When architect, Matt Wolfert described the design for heating and cooling the new addition, he used contemporary terms such as “sustainable” and “green”; however, the Board of Education was just as impressed with some of his traditional vocabulary – words like “energy conservation” and “savings”. In the end, the Board authorized the plans to proceed with geothermal heating and cooling.
What is Geothermal?
Engineer Manus McDevitt met with seventh and eighth-graders on March 4th and explained that the concept of geothermal heating can be traced back to the ancient Romans who used heat from the earth in the form of natural hot springs to heat their public baths and pools. Geothermal uses a similar concept, but not from hot springs.
The earth 200 feet below the surface of Kenosha County is about 52 degrees Fahrenheit even in mid-winter. Geothermal heating takes advantage of this fact by piping a water/glycol mix down to this depth to heat the water and brings it to the surface. This, in turn, is supplemented by heat pumps in winter to raise the temperature of the 52 degree water to something more comfortable. Cooling the addition in summer works in a reverse manner by exchanging the heat and humidity above the ground with the coolness of the 52 degree earth temperature.Normally the bore holes are drilled 300 feet deep, however, a test bore drilled on the Trevor site in February revealed limestone fractures at around 210 feet. This means that the District’s bores will be shallower. As a result, more bores will be drilled – approximately 80 in all located in a bore field. Approximately seven miles of six inch pipe will connect the bore field to the building. The bore holes and pipes will be covered with soil so that athletic fields will rest on top of the bore field and no hazardous conditions will be created.
What About Savings?
On the average, geothermal heating and cooling costs 25-30% less than conventional heating and cooling. However, the initial cost to install geothermal is more expensive. The District estimates it will take approximately ten years of savings on utility costs to pay for extra costs of installing geothermal. After this, all savings will be realized by the District.
