DAYLIGHTING RESEARCH On the lighter side...

by Jim Love

Over the past decade, one of my principal research interests has been lighting and the use of daylight as a substitute for light from electric sources. Lighting is a critical factor in the visual experience of environments, in the performance of tasks, and in energy use in buildings. In Alberta, 90 percent of the electricity we use is produced in coal-fired plants, so environmental degradation is also a byproduct of electric lighting. Improvement of lighting in all these terms requires an interdisciplinary approach. One must provide for the visual requirements of the building occupants, which requires some enquiry into the effects of lighting on their functioning and mood. Robert Nemeskeri, a student in the Committee on Resources and the Environment interdisciplinary programme, and I undertook an extensive investigation of user responses to offices adjacent to and distant from windows to assess factors such as user satisfaction and glare; another variable was the type of electric lighting. "The relationship of the architects' compositional intentions to the means of introducing daylight must be reconciled..." Daylight is a solar resource, so one must acquire knowledge of atmospheric science to understand the nature of the resource. Under contract with the Atmospheric Environment Service of Environment Canada, I am operating Canada's station as part of an international network that will provide better data for daylighting design, as well as for photovoltaic and thermo-solar systems. No reductions in electrical energy use will be achieved unless the electric lighting is switched off or dimmed. This can be achieved by automatic means, which requires application of control theory, or by manual switching. In either case, one must anticipate the behaviour of the users with respect to the acceptance of automatic controls or the use of manual switching. I am currently both investigating user behaviour with respect to manual switching and working with an Alberta company that is developing an automated approach to lighting control. The interactions of lighting and daylighting with heating and cooling systems of the building should be accounted for. The massing, fenestration, and glazing of buildings affects the depth of daylight penetration, the uniformity of its distribution, and qualities of the visual environment such as the degree of glare. The relationship of the architects' compositional intentions to the means of introducing daylight must be reconciled, which requires an appreciation of architectural design. Technologically, many more choices have emerged over the past ten years in terms of glazing types, electric lighting, and controls, and the rate of change is not abating. I have been involved as an "expert consultant" to Natural Resources Canada's C2000 Advanced Commercial Building Technology demonstration programme, which requires that these issues be addressed in practical terms. Other aspects of this work include monitoring the performance of spaces and buildings with special daylighting features, evaluating the performance of design methods such as computer simulation and scale-model photometry, and the development of performance indicators. In summary, knowledge from psychology, architecture, electrical engineering, mechanical engineering, and atmospheric science must be brought to bear. The work has its principle outlets through scholarly publications, industry guides (I was the principal author of the daylighting chapter of the most recent edition of the Illuminating Engineering Society of North America's "Lighting Handbook," and collaboration with industry and practitioners. "...knowledge from psychology, architecture, electrical engineering, mechanical engineering, and atmospheric science must be brought to bear." An offshoot of this work is that the expertise and facilities we have developed at The University of Calgary are employed by a range of organizations. This has resulted in performance testing for a manufacturer of mirror light pipes, consulting on national regulations for efficiency of lighting products, and development of a literature review on approaches to the regulation of residential daylighting in northern countries.

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