With three cooling towers, three chillers (250-, 430- and 750-ton) and 24 AHUs (two per floor), the UV installation at the BayView Corporate Tower site presented some challenges.
“The existing AHUs were 25-years old and some offered limited access to the cooling coils,” notes Darren Ambrosi, a project manager with Sustainable Management Solutions. “Because of the tight access, we recommended a UV-C product that installs in about half the time of conventional fixtures and offers flexible configurations, such as those required at BayView.”
As a result of the installation flexibility of the fixtureless UV-C lamp system, the retrofits were completed in just four days, using only two installers from Sustainable Management Solutions.
UV-C lamps were simply placed inside each of 24 AHUs “downstream” on the cooling coil and above the condensate drain pan. This installation method is favored in ASHRAE recommendations because the air downstream approaches saturation, meaning that within this plenum there could be raw water, damp insulation, and other conditions that are known contributors to the growth of mold and some bacteria. Also, coil drain pans are often extended in this location to catch raw water carry-over from the cooling coil.
Although the UV-C technology helps save energy, reduce maintenance and extend equipment life, the system does require periodic interventions. For example, routine lamp replacements are required, along with the changing of filters that trap all inorganic particles, like soot and construction dust, which are not affected by UV lights.
Following the UV-C retrofit, Fontaine was impressed with the boost in system performance. “The overall transformation in efficiency was incredible,” he remarks. “Airflow levels increased by 47 percent in one air handler [roughly 10,000 CFM], the coils look brand new, the condensate pans are essentially contaminant-free and the tenants are very happy!”
Payback Exceeded Expectations
To evaluate the success of the installation, Willis commissioned an independent performance test by HVAC consultant John Kneiss, president of K & P Mechanical Solutions Inc., Dania, Fla. “Our goal was to measure the performance of the HVAC system cooling coils before and after the UV fixtures were installed,” Kneiss explains.
PHOTOS: Mitchell Zachs, magicalphotos.com