Computer model and simulation of a traditional passive cooling ventilation system in a Modern building in Mazara del Vallo (Italy)

Traditional and modern natural ventilation techniques have been integrated in a hybrid system for a retrofitting of public building in the city of Mazara del Vallo (Italy). The hybrid ventilation and air cooling system integrates a wind tower, an indirect evaporative heat exchanger, a ground cooling pipe network and ventilated façade. The first idea was to design a passive cooling system inspired to the typical wind towers of the Middle East, being the area very well ventilated. On the other hand, air humidity in summer is quite high and therefore the effectiveness of indirect evaporative cooling is quite low. For this reason, it was adopted a second passive cooling system consisting in a ground heat exchanger which cools down further the air stream. Air exiting form the buried pipes is then drawn into the building. The whole system has been designed in order to achieve the required air-flow rate by natural ventilation using the wind tower. A back-up ventilation system will fulfil for the required air change if the natural ventilation system doesn’t guarantee the specified flow rate. From the thermal point of view, the system was designed, modelled and tested by using a dynamic simulation software (TRNSYS). The building has been simulated with a two-zones model coupled with a natural ventilated façade. The climate of the site as well as the influence of the solar radiation on the building were investigated by means of the software ECOTECT. Results are interesting in terms of energy saving for cooling and air circulation and gives useful hints to refine the design process.