Marine Corps Air Station Beaufort, Beaufort County, SC, is home to Marine Aircraft Group 31 (MAG-31), one of the Corps' largest aircraft groups, consisting of seven F/A-18 Hornet Squadrons. The sprawling station covers 6,900 acres, occupies 3.9 million square yards of runways and taxiways, and has played a key role in national and worldwide training exercises and operations, hosting all active-duty USMC RA-18 air operations on the East Coast assigned to MAG-31. MCAS Beaufort has also been designated an alternate landing site for NASA's Space Shuttle.

Commissioned Naval Air Station Beaufort on June 15, 1943, the facility was home base for advanced training and operations of East Coast anti-submarine patrols during World War II. The base was deactivated after the war, reactivated as a Marine Corps Auxiliary Airfield in 1956 and finally re-designated Marine Corps Air Station Beaufort four years later, on March 1, 1960.

Two Navy F/A-18 squadrons also call MCAS Beaufort home. For six months after Sept. 11, 2001, squadrons based at the station, including Marine Fighter Attack Squadron 251 and Navy Strike Fighter Squadrons 82 and 86 flew F/A-18s over Afghanistan in support of Operation Enduring Freedom. Together, the three squadrons dropped more than 1.3 million pounds of ordinance on Taliban and Al Qaeda fighters. In 1993, squadrons from the station participated in Operation Deny Flight during the Balkans conflict, which prevented warring parties in Bosnia-Herzegovina from using air space as a means for war. Other major tenant Fleet Marine Force units headquartered at MCAS Beaufort include Marine Wing Support Squadron 273, which has combat engineer, utilities, heavy equipment, motor transport and construction sections. Another is Marine Air Control Squadron 2, which is capable of establishing a fully functioning expeditionary airfield. Marine Aviation Logistics Squadron 31 performs aircraft maintenance, and Combat Service Support Detachment 23 supports the station with communications, supply, dental and medical personnel, and military police.

MCAS Beaufort is home to 4,200 Marines and sailors and employs 700 civilian workers. In total air station military members, their families and the civilian employees number nearly 13,000. The size of the air station, combined with MAG-31's reputation for tactical proficiency, has earned Beaufort the title “Fightertown.”

The station's mission is to provide the highest quality facilities and support in order to promote the readiness and quality of life for all its Marines, sailors, civilian personnel and family members. By the end of the 20th century, however, the base physical plant had begun to show signs of wear. Although some facilities dated as far back as the 1950s and mechanical equipment was in need of upgrades, funds for repair were not readily available. A systematic approach that would address the range of obvious updating and replacement challenges was difficult to implement.

Despite these liabilities, MCAS Beaufort was under simultaneous directives from the departments of Energy and Defense to improve energy efficiency while upgrading facilities for troop comfort and readiness. Stressing the all-volunteer nature of the armed services, Secretary of Defense Donald Rumsfeld has made quality of life on bases a service priority, not only to attract new recruits but also to keep trained personnel in the military. Concurrently, DOE has made energy reduction a goal for all federal facilities. The command at MCAS Beaufort, therefore, was under a dual mandate to develop financial and operation plans that included meeting federal energy efficiency targets and reducing operating costs while at the same time making necessary building upgrades and meeting environmental regulations. To accomplish these conjoined tasks, the air station entered into a two-phase design/build contract with Trane Commercial Systems. Robert L. Johnson, Trane institutional markets leader, says the project's aims were interrelated. “The goal,” says Johnson, “was to reduce energy consumption and improve energy efficiency while providing troops and civilian workers a more comfortable and productive environment in which to work and live. What we were able to do was put together strategies that addressed both issues simultaneously.”

