Clean Mountain Air

A second case study involves a classroom building for Sierra College in Truckee, California, elevation 5,800 feet, characterized by snowy but sunny winters and cool, low-humidity summers. Sacramento architects Lionakis Beaumont Design Group worked with Vail, Colorado-based Beaudin Ganze Consulting Engineers (BGCE) to take full advantage of climate factors to reduce fossil-fuel consumption. They oriented the building to the south to maximize solar access for heat, light, and snow melt. In keeping with a ski-lodge vernacular, they used stone, wood, and exposed structure but stopped short of roof overhangs because of the structural load and hazards snow would cause. Now in construction, the building is expected to achieve LEED Silver.

BGCE senior associate Wesley Ploof, PE, reports on the firm's energy modeling effort. He explains they chose EnergyPro as their primary software because its output directly documents Title 24 compliance. "For most of our work outside California, we prefer to use Trane Trace. It's very effective all-around software-it documents LEED compliance in terms of comparisons to a minimally ASHRAE-compliant building."

Ploof's colleagues modeled a variety of wall insulation levels and glazing types before establishing an optimum combination that fit the budget. When they realized they wouldn't be able to rely on overhangs for solar shading, they gave extra emphasis to high-quality, spectrally selective glass to keep unwanted solar heat gain down. They recommended smart controls to regulate temperature and lighting, room by room, hour by hour, according to daylight availability and number of occupants. Because the modeling looked at hourly interactions of external and internal thermal conditions, BGCE was able to recommend a mechanical system without refrigerants. The system instead relies on evaporative cooling, economizer cycles, and natural ventilation. As a result of all this moving air, the energy required for fans is actually higher here than in a comparable conventional building, while the overall mechanical system is far less energy consumptive.

These reduced operating costs will pay for the extra design effort over time because, unlike many commercial building owners, the institutional owner is also the tenant and will directly benefit from future savings.