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A Lesson In Daylighting

A Lesson In Daylighting

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    Mount Angel classroom prototype

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    Mount Angel classroom prototype

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    Mount Angel classroom prototype

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    Mount Angel classroom prototype

Three of the Northwest's experts on energy efficiency prove what daylight can do.

» As sustainability and energy efficiency have come to occupy an ever-greater role in mainstream architecture, no building type has embraced these principles more than schools. Maybe it is a result of the reported higher test scores that come when students learn in naturally lit classrooms, or the reduced operating expenses that ease the burden of constricted education budgets. No matter the motivation, the Northwest is now dotted with elementary, middle, and high schools that offer better learning environments and significantly reduced operating expenses through sustainable high-performance design.

Recently, a trio of the Northwest's foremost experts on energy-efficient design resolved to build a full-scale mockup of a K-12 classroom: G.Z. Brown, professor of architecture at the University of Oregon and director of the Energy Studies in Buildings Laboratory in Portland and Eugene, Oregon; Mike Hatten, principal of SOLARC Architecture and Engineering; and Heinz Rudolf, principal with BOORA Architects and designer of several nationally renowned LEED-rated Northwest schools. Responding to utility company and lighting designers' doubts that a high-performance classroom could be constructed using available light and outside air so that no electric lights, heating, or air conditioning would ever be needed during the day, the three came together to create a classroom that adeptly employed these principles. They also wanted to prove that such a space could be built and priced at a lower cost than the current standard construction rates for a regular K-12 classroom.



RETHINKING THE SKYLIGHT
Their approach starts with a wide skylight in the middle of the room. But this is no ordinary skylight. 'In order to meet the required light levels on overcast days you need a large opening,' Brown explains. 'But that means the rest of the time, it's too big.' As a result, the skylight, constructed of polycarbonate, is outfitted on top with a succession of integrated louvers that automatically adjust based on sensor readings, opening and closing in relation to the amount of available sunlight, so that a minimum interior light level of 20 to 40 footcandles (a range chosen by the team because it represents existing national and international standards) is maintained at all times during daylight hours.

Another issue of concern was the distribution of light from the center to the perimeter areas of the classroom. A specially designed apparatus called the 'halo,' a rectangular-shaped fixture that hangs below the central skylight, addresses this. Each of its four sides consists of translucent cellular plastic that reflects a portion of the light from above onto the ceiling and walls. 'The edge of the classroom gets two sources of light: from the skylight, called the sky component, and reflected light off the halo and ceiling,' Brown explains. 'The middle of the room gets light reflected around the room and light that penetrates through the halo.'

Part of what Brown, Hatten, and Rudolf hoped to illustrate with the prototype was that a classroom could be lit during the day without any electric light. The team based this premise on the assumption that classrooms are primarily occupied only during these hours, but because there are times when K-12 facilities are used at night, Brown and his team decided an electric source was also needed to round out the halo's functionality. 'What contributes to the cost of a lighting system is the number of fixtures that the wires must travel to,' Brown continues. 'So we used one big light, put it in the middle of the room, and shined it toward the ceiling. We light the whole space with just that one fixture, a 450W HID pointed upward.'

THEORY INTO PRACTICE
The classroom that Brown, Hatten, and Rudolf envisioned has been built on the Mount Angel Abbey campus in Saint Benedict, Oregon, about an hour's drive from Portland. Although the team always intended for its idea to move from model to full-scale mockup, it owes its speedy realization to happy circumstance. During a visit to the Energy Studies in Buildings Laboratory in Portland, architect Kent Duffy, principal at SRG Partnership, saw Brown studying a model of the classroom. Intrigued, Duffy asked about using the prototype classroom concept for a new academic building consisting of classrooms and offices SRG was designing at the seminary. The Mount Angel Abbey Academic Center is currently under construction, slated for completion by end of summer 2006. Meanwhile, the full-scale mockup remains available for testing purposes and is housed in a warehouse at the school.

The results of the Mount Angel prototype are impressive. 'We're looking at some fairly phenomenal Energy Use Index numbers,' Hatten says of the seminary building's classrooms, based on monitoring of the prototype. 'We're projecting 28,400 BTUs per square foot annually. The base-case code-compliant classroom would be 73,200. That's 62 percent better than code.' Brown believes that with additional insulation, energy savings could be even higher: as much as 70 percent better than code requirements.

FROM THE GROUND FLOOR UP

Although the classroom mockup is complete, Brown and Hatten believe there is still opportunity for further experimentation. For example, the current version is designed to meet weather conditions specifically west of the Cascades, where the climate is moderate. Ultimately, it is hoped a modified configuration could be adapted to the range of temperatures east of the mountains, or perhaps another climate altogether. 'It is likely to require some aspect of supplemental heating and/or cooling,' Hatten says. The classroom layout is also geared specifically for single-story structures, but a version of the design could be adapted to two-story buildings using light shafts between the upper and lower floors.

The efforts of design experts like Brown, Hatten, Rudolf, and Duffy will continue, as more and more institutions embrace the opportunity for enhanced human performance and energy efficiency that comes with sustainable schools. The Mount Angel prototype is merely one step in a longer journey, but it is also something not to be forgotten anytime soon: the project proves that even in the Northwest, it is entirely possible to light, heat, and cool classrooms using only the natural resources of sun and wind. brian libby



A freelance writer living in Portland, Oregon, Brian Libby's focus is on architecture and film.

DETAILS
project Bazacle Causeway, Garonne River, Toulouse, France
lighting designer Concepto, Bagneux, France
technical design Beture Infrastructure, Maisons-Alfort, France communication Agence MC3, Toulouse, France
installation engineers AMEC SPIE, Toulouse, France
civil engineers SPIE Batignolles, Cergy-Pontoise, France
photographer Roger Narboni, Bagneux, France
project size 886 linear feet
project cost approximately $600,000 (500,000 Euros)
watts 2W per fixture