Developing a physical BIM library for building thermal energy simulation

• We create a Modelica library for BIM-based energy simulation.
• We validate the ModelicaBIM library through simulation result comparisons.
• The ModelicaBIM classes can represent BIM object attributes as parameters.
• The ModelicaBIM structures can represent object semantics and hierarchy of BIM.
• ModelicaBIM helps simulate and analyze component-level energy performance.

Insufficient interoperability resulting from complex data exchange between architectural design and building energy simulation prevents the efficient use of energy performance analyses in the early design stage. This paper presents the development of a Modelica library for Building Information Modeling (BIM)-based building energy simulation (ModelicaBIM library) using an Object-Oriented Physical Modeling (OOPM) approach and Modelica, an equation-based OOPM language. By using the ModelicaBIM library, our project investigates system interfaces between BIM and energy simulation, which can perform semi-automatic translation from the building models in BIM to building energy modeling (BEM) using a BIM's authoring tool's Application Programming Interface (API).The ModelicaBIM library consists of OOPM-based BIM classes and OOPM-based BIM structure. OOPM-based BIM classes represent building component information. OOPM-based BIM structure consists of test case models that demonstrate (i) how building information in BIM can be transformed to OOPM and (ii) how design operations in BIM, such as changing a building geometry and editing building components, can be translated into BEM. A case study for simulation result comparisons has been conducted using (i) OOPM-based BIM models in the ModelicaBIM library and (ii) LBNL Modelica Buildings library (a Modelica-based building thermal simulation library developed by Lawrence Berkeley National Laboratory). Our implementation shows that the ModelicaBIM library enables (i) objects in BIM to be translated into the OOPM-based energy models and (ii) existing OOPM library to be utilized as a simulation solver for BIM-based energy simulation.

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