This document presents the theoretical study of evaporative cooling designed for the outdoor spaces in the Spanish pavilion of the coming International Exhibition in Zaragoza 2008. The system designed used some ceramic pillars located in the external spaces of the building, as means of heat exchanger, causing the temperature to drop as well as an increase of humidity in the air-flow going through. The result of the study concludes that by using the system designed, a considerable local cooling effect is obtained as well as flulfilling the objectives of architectonical integration, being it also a spreading and didactic system suitable for such an event as an International Exhibition.