A passive evaporative cooling system by natural ventilation

Evaporative cooling is used extensively for cooling in climates with medium to low humidity. In residential buildings the conventional mechanical systems tend to be both noisy and unsightly protuberances on buildings, whilst traditional cooling systems incorporated into the building structure which employ chimneys and the like tend to be designed for the specific building and so may not have wide application. Here a proposal is presented for a passive evaporative cooling system which makes use of natural ventilation at the building facade. The system makes use of the evaporative effect from water falling vertically along guides to produce a reduction in the temperature of the air entering the building. It can also be used as a design element in the building facade. Such a system provides an inexpensive, energy efficient, environmentally benign (not requiring ozone-damaging gas as in active systems) and potentially attractive cooling system. A numerical study is presented to demonstrate the system efficiency and airflow rate through a building, making use of measured outside wind speed and direction, building geometry and surroundings. The likely effect of the system on the indoor air temperature is discussed; further work is being undertaken to explore the integration of such a system into the building fabric.