HVAC FORENSICS AND HUMIDITY SOLUTIONS
CCE consulted with the church to offer our professional opinion on the HVAC systems in their newly constructed 25,000 square-foot addition. Concerns with thermal comfort and humidity control were brought to our attention. We were present to provide HVAC forensics expertise in support of the owner in negotiations with the general contractor and original HVAC engineer of record, where we agreed on a plan for the contractor to resolve the concerns. The solution involved adding variable refrigerant controls to three rooftop HVAC units, a new HVAC system to enable segregation of interior and exterior rooms, and a VRF HVAC system for an interior office with high internal heat gains.
New Church Addition Temperature and Humidity
Private University Dormitory
CCE was contracted to diagnose and solve issues with high humidity and thermal comfort conditions in the common areas and corridors of this 56,000 square-foot dormitory. The solution included an energy recovery dedicated outdoor air system (DOAS) for each of the two dormitory wings. The new BACnet controls system interfaces with the University’s existing campus building automation system to allow monitoring and alarming of humidity and temperature. The 1920s vintage wood structure required all new ductwork and piping to be accurately routed from the roof down through new chases and ceiling spaces between the floors. Additionally, the building’s existing exhaust system was routed to the new DOAS units to take advantage of their energy recovery capability.
Metal Building Laboratory
Public University Meeting Center
This building had 24-inch thick walls and very few windows. The facility saw extremely high humidity levels in the event rooms, where occupancy fluctuated from empty to full assembly occupancy. The existing HVAC equipment had been significantly oversized. CCE’s solutions included adding variable frequency drives for fan speed adjustment, new steam reheat coils in existing modular air handlers, and a new reheat cycle control algorithm for each of four air handlers. A controls system upgrade was also included to give facility personnel system monitoring and alarming capabilities.
CCE conducted a forensic evaluation of the facility’s annual summertime high humidity levels. We spent many hours on-site familiarizing ourselves with the facility, while trending humidity and temperatures on the HVAC systems for analysis. The investigation included discovering significant sources of unconditioned infiltration, determining several of the roof top units regularly short cycled in cooling mode, and that some of the HVAC systems were not operating as originally intended. Our solutions included rebalancing the HVAC systems to maintain acceptable building pressurization, retrofitting the existing roof top units with modulation refrigerant bypass valves to improve system dehumidification capability, and repairing existing equipment to function properly.
Behavioral Health Clinic
Internet and Telephony Data Center
CCE was engaged to resolve insufficient cooling, summer high humidity, and winter low humidity concerns within this data center. We investigated the data center equipment heat output and performed room cooling load calculations, which indicated the need to redistribute the cooling air between the equipment rooms. We observed the condition of the existing HVAC equipment and duct systems, which allowed major air infiltration through the exterior ducts and HVAC equipment. The complete HVAC solution included replacing two oversize HVAC units, adding dampers and new diffusers to deliver air to the required rooms, and adding HVAC equipment staging with remote alarm controls.
The study focused on the performance of the HVAC system in controlling temperature and relative humidity in the occupied building. CCE found the primary cause of high humidity in the building was infiltration of outdoor air into the attic via poor building envelope, combined with malfunctioning relief air dampers between the attic and the second floor occupied space. Additionally, the energy saving HVAC control sequences were not cooling the air handler supply air sufficiently to provide dehumidification capacity to offset the infiltration. The solutions involved resolving the attic air infiltration problem, and adding HVAC controls for dehumidification and positive building pressure control.
Fraternity House Humidity
Regional Hospital Above Ceiling Humidity
We were commissioned to investigate and alleviate high summertime humidity in the Second Floor Day Room, Nurse Station and Dining Area of this facility. We discovered the cause of the humidity was a combination of negative building pressure caused by a non-functional kitchen hood makeup air system, and large openings in the roof communicating with the Dining Room above ceiling plenum. Our solution included repairing or replacing the adjacent kitchen hood makeup air unit fan. In addition, we recommended constructing two generator exhaust flue chases between the first floor generator room and the roof, to block outdoor air from flowing through the roof thimbles into the ceiling cavity above the Dining Room.
Additional Forensic Experience
Private University Cafeteria