Within the Arctic Circle, among icebergs and glaciers, there is a fortress in Thule Air Base, Greenland. Inside, U.S. Air Force men and women have their eyes locked on computer radar screens. They have the immense responsibility of tracking foreign military rockets and missiles using large powerful radars. The moment a threat is detected they’re able to communicate directly with the White House.
This is one of several critical missions they are performing for America’s national security at Thule Air Base, supported by the U.S. Army Corps of Engineers, New York District. The base is home to hundreds of active-duty U.S. Air Force personnel and American, Danish and Greenlandic civilian contractors.
For decades, under extreme Arctic conditions, the Army Corps has constructed facilities for the base in support of the Air Force’s mission.
These facilities include aircraft runways, dormitories and medical centers. Most recently the Army Corps improved the base’s heating system by replacing outdated and inefficient boilers with energy-efficient exhaust gas boilers that will save the U.S. Air Force and taxpayers millions of dollars in fuel costs.
“Two Lee” – is a 254 square mile base located in a coastal valley in the northwestern corner of Greenland, within the Arctic Circle. The base is the United State’s northernmost military installation and is nestled between mountains and surrounded by icebergs and glaciers as far as the eye can see.
New Energy-Efficient Heating System
The base’s heating system boilers were in need of replacement because they were either no longer operational or operating very inefficiently. Recoverable heat from the system was being lost to the atmosphere and a considerable amount of fuel was being consumed to make up for this loss. The U.S. Air Force expressed to the Army Corps that it needed to replace and upgrade the boilers and make the heating system more energy efficient.
The Army Corps at the request of the U.S. Air Force has designed the system and is performing this work with Denmark-based contractor GC/MTHøjgaard. According to Stella Marco, project manager with the Army Corps’ New York District, the new system is expected to save the U.S. Air Force and tax payers $3 million annually in energy and fuel costs.
Before this project began, the base’s heating system consisted of three structures that included a building called the M-Plant that provided the base’s electricity and some steam and two steam plant facilities that provided the base’s steam for heating and hot water. All of these buildings used considerable fuel to run engines and boilers.
The Army Corps is removing the old boilers and installing four new exhaust gas boilers in the M-Plant which will practically consolidate all steam production under the M-Plant’s roof. To make room for these boilers an extension was built onto the M-Plant. The two steam plants will serve as an emergency backup heating source. This consolidation will save the base approximately 1.6 million gallons of fuel annually.
Two boilers were installed this past summer and two more will be installed next summer when it’s warmer again to perform construction.
The new exhaust gas boilers are connected to the M-Plant’s existing five 12-cylinder Cooper-Bessemer diesel engines that drive five large generators, each rated at 3,000 kilowatts. Each diesel runs on jet fuel (JP-8). These large engines produce an abundance of exhaust fumes at a temperature of 700-840 degrees Fahrenheit.
“The diesel engines that drive these generators are very much like those found in today’s vehicles only much larger and stationary,” said Robert Philbrick, Air Force Team Leader, U.S. Army Corps of Engineers, New York District.
“They convert fuel oil into mechanical energy to turn the electric generators, instead of turning vehicle wheels. The exhaust fumes from these engines are usually released directly to the atmosphere via an exhaust pipe,” said Philbrick.
“The new boilers the Army Corps is installing are energy efficient and economically feasible because they’re taking these exhaust fumes to create steam that can be used for heating and hot water throughout the base. The old boilers, due to their age and disrepair, wasted the fumes to the atmosphere,” added Philbrick.
The exhaust fumes are lead into the exhaust gas boilers by the exhaust pipes. An exhaust gas boiler is a large cylinder that is filled with water with tubes or pipes submerged in the water that run from end to end of the cylinder.
The fumes enter the boilers tubes and heat the water surrounding them converting the water into steam. When the exhaust fumes leave the boiler it’s about 330 degrees Fahrenheit. This steam is then piped to all of the base’s buildings to use for heating and hot water.
When the steam reaches a building it goes into a mechanical room where it enters a heat exchanger and the steam is used to create hot water. The hot water flows through the building’s radiators and heat the rooms.
Construction work in an Arctic Environment
Construction can be challenging due to severe weather and limited daylight, which requires the use of unique building techniques and fast paced construction.
Construction is limited to the summer and autumn months, from May through October, because there is sufficient sunlight and temperatures are bearable to work in. Temperatures can reach 40 degrees Fahrenheit and there is 24 hours of sunlight from June through August.
During the remainder of the year, there are severe storms and temperatures have dropped as low as minus 30 degrees Fahrenheit. There is also 24 hours of darkness from November through February.
It is also only during the summer months that shipments of building materials and fuel can be received via cargo. During the summer, Greenland’s iced shipping lanes can be broken up to allow supply ships into port. Greenland is locked in by ice nine months out of the year.
Shipped in building materials include prefabricated parts that enable workers to perform construction rapidly.
In addition to having a short construction window, workers have other challenges including a ground foundation comprised completely of ice.
Most of northern Greenland is covered with permafrost – permanently frozen ground – ranging from 6 to 1,600 feet in depth.
Because of permafrost, most structures have to be elevated including the M-Plant building extension. “If buildings are not constructed off of the ground, the heat from inside the building can melt the permafrost, making the ground unstable and causing buildings to sink,” said Paul Jalowski, Resident Engineer, U.S. Army Corps of Engineers, New York District.
The buildings need to be elevated one meter from the ground. Buildings are elevated with the use of spread footing that goes down about 10 feet deep and concrete columns come up and support the floor system above the ground.
In the case of the M-Plant building extension, the building’s flooring was also insulated to prevent any heat from the building or its equipment, such as the boilers, from heating the permafrost.
Besides buildings, the base’s steam and electrical piping conduits also need to run above ground for the same reason.
Thule Air Base is in the throes of its winter storm season and severe temps can cause frostbite in less than a minute. The base is now benefiting from their more efficient heating system and fuel costs will no longer take a bite out of the U.S. Air Force budget.