Park Elementary School, located in Columbia, Pa., was in need of a new HVAC system. The school’s aging system included hot water heating only vertical unit ventilators and cooling only constant volume packaged DX rooftop units, which served the classrooms, and constant volume packaged DX rooftop units with hot water heating coils, which served the gymnasium, cafeteria, and administrative offices.

“For this project, I wanted the replacement equipment to be energy efficient, provide a more comfortable environment for the students and teachers, and improve the school’s indoor air quality (IAQ), including meeting the current ventilation code requirements,” said Gary Trostle, specifying engineer for the Columbia School District.

Troy Schreffler, an AAON sales representative with HC Nye Co., presented Trostle with the replacement solution of Variable Air Volume (VAV) RN Series packaged DX rooftop units with AAONAIRE® total energy recovery wheels and 10-100 percent variable capacity scroll compressors for the classrooms and constant volume RN Series packaged DX rooftop units with AAONAIRE® total energy recovery wheels and 10-100 percent variable capacity scroll compressors for the gymnasium, cafeteria, and administrative offices.

“Including factory installed energy recovery wheels and variable capacity compressors on the units substantially improved their energy efficiency and ability to provide occupant comfort,” explained Schreffler.

For heating the constant volume units and VAV terminal units included hot water heating coils.

Variable capacity compressors were specified, “because the VAV units needed something that would give us good temperature control as the volume of air supplied is decreased,” Trostle said. In addition, variable capacity compressors allow the constant volume units to be able to consistently match the space load, improving those units’ energy efficiency and improving occupant comfort.

AAONAIRE® total energy recovery wheels reduce the units’ energy consumption by pre-heating, pre-cooling, humidifying, and dehumidifying the ventilation outside air (depending on the conditions). Because RN Series units can be specified with up to 100 percent outside air, meeting the current ventilation requirements and improving the school’s IAQ was not a problem.

As Mike Miller, Columbia School District’s operations and maintenance manager said, “The AAON units provide the students and teachers with a comfortable learning environment and save the school district money because they are energy efficient and easy to service and maintain.”