Operational mode optimization of indirect evaporative cooling in hot climates

Abstract

This study experimentally investigates the performance of an indirect evaporative cooling fresh air-handling unit at different modes of operation under harsh climatic conditions experienced in Qatar. Temperature and relative humidity are measured at various points within the fresh air handling unit for each mode of operation and, the measured data are stored and analyzed. Cooling performance indices are evaluated in terms of temperature difference across the heat exchanger, dry and wet bulb temperature effectiveness, thermal conductance, and cooling load. Different modes of operation are achieved by pre-treatment of the secondary air using either mist injection, water shower, or a combination of mist and water shower. It is found that indirect evaporation can achieve reductions of up to 43% of the unit's cooling capacity compared to dry operation. A sequence of operations to sustainably optimize energy consumption and reduce carbon emissions is determined. Keywords: Cooling load, Effectiveness, Energy saving, Indirect evaporative cooling, Mode of operation