MAE PhD Defense – Williams Eades

TITLE: Beneficial Use of Air Handling Unit Condensate for Laboratory HVAC Energy and Water Recovery in Hot and Humid Climates

ADVISOR: Dr. Stephen Terry

DATE & TIME: Friday, March 2, 2018 at 10 AM

LOCATION: EB3 – 3115

ABSTRACT:

This research examines ways to reduce energy and water consumption in laboratory HVAC systems. The data add to existing research into reduced potable water consumption derived from air handling unit (AHU) condensate for sites situated in hot and humid climates. It also explores and validates the potential for energy recovery.

The literature shows that hot, humid climates can be ideal for AHU condensate to be leveraged as a source for pre-cooling and dehumidifying. The findings also reveal locations best suited for its application, because condensate generation is greatest when pre-cooling and dehumidification are needed most. Psychrometric relationships are used to predict condensate generation based upon ambient meteorological conditions.

Since laboratories require high volumes of 100% outside air, data show they are the perfect candidates to re-use relatively pure, cold condensate. This study analyzes AHU condensate utilization for both energy and water recovery modes; evaporative pre-cooling for sensible energy recovery, and condensate as a source for cooling tower make-up water. An optimization scheme is presented that maximizes energy and water savings based on outside air enthalpy, condensation generation, and energy recovery mode.

In addition to offsetting potable water demand, the findings demonstrate that utilizing condensate for cooling tower make-up is especially attractive where low alkalinity, conductivity and total dissolved solids in the condensate help to increase condenser water cycles of concentration before blowdown is required. This study shows that using AHU condensate as a water source for evaporative cooling provides for a relatively simple, low cost method to pre-cool single pass exhaust air whose energy is captured in a sensible energy recovery system.

The analysis demonstrates that energy and water savings on the order of 10% and 30% can be achieved with minimal additional pumping power for some of the earth’s fastest growing population centers. Although this study focuses on 100% outside air applications, it also demonstrates that potential energy and water savings are possible for more traditional air conditioning applications.

BIOGRAPHY:

William Eades currently serves as the Facility Operations Branch Chief for the U.S. Environmental Protection Agency’s Research Triangle Park, N.C. Campus. He has also held a variety of engineering positions for the State of North Carolina, the private sector and the U.S. Air Force. His bachelors and masters degrees in Civil Engineering are from N.C. State University. Mr. Eades is a North Carolina registered Professional Engineer and a Certified Energy Manager.