Performance characterization of an adaptive-controlled air handling unit to achieve thermal comfort in Dubai climate

Recent technological advancements in the HVAC industry enable optimized occupant thermal satisfaction and system efficiency, thanks to better control of the comfort parameter. Current work aims to automatically control the thermal comfort parameters: dry bulb temperature, air-velocity, and relative humidity. This is achieved using an air handling unit (AHU) equipped with a fresh air control for air quality control, a chiller unit that runs on a VCR cycle for cooling and dehumidification, an ultrasonic mist humidification system, and an air volume control system installed in the ductwork for temperature control. These systems are automatically controlled based on the feedback from various sensors installed in the target space to fit to the ASHRAE Standard 55. Experiments are conducted for varying air velocity at different daytime periods in Dubai. Air temperature and humidity are measured at each stage of the AHU. Total time for achieving thermal comfort is recorded. Results indicated that maximum coefficient of performance (COP), dehumidification effectiveness (DE), humidification effectiveness (HE), predicted mean vote (PMV) and bypass factor were 8.60, 0.96, 36%,-0.62 and 0.48 respectively when outdoor conditions reached 42 degrees C and 50% RH. The operational efficiency of the current adaptive-controlled system is found to be 21.50% more efficient than a conventional system.