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The expansion of Washington D.C.'s Dulles International Airport showcases energy conservation, ice harvesting and thermal storage
n the early 1960s when Washington D.C.'s Dulles International Airport (IAD) was originally constructed, few locals believed that the airport would ever reach the design capacity of the initial terminal building, much less exceed it. In the ensuing decades, however, the explosive development of formerly rural Loudun and Fairfax counties has contributed to the dramatic growth of air traffic through the airport. IAD currently accommodates 850 flights and 34,000 passengers traveling through its terminal everyday and traffic is still growing. For this reason, Dulles is in the midst of a major expansion. In the past few years, this effort has encompassed expansions of the original terminal and Existing Utility Building (EUB), the construction of a new Midfield Concourse, a new Ramp Control Tower and a new commuter terminal. As a subconsultant to Hellmuth, Obata and Kassabaum, Michael Baker Corporation performed the mechanical, electrical, plumbing and fire-protection engineering for the new Midfield Concourse, the new Ramp Control Tower and the Utility Building East Expansion (UBEE).
Fulfilling a vision
The Metropolitan Washington Airports Authority (MWAA) initially envisioned the new Midfield Concourse as a 44-gate, 4,000-foot-long, stand-alone project. The building was to contain all of the utilities necessary for its operation. As its first project task, Baker was asked to perform an analysis of what equipment would be required to heat and cool the building. MWAA's sole requirement for the heating ventilation and air-conditioning (HVAC) systems was that no rooftop equipment be used. Roof-- mounted equipment was deemed visually undesirable in a facility in which the majority of its users enters or leaves the facility in an airplane. It was quickly determined that cooling towers would not be acceptable in the Midfield environment since the towers' plumes could restrict visibility from either the ground-control or the flight-control towers. Similarly, it was determined that the combustion gasses from fuel-fired boilers would present a similar problem. This left electric boilers and air-cooled chillers as the means of heating and cooling the new concourse. Further analysis, however, revealed that electric boilers would be too expensive to operate and that air-cooled equipment, which would have to be located at grade, adjacent to the building, would...