15 AM 10/03/2012, Per Sahlin wrote:<br>
<blockquote type=cite class=cite cite="">Content-Language: en-US<br>
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boundary="_000_E7DE1359657DA948A14588A22C4C7D9701A24ED534DAEQSRVSBS01E_"<br>
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Hi Pavel,<br>
<br>
It is difficult to explain these things in totally concrete terms. It has
to do with simulation model scalability, portability, abstraction and
ease-of-use.<br>
<br>
Both Simulink and Modelica tools offer ways of describing and simulating
the behavior of a wide class of dynamical systems. This allows you to
tailor exactly the equations you want to use, for example in the way you
outline below. This total freedom is often needed in building simulation
problems, since the number of different component models needed for
various studies is for all practical purposes infinite. No tool with a
fixed set of models will ever be sufficient.<br>
<br>
Now, a full-fledged building zone model like that of E+, or our tool IDA
ICE, will not require 2-3 equations, but rather on the order of a
thousand variables per zone. A fair number of these represent things that
are meaningful to observe directly, such as the temperature of the third
layer of a particular wall and others are just help variables that are
needed to compute for example a sliding average. If you then want to
model a thousand zone building, you get by all standards a fairly complex
and large system of ordinary differential and algebraic equations (DAEs)
to solve. This is where the scalability comes in; not all approaches will
be able to handle this size of problem.<br>
<br>
When you have this many equations to keep track of, no single person or
even team will have the required expertise about each type of process
that needs modelling. Portability and abstraction becomes needed. If you
can specialize in a particular field, such as advanced heat pump
modelling, and then package your models in a way that will plug
right into relevant neighboring models and in a variety of tools, many
people can use them without knowing each detail. This is the ultimate
purpose of Modelica and FMI.<br>
<br>
A building simulation model must also be possible to set up and operate
by a person that knows absolutely nothing about Modelica, DAEs and
variable timestep solvers. Therefore, it must also be possible to package
these equation-based models in a way that, on the surface, looks much the
same as traditional BEM tools – the ease-of-use.<br>
<br>
I hope this was of some help. If you are interested to learn more about
these things, browse the conference proceedings available on
<a href="https://www.modelica.org/publications">
https://www.modelica.org/publications</a> , where you can see how
Modelica has been applied in many different domains.<br>
<br>
Best regards,<br>
<br>
Per<br>
<br>
<br>
<br>
<br>
<b>From:</b> pdybskiy@gmail.com
[<a href="mailto:pdybskiy@gmail.com" eudora="autourl">
mailto:pdybskiy@gmail.com</a>] <b>On Behalf Of </b>Pavel Dybskiy<br>
<b>Sent:</b> den 9 mars 2012 12:57<br>
<b>To:</b> Per Sahlin<br>
<b>Cc:</b> bldg-sim@lists.onebuilding.org<br>
<b>Subject:</b> Re: [Bldg-sim] A critical juncture for Modelica/FMI next
week<br>
<br>
Per,<br>
<br>
It is impressive ... but it sounds too abstract to me to
digest. <br>
Can you help me to think about FMI in terms of a BEM (building energy
modeling) task.<br>
<br>
For example:<br>
1) There is a system of ODEs (2 o3 equations), which represents a
simple (say 3R2C or 3R3C) thermal network (TN), which in turn models a
thermal zone. <br>
<br>
2) There is another set of equations and inequalities that specifies HVAC
system.<br>
<br>
3) There is a given weather file (temps, radiation, etc) which provides
some set of time series variables (1hour sample time) for those
ODEs.<br>
<br>
4) There are 2-3-4 schedule files, which specifies other sets of
variables/parameters ( 1hour - 1day - 1month sample time ) for
those thermal zones and HVAC. <br>
<br>
Today I am using Matlab/Simulink to simulate this (1-4) problem.<br>
<br>
In case if I need more complex building and HVAC models I may think about
BCVTB(LBNL) (people already do this) to co-simulate various combinations
