Consulting-Specifying Engineer - October 2008 - (Page 44)

The 320,000 sq ft Alliant Energy World Headquarters in Madison, Wis., uses a cooling system comprised of variable-speed water-cooled centrifugal chillers that serve the building and build 3,240 ton hours of ice storage. To enhance the cooling system even more, a water side economizer is used. The hot water for the heating systems comes from multiple sealed combustion boilers. The distribution for both the hot water and chilled water system is done via variable speed primary/secondary pumping. The airside system of the building uses multiple variable-speed air-handling units and fan-powered variable air volume boxes. Future expansion was taken into account when designing the mechanical system. financial implications. Ultimately the client is the final authority; design professionals are responsible for providing sound advice that will aid the owner’s decision-making process. This serves two purposes. First, professional ethics demands an honest and open dialogue based on available facts, and second, to limit the liability exposure for inaccurate advice. appearance of an acceptable guideline for the profession. However, LEED guidelines are not specific; they do not outline systems, components, or methodologies. LEED is more a list of suggestions regarding environmental considerations and energy efficiency and relies on industry standards such as ASHRAE to establish benchmarks. Design documents, narratives and point data sheets are submitted to the USGBC for a subjective review, subsequent award of points, and eventually a plaque to be placed on the building. There is a potential for feel good versus practical. Inevitably there may be circumstances in which the driving force will be to maximize points rather than the technical practicality or financial considerations for an appropriate functional design. Generally speaking, anything will work if enough money is thrown at it. Obviously this needs to be discussed with the owner. There is a fine line between leading technology and bleeding technology. There is nothing wrong about pushing the design limits. However, does the client want to be a research project? Years ago, a medical facility wanted to have a state-of-the-art heating and cooling system, and geothermal systems were being presented as the latest and greatest technology. Getting heat from the earth, a virtually unlimited supply, for the building was a substantial task and would require approximately 1,700 tons of cooling. Utility rebates and other financial incentives justified the first cost. In lieu of wells, a small lake was created as the heat sink. Geothermal heat pump systems work because there is a continuous cooling load. Mechanical energy used to do the cooling is recovered for heating. A requisite component is a continuous cooling load in the winter months. The lake was built, heat exchangers installed, several hundred heat pumps were installed, and the system was commissioned and monitored. Generally speaking, anything will work if enough money is thrown at it. Perception is everything The perceived authority/guideline is LEED. The manuals provide a list of measures that can be implemented with a ranking system that assigns points. The total number of points provides an indication of how successfully the building meets the environmental and energy efficiency guidelines set forth by the USGBC. This has the 44 Consulting-Specifying Engineer • OCTOBER 2008 Photos courtesy: Alliant Energy

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Consulting-Specifying Engineer - October 2008 Contents Viewpoint Letters News M/E Roundtable Cities Under One Roof Eight Design Tips for Integration Is 'Green' Really New? Down the Drain Product of the Year Awards Codes & Standards Case Study New Products Equipment Lifecycles Advertiser Index Green Space

Consulting-Specifying Engineer - October 2008

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