2. Foreword

This publication is the official report of IEA EBC Annex 60, which was conducted from 2012 to 2017 through a collaboration among 42 institutes from 16 countries. Annex 60 developed and demonstrated new generation computational tools for the design and operation of building and community energy systems. The report is aimed at users of simulation, HVAC and urban energy system designers as well as researchers in the field of energy systems for the built environment.

A key driver for this work are the trends towards zero energy and electrification of the energy infrastructure that demands that buildings and district energy systems become increasingly integrated to reduce energy use, power density and to shift load. Typical measures include high-performance facades, energy storage, waste heat utilization within and among buildings through near ambient-temperature networks, and heat pumps that boost waste heat and renewable sources to usable temperatures. Advanced controls need to orchestrate this operation while providing electrical load shifting and load shedding capabilities, and bidding these capabilities into a dynamic electricity market. What are the implications on building simulation and associated computing and the digitalization of the entire planning process including BIM tools?

Clearly, building simulation programs face new challenges to support such systems throughout the building life cycle. They must become a modular service that integrates seamlessly with other tools, sometimes at small time-steps and below the level of a whole building, during design and operation. This represents a radical structural shift from conventional building simulation programs, which provide little workflow automation for design, analysis and optimization and no facilities for runtime integration. This situation leads to new functional requirements which are not addressed by existing building simulation programs, which are often load-based, assume ideal and non-integrated steady-state control of each individual subsystem, and are hard to extend from design to operation, and from buildings to districts.

In the meantime, other engineering sectors have been making large investments and substantial progress in next generation computing tools for the design and operation of complex, dynamic, engineered systems based on the open standards Modelica, a modeling language, and Functional Mockup Interface (FMI), a standard for exchanging models.

Annex 60 transfers and adapts these technologies to the buildings industries through the collaborative development of Modelica libraries, FMI-technologies, and translators from Building Information Models (BIM) to Modelica.

Due to this large ecosystem of technology that can be adapted for the buildings industry, due to the evolving requirements that demand new approaches for modeling, simulation and optimization that are a shift from todays practice in building performance simulation, and to have a means to collaboratively develop software, all work in Annex 60 was based on the following three open standards:

  • The equation-based, object-oriented Modelica language which allows graphical composition of models for simulation, operation and optimization. The models may be multi-physics system models, such as energy systems that couple thermodynamics, heat transfer, fluid dynamics, and electrical systems. These physics-based models can be combined with data-driven models and with models of continuous-time, discrete-time, and event-driven feedback control systems.
  • The Functional Mockup Interface (FMI) Standard, a specification that describes how to encapsulate and exchange models or simulators, independent of the authoring tool or application domain. The FMI standard is currently supported by more than 80 tools.
  • The Industry Foundation Classes (IFC), the only life cycle model of buildings that is an open international standard, governed by ISO 16739. BIM models described by IFC may be HVAC components or entire building energy systems. A building services-related BIM model originating from the digital planning process cannot serve as basis for simulation without further knowledge-based transformation.

Using these standards, the core research problem that has been solved within Annex 60 was the coordinated development, application and demonstration of new generation computational tools for building and community energy systems that are based on open standards and that allow buildings and energy grids to be designed and operated as integrated, robust, and performance based systems.

In hindsight, embracing these standards was instrumental for collaborative research and development, as there was a clear specification of the technology, formalized through standards, that served as the basis of the collaborative development. Probably most important, working through these standards allows the building simulation community to collaborate with experts from other fields, such as experts in multi-physics modeling, hybrid systems, numerical methods, computer algebra, compiler technology or language design, that are important for the new requirements that the building simulation community faces, but that are generally not present in our community.

Software development is an investment in foundational tools that encapsulates sophisticated, complex methods to make them accessible to non-experts through easy-to-use interfaces. By committing to standards rather than a particular tool provider’s implementation, the software developed in Annex 60 that does not rely on, and hence locks customers into the use of tools provided by any single vendor.

2.1. Operating Agents and Task Leaders

The operating agents were

Michael Wetter
Building Technology and Urban Systems Department
Energy Technologies Area
Lawrence Berkeley National Laboratory, USA


Christoph van Treeck
Chair in Energy Efficiency and Sustainable Building (E3D)
RWTH Aachen University, Germany

Annex 60 was structured into the following subtasks and activities.

Subtask 1: Technology Development

Led by Michael Wetter, LBNL, Berkeley, CA

Activity 1.1: Modelica model libraries

Led by Michael Wetter, LBNL, Berkeley, CA

Activity 1.2: Co-simulation and model exchange through Functional Mockup Units

Led by Frederic Wurtz, Grenoble University, Grenoble, France

Activity 1.3: Building Information Model

Led by Christoph van Treeck, RWTH Aachen University, Germany

Activity 1.4: Workflow automation tools

Led by Sebastian Stratbuecker, Fraunhofer IBP, Holzkirchen, Germany

Subtask 2: Validation and Demonstration

Led by Lieve Helsen, KU Leuven, Leuven, Belgium

Activity 2.1: Design of building systems

Led by Christoph Nytsch-Geusen, Berlin University of the Arts, Berlin, Germany

Activity 2.2: Design of district energy systems

Led by Dirk Saelens, KU Leuven, Leuven, Belgium

Activity 2.3: Model use during operation

Led by Ignacio Torrens, Eindhoven University of Technology, The Netherlands

Subtask 3: Dissemination

Led by Christoph van Treeck and Michael Wetter

2.2. Authors of the Final Report

The final report was co-authored by the participants listed below, and edited by the operating agents Michael Wetter and Christoph van Treeck.