of E+ and Matlab models.<br>
<br>
What role and how can FMI/FMU play in such a game? <br>
<br>
Thank you<br>
<br>
Pavel<br>
<br>
<br>
On Fri, Mar 9, 2012 at 5:30 AM, Per Sahlin
<<a href="mailto:per.sahlin@equa.se">per.sahlin@equa.se</a>>
wrote:<br>
Dear all,<br>
<br>
There is a meeting of the FMI
(<a href="http://www.functional-mockup-interface.org">
www.functional-mockup-interface.org</a>) design group Monday and Tuesday
next week where most likely the level of ambition of FMI 2.0 will be
settled. Different application areas have different needs and priorities
and I think it would be wise to provide some input from the building
simulation community to this meeting. Let me first give some
background.<br>
<br>
The ultimate purpose of equation based simulation and Modelica
(<a href="http://www.modelica.org">www.modelica.org</a>) is to enable
model exchange between users and tools. However, the Modelica language is
by necessity a very complex and rapidly evolving “beast.” It is
essentially impossible to keep tools in good sync with each other in
their interpretation of Modelica. In practice, this means that porting
complex model libraries, such as the MSL Fluid and Media libraries and
derivatives, from one tool to another often involves man years of work,
if possible at all. This is where FMI comes in. FMI provides a means to
exchange pre-compiled model units and this can be radically simpler than
to achieve a common understanding and interpretation of the underlying
Modelica code. FMI 1.0 has proven this since a number of years. However,
for our application FMI 1.0 is severely limited.<br>
<br>
There are three key areas where FMI 2.0 has previously been planned to be
enhanced in ways that in my opinion are essential to the building
simulation community:<br>
<br><br>
- Introduction of
physical connectors (now only direct variable-to-variable connections are
supported)<br><br>
- Support for
arrays, the size of which is determined by parameters that can be changed
after compilation (only scalars in FMI 1.0)<br><br>
- Support for
sparse analytical Jacobians<br>
<br>
In the building simulation world of multiple-port tanks and zones, where
many components are built around discretized PDE:s, FMI without
these features is unlikely to become very useful. At the same time the
FMI design group is facing some seriously conflicting goals:<br>
<br><br>
- FMI must not be
too rapidly evolving – otherwise much of the purpose is lost<br><br>
- The standard must
not be too complex for vendors to support<br><br>
- There is an
urgent need to upgrade v. 1.0 to something more powerful<br>
<br>
Therefore, there is a distinct risk that some of the planned enhancements
of 2.0 are postponed. For reasons of stability, it could take a very long
time before the next major release.<br><br>
<br><br>
If you share my concern about these issues, please write a few lines to
underline why we need these features to me. I will compile for the
FMI design committee.<br><br>
<br><br>
Best regards,<br><br>
<br><br>
Per Sahlin<br><br>
<br>
<br>
-----------------------------------------<br>
Per Sahlin<br>
EQUA Simulation AB <br>
<a href="mailto:per.sahlin@equa.se">per.sahlin@equa.se</a> <br>
<a href="tel:%2B46%C2%A0%C2%A0%208%20546%2020%20111">+46 8
546 20 111</a><br>
<a href="tel:%2B46%2070%20422%2003%2002">+46 70 422 03 02</a>
(mobile)<br>
<a href="tel:%2B46%C2%A0%C2%A0%208%20546%2020%20101">+46 8
546 20 101</a> (fax)<br>
plurresahlin (skype)<br>
Råsundavägen 100<br>
169 57 SOLNA, Sweden<br>
<a href="http://www.equa.se">http://www.equa.se</a>
<br>
-----------------------------------------<br>
<br>
<br><br>
<br>
<br>
<b>Subject:</b> Re: teleconference about IEA proposal
"Modelica-based next-generation tools for new and existing buildings
and communities"<br>
<br>
All,<br>
<br>
Thanks to those who contributed to today's conference call. Attached
please find the meeting minutes. Please let me know any important
omissions or corrections.<br>
<br>
As discussed, I also added a google doc where each of you can add your
interest in participation and in leading a particular subtask. There is
also a column in which you can specify your funding situation for the
