I liked watching the simulations, you could see what actually happens—you can't see it like that in a book.” — from a student at Arlington High School, Massachusetts, USA

What is it?

Based on computational physics research ([1], [2], [3]), Energy2D is an interactive, visual multiphysics simulation program that models all three mechanisms of heat transfer—conduction, convection, and radiation. Energy2D runs very quickly on most computers and eliminates the switches among preprocessors, solvers, and postprocessors typically needed to perform computational fluid dynamics simulations. As a result, students can use it as an inquiry and design tool to explore and analyze heat and mass flows in two-dimensional structures under different environmental conditions such as sunlight and wind. They can design "computational experiments" to test a scientific hypothesis or solve an engineering problem. As such, physical science, Earth science, and engineering teachers from middle schools to colleges may find Energy2D a useful tool in their classes to teach science and engineering concepts and skills without resorting to complex mathematics.

In addition to heat transfer, work is also underway to incorporate other types of energy transformations (e.g., phase changes and chemical reactions through the Stefan condition), to support multiple types of fluids (e.g., air and water), and to provide sensor interfaces for creating mixed-reality applications.

What is the goal?

The ultimate goal of Energy2D is a versatile computer-aided engineering (CAE) system for students to learn science and engineering through virtual experimentation, investigation, and design. Therefore, the capability of creating complex, accurate scientific simulations of engineering problems is the most important goal of Energy2D. Realizing that many existing engineering simulation programs are simply unrealistic to use in the classroom, our main objective is to rethink a CAE system that empowers, rather than frustrating, the majority of students.

How to run and use it?

Energy2D can be used as a desktop app for creating your own energy simulations or thermal simulations. Your simulations can be deployed as Java applets embedded in web pages. The Energy2D applet runs within any web browser on Windows and Linux, as well as Safari or Firefox on Mac OS X 10.7.3 or higher (the mininum version that supports Java 7), provided that Java is installed and enabled. A Dart version, which will work on Android, Chrome OS, and iOS, is also being developed.

An IR image of a heated model house with a ceiling An IR image of a heated model house without a ceiling
An Energy2D simulation of a heated house with a ceiling An Energy2D simulation of a heated house without a ceiling

How well does it model reality?

The conduction part of Energy2D is highly accurate, but the convection and radiation parts are not 100% accurate. Hence, in cases that involve convection and radiation, Energy2D results should be considered qualitative. Qualitative results, however, may be good enough to convey the ideas in many educational settings. The pictures to the right show a comparison of the results of Energy2D simulations with images from infrared (IR) thermography for a simple model house. The thermal patterns predicted by Energy2D roughly match those from an IR camera.

How to cite it?

Charles Xie, Interactive Heat Transfer Simulations for Everyone, The Physics Teacher, Volume 50, Issue 4, pp. 237-240, 2012.

What people are saying about it?

Thank you for your absolutely great app which helps me a lot for visualizing my lecture in thermodynamics. It is also very nice to see that three platforms are supported and every single one is free to use. That is just awesome and I want to say thank you for all users. I do not know how many messages of this type you are receiving.” — from Martin Weise, Austria

In gearing up to teach a course called Building Science this semester, I somehow stumbled across your program Energy2D and Energy3D. I was really impressed by how simple and easy these tools were and I'm definitely going to integrate them into some portion of my lectures.”— Prof. Brent Stephens, Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, USA

I am currently involved in renewable energy related research activities and teaching. I have downloaded and demonstrating Energy2D for my heat transfer course. It is really a very useful tool.”— Dr. Mazharul Islam, Department of Mechanical Engineering, Taibah University, Saudi Arabia

...what was really interesting, was that when I continued playing with the simulator, sometimes my convection examples would split into two cycling air cells, one above and to the left, one below and to the right, with the hot air blasting right for the cold source, rather than rising. That's really interesting, because I've experienced this when using smoke demonstrations in class, and the fact that the simulator can capture that behavior shows how accurate this teaching tool actually is.” (Link to the source)

...this free software is basic, yet you can modify properties and all, the desktop download gives better results and the pages have a choice of practical setups to download and use that are very practical” (Link to the source)


Developed by Charles Xie. © 2010-2014 The Concord Consortium.

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