QuietMod Chiller Enclosure: Carmel, Indiana

Challenge

Carmel, a medium-sized city located just north of Indianapolis, Indiana, operates an outdoor ice rink from early November through spring. The ice is produced by a 76 ft by 8 ft Trane chiller located on a 20 ft high mezzanine in a courtyard surrounded on three sides by tall buildings. In summer, the same chiller provides cooling for the surrounding buildings. The courtyard geometry amplified the chiller noise to levels that exceeded the city's 50 dBA noise ordinance. Previous attempts by the city to resolve the problem had failed.

Solution

A turnkey solution was developed, engineering every element from analysis through installation. The project began with gathering all relevant information including a sound study commissioned by the city and technical data on the chiller.

The mezzanine's structural capability was analyzed and the city was advised on required modifications to support the enclosure. A custom QuietMod acoustical enclosure was then designed to fit around the chiller without affecting critical airflow. The design included a structural steel frame, modular acoustical panels, access doors for maintenance, and acoustical silencers for intake and exhaust air handling more than 300,000 cfm.

The airflow requirement was the defining engineering challenge. The chiller depends on massive air volume for heat rejection, and any enclosure that restricted airflow would compromise chiller performance and void manufacturer warranties. The silencer design balanced acoustic attenuation with minimal pressure drop across the system.

Results

The enclosure achieved the city's noise ordinance goal. There have been no noise complaints since installation. The project succeeded through a team approach with members from multiple areas of expertise, including the local representative who managed field coordination and the engineering team who developed the acoustic and structural design.