Air-conditioning accounts for a 60–70% of energy use in build-ings,which, in turn, can be estimated to be of the order of 40–45% of the total energy consumption of developed countries, as reported
in a survey recently collected by Pérez-Lombard et al. This is one of the reasons why the adoption of sustainable HVAC strate-gies has become a topic upon which nations are focusing a numberof new dispositions in matter of rational use of energy, see, e.g.,Directive 2002/91/EC [2]. In this perspective, evaporative cooling,both direct and indirect, may help to reduce the energy demand ofair-conditioning systems.