Bonhag Associates, PLLC, was retained to design the HVAC systems for the Fitness Center and lounge area at Peterson Athletic Facility at Middlebury College. The existing facility is two stories high with full glass walls floor to ceiling, on both floors with three exposures. The spaces were currently heat-only; any cooling was obtained through natural ventilation and operable windows. The college wanted to maximize the use of the space during the warmer summer months. The college had opted not to install shades on the windows as they did not want to disrupt the view of the rustic Vermont setting; as such, there were times when the temperature in the space was high.
Bonhag Associates, PLLC, performed a study to look at the space orientation, usage, and available mechanical spaces to determine the best solution for providing proper air conditioning to the space. In the study, we reviewed all the available options which included but were not limited to DX systems with fan coil units, conventional VAV with chilled water, and a chilled beam/ceiling system. Additional factors that were taken into consideration were the owner's construction time line and serviceability. After looking at all these factors and the first cost and operating cost it was our recommendation to the owner to install a hybrid HVAC system. For the lounge area, located on the second floor with attic space, we recommended a conventional constant volume air system with a chilled water coil. For the fitness area on the first floor, where mechanical space was very limited, we recommended the installation of passive chilled beams and ceiling tiles with a chilled water coil retrofitted into the existing air system for dehumidification control.
After consideration and discussion, the owner approved the scope as outlined above and we proceeded to design and specify the new equipment required for this system which included cooling coils for the existing air systems, a new air handler for the lounge, an air-cooled chiller for both the cooling coils and the chilled beams and ceiling system, chilled water pumps, passive chilled beams and passive chilled ceiling tiles as well as the interface into the existing Facility Management Control System. Careful attention was paid in the design and equipment selection process to ensure that the existing AHU and new chilled coil would provide sufficient dehumidification for the space to prevent condensation from forming on the ceiling tiles of the space. Controls were specified to monitor the moisture on the surface of the chilled water supply piping and the chilled tiles in order to be sure that pumps are shut down prior to any water being generated on the supplies to the ceiling or beams.
When we performed the final punch list at the project, the outdoor air temperature was 96°F and the interior of the space was maintaining a set point of 74°F. The patrons were expressing their satisfaction at the draft-free conditioned space to the staff of the facility.
