In early 2013, the Kentlands Community Center’s 15-year-old air source cooling system with gas furnace heating had reached the end of its useful life. The Center’s staff considered various replacement options and elected to go with a geothermal system for the retrofit. Concerns over the amount of drilling that would be needed for a closed-loop geothermal system were put to rest through the recommendation by a geothermal consultant to use standing columns, which allowed the drilling contractor to bore just two well holes.
The two column wells were drilled 900 ft. into granite rock and cased to 100 ft. The static water level settled at 14 ft. with a pumping yield for each of 4 gallons per minute. Harvey Hottel Inc. utilized four 6-ton horizontal Bosch FHP geothermal pumps, single and two-stage, to provide heating and cooling for the building.
The initial concern over the amount of excavation required to drill and connect 20 or more geothermal wells for a closed-loop system. The standing column solution required only two wells.
Kentland Community Center managers are satisfied with the install. The entire installation, once started, required less than two months to complete, and the system has performed better than expected. After the extreme winter of 20143-2014, Kentlands was pleased to report that they experienced superior heating performance that winter and a reduction of about 40% in energy costs, despite the weather.
Name of project: Kentlands Community Center, Gaithersburg, MD
Workers Onsite: Harvey Hottel Inc./GeoSolar Energy
Date Started: July 2013
Date Finished: September 2013
Manufacturer/Model Name: Bosch FHP ES 070-3 & ES 071-3
Bosch Thermotechnology – boschheatingandcooling.com