Sustainable Upgrade with a Great Payback
Thornton, IL
Millies Engineering Group, working with JMA Architects, successfully completed a mechanical systems upgrade on 43,000 square foot Wolcott Jr. High School in Thornton, Illinois. The project consisted of removing and replacing standard efficiency gas fired water heating boilers and domestic water heaters with high efficiency systems. The existing boilers and water heaters were past the end of their expected operational life and the Owner had a desire to upgrade to energy efficient systems. Also, the existing domestic hot water heating system could not keep up with current demand.
To meet the Owner’s requirements, MEG implemented the following design concepts:
Replacement of one existing standard efficiency (80%) hot water heating boiler with two high efficiency (93%) condensing boilers with variable speed drives on distribution pumps to improve energy efficiency. The hot water distribution system is designed to vary the supply water temperature based upon outside air temperature. This allows for the supply water to be as low as possible, while still maintaining space temperatures. By keeping the supply water temperature low, we are able to increase boiler efficiency (condensation of flue gasses) for longer periods of time.
Replacement of two standard efficiency, natural draft domestic hot water heaters with three continuous flow gas fired domestic water heaters. The continuous flow water heaters do not “store” hot water in a tank, but provide hot water on demand. By removing the need to heat the “stored” water in the tank, the continuous flow water heaters save energy by reducing gas consumption. The Owner has received no complaints regarding domestic hot water in nearly two years of operation.
It is anticipated that these energy efficiency items will help the building perform between 20% and 25% better than the previous systems. This additional energy efficiency is achieved with only a minimal increase in construction costs.