A Large Portion of Alphabet Soup
At MCAS Beaufort, Trane operated under what the Federal Energy Management Program (FEMP) describes as a Technology Specific Super Energy Savings Performance Contract (Super ESPC). The ESPC program was established with a 1992 Congressional energy bill and was extended until 2016 under the recently passed Energy Act of 2005. Energy Savings Companies (ESCOs) such as Trane arrange financing to develop and install energy and water conservation and renewable energy projects at federal facilities. ESCOs conduct a comprehensive energy audit of a facility and identify improvements that will save energy and reduce utility bills. Most important for federal contractors, ESCOs must guarantee that energy improvements will result in a specified level of annul cost savings and that these savings will be sufficient to pay the company for its work for the duration of the contract. The federal agency in turns uses a portion of the guaranteed energy cost savings to pay for building improvements over the life of the contract. At the completion of the contract, all additional cost savings accrue to the agency. So far ESPC projects worth $1.7 billion have been implemented in 18 different federal agencies and departments in 46 states, saving 13.6 trillion BTU annually, a savings of $4.7 billion in federal energy costs.

To help streamline the complex contracting process, FEMP has implemented Super ESPCs, which are umbrella contracts that allow agencies to undertake multiple energy projects under the same contract by working with pre-qualified ESCOs such as Trane. As the air-conditioning systems and services business of American Standard Companies, Trane has supplied more HVAC products, systems and services to federal, state and local government customers than any other manufacturer. The company had bid on a previous contract at MCAS Beaufort to upgrade base housing, and although it lost the bid to a local utility, it was familiar with operations at the base.

Super ESPCs make it possible for a federal customer to install building efficiency improvements and replace equipment without incurring upfront costs. As FEMP describes it, private sector companies guarantee the federal agency energy cost savings and lower utility bills and operations and maintenance costs along with infrastructure improvements that will enhance mission support and help make progress in meeting federal energy, water and emission-reduction goals.

A critical factor, says Johnson, is that ESPCs must pay for themselves. “The cost of the project cannot exceed the energy savings in any given year.” From the standpoint of the MCAS Beaufort staff, the benefits of the Super ESPC with Trane included not only the guaranteed energy savings but also a 15-year extended warranty on all equipment installed, design/build capabilities, and Trane's local warranty and maintenance support.

“We considered both the ESPC and UESC (Utility Energy Savings Contract),” says Neil Tisdale, maintenance and utility director for MCAS Beaufort. “ESPC gave us the extended warranty, and ESPC contractors commit to monitoring and maintenance for the life of the contract. Savings were guaranteed, and we were able to leverage repair dollars into the contract. And because the savings were complicated, the monitoring and verification requirements of the plan were beneficial. UESCs haven't had this requirement.”

“These performance contract projects are very interactive,” says Johnson. “The customer helps design the goals and outcomes. And I'm talking about a base team, not just the procurement officer or the utility manager. What we end up with is not their spec or our spec but something we both own. We use our Trane modeling program to model energy use in a given building or set of buildings prior to the project and then predict what it will be when we're finished. The final step is the onsite monitoring and verification.”

Accomplishing the contract's conjoined objectives of comfort and energy efficiency required what Johnson described as bundling projects, meaning opportunities were seized as they presented themselves. Critical project elements included replacing the base's central heating plant (a natural-gas-fired, 40-BTU-per hour, high-temperature, hot-water system) with a 1.5-MW co-generation microturbine plant. Those buildings not served by the microturbines were fitted with various types and sizes of geothermal water source heat pumps. A 750-ton chiller plant was installed, along with more efficient and energy-saving T-8 lighting in the base's maintenance hangars.

The various elements of the Super ESPC were tied together with a new centralized energy management system that was installed before the Trane contract (all ESPC elements had to be compatible) as a turnkey project from Pacific Northwest National Laboratory. PNNL surveyed the base, performed economic analysis and developed the required justification for funding. Buildings are connected using a combination of wireless, DSL, fiber-optic and dial-up. The system monitors base energy usage and sends out load-shedding commands during peak demand periods. Commands initiate start-up on the microturbines, change building temperature set-points and, if need be, secure systems. The system is also used to schedule occupancy periods for buildings and has proved extremely useful for remote systems monitoring and troubleshooting. Buildings are checked daily.

Tisdale characterizes the Trane project as seven energy conservation measures that included the geothermal heat pumps, the building automation system (as the military describes energy management systems), lighting, building envelope (windows, roofing, swimming pool leaks), motors and drives and central utilities and central HVAC system upgrades. He estimates energy cost savings for the $22 million project at $1 million annually.

