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Environmental Technology Center at Sonoma State University

The Environmental Technology Center at Sonoma State University is one of the few buildings in the US that produces more renewable electricity that it uses. It is one of less than 100 buildings in the US to be listed on The High Performance Buildings Database. It is sponsored by the U.S. Department of Energy. There is more information on the Sonoma State University website.

The conceptual design by AIM Associates won a National Science Foundation grant to design and construct a facility that will teach, display & be a state-of-the-art, example of energy efficiency, passive solar, daylighting, renewable energy, and resource efficient materials. Funding was also provided by a California Petroleum Violation Fund grant and matching funds by the university.

Occupancy uses include a one hundred person seminar room, a conference room, student research area and offices. AIM Associates assembled a team of nationally recognized leaders in each of the aspects of sustainability. The synergistic results of the integrative design process have resulted in a building design that will use less that 20% of the energy of a conventional building meeting the pre-2001 California energy code.

Inside the ETC

Energy performance was a key consideration of the design process from the outset. Energy 10 energy use simulation were used in an iterative process of trying different variables one at time to find their affect on the energy use. The variables included window size, placement, shading and glazing, floor thermal mass, wall thermal mass, wall and roof insulation, daylighting apertures, natural ventilation apertures, etc.. Form•Z was used for 3-D modeling of building form and to study sun penetration and overhangs for sun shading windows and roof monitors. COMPLY 24 (with DOE-2 engine) was used to fine tune the building envelope, design evaporative cooling, solar boosted radiant heating, etc.. Dr. J. Doug Balcomb, head of the Energy 10 project at the National Renewable Energy Laboratory used an advanced beta version of Energy 10 for peer review. His input came at a critical time in helping us to refine the amount of interior thermal mass, passive solar features and natural ventilation. His encouragement led to our wind tunnel testing.

A half inch per foot scale working model was tested at the PG&E Energy Center in San Francisco on the helidon for sun penetration. It was also used at the University of California School of Architecture Overcast Sky Simulator for quantitative measurements of daylighting with variables of roof monitor configurations, window sunshade positions and wall paint colors of white versus a pastel versus a medium tone. George Loisos used Radiance lighting simulation software to fine tune the roof monitor form and size to achieve the specific daylighting goal of a minimum of 50 foot candles of daylighting in the Seminar room on an overcast day in December. Skylights were added to increase the overcast sky lighting levels; and to have the added teaching feature of side by side comparison of roof monitor versus skylight. Operable diffusion devices will control the glare of direct sun light but allow solar penetration when desirable for passive solar heating. Operable sunshades/ light shelves control the glare of direct sun light at the offices.

The ETC at dusk

When we reached the point of saving 80% of the building's energy use, the fans for night cooling became proportionately a large power user. We realized how important a role natural ventilation could play. Graduate architecture students at UC Berkeley built a scale model and tested it in the wind tunnel. The test information was used to refine the building form for natural ventilation.
Many of the building’s materials selected for their attributes favorable to sustainability. The lumber used for the roof trusses and posts is certified sustainable by FSC. Composite structural panels were used for walls and roof. The skins are made of OSB (oriented strand board) made efficiently from small trees). Some day they will be made from agricultural fiber such as straw or hemp. The core was originally to be made of compressed straw but they would have been shipped from Texas, been heavy and of only mediocre insulating quality. The current composite panel choice has cores made of steam expanded polystyrene with recycle content. The concrete used for foundations, floor slab, etc. will have the Portland cement reduced by 50% by substituting the pozzolanic waste products of fly ash and rice hull ash. Siding is integral color, long lasting, low maintenance cement fiber shingles. The roof is standing seam steel with integral photo voltaic cells that produce more electricity than the building is using!

A quick review indicates that this building if it had been built with all the budget deferred items and construction had been done per spec the building would qualify for a LEED Platinum Certification. As it is it could certainly qualify for Silver and perhaps Gold Certification.

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