Heliodon - Physical tools developed to study and test the solar performance of building models.

This article is a an excerpt from the classes held in the last week of May 2013. Students were instructed to examine the solar penetration of their architectural models with the aid of a mobile Heliodon. [Illustrated below]

A mobile direct sunlight medium-duty quasi-universal heliodon mounted on lockable wheels, set for 22.5 degree latitude North, 6 May, or 7 August. The components constitute an integrated simulated earth-latitude-time-DAY system assembly, all mounted onto a circular shaft which is then mounted onto a movable cart on lockable wheels. The overall space dimension for storage of the heliodon is 760 mm x 560 mm x 1100 mm high, when it is not in operation.  

Building models of less than 10 kg of medium size, built on a strong and rigid plate such as an aluminum plate, can be mounted onto the heliodon by G clamps. Skillful manual operation will allow even larger and heavier models to be partially fixed by G clamps onto the heliodon, and partially manually held in position during heliodon, extending its practical use to a wider range of model size and weight.

************************************************************************************

Examining the model outdoor using natural sunlight.

Examining the model indoor using an assembly of Fresnel Lens 

and Quartz Lamps with the Heliodon.

Adjusting the assembly of components.

The combined Northern Hemisphere-Southern Hemisphere Day Selector of the heliodon, showing the unblocked parallel light going through the gnomon aperture for working the full range of days shown in the day selector scale. The light spot casting onto the day selector scale can be adjusted by moving the heliodon on its wheels and operating the handle so that the light spot will fall between the 2 long parallel lines at the centre of the Day Selector Scale. 

The Time Selector is a revolving ring attached to the simulated earth axis.

These assemblies produce reasonably strong quasi-parallel light falling onto building models,  minimizing dimensional errors of the shadows of the components of building models. 

It is expected that this mobile heliodon will help educate effectively the students studying architecture, building and engineering courses, and for general education in universities. This heliodon is a convenient, mobile and affordable tool to be used by the building and architecture profession, and the general public on solar architecture design. This will arouse the general public in wider acceptance and demand on more integration of solar design into buildings, contributing to building a sustainable world.

This reported heliodon should provide the speed and accuracy demanded for detailed scaled physical day-lighting model study, complementing computational day-lighting modeling, in accurate day-lighting analysis.

This reported heliodon should be further reviewed and compared with other heliodons, in order to provide a comprehensive set of heliodons for use in education institutes and offices of architects and building professionals. 



Related articles on-line:

K.P. Cheung, “A table top heliodon developed for use in an architect’s design studio”, International Journal on Architectural Science, Vol. 2, No. 4, pp. 118-128 (2001). http://www.bse.polyu.edu.hk/researchCentre/Fire_Engineering/summary_of_output/journal/IJAS/V2/p.118-128.pdf

K.P. Cheung, H.M. Kam and C.F. Lam, “A Multi-Lamp Heliodon for Architectural Schools”, International Journal on Architectural Science, Vol. 1, No. 1, pp. 46-58 (2000). http://www.bse.polyu.edu.hk/researchCentre/Fire_Engineering/summary_of_output/journal/IJAS/V1/p.46-58.pdf

K.P. Cheung, and S.L. Chung, “A Table Top Heliodon with a Moving Light Source for Use in an Architect's Office”, International Journal on Architectural Science, Vol. 3, No. 2, pp. 51-60 (2002). http://www.bse.polyu.edu.hk/researchCentre/Fire_Engineering/summary_of_output/journal/IJAS/V3/p.51-60.pdf

Kwok Pun CHEUNG. U S Patent No. US6523270 B1. A Universal Heliodon-Sundial, patent issued by US Patent Office on 25 February 2003. http://hub.hku.hk/handle/10722/142203 , also searchable at http://portal.uspto.gov/external/portal/!ut/p/ 

K.P. Cheung “A discussion on the design principles of a patented portable direct sunlight light-duty universal heliodon mounted on a camera tripod”. International Journal on Architectural Science. Department of Building Services Engineering. The Hong Kong Polytechnic University. Volume 8, Number 4, p.98-113, 2011. http://www.bse.polyu.edu.hk/researchCentre/Fire_Engineering/summary_of_output/journal/journal_AS.html