Simplifications for hydronic system models in modelica

Jorissen, F.; Wetter, M.; Helsen, L.

doi:10.1080/19401493.2017.1421263

Title: Simplifications for hydronic system models in modelica

Abstract

Building systems and their heating, ventilation and air conditioning flow networks, are becoming increasingly complex. Some building energy simulation tools simulate these flow networks using pressure drop equations. These flow network models typically generate coupled algebraic nonlinear systems of equations, which become increasingly more difficult to solve as their sizes increase. This leads to longer computation times and can cause the solver to fail. These problems also arise when using the equation-based modelling language Modelica and Annex 60-based libraries. This may limit the applicability of the library to relatively small problems unless problems are restructured. This paper discusses two algebraic loop types and presents an approach that decouples algebraic loops into smaller parts, or removes them completely. The approach is applied to a case study model where an algebraic loop of 86 iteration variables is decoupled into smaller parts with a maximum of five iteration variables.

Authors:

^[1]; Wetter, M. ^[2];

^[1]

Univ. of Leuven (Belgium); EnergyVille, Genk (Belgium)
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Publication Date:: 2018-01-12

Research Org.:: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office

OSTI Identifier:: 1437004

Grant/Contract Number:: AC02-05CH11231

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Building Performance Simulation

Additional Journal Information:: Journal Volume: none; Journal Issue: none; Journal ID: ISSN 1940-1493

Publisher:: Taylor & Francis

Country of Publication:: United States

Language:: English

Subject:: 42 ENGINEERING

Citation Formats


                    Jorissen, F., Wetter, M., and Helsen, L. Simplifications for hydronic system models in modelica.  United States: N. p., 2018. 
Web.  doi:10.1080/19401493.2017.1421263.

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                    Jorissen, F., Wetter, M., & Helsen, L. Simplifications for hydronic system models in modelica.  United States.  https://doi.org/10.1080/19401493.2017.1421263

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                    Jorissen, F., Wetter, M., and Helsen, L. Fri .  
"Simplifications for hydronic system models in modelica".  United States.  https://doi.org/10.1080/19401493.2017.1421263.  https://www.osti.gov/servlets/purl/1437004.

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@article{osti_1437004,

  title        = {Simplifications for hydronic system models in modelica},

  author       = {Jorissen, F. and Wetter, M. and Helsen, L.},

  abstractNote = {Building systems and their heating, ventilation and air conditioning flow networks, are becoming increasingly complex. Some building energy simulation tools simulate these flow networks using pressure drop equations. These flow network models typically generate coupled algebraic nonlinear systems of equations, which become increasingly more difficult to solve as their sizes increase. This leads to longer computation times and can cause the solver to fail. These problems also arise when using the equation-based modelling language Modelica and Annex 60-based libraries. This may limit the applicability of the library to relatively small problems unless problems are restructured. This paper discusses two algebraic loop types and presents an approach that decouples algebraic loops into smaller parts, or removes them completely. The approach is applied to a case study model where an algebraic loop of 86 iteration variables is decoupled into smaller parts with a maximum of five iteration variables.},

  doi          = {10.1080/19401493.2017.1421263},

  journal      = {Journal of Building Performance Simulation},

  number       = none,

  volume       = none,

  place        = {United States},

  year         = {2018},

  month        = {1}

}

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Journal Article:

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Accepted Manuscript (DOE)

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https://doi.org/10.1080/19401493.2017.1421263

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Cited by: 1 work

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Figures / Tables:

Table 1: Illustration and short description of the main component models that are used in the example models.

All figures and tables (7 total)

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Works referenced in this record:

Modelica BuildingSystems − eine Modellbibliothek zur Simulation komplexer energietechnischer Gebäudesysteme
journal, February 2013

Nytsch-Geusen, Christoph; Huber, Jörg; Ljubijankic, Manuel
Bauphysik, Vol. 35, Issue 1
DOI: 10.1002/bapi.201310045

Modelica Buildings library
journal, March 2013

Wetter, Michael; Zuo, Wangda; Nouidui, Thierry S.
Journal of Building Performance Simulation, Vol. 7, Issue 4
DOI: 10.1080/19401493.2013.765506

Depth-First Search and Linear Graph Algorithms
journal, June 1972

Tarjan, Robert
SIAM Journal on Computing, Vol. 1, Issue 2
DOI: 10.1137/0201010

Depth-first search and linear graph algorithms
conference, October 1971

Tarjan, Robert
12th Annual Symposium on Switching and Automata Theory (swat 1971)
DOI: 10.1109/swat.1971.10

Works referencing / citing this record:

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica
journal, December 2018

Jorissen, F.; Boydens, W.; Helsen, L.
Journal of Building Performance Simulation, Vol. 12, Issue 4
DOI: 10.1080/19401493.2018.1544277

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica
text, January 2018

Jorissen, F.; Boydens, W.; Helsen, L.
Taylor & Francis
DOI: 10.6084/m9.figshare.7441316.v2

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica
text, January 2018

Jorissen, F.; Boydens, W.; Helsen, L.
Taylor & Francis
DOI: 10.6084/m9.figshare.7441316

Figures / Tables found in this record:

Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.

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Similar Records

Title: Simplifications for hydronic system models in modelica

Abstract

Citation Formats

Figures / Tables:

Modelica BuildingSystems − eine Modellbibliothek zur Simulation komplexer energietechnischer Gebäudesysteme journal, February 2013

Modelica Buildings library journal, March 2013

Depth-First Search and Linear Graph Algorithms journal, June 1972

Depth-first search and linear graph algorithms conference, October 1971

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica journal, December 2018

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica text, January 2018

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica text, January 2018

Modelica BuildingSystems − eine Modellbibliothek zur Simulation komplexer energietechnischer Gebäudesysteme
journal, February 2013

Modelica Buildings library
journal, March 2013

Depth-First Search and Linear Graph Algorithms
journal, June 1972

Depth-first search and linear graph algorithms
conference, October 1971

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica
journal, December 2018

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica
text, January 2018

Model implementation and verification of the envelope, HVAC and controller of an office building in Modelica
text, January 2018