Active evaporative cooling for pilgrim tents in Mina, Makkah: A sustainable approach to energy and water efficiency

Cooling tens of thousands of pilgrim accommodation units (or tents) in Mina, Makkah using traditional direct expansion (DX) systems demands substantial electricity, leading to high operational costs and significant CO 2 emissions. This study explores active evaporative cooling (EC) as an energy-efficient alternative, despite its high water consumption. A parametric study optimizes EC operation to achieve thermal comfort while balancing water and energy usage. An energy model developed using Design Builder software determines the cooling load of a standard tent, followed by computational fluid dynamics simulations for various EC supply condition scenarios based on the adiabatic cooling process. Since water and energy consumption vary in opposing directions, the study identifies two optimal thermal comfort solutions: one emphasizing water efficiency and the other prioritizing energy savings. Given the extensive availability of 150,000 pilgrim tents in Mina, implementing EC at optimum settings could lower energy consumption by 685-716 MWh, reduce CO 2 emissions by 390-409 tons, and cut operational costs by 68% during the peak hour on a typical summer day compared to conventional DX cooling.