(137c) Estimation of Air Handling Units Condensate Recovery in the Medical Campus Buildings At University of Alabama At Birmingham

According to the U.S. Drought Monitor (U.S. Drought Mitigation Center December 13, 2011), the majority of the Southeastern states are classified as being in a state of “moderate”, “severe”, “extreme”, and or “exceptional” drought. Due to the prevailing drought conditions in the southeastern U.S., it is appropriate and necessary to conserve water resources by using them as efficiently and responsibly as possible. The increasing population, socioeconomic developments, and industrialization will have significant impacts on the way we consume water today. There will be an imbalance in the water supply and demand if water is not used more efficiently. Water and energy are interdependent and hence it is necessary that building operators and industry leaders realize that water conservation is as important as energy conservation.

Air Handling Units (AHUs) are commonly used for space conditioning in commercial, industrial, and institutional buildings and take advantage of large amounts of chilled water internally for cooling their coils as warmer air is forced across them. During the hot summer months, a large quantity of water is condensed when hot air passes through the cooling coils. In the past, condensate formed during this process was dumped into storm drains resulting in discarding large quantities of usable water. The Energy Management Division (EMD) of the Facilities Management Department at the University of Alabama at Bimringham (UAB) has taken the initiative to collect this water and reduce the make-up water requirement of their three major centralized cooling plants on campus. EMD is currently conducting a pilot study in five campus buildings to investigate the performance of the condensate recovery system.

This research study focuses on the development of a design model that can be used to accurately predict condensate volumes for the given outdoor weather conditions and indoor operating conditions. In a similar study, Perry et. al. (2010) developed a model to estimate condensate volumes, the results obtained using their model were 30% different than the actual condensate flow rates. Thus, this current study addresses minimizing the errors in predicting the amount of condensate recovery by developing a model that is validated using different statistical analyses. In order to conduct this study, condensate recovery units have been installed in five campus buildings. These units consist of an assembly of pipes, water storage tanks, water meters, thermometers, pressure gauges, and filters. The temperature and relative humidity data are collected daily from the Birmingham Airport Weather Station and a local weatyher research station on campus. Condensate water recovered in each tank is recorded on an continuous basis using water level loggers during the summer of 2012 and is compared with the predicted values obtained using the model. One of the goals of this research is to analyze the performance of this model for Birmingham, Alabama since there has been no similar study previously conducted for this location and will be compared with other cities in the southeastern United States. The results of this study will also be compared with the previous studies conducted by Perry et. al. (2010) and Bryant and Ahmed (2008). The viability of the model is analyzed using sensitivity analysis and uncertainty analysis. Our presentation includes a discussion on life cycle assessment and life cost analysis of the condensate collection systems. Finally, cost savings are calculated on an annual basis which will further be used to determine the payback period of each condensate collection system.