High Performing Buildings - Winter 2008 - (Page 21)

LESSONS LEARNED Although east-west is the conventional energy-efficient orientation for a rectangular-shaped building, north-south orientation produced a number of advantages at the southerly latitude of 29° 38' 49" N. Daylight Duration The total duration of daylight hours increased more than 30% with the north-south orientation. Half of the solar day is glare-free light (west/morning and east/afternoon) and the other half of the solar day has the sun traverse from sunrise to noon and noon to sunset. Modern glazing, lighting technology, exterior wall options and interior architecture strategies used in high performance buildings have helped to solve past problems caused by glass façades. In addition, at this latitude, the noonday sun is high in the sky, varying from 37° in the winter to 83.8° in the summer. For this reason, significant reduction in the net deep daylight potential of a south-facing elevation exists. Circadian Cycle Preserving the natural or benign variability of the light while the glare, heat and ultraviolet components are moderated results in an interior space that tracks a day in nature. The variability of cloud cover, angle of the sun, and color of the sky creates a stimulating and deep-seated connection to circadian and seasonal cycles that are central to human biological function. Energy Savings Because the number one consumer of electricity in the workplace and learning environment is electric lighting, the most economically beneficial use of solar energy is to use its visible light spectrum to directly replace electric light, avoiding pumps, collectors, silicon panels, inverters, etc. Therefore, maximizing the amount and depth of daylight projected into Rinker Hall reduced energy use from electric lighting. An important tool available to the architect/engineer to reduce energy use from electric lighting is the continuous dimming photocell sensor with the solid-state electronic ballast of the lighting system combined with an effective low-angle daylight louver and diffusion system, appropriate ceiling geometry, and a range of interior surface reflectances. The final facilitation of this strategy comes with joining the thermally advanced performance of exterior walls to the correct ratio and positioning of the high performance and wavelength selective glazing. The lesson learned is that the thermal advantage to be gained in the conventional east-west orientation can be more than offset in the north-south orientation by the additional electrical lighting savings, not to mention the productivity and well-being enhancements of an optimized distribution of low-angle daylight. Materials Minimization A vigorous pursuit of materials minimization led in one case to an acoustical problem associated with HVAC noise in several classrooms. In a visually shielded area at the front of the typical classroom, a 100% accessible ceiling, open to the underside of the slab above, was used to achieve maximum accessibility for future retrofits. Overzealousness in leaving this exposed underside of slab had to be compensated for by an acoustic surface retrofit on the exposed slab. The metal and glass building is preferable for Rinker's location in a humid climate belt, while the freestanding masonry wall addresses campus context and moderates high thermal loads on the west. escalations and does not capture the productivity and well-being beneﬁts. Rinker Hall raises a basic question about green premiums, which is the additional cost of sustainable design. If this building was completed at the same cost per square foot of a nongreen building via strategic redistribution of total dollars and also met the conventional building schedule, no premium exists. Simply stated, for any given budget and schedule, there is a highest sustainable outcome, and Rinker Hall conﬁrms how signiﬁcant that highest outcome can be. • Photo © Timothy Hursley ABOUT THE AUTHOR Randolph Croxton, FAIA, is the president of Croxton Collaborative Architects, P .C., located in New York City.

Table of Contents Feed for the Digital Edition of High Performing Buildings - Winter 2008

High Performance Buildings - Winter 2008 Passing On the Gift: Heifer International Headquarters Head of the Class: University of Florida’s Rinker Hall How Far Can You Go? Pearl River Tower The Proof Is Performance: How Does 4 Times Square Measure Up? Lighting the Way: Two Guilford County Schools Montreal’s Retail Example: Mountain Equipment Co-op® (MEC)

High Performing Buildings - Winter 2008

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