Portland (ME) Airport’s Geothermal Project – Providing the Cooling (and heating) Power of an Iceberg

06.27.2011 | HMMH |

by Steve Barrett

Portland International Jetport in Portland Maine is in the latter phases of constructing a $75m airport terminal expansion.  As part of the project, the City of Portland received $2.5m in funding from the FAA’s Voluntary Airport Low Emission (VALE) Program for a geothermal heating and cooling system that will serve the new terminal building.  VALE provides dedicated funding for projects that reduce airport emissions.  The funded geothermal system in Portland will avoid the need for 50,000 gallons of oil (and the emissions associated with its combustion) that would be needed to heat the space each year.  The upfront investment has an economic payoff as well producing $200,000 a year in savings and $8m over the life of the system.  The airport is seeking LEED Silver Certification for the terminal as a green building.

Bob Miller, Phil DeVita, and I got a close-up look at the terminal and geothermal system last week when Roy Williams, Deputy Director at the Airport, facilitated a tour for us.  After welcoming us and affirming the success of the geothermal system and terminal project, which is expected to be complete in September, he turned us over to the care of Turner Construction, the construction manager for the Terminal Project.

We donned hard hats, orange vests and protective eye ware (Bono-style) for our tour through the active construction zone.   As we made our way from the construction trailer to the new terminal building, we looked over at the geothermal wellfield which is now covered by a new employee parking lot.  The visuals of a geothermal system are akin to an iceberg where the bulk of the system and its “gravitas” lie below the surface.  The wellfield consists of 120 wells dug 500 feet deep to tap groundwater used to deliver heating and cooling as dictated by the weather.  Inside the terminal building, weaving our way through the work-in-progress, we found the tip of the geothermal iceberg residing in the mechanical room.  It consisted of a myriad of pipes: large arteries pumping water directly from and back to the wells, and smaller capillaries distributing conditioned water throughout the building.  Eight heat exchangers warm and cool the water from its base temperature of 55 degrees Fahrenheit before circulating it.  The footprint of the entire system occupies a room about the size of an elementary school classroom.

With its large windows delivering lots of natural light and the eight enormous wooded beams and rich wood ceiling, even half finished, the terminal made a good impression.  Just wait until the finished product is unveiled this fall!  The terminal’s less flamboyant geothermal system gave us HMMHers some perspective on how airport geothermal has been effectively utilized for both the environment and energy efficiency.  This information will be valuable to us as we are presently working with Manchester-Boston Regional Airport (NH) on a VALE geothermal project conceived to be nearly an order of magnitude larger than the system in Portland.  Now that will be an iceberg!