Utility-Financed GHPs Breathe Fresh Air into Historic Marine Corps Facility
April 30, 2003
Geothermal or ground source heat pumps (GHPs), well known for their cost and energy advantages in retrofits of military family housing, are also becoming the system of choice for a wide range of other HVAC applications. This renewable energy technology uses the earth's energy to heat and cool buildings, and to heat domestic water. Energy management staff at Marine Corps Base Camp Lejeune found GHPs to be the most cost-effective option available to replace the old, ineffective HVAC system in Marston Pavilion, a historic building and community center for the base. The new GHP system costs 60 percent less to operate than the old system and provides excellent air quality and thermal comfort for the Pavilion–for the first time in memory for many of the building's users.
Marston Pavilion, set on the scenic waterfront of the New River in North Carolina and surrounded by parkland, is the site of large, high-profile events, such as the regional Marine Corps Balls, and many other Camp Lejeune social functions. As a recreational facility, Marston Pavilion was unlikely to be funded for an upgrade ahead of more critical Marine Corps priorities. However, the large energy and cost savings to be gained through retrofitting with GHPs made it a good candidate for alternative financing. The project was completed under Camp Lejeune's utility energy services contract with Carolina Power & Light (CP&L).
Constant repairs just to keep Marston Pavilion's old HVAC system running cost about $63,000 per year. Plus the system had fundamental problems that could not be repaired. Without any ventilation system to bring fresh air in, the building was usually overheated, stuffy, and humid.
Designing the new system was an exercise in balancing capacity and efficiency, according to Robert Reierson, Operations Manager for Progress Energy Solutions, Inc., the energy services company that carried out the project for CP&L. Besides providing ventilation to accommodate 1,000 occupants (and complying with building codes), the new system needed heating and cooling operations to work quickly, as occupancy in the building can swing from 12 to 1,000 in a short time. The new system optimizes efficiency and flexibility using two sets of GHPs connected to 104 bores drilled to a depth of 200 feet.
Ventilation is provided by five water-to-water GHPs with an air-handling unit and an exhaust heat recovery system. Ventilation air flow is adjusted by carbon dioxide sensors to prevent over-ventilation during periods of low occupancy.
Three water-to-air GHPs provide heating and cooling of the building's interior. A variable-frequency drive for the water distribution system maximizes efficiency by maintaining water flow to the heat pumps at an amount just sufficient for needed cooling or heating. A fluid cooler is connected to the system to provide extra cooling capacity for the building's high cooling requirements without installing excessive and expensive bore length.
The finished system delivers about 80 tons of capacity and will pay for itself in about 19 years, although the bundle of financed energy-conservation measures has a 10-year payback.
For more information about the Marston Pavilion project, please contact Jim Sides, Camp Lejeune Energy Program Manager (910-451-5950, ext. 201 or SidesJC@lejeune.usmc.mil), or Kevin Johnson, Managing Director, Federal Energy Services, Carolina Power & Light (919-546-7247 or Kevin.Johnson@pgnmail.com).
For information about FEMP's Financing or GHP Programs, contact Tatiana Strajnic, FEMP Project Financing Team Lead (202-586-9230 or Tatiana.firstname.lastname@example.org); John Shonder, FEMP GHP Team Lead (865-574-2015 or email@example.com); or Brad Gustafson, FEMP Utility Program Team Lead (202-586-5865 or brad.gustafson@ ee.doe.gov). The Southeast Regional Office FEMP contact is Lisa Hollingsworth (404-562-0569 or firstname.lastname@example.org).