Atlantic High School Geothermal Studies

Project Data:
Atlantic Community High School
Atlantic, Iowa Atlantic Community School’s new High School is located on the south side of Atlantic, Iowa. The total construction cost was $8.9 million. The project was completed in Spring of 1996.

Heating/Cooling System:
Geothermal Heat Pumps: Primary loop heat rejection and heat addition provided by closed ground loop piping system. Individual heat pumps serve each classroom and are generally located above the ceiling. Conditioned ventilation air supplied directly to the heat pumps with preheat propylene glycol loop served by a chiller/heater.

Building Floor Area:
110,700 sq. ft.

Installed Capacity:
407 tons

Installed Heat Pumps:
67 water source heat pumps sized from 1 ton to 66.5 tons.

Geothermal Heat Exchange:
480 vertical bores, 133 feet deep. The Geothermal Heat Exchanger is configured with 8 bore fields with 60 bore holes in each field. Flight Auger (Dry Boring) method was used which saved approximately $92,000 over a deeper bore hole using a wet boring method.

Underground Piping:
The piping was high density polyethylene (PE3408). 24 miles (127,680 feet approx.) of vertical pipe, 1 mile (6,000 feet approx.) of horizontal pipe, and 1,320 fused joints were used. The bore holes piping is 1 inch and the headers are 3 inches. The main headers to the school are 8 inches.

Projected Annual Heating and Cooling Energy Cost:
$38, 320

Payback Period:
8-12 years
(Favoring the Geothermal Ground Source Heat Pump System and dependent on the alternative system considered.)