Elara Engineering recently completed an energy evaluation of a retro-commissioning project at 95th Street Naperville Public Library aimed at improving mechanical system functionality. The 73,000 square foot Public Library was experiencing consistent, large scale comfort issues resulting from a mechanical system that was operating incorrectly. At the time of Elara’s initial involvement, the Library was considering replacement of major equipment and the building controls system in an effort to correct comfort issues. Through retro-commissioning efforts and focused repairs Elara was able to assist the Library in responsibly restoring the existing mechanical system to operate as it was originally designed.
Although the mechanical system was designed to operate at unusually low chilled water temperatures, the chiller plant was operating at an elevated temperature of 42 degrees causing terminal equipment to operate at full speed without improving space comfort. As part of Elara’s retro-commissioning efforts, the mechanical piping system was tested for appropriate quantities of glycol and adjusted. Additionally, faulty controls were identified and repaired. With the appropriate chilled water temperature restored, Elara turned its retro-commissioning focus on restoring air handling units and fan powered boxes to the original intended design operation and integrated additional energy savings measures.
Since retro-commissioning efforts were concluded, Naperville Public Library has recorded a normalized electrical energy savings of 11% and natural gas energy savings of 29% reflected in more than $20,000 in avoided utility costs annually. Additional substantial costs were avoided through reuse of the existing equipment and controls and extending their useful life. Reports of improved comfort throughout the library have reportedly been noted by guests, improving the occupant library experience.