Name Affiliation
Baetens, Ruben KU Leuven, Belgium
Bazjanac, Vladimir Standford University, CA, USA
Blum, David Lawrence Berkeley National Laboratory, Berkeley, CA, USA
Cao, Jun RWTH Aachen University, Aachen, Germany
Fuchs, Marcus RWTH Aachen University, Aachen, Germany
Jorissen, Filip KU Leuven, Leuven, Belgium
Keane, Marcus M. National University of Ireland, Galway, Ireland
Lauster, Moritz RWTH Aachen University, Aachen, Germany
Maile, Tobias Maile Consulting, Fellbach, Germany
Mitterhofer, Matthias Fraunhofer Institute for Building Physics IBP, Holzkirchen, Germany
Nouidui, Thierry S. Lawrence Berkeley National Laboratory, Berkeley, CA, USA
Nytsch-Geusen, Christoph Berlin University of the Arts, Berlin, Germany
O’Donnel, James University College Dublin, Dublin
Picard, Damien KU Leuven, Leuven, Belgium
Pinheiro, Sergio University College Dublin, Dublin
Protopapadaki, Christina KU Leuven/EnergyVille, Belgium
Reinbold, Vincent KU Leuven/EnergyVille, Belgium
Saelens, Dirk KU Leuven/EnergyVille, Belgium
Sterling, Raymond National University of Ireland, Galway, Ireland
Stratbuecker, Sebastian Fraunhofer Institute for Building Physics IBP, Holzkirchen, Germany
Thorade, Matthis Berlin University of the Arts, Berlin, Germany
Tugores, Carles Ribas Berlin University of the Arts, Berlin, Germany
van der Heijde, Bram KU Leuven/EnergyVille, Belgium
van Treeck, Christoph RWTH Aachen University, Aachen, Germany
Wetter, Michael Lawrence Berkeley National Laboratory, Berkeley, CA, USA
Wimmer, Reinhard RWTH Aachen University, Aachen, Germany

2.3. Project Participants

The following 42 institutes from 16 countries participate in Annex 60:

Institute Country
Lawrence Berkeley National Laboratory USA
Massachusetts Institute of Technology USA
Purdue University USA
Stanford University USA
Texas A&M University USA
UCI Engineering, Inc. USA
University of Alabama USA
University of Miami USA
University of Texas, San Antonio USA
RWTH Aachen University Germany
Maile Consulting Germany
TU Dresden Germany
KIT Karlsruher Institut of Technology Germany
Fraunhofer ISE Germany
Berlin University of the Arts (UDK) Germany
Fraunhofer IBP Germany
AEC3 Germany
Austrian Institute of Technology Austria
AEE-Intec Austria
KU Leuven Belgium
Cenaero Belgium
University of Liège Belgium
Pontifícia Universidade Católica do Paraná Brazil
Chongqing University China
Aalborg University Denmark
University of Southern Denmark Denmark
LGCgE, Université d’Artois France
Grenoble University France
I2M University of Bordeaux France
CSTB France
EDF France
National University of Ireland, Galway Ireland
University College Dublin Ireland
Università Politecnica delle Marche Italy
Eindhoven University of Technology The Netherlands
Exergy Studios Slovakia
Swegon AB Sweden
EQUA Simulation AB Sweden
EMPA Switzerland
Masdar Institute United Arab Emirates

2.4. Acknowledgements

This research was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technologies of the U.S. Department of Energy, under Contract No. DE-AC02-05CH11231.

This research was supported by the European Union through the Seventh Framework Programme (FP7/2007-2013) under grant agreement nº 285408.

This research was supported by the European Union through the Seventh Framework Programme (FP7/2007-2013) under grant agreement nº 284920.

This research was supported by the International Energy Research Centre and Enterprise Ireland under project n. CC-2011-4005B and by the Irish Research Council - D’Appolonia enterprise partnership scheme.

This research was supported by the German Federal Ministry of Economic Affairs and Energy (BMWi), national research project EnTool:EnEff-BIM (EnOB), promotional references 03ET1177A, 03ET1177B, 03ET1177C, 03ET1177D, 03ET1177E.

This research was supported by the German Federal Ministry of Economic Affairs and Energy (BMWi), national research project EnTool:CoSim (EnOB), promotional references 03ET1215A, 03ET1215B, 03ET1215C, 03ET1215D.

This research was supported by a Marie Curie FP7 Integration Grant within the 7th European Union Framework Programme project title SuPerB, project nº 631617 and Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq) under the Programme Science without Borders in Brazil.

Research participants collaboratively worked together under the umbrella of the IEA EBC framework. Duplications of work were avoided and participants benefitted from collaboration and synergies which became possible due to the strong organizational Annex 60 framework.