respective work, and a column in which you can add demonstration objects
that could be included in the revised proposal. The link to this
spreadsheet is<br>
<a href="https://docs.google.com/spreadsheet/ccc?key=0AnSvCGCOHhzXdHBOSDRuLXJOd2tvSlBzUXBHaU93NVE">
https://docs.google.com/spreadsheet/ccc?key=0AnSvCGCOHhzXdHBOSDRuLXJOd2tvSlBzUXBHaU93NVE</a>
<br>
Anyone with the link can edit and view the document. So don't add
sensitive information or proprietary information. You are free to share
this document, as well as the proposal, at<br>
<a href="https://docs.google.com/a/lbl.gov/document/d/1ia1jyXrvf1jUynN_1-3QBx0quYdXlOdYgPTacpE6lLU/edit?hl=en_US&pli=1">
https://docs.google.com/a/lbl.gov/document/d/1ia1jyXrvf1jUynN_1-3QBx0quYdXlOdYgPTacpE6lLU/edit?hl=en_US&pli=1</a>
<br>
with your ExCo delegate and/or your potential funding agency.<br><br>
Depending on how many people work on the respective subtasks, some
subtasks might be combined in future revision. For now I kept the
structure that resulted from the Sydney meeting.<br>
<br>
All the best,<br>
<br>
Michael<br>
On Thu, Feb 2, 2012 at 3:16 PM, Michael Wetter
<<a href="mailto:mwetter@lbl.gov">mwetter@lbl.gov</a>> wrote:<br>
All,<br>
<br>
We would like to schedule a teleconference with those of you who are
interested in participating in the IEA proposal "Modelica-based
next-generation tools for new and existing buildings and
communities" that was discussed in Sydney last November.<br>
<br>
To schedule the call, please respond by Wednesday February 8 to the poll
at
<a href="http://www.doodle.com/c5fvhz5uuzuq7ykr">
http://www.doodle.com/c5fvhz5uuzuq7ykr</a>. <br>
If you like to be removed from future emails, please respond to me.<br>
<br>
The proposal is at
<a href="https://docs.google.com/a/lbl.gov/document/d/1ia1jyXrvf1jUynN_1-3QBx0quYdXlOdYgPTacpE6lLU/edit?hl=en_US&pli=1">
https://docs.google.com/a/lbl.gov/document/d/1ia1jyXrvf1jUynN_1-3QBx0quYdXlOdYgPTacpE6lLU/edit?hl=en_US&pli=1</a>
and attached to this email. This version addresses the feedback from the
Sydney meeting, as well as feedback received from the Fraunhofer
Institute in Kassel.<br>
<br>
The items to be discussed at the phone call are below. <br>
<ol>
<li><b>Outline of next steps.</b>
<li>Proposal due April 16, presentation to IEA ExCo meeting on June 14.
<li>If approved, there will be a 1 year planning period (we will check
whether this can be accelerated), followed by 3 years of research and 1
year of reporting.
<li><b>Expression of interest of research groups to work on the proposed
research.</b>
<li>Individual research groups should express what tasks they like to
contribute to, and are likely to get funded from their respective
country.
<li><b>Indication of subtask leaders.</b>
<li>Note: Subtask leaders need <u>not</u> be finalized by June, but an
indication of what country will lead what task is recommended. The
subtask leaders can be finalized during the planning period.
<li>Subtask leaders need a minimum commitment of 3 months/year.
<li><b>Inform your ExCo delegate.</b>
<li>The ExCo delegates will need to verbally confirm at the June meeting
that funding will be available in their country and that the proposal is
in the interest of their country. For the proposal to be accepted, around
five (minimum 3) countries need to commit to participate. It therefore is
essential that you discuss the proposal and your interest to participate
with your ExCo delegate prior to the June meeting. See
<a href="http://www.ecbcs.org/contacts.htm">
http://www.ecbcs.org/contacts.htm</a> for a list of ExCo delegates.
<li><b>Other points of discussion.</b>
</ol> <br>
Please let me know if there is anything else you would like to add to the
agenda.<br>
<br>
All the best,<br>
<br>
Michael Wetter & Jan Hensen<br>
<br>
<br><br>
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<br>
-- <br>
Best Regards,<br><br>
Pavel Dybskiy<br>
<a href="http://M.A.Sc">M.A.Sc</a>. Candidate, Department of
Architectural Science<br>
Faculty of Engineering, Architecture and Science, Ryerson University<br>
E-mail:
<a href="mailto:pdybskiy@ryerson.ca">pdybskiy@ryerson.ca</a>;<br>
telephone: 647-984-4940<br>
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