(Carbon) credits where credits are due: Autodesk helps to overhaul EnergyPlus


Thanks to an article just published in Building Design & Construction, it would seem that programmers at the Autodesk “Factory” have generously donated their skills to modernise the U.S. Department of Energy’s analysis tool, EnergyPlus.

Autodesk’s software engineers translated EnergyPlus (more than 600,000 lines of Fortran code) to C++ which is better supported on mass-market hardware and software platforms. In addition, the new version works better with BIM design applications, auditing tools, and energy dashboards (See below). Autodesk (working pro bono) turned over brand new engine source code to the U.S. Department of Energy for a complete rewrite EnergyPlus. The new code will be made available under the DOE’s open source license.

EnergyPlus 8.2 now allows designers to run energy model simulations in less than a few hours as opposed to days, or even weeks, under the previous version.

For more than a decade, the U.S. Department of Energy has made its EnergyPlus energy analysis and thermal load simulation program available for free to Building Teams. But without a major rewrite of the program since its creation, EnergyPlus had become woefully out of date, leading to painfully slow performance and occasionally inaccurate analysis results.

EnergyPlus is a whole building energy simulation program that engineers, architects, and researchers use to model energy and water use in buildings. Modeling the performance of a building with EnergyPlus enables building professionals to optimize the building design to use less energy and water. Each version of EnergyPlus is tested extensively before release.


EnergyPlus models heating, cooling, lighting, ventilation, other energy flows, and water use. EnergyPlus includes many innovative simulation capabilities: time-steps less than an hour, modular systems and plant integrated with heat balance-based zone simulation, multi-zone air flow, thermal comfort, water use, natural ventilation, and photo-voltaic systems. Read about new features.


IMPORTANT: EnergyPlus User Interface

It is important to note that EnergyPlus is a stand-alone simulation program without a ‘user friendly’ graphical interface. EnergyPlus reads input and writes output as text files. A number of graphical interfaces are available.

Using these graphical interfaces, it is possible to import geometry and data from current BIM platforms and utilise the EnergyPlus engine. See the list below.

Autodesk Revit, Graphisoft ArchiCAD, Bentley Microstation : DesignBuilder

3D models created in Revit, ArchiCAD or Microstation can be loaded into DesignBuilder through a gbXML import process. Revit users can access DesignBuilder while working on their BIM models through a plugin, which allows the model to be checked and analysed without leaving Revit.

Alternatively building models can be assembled quickly and easily within the DesignBuilder modeler by drawing and positioning 3-D blocks. Blocks once drawn can be cut, stretched, merged with other blocks etc then partitioned into zones. Realistic 3-D elements allow correct room areas and volumes to be used in daylighting and CFD simulations and add to realism in rendered views.

Bentley AECOSim: Bentley Energy Simulator

Bentley Systems released the second version of its new building performance simulation product, AECOsim Energy Simulator, in May 2013.

Built on top of Bentley’s BIM platform, Energy Simulator allows users to work seamlessly between industry CAD, BIM, and AEC applications such as MicroStation, AutoCAD, Revit, and others and supports standard file formats such as gbXML, DXF, DGN, DWG, PDF, BMP, JPG, and PNG.

Autodesk Revit, Trimble SketchUP: Sefaira

Sefaira can directly analyze SketchUp and Revit files, plugging seamlessly into popular workflows. Architects can begin an analysis by specifying only two additional inputs: space use and location. Other parameters are set to standard values, which can be manually overridden by the user at any time. No specific expertise is required.

Rhinoceros3d (Grasshopper): Mr.Comfy

Mr.Comfy is a Grasshopper3d component, written in Python, that allows designers to dynamically visualize EnergyPlus building simulation results in Rhinoceros3d models. Instead of using charts or tabular data, energy consumption, zone temperatures or any other available report variable can be directly displayed through color-coded surfaces (and numeric values) where they occur – in the individual spaces of a design.

Trimble SketchUP: OpenStudio

The new OpenStudio graphical applications include the updated SketchUp Plug-in, the stand alone OpenStudio application, the ParametricAnalysisTool, RunManager, and ResultsViewer.  The SketchUp Plug-in is an extension to the popular 3D modeling tool that adds OpenStudio context to the SketchUp program.  The Plug-in allows users to quickly create geometry and assign space attributes using the built-in functionality of SketchUp including existing drawing tools, integration with Google Earth, Building Maker, and Photo Match.

The OpenStudio application is a graphical energy-modeling tool. It includes visualization and editing of schedules, editing of loads constructions and materials, a drag and drop interface to apply resources to spaces and zones, a visual HVAC and service water heating design tool, and high level results visualization. Radiance can also be integrated into the simulation workflow. OpenStudio includes graphical interfaces along with a Software Development Kit (SDK). Visit the OpenStudio website for more information, downloads, and support.



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