Computers with solar 3-D programs are an alternative for the analysis and presentation applications of heliodons. However, for the initial learning of the broad concepts and for developing a mental model of the solar geometry as related to buildings, heliodons with conceptual clarity are far superior.

Learning the complex geometry of the sun as related to a building is like learning the street pattern of a complex medieval town by driving around it in a vehicle that has only one window, the windshield. A much faster and deeper understanding of the town would occur by exploring on foot. Not only is one free at all times to move in any direction, but also one is free at all times to look back or sideways. Because every view is in complete context of where one is, a mental pattern of the town will emerge faster,
be more complete, and last longer than through a controlled drive-through. Thus, I believe, the initial learning of solar geometry will always be better with a heliodon like the Sun Emulator than with a computer program.

For the student still new to this knowledge, a heliodon would also be very useful in the analysis stage of design. It is not easy to know how a solar access analysis should be performed using a computer program (i. e. what time of day or year should be investigated). A heliodon’s intuitive clearness and immediate feedback helps in planning and performing a solar analysis.

Even at the presentation stage, a heliodon can be more advantageous than a computer. Although the presenter may not need the heliodon’s conceptual clarity, the audience, which is often much less informed about solar geometry, would understand the logic of the solar responsive design more easily and believe in it more fully by seeing it through a heliodon.

For many years it was believed the 3-D computer modeling will replace the need for physical modeling. However, at the Auburn University School of Architecture, physical modeling is as popular as ever even though 3-D computer modeling is also extensively used. We evolved in a world of physical objects, and it is therefore not surprising that physical models are so engaging, immediate, and intuitively clear.

4. Conclusion

It is hard to believe that a rather simple mechanical device could be a such a powerful teaching and design tool. It is also hard to believe that such a device could have a major impact on our energy future, the environment, and especially global warming. My 27 year teaching experience with heliodons makes me believe that "conceptually clear” heliodons truly are powerful teaching tools that can greatly convince and motivate people. Also since they never wear out and will never become obsolete, they are a good investment for creating a better future.

More information about the Sun Emulator is available from my Auburn University website: www. cadc. auburn. edu/sun-emulator and the manufacturer’s website: www. hpd-online. com