Geothermal
According to Johnson, the subject of geothermal heat pumps was already on the table when Trane signed on. Tisdale says the idea was based on his own experience installing a heat pump at his home in the aftermath of Hurricane Hugo. Not only was the unit reliable but it cut his power bill in half.

Geothermal heat pumps are electrical heat pumps that draw heat from the ground or discharge heat into the ground or groundwater instead of into the air. The technology is made possible because ground temperature 10-12 feet below the earth's surface stays a relatively constant 65 ° F. Open-loop geothermal heat pumps use heat found in rocks or fluids at various depths beneath the surface of the earth. Closed-loop geothermal heat pumps (the type installed at MCAS Beaufort) pipe fluid (in this case water) in closed piping systems, which receive heat from the earth or discharge heat back. Much less energy is needed to move heat than is required to create it through combustion-based systems. And there are no pollutants.

“Effectively, what's happening,” says Johnson, “is you are using the ground as a method of exchanging heat, either to the ground or from the ground, and then bringing it back. This is viewed by the federal government as a renewable energy source in that you eliminate the fan energy required to reject the heat you'd normally have in a heat pump with a condenser. To set the system up correctly you have to test to establish how much heat the ground can take coming into it at any given period of time. Test drilling also helps you understand what the conductivity is, which tells you what your rate of rejection will be, which tells you how large your well field has to be.”

David Hayden, federal account executive for The Trane Company, explains how this worked out in South Carolina. “We drilled a series of 400-foot-deep wells and dropped water pipes into them. The water pipe goes down and back up the well and is connected to single or multiple water source heat pumps in the building, which reject heat from the building to the water, which rejects it into the ground as it goes down and up the well.”

In 1995 Tisdale commissioned a study that concluded heat pumps would be a feasible replacement for failing HVAC units in base housing. As a result of the study, the base entered into a utility energy service contract with South Carolina Electric and Gas Co-Energy Group and installed a total of 1,236 heat pumps, averaging about two tons per unit. The units were designed to maintain 75° F and 50% RH during a peak design day for Beaufort and make 125° F domestic hot water with waste heat. Calculated energy savings amounts to 34,000 MBTU a year or $880,000 annually.

The success of the residential contract convinced Tisdale that heat pumps were also the way to go for public buildings on the base, including the movie theater and bowling alley as well as administrative and industrial buildings such as the provost marshal's office and MAG-31 headquarters buildings. “Geothermal heat pumps are much more energy efficient than boiler plants,” says Tisdale. “Geothermal heat pumps can transfer 4 BTU of usable heat into a space for every 1 BTU of electricity put into the operation of the heat pump. In contrast, our boiler plant generated 0.8 BTU of usable heat for every 1 BTU of natural gas burned.

“Because there's a lot of drilling involved in this kind of installation, you have to know where your underground utilities are. You will probably have to secure authorization from your state environmental agency, which will have to buy off on the type of grout you use and how the wells are capped. I had to give the state drill logs and locations of all the heat exchangers I put in the ground.” An additional recommendation is to invest in a review of the project by a second consultant. Tisdale had Oak Ridge National Laboratory run models to verify that the design for the housing contract would function as projected. “The design came up with 203 linear bore feet per ton for the heat exchangers. Oak Ridge came up with 254 feet per ton. We went with the higher number to be safe.” (Which means, says Tisdale, that crews had to drill 254 feet to acquire the heat rejection equivalent to one ton of air conditioning—significant because the more feet per ton, the higher the cost per ton.)

Tisdale also recommends that anyone considering heat pumps connect with the International Ground Source Heat Pump Association and take one of the organization's installation workshops. “One of the things they recommend is to use polyethylene piping instead of PVC for heat exchangers and ground loop systems. The PVC we used in my house leaked.”

Nor are all buildings necessarily candidates for heat pumps. Function, says Tisdale, is the key factor. “If you're just doing heating, it's not a good idea to go geothermal. You have to provide a larger well field because you're not warming it back up in the summer. In cases like warehouses, we actually found it more economic to use electric boilers. The large expense of installing a heating-only well field for these buildings, combined with the elimination of line-losses when they were removed from the high-temperature hot water distribution system made electric boilers an economic approach for our warehouses and hangar spaces.”

