Some school buildings are designed to take advantage of geothermal energy. The temperature of the earth, deep in the ground, remains fairly constant throughout the year even when the air temperature experiences wide fluctuations from winter to summer. This constant ground temperature varies by latitude but is generally between 45 degrees F—75 degrees F at a depth of six feet. Geothermal heating and cooling systems are designed to take advantage of this thermal constant by pumping air or water into the ground to be heated or cooled to the earth’s stable temperature. Once the ground warms or cools the circulating air or water, it takes very little extra energy to bring it to the desired temperature for a comfortable building. The conditioned air or water may then be used in radiant heating or cooling systems embedded in the building’s floors, or as part of the building’s HVAC (climate control) systems. Geothermal climate control systems make buildings more comfortable and may save their schools a substantial amount of energy as compared to conventional heating and cooling options. These systems have reasonably short payback periods, generally take up less room in the school than conventional heating and cooling equipment, and run quietly.
Twenhofel Middle School in Independence, Kentucky, has a geothermal heating and cooling system that uses only half the energy of a typical climate control system. Each classroom can adjust its own temperature independently to maximize comfort. The building includes a “truth window” in the science lab’s ceiling so students can see the climate control system’s ducts and other utilities.
In 1997, the architecture firm, White Arkitekter, helped Östratorn School in Sweden to create a large school building addition that includes many innovative green building techniques. The overall building design incorporates passive solar features including numerous surfaces made from concrete and brick, which absorb heat and help to moderate the temperature inside. Awnings are placed strategically on the east and west sides to reduce indoor temperatures in the spring and summer. The building relies heavily on daylight as a primary lighting source, so it avoids much of the typical heat gain that results from standard lighting fixtures. It also has a radiant heating and cooling system.