Green buildings save green in Arizona

In Phoenix, Arizona, where the temperatures can soar well above 110ºF in the summer, the state government is always looking for ways to conserve energy and use resources more wisely. Since research shows that new commercial construction can achieve dramatic energy savings using an integrated design approach and carefully implemented energy performance strategies, the State of Arizona adopted LEED (Leadership in Energy and Environmental Design) guidelines for their new buildings. LEED provides a framework for assessing building performance and meeting goals for sustainable site development, water savings, energy efficiency, materials selection, and indoor environmental quality.

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When two new state buildings were up for bid – the Arizona Department of Administration (ADOA) and the Department of Environmental Quality (ADEQ) – recent State mandates required that the buildings be designed to take advantage of all energy saving initiatives consistent with LEED certification. Opus West, a member of the Opus Group – a national, award-winning full service architectural and engineering firm submitted the winning designs for the buildings. To comply with the State of Arizona's energy conservation goals, Opus West utilized a number of energy conservation methods such as high performance glazing to lower energy consumption. For heating, ventilating and air conditioning, the building design relied on floor-by-floor vertical self-contained units.

Daikin representatives, Climatec, and Rick Sturm, President of Cornerstone Engineering, the mechanical design engineers for the project, felt that they had the ideal solution for the State of Arizona using Daikin SWP Self-Contained Air Conditioning Units.

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The Daikin SWP units offered tremendous design flexibility – with 75 pre-engineered compressor and coil combinations, air and waterside economizer capability and variable frequency drive fan control – versus other self-contained systems being considered for the project. Using a waterside economizer to precondition outside air with cooling tower water, Daikin was able to mix and match coil sizes, rows, fans and compressors to more closely match the load of the overall system.

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This design flexibility resulted in the Daikin units offering an energy use rating that measured below 0.7 KW/ ton. While the equipment cost of the Daikin self-contained units was higher, Arizona law requires that all energy saving components or designs to be evaluated. If the payback for the additional cost is eight years or less, then the component or design change has to be made. After reviewing all submittal data, Sturm was able to demonstrate to Opus West and the State of Arizona that the added cost of the Daikin units was paid back in 27 months of operation. In addition, the high efficiency of the Daikin units helped both buildings achieve LEED certification.