Overview

Penn State University (PSU) contracted Entech to perform an HVAC evaluation for Cedar Hall, as well as design a two-phase approach with corrective actions to address the HVAC system deficiencies found during the study and to improve the reliability of the system and the capabilities for humidity control.

Cedar Hall is a 4-story residence hall building located on PSU’s Altoona Campus constructed in 1996-1997.

The recently replaced cooling tower and chillers, along with the original hot water boilers, serve dual-temperature fan coil units (FCUs) that condition each dorm room. The ventilation air, as is often the case for dormitories of this era, was introduced directly through wall louvers to the FCUs. This created a challenge for humidity control, made worse due to a lack of any conditioned make-up air for the building exhaust systems.

During the HVAC study for Cedar Hall, we found several system deficiencies to be included in corrective efforts during the two-phase approach to improving the HVAC system: moisture issues, make-up air, and FCUs.

Cedar Hall experienced several moisture-related incidents which previously caused the periodic loss of use of the building for student housing, as well as required the replacement of materials like carpets, pipe insulation, and wall finishes. While the incidents were deemed to be atypical conditions, they did highlight the building’s limited humidity control capabilities.

Another system deficiency was the lack of consistent preconditioning on the make-up air for the bathroom and laundry exhaust which contributed to the humidity issues. The bathroom and laundry exhaust systems operate continuously and drive the need for make-up air. This make-up air enters the building primarily through small louvers/dampers at each individual FCU and is not effectively dehumidified.

Lastly, the 20+ year-old fan coil units became maintenance intensive due to the high rate of failure of the associated thermostats and to the age of the key components, including the valve actuators, dampers, and fans.

Following the study, major design components to improve the humidity control capabilities in Cedar Hall included: improved controls and replacement of the FCUs, additional air handling units in the building’s attics to properly condition and manage the building’s make-up air, and operational improvements. Operational practice improvements included: not over-cooling spaces, not running fans continuously, maintaining conditioning during building downtime, and providing periods of ventilation.

With design and construction for this two-phase approach now complete, PSU can feel confident in the reliability and efficiency of their building’s HVAC system.