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Reducing the volume of air moved around the new Meeting House addition with this strategy means less ductwork, lower fan energy costs, and reduced noise. And more fresh air can be provided to occupants at a reduced energy cost.

Based on utility bills from 2010, the addition's energy use intensity (EUI) is 9.75 kilowatt-hours per square foot per year (105 kWh per square meter per year).

ArchitectureWeek will discuss this sensitively designed project in depth in a forthcoming article.

Green School Rebuilding

A deadly tornado swept through Greensburg, Kansas, in May 2007, killing a dozen people and destroying most of the buildings. Afterwards, this town of under 1,000 people developed a sustainable comprehensive master plan for rebuilding.

One key element was the school system. Kiowa County Unified School District 422 opted to combine all its schools in a single building designed to achieve LEED Platinum certification, setting a precedent for green design that the City of Greensburg later mandated for all new public buildings. The school was sited in a new location along Main Street to encourage density and walkability.

BNIM's design for the two-story, 132,000-square-foot (12,300-square-meter) Kiowa County Schools building focused on daylight optimization in occupied spaces. The classrooms are arrayed along two single-loaded corridors — each oriented east-west to optimize solar orientation and natural ventilation — forming the two long bars of an irregular H shape. The preschool, elementary school, and middle school classrooms are located in the southern bar, whose plan bends slightly to create distinct zones for the three schools. The high school occupies the second story of the northern bar, above shared spaces such as the cafeteria and distance-learning facilities. Linking the two main wings, a short connector contains the main entrance and library, and on northernmost side of the school stands the gymnasium.

During normal school hours, classrooms and other interior spaces are almost entirely daylit, with perforated exterior sun shading devices, interior light shelves, and roller shades enabling control of the amount and quality of daylight entering. The combination of low, south-facing operable windows and north-facing clerestories takes advantage of prevailing breezes from the southwest for cooling.

The building uses an estimated 8.15 kWh/ft²/year (87.7 kWh/m²/year) of energy — all wind-generated, mostly from a wind farm outside of town.

Energy-Efficient Research

In Golden, Colorado, a new government office building takes the Greensburg school's H-shaped, east-west-oriented plan and scales it up in size.

Like the Greensburg building, the Research Support Facility at the Department of Energy's National Renewable Energy Laboratory (NREL) arranges offices in two long, narrow, 60-foot- (18-meter-) wide wings to facilitate daylighting and natural ventilation. Ninety-two percent of regularly occupied spaces are daylit, with aggressive shading to limit solar gain.

Targeting net-zero energy use and LEED Platinum certification, the 222,000-square-foot (20,600-square-meter) facility is estimated to use 50 percent less energy than if it were built to the ASHRAE 90.1-2004 standard. Delivered by a design-build team including architect RNL and Haselden Construction, the new building provides space for over 800 staff and also houses a data center for the NREL campus. The project is also intended to demonstrate green technologies for the building industry.

Thermal comfort is addressed through an integrated system of thermal mass, radiant slabs, night purging, and natural ventilation. A labyrinth of massive concrete structures in the crawl space stores waste heat from the data center and heat from the transpired solar collectors for passive heating. A technology developed at NREL, the solar collectors employ a dark-colored, perforated metal plate on the south side of the building to preheat ventilation air.

Keeping the building footprint narrow to facilitate passive design features also led to a correspondingly high quantity of exterior envelope, which was challenging to design and construct within the overall budget. To address this, the team used modular construction — specifically, insulated precast wall panels — and optimized the amount of glass, avoiding over-glazing the main office wings.

The detailed energy model for the building predicts an EUI of about 9.7 kWh/ft²/year (104 kWh/m²/year). The onsite photovoltaic system, which is not yet complete, is sized to achieve net-zero energy use for a slightly higher EUI.

The construction cost $57.4 million, or $259 per square foot ($2,790 per square meter). The total project cost of $64 million does not include photovoltaics.   >>>

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SUBSCRIPTION SAMPLE The primary structural system of the new Unitarian Meeting House addition consists of unmilled wood columns and wood-laminate beams. Synthsized Photo: Zane Williams/ The Kubala Washatko Architects, Inc. Extra Large Image SUBSCRIPTION SAMPLE The primary spaces of the Meeting House addition are arrayed along a shallowly curving, glazed circulation spine that extends from a modest covered entrance at its eastern end. Synthsized Photo: Zane Williams/ The Kubala Washatko Architects, Inc. Extra Large Image To replace school buildings in Greensburg, Kansas, that were destroyed in a devastating 2007 tornado, BNIM designed a new, combined K-12 facility to serve the entire Kiowa County school district. Photo: © Farshid Assassi Extra Large Image Targeting a precedent-setting goal of LEED Platinum certification, later mandated for all new public buildings in Greensburg, the Kiowa County Schools building includes numerous green features, such as extensive daylighting, rainwater collection, and a 50-kilowatt wind turbine. Photo: © Farshid Assassi Extra Large Image SUBSCRIPTION SAMPLE Reclaimed wood was used on the interior and exterior of the Kiowa County Schools building. Photo: © Farshid Assassi Extra Large Image RNL designed a new Research Support Facility for the Department of Energy's National Renewable Energy Laboratory in Golden, Colorado. Photo: Frank Ooms Extra Large Image Targeting net-zero energy use and LEED Platinum certification, the NREL Research Support Facility is extensively daylit, and employs a rooftop photovoltaic array along with transpired solar collectors mounted on its south facades. Photo: Frank Ooms Extra Large Image The entry of the NREL Research Support Facility is in the narrow central bar of the H-shaped building plan, at the head of a widening courtyard. Photo: Frank Ooms Extra Large Image   Click on thumbnail images to view full-size pictures.