Advocate Chiller Plant Project
Monday, July 29, 2013 at 10:31AM Click here for the Case Study One-Pager.
Advocate Illinois Masonic Medical Center replaced all of the main hospital chillers serving the campus with new high-efficiency models. The total operating efficiency of the new plant is between 0.42 - 0.56 kW/ton, including pumps and cooling towers. Three main water-cooled chillers and several smaller air-cooled chillers had exceeded their expected service life by more than ten years on average. Although still in operation, the machines were becoming difficult to maintain and used refrigerants that have been phased-out of production. New chillers were installed to provide the facility increased reliability and efficiency.
Grumman/Butkus Associates performed a life-cycle cost analysis as part of the chiller plant design to select water-cooled chillers, cooling towers, and pumps that have a low cost of ownership over the life of the equipment. The new 700-ton chillers utilize magnetic bearing compressors for high efficiency operation over a wide range of operating conditions. The chilled water distribution system was converted to a variable primary pumping arrangement. The prior plant configuration used a constant flow primary loop with variable flow secondary pumping. Energy management and control capabilities of the plant were enhanced by reducing the number of pumps and upgrading the plant to DDC control. The control system for the new plant includes all-variable control with ability to monitor power consumption for all of the components as well as monitor calculated efficiency for each chillier.
Four air-cooled chillers were also replaced with new high-efficiency units selected based on first cost, estimated energy usage throughout the cooling season, and maintenance factors. These air-cooled systems serve distinct areas of the campus and allow the main chilled water plant to be shut down during the winter while critical departments may still require cooling due to heat generated from medical activities.
Overall Advocate Illinois Masonic Medical Center received over $269,000 of incentives from ComEd Smart Ideas for Your Business program to implement the high-efficiency systems incorporated into the design instead of basing the requirements on conventional replacements.