|
|
Joseph Firrantello, P.E., Penn State University
|
|
|
William Bahnfleth, Ph.D., P.E., Pennsylvania State University
|
|
|
Ross Montgomery, P.E., Quality Systems and Technology Inc.
|
|
|
Paul Kremer, Pennsylvania State University
|
The energy use-related effects of ultraviolet germicidal irradiation (UVGI) to mitigate biological fouling (biofouling) of a chilled water cooling coil are investigated via a field study. A visibly bio-fouled cooling coil in an air-handling unit serving an operational building in a hot, humid climate is monitored for 5 months to establish a fouled coil baseline. Parameters monitored include air flow rate, airside pressure drop, air temperature and humidity upstream and downstream of the coil, chilled water flow rate, entering and leaving chilled water temperature and waterside pressure drop. A UVGI coil irradiation system is installed on the downstream side of the coil following typical manufacturer guidelines, and the system is then passively monitored over a period of 10 months. An average improvement of 5.2% to 7.9% in coil airside pressure drop, and 11.9% to 12.7% in heat transfer coefficient (both 95% confidence interval) are estimated by comparing data from the baseline and post-irradiation periods. Complexities of the physical phenomena involved, e.g. the effect of both airflow and latent load on airside pressure drop, are taken into account.
