High Performing Buildings - Spring 2008 - (Page 26) W AT E R S U P P LY A N D U S E The water use strategy for this building includes rainwater harvesting on a large section of the building’s roof. Rainwater collection on 38% of the roof area, 3,994 ft2, reduces projected potable water use by 77% compared to a baseline building. Rain from the roof is routed through one of two rain washers. The rain washers strain out large debris such as leaves and twigs before the water enters a 10,000 g , gallon underground g cistern. Water from the cistern is filtered and chlorinated before servicing lavatories in the restrooms and classroom, as well as the janitor’s mop sink. The exterior wall hydrants and spray for the composting bins, when necessary, use filtered, nonchlorinated water. Potable water from the local municipality services the drinking fountains, a lavatory in the kitchenette, and one of two lavatories in the classroom. A municipal water connection to the rainwater cistern serves as a backup water supply in the event of extended drought. North Georgia has experienced extreme drought conditions since the building opened in July 2006. In spite of the drought, the rainwater cistern maintained adequate water for the building’s nonpotable uses for 15 months. In October 2007, municipal water was added to the cistern for the first time. heating required to condition ventilation air. With the photovoltaic energy generation, the estimated annual net grid-supplied energy consumption of this building is 56,016 kWh. Without the photovoltaic production, the annual energy cost is $11,996 26 HIGH PERFORMING for the budget building and $7,380 for the proposed building. Factoring in the energy use reduction from the photovoltaics, the total annual energy cost is $5,894. Overall, when compared to Standard 90.1-1999 base case, the building saves 57,969 Spring 2008 kWh or $6,102 per year (including the photovoltaic production). An estimated 27 tons of CO2 emissions are avoided per year. Figure 2 compares the electricity end use cost breakdown between the base case building and design case building. BUILDINGS
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.