It is not often that travelers slow down and admire their surroundings while racing to catch a flight, but the airport in King County, Wash., warrants a pause.
The historic and efficient King County International Airport is one of the country’s busiest non-hub airports, averaging 200,000 takeoffs and landings annually, primarily cargo flights followed by local passenger and private flights. During a visit by Washington, D.C.-based U.S. Department of Energy (DOE) representatives to King County—a partner of the DOE Better Buildings Challenge—airport officials led a walking tour that provided a close look at how the county performed a deep energy retrofit of the airport terminal. (Read the DOE case study of the terminal.) By incorporating high-efficiency energy technologies and practices into the airport’s heating, cooling, and lighting systems, the county produced an impressive 60 percent energy savings and $31,000 per year in cost savings, as well as provided a model for similar deep retrofit projects. The Better Buildings Challenge exists to support and highlight its partners’ leadership in energy efficiency and share their solutions so that other organizations can achieve similar impactful results. Learn more here.
To achieve energy savings of 60 percent in its historic airport terminal while improving traveler and building occupant comfort and reducing staff time spent on building maintenance, King County focused on six key strategies:
1] A long-term investment perspective: The county and its project partners understood that the mechanical system was at an age at which it needed to be replaced; the incremental cost of selecting highly efficient technologies over less efficient replacements was an estimated $350,000. But with a return of around $31,000 per year from energy cost savings and a utility efficiency rebate of $74,000, the investment in efficiency pays back in less than nine years and delivers net cost savings thereafter.
2] Working with the state and local utility: The county successfully worked with state and utility partners to further improve the project finances. The Washington State Department of Commerce awarded a $300,000 grant to King County to help fund the project. Seattle City Light, Seattle’s publicly owned electric utility, provided additional energy-efficiency incentives of $74,000.
3] Holistic approach: The county replaced mechanical and lighting systems throughout the 25,000-square-foot facility, in addition to the lighting for the building exterior and parking lot. The project highlighted how this approach coupled with a modern design can dramatically reduce energy use.
4] State-of-the-art technologies: a. Variable Refrigerant Flow (VRF) heat pumps and a Dedicated Outdoor Air System (DOAS) replaced existing multi-zone air-handler rooftop units. The VRF system is fully programmable with controlled zones and set points aligned for occupancy and use. Carbon-dioxide sensors control ventilation in conference rooms.
b. The county installed two new, high-efficiency heat-recovery ventilators, which achieve up to 90 percent heat recovery, providing building ventilation previously delivered by the rooftop multi-zone air handlers noted in bullet a. The innovative heat-recovery ventilators are relatively new to North America and create deeper energy savings than traditional heat recovery, as well as significantly reduce the need for supplemental heating and cooling.
c. The county replaced interior lighting with a mix of innovative and cost-effective technologies. In most spaces, 15-watt LED lamps replaced 32-watt fluorescent tubes. Some areas with high use and sufficient daylighting received fixtures with luminaire-level lighting controls. These spaces take advantage of daylight harvesting and occupancy sensors.
d. Utilizing these fixtures created the unexpected result of a perceived increase in lighting output from the LED lamps and caused airport staff to report some spaces as over-lit. Consequently, in those zones, the airport dimmed those fixtures to 75 percent output, improving visual comfort and enhancing energy savings.
e. The county upgraded outdoor airport ramp and parking-lot lighting to LED technology from traditional metal halide and high-pressure sodium fixtures, as well as employed night setbacks to 50 percent of full lighting levels. A microwave-based occupancy-sensing system controls exterior lighting at night, dimming the parking-lot lights when no vehicles are present and the tarmac lighting when no planes are approaching.
5] Staff engagement to ensure savings: Prior to the retrofit, staff often used personal electrical devices, such as fans, task lights and space heaters, in their workspaces. Following the deep energy retrofit, staff discontinued the use of these personal electrical devices to further reduce energy use and improve energy cost savings.
6] Addressing unique building challenges: The Main Terminal is a 2-story masonry brick building constructed in 1929, making it one of the oldest airport terminals in the country. There have been several renovations and numerous interior improvements since original construction, including heating system conversions from coal to oil to natural gas and now carbon-free electricity. This project illustrates how historic buildings can achieve deep energy reductions, exceed advanced energy-code requirements and reduce climate-change impacts. The county’s project team also successfully obtained special Federal Aviation Administration clearance for use of a crane to set new rooftop VRF and DOAS equipment and remove the old HVAC rooftop units.
Photos: KING COUNTY