Buildings where geothermal heat pumps have been installed have scored high on the comfort scale, Tisdale says. “Our headquarters building has console units and some above-the-ceiling units. The building went from a system of four zones per floor to every room having a thermostat, which means that if they have to, they can heat in one space and air-condition in another simultaneously. This has eliminated complaints that one side of the building was roasting while the other side was cool.”

Microturbines
Historically, the total electrical load of MCAS Beaufort had been between eight and10 MW, Hayden reports. The central heating plant was a nonstop operation run by an outside contractor that accounted for some $400,000 in labor costs annually. The 15 100-kilowatt Elliott microturbines (Elliott Energy Systems, Inc., Stuart, FL) that replaced the old high-temperature, hot water plant run parallel at the same location to feed one leg of the old distribution system (the other three legs were abandoned) and bring the load down to 7 MW. The microturbines can run on either natural gas or propane and the fuel source can be changed while the turbines are in operation. The 1.5 MW of electricity picks up approximately 11%-12% of the base's electrical load and in the process provides hot water for heating and domestic hot water for the base's medical-dental facility, mess hall, and barracks complex. The recuperator on the exhaust has a water coil that heats water and sends it to a 30,000 gallon hot-water storage tank, which is controlled to 150° F (a substantial drop from the 350-375°F maintained in the old high-temperature hot water system). “It's like charging a battery,” says Tisdale.

“The way our heat exchangers are designed, we can operate pretty much anything out in the field at 150°, which is one of our control points for the microturbine plant. As the temperature starts dropping, we can stage on the turbines to make hot water. The other method of control is peak shaving. About 12:30 in the afternoon the turbines start ramping up and coming on line when they see we're above the point we're trying to control to. It may take all of them to come on to knock the peak down. During this time the units will generate quite a bit of heat, and the storage tank temperature can go as high as 240°. When we're out of the demand period, we can turn them off and run on the tank for the entire night.”

Although emergency power generation is receiving more attention at military installations, Beaufort's cogen plant is not configured for it. In fact, says Tisdale, the microturbines won't run unless there's power on the grid.

Energy Management System
Tisdale says one thing that proved critical to the contract's success was Beaufort's new energy management system, which networks all facilities on base. “With this system we are able to look at every building on the base, usually within an hour in the morning, and see that it's working. One thing this has added to increased comfort levels here is that we are able to check to see that the systems are actually operating. This way we catch things before they end up being a problem. Having the energy management system installed also allowed us to see load profiles and the inter-relationships between equipment. This helped lead me to thinking about things like the cogeneration plant and water storage for peak load reduction. What I learned from all of this is that if you really want to reduce energy consumption, it's better to look at your whole facility as one functioning unit as opposed to looking at individual buildings.”

The first phase of the Trane Technology Specific Super EPSC included retrofitting 33 buildings; the second phase added five more buildings and built the 750-ton variable primary chilled water flow chiller plant using two Trane Earthwise CenTraVac centrifugal chillers, which Johnson says reduce energy consumption up to 18%. “We get some energy savings by varying the water flow for the chilled water,” says Tisdale, but he also says he wishes he'd included some ice or chilled water storage with the new chiller plant to get additional peak demand reduction.

Of all the seven ECMs implemented, Johnson points to the replacement of conventional lighting in the maintenance hangers with high-efficiency T8 lighting as an example of how the two project goals were melded. “The high-intensity T8 lighting will save a significant amount of energy, about 30 percent of the energy used with the old lighting. But even more importantly for the folks who are working on the planes is the fact that the new lighting illuminates the work surfaces much more vividly. Not only can they see better what they were doing on top of the planes, but the lighting also creates less shadows than high-pressure sodium lighting. The people working under these jets were delighted about the new lighting, not from the energy standpoint, but the fact that now they can see what they're doing.

“This is just one case where what started out as an energy project resulted not only in energy efficiency but also workforce productivity.”

PENELOPE GRENOBLE O'MALLEY is a frequent contributor to environmental publications.

DE - March/April 2006