Novel design and modelling of an evaporative cooling system for buildings

Passive evaporative cooling has great potential as an alternative to conventional air‐conditioning in arid hot climates because of its low cost and zero pollution. This paper describes a novel evaporative cooling system with an automatic wind‐tracking device to improve its operating efficiency. The design and operating principles are discussed. A mathematical model is simplified by the assumption of convective heat and mass transfer of staggered streamlets of water. A computer program has been developed to calculate the deflection and length of spray water streamlets, as well as evaporative water mass, minimum cooled water temperature and required cooling time. A typical example illustrates that approximately 20 kg water are evaporated and around 26 min are required for 980 kg of water to be cooled from 28°C to the wet bulb temperature of 19.2°C of ambient air in a typical arid hot climate (relative humidity = 0.30, dry bulb temperature = 32°C and wind velocity = 4 m s^?1). The application of adsorbents, would allow the evaporative cooling system to be applied in hot, humid climates, in addition to hot climates with low humidity. Copyright © 2006 John Wiley & Sons, Ltd.