New Novak Elementary School
Linn-Mar wanted its new elementary school to show improved energy performance over an earlier prototype school design in the districts’ other two elementary schools. With assistance from Alliant Energy and The Weidt Group, an energy analysis showed that a change in the operation of the geothermal loop related to unoccupied conditioning of the gymnasium could save energy. Instead of operating water-to-water heat pumps for heating the gym when unoccupied, a 24KW electric heater was added to the gym AHU. During occupied hours the gymnasium HVAC system reverts to normal operation on the geoexchange loop. The resulting pumping energy savings, along with other improvements to the building envelope and lighting systems, has allowed Novak Elementary to operate at about 27% energy cost savings compared to Echo Hill Elementary and 17% energy cost savings compared to Linn Grove Elementary for a 2-year period spanning 2010-2012.
The main sustainable design feature was a 190-ton closed-loop geoexchange system designed to serve the current building size, and expandable to accommodate a planned addition. The HVAC system included Dedicated Outdoor Air Systems with total-energy enthalpy wheels. The gymnasium AHU controls included CO2 monitoring for Demand-Controlled Ventilation. The lighting design included a watts/SF rate that was lower than the code-mandated level and incorporated day-lighting controls and occupancy sensors for further energy savings.