Because the air does not have to be blown down from the ceiling to the audience, the velocity of air can be greatly reduced, and smaller, quieter fan motors can be used. This also saves energy and results in better, quieter room acoustics.
The higher supply-air temperature also means the air systems can use outside air without cooling for a greater proportion of the year. This type of system is called "displacement ventilation," and it relies on natural convection to lift the warm, stale air to a higher level.
Because the air above 6 feet (1.8 meters) is not mixed, about half the heat gain from people and nearly all the lighting gain is convected out of the space before it causes a temperature gain in the occupied zone. Carbon dioxide sensors further limit unnecessary heating and cooling of outdoor air.
Another advantage of this system is that the supply air is in contact with the concrete structure below the seating. This allows the structure to perform as heat storage. At night after a performance, cool night air can be blown into the plenums, cooling down the concrete mass. The following day, warmer outside air can be introduced, and the structure will absorb the heat, cooling the air before it enters the occupied zone.
The smaller, 250-seat studio theater is cooled from above by a variable air volume (VAV) air handler and heated from below with an under-floor hydronic (radiant) heating loop. This duct system with floor registers allows for a much smaller heating system than is found in traditional theaters.
The main lobby is cooled with a variety of custom displacement diffusers at each of the four floor levels. Poured concrete "trenches" provide an air path that serves the lowest level.
To reduce the need for cooling, the Mondavi Center is protected from the strong California sun in a variety of ways. The public lobby, which is wrapped in glass to provide views to adjacent parks, is shielded from excessive heat gain by exterior aluminum sunscreens.
These screens were carefully designed to block the sun's rays before the radiant heat enters the space but to not block the views in or out. At the same time, windows and skylights are designed to optimize natural illumination, reducing the need for electric lighting.
On the east wall of the lobby, a large white steel trellised canopy acts as a sun visor to protect the lobby glass and to provide shade over the entire entry porch and pedestrian walkway leading into campus. This architectural language of trellises and shaded walkways and porches carries on a campus tradition that is functional and beautiful.
The building's mass is sited on the east-west axis for optimum solar orientation. Exterior surfaces are well insulated, especially the fly tower. Light-colored, heavy exterior materials minimize heat absorption. Heavy and dense interior materials in the large performance hall and lobby provide mass for night-cycle cooling.
Passive cooling is achieved through double roof and double wall construction. Two feet of air space separate the inner and outer walls. Likewise, there is a basement under Jackson Hall, and a "technical attic" at the ceiling. This creates a "box within a box" for the desired acoustical isolation of the hall.
The exterior walls are made from sandstone from India. The color of the stone recalls the dominant warm and neutral tones of other UCD campus buildings and early agrarian buildings of the region. This stone and the slate paving tiles are used on both exterior and interior to blur the line between architecture and landscape.
The exterior materials, such as the white single-ply roof and the light tan veneer stone, were chosen not only for their durability and appearance but also for low absorption of solar radiation.
Many products used in construction were made from natural and/or recycled materials. Douglas fir was provided by Ruby Lake Wood Products, a certified sustainable supplier of recycled fir salvaged from the bottom of lakes in Canada. Sustainably grown bamboo was chosen for the wood flooring system in Jackson Hall.
Nontoxic materials with low volatile organic compounds were specified for paint, wood sealer, and adhesives.
And capping its list of sustainability attributes is the facility's nod to low-energy transportation. The Mondavi Center is served by the campus shuttle bus, which is fuelled by natural gas, and the new building provides parking for 125 bicycles.
Despite material choices designed to make the new facility fit comfortably into its agrarian environment, the Mondavi Center changes the appearance of the campus, where the visual focus is no longer the water tower.
Stanley Boles, FAIA is principal of BOORA Architects, in Portland, Oregon.
Architect: Boora Architects
Cost consultant: Davis, Langdon, Adamson
Acoustical design: McKay, Conant, Brook
Landscape design: Peter Walker and Partners
Theatrical design: Auerbach + Associates
Landscape documentation: Walker Macy
Structural, mechanical, plumbing, electrical, and telecommunications design: Arup
Civil engineer: Morton & Pitalo
Lighting design: Auerbach + Glasow
Graphics design: Mayer Reed