Chesapeake, VA

Great Bridge Middle School

Great Bridge Middle School-South was built in 1955 and has undergone two expansions since then. It is now a 112,000 square-foot complex of classrooms, administrative ovfices, gymnasium, cafeteria/kitchen, band room, and machine shops, serving over 1,300 students. As part of its 1994 renovation, a geothermal heat pump system was evaluated and compared with packaged, through-the-wall, air-source heat pumps. The new heating and cooling system had to meet ventilation air requirements of 15 cfm per student.

The capital cost premium for the GHP system was $240,000, but it yielded annual energy savings of $41,500, corresponding to 37 cents per square foot per year and a simple payback period of 5.8 years. Each GHP unit has its own ground loop and circulating pump, which results in more boreholes than normally would be expected for a building of this size.