High Performing Buildings - Winter 2008 - (Page 6)

Photo © Timothy Hursley The 22-acre reclaimed site is among the largest brownfield recoveries in Arkansas. Approximately 97% of building materials on the site were recycled, providing enough fill material to cover demolition costs. on each ﬂoor used for outdoor meeting rooms and tree-like columns extend visually into the wetland, representing the symbiotic relationship possible between the man-made and natural. The building and site blend seamlessly into Riverfront Park, extending existing paths into the building for access to the river and trails. The building incorporates a raised ﬂoor system, light and motion sensors, low or non-toxic emitting materials, and high recycled material content. An inverted heavy timber roof directs rainwater through an exposed collection system to a tower for reuse as gray water within the building. Glass wrapped stairs are pulled to the edges and ﬂoat over water, allowing natural convection to pull cooled air off the water’s surface up through the stairs. Water is collected through permeable gravel-pave parking into bioswales between parking bays. Vegetation naturally scrubs pollutants and moves it to where it is needed. Water is then stored in the wetlands that surround the building, irrigating the site with little reliance on outside sources. An industrial wasteland is becoming a thriving ecosystem. Daylighting The design team made several key decisions early on that had a major impact on the overall efﬁciency of the building. The most signiﬁcant of those was optimizing the daylighting capabilities of the facility. With a W AT E R C O N S E R VAT I O N S Y S T E M S In this project, water is retained, recovered and recycled to reduce the use of potable water from the city. Water conservation features include collecting rainwater, recovering water from the lavatories, and using condensate from one ventilation unit. These features and others, such as waterless urinals in the men’s toilets, produced a 65% reduction in potable water use compared to a conventional building. The roof is sloped to facilitate the collection of rainwater in a 20,000 gallon tank. The stored water is made available to offset use of potable water. Over the course of a year, more than 528,000 gallons of water are recovered from the roof and used instead of potable water. Water is also recovered from lavatories and showers for recycling and re-use. Over the course of a year, more than 259,000 gallons of this gray water are recovered and recycled. The condensate from one of the ventilation units is added to the water for recycling. Only one unit is used because the length of the building prevents gravity drainage of the other ventilation unit’s condensate for recycling. The condensate and gray water are drained into a two compartment gray-water tank. The gray-water system strains and filters the water and uses an ozonation system to sterilize it for use in appropriate systems. The ozonation also prevents foaming when the water is recycled and reused. An ultrasonic water level measurement device controls the admission of rainwater or RPZ isolated potable water to the system. The water is used as flushing water for the toilets in the building and makeup water for the cooling tower. If the gray water and condensate drainage can supply these uses, no rainwater or potable water is admitted to the system. If the level drops to a point that indicates additional water is needed, then rainwater is admitted from the rainwater tank. If rainwater has been exhausted and more water is needed, than potable water is used. This building is projected to use 1,182,000 gallons of potable water per year compared to a conventional building’s requirement for 3,402,000 gallons of potable water. The project has no landscape irrigation that uses potable water and no irrigation was considered in the conventional building calculations even though conventional landscaping would consume large amounts of water. The natural water feature that surrounds the building is not supplied by the gray-water system. Site groundwater is used for that purpose. 6 HIGH PERFORMING BUILDINGS Winter 2008

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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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