“The BRT program holds a lot of value for facility managers both old and new. The PennTAP sessions provided excellent information and speakers. The interactive nature and the opportunity to visit other facilities, see firsthand their challenges, and have group discussions about how to deal with them is pure gold.”
— Ken Pitts, Supervisor of Utilities and Building Maintenance
Lower Merion High School uses 24 Heat Recovery Unit (HRU) air handlers to control the heating and cooling of the main parts of the building. These units have five main dampers that cycle air based on heat recovery wheels and have heat and cool coils separated at the supply and return. Upon investigation into the efficiency of these units, the school district found that many damper motors were not working properly, thus causing air delivery issues to the building.
The PennTAP Connection
PennTAP hosted a series of three Building Re-Tuning (BRT) workshops in the Delaware Valley Region. Each workshop included guest speakers, material review, and building walk-throughs. Lower Merion School District team members began to investigate their HRU air handlers after the first BRT workshop.
This project was funded by the Pennsylvania Department of Environmental Protection and the U.S. Department of Energy’s State Energy Program. Taking the tools and lessons from PennTAP’s BRT workshops, Lower Merion School District team members worked with Johnson Controls Inc. (JCI) to assess the operation of the HRU units and conducted prescriptive troubleshooting to determine opportunities for correction. Upon experimentation, the team found the HRUs were working as designed. However, at the Lower Merion High School, there was a flaw in the JCI code that closed the bypass damper but kept the heat coil open during certain environmental conditions. Due to the split design of the coil, this meant that multiple times a day, the unit was blowing heated air out onto the roof.
After troubleshooting with JCI, the company corrected the faulty code and wrote a program for closing the outside dampers. This program will optimize ventilation during extreme cold to prevent frozen coils and when engaged, gives the maintenance team an easy way to check linkage tightness and fully close the outside dampers to ensure energy efficiency. This preventative maintenance measure
will ensure future energy and cost savings. Short-term energy analysis of the Lower Merion High School upgrade displayed favorable results with 6.5% reduction of energy used. As this continues, annualized cost savings should be about $3,800 and about 9,800 therms of natural gas for that school.
About the Company
Lower Merion School District
301 East Montgomery Ave.
Ardmore, PA 19003