Journal of Energy and Power Engineering 5 (2011) 238-242 – Prof. ing F. Fucci, Prof. L. Brunetti, and Prof. G. La Fianza
Dept. SA. VA., Faculty ofAgriculture, Universiiy of Molise, Via De Sanctis 86100, Campobasso, Italy
Received: June 01, 20010/ Accepted: September 14, 2010 / Published: March 31, 2011.
Abstract: This paper describes a particular stack performance realized in a building (school) at real s cale by computation of the wind induced ventilation and a comparison of the stack performance (airflow rate extracted and wind speed) respect to other systems (wind catcher, wind jetter and wind turbine) are also showed. The realization of the system, actually working, shows the synergy between a plant desìgn and installation using traditional energy sources with innovative engineering techniques providing for the use of integrative energy. In this case, the wind action plays an important role for the conditioning of the school, integrating and giving a significant energetic contribution to the air cooling system. The school buildìng (a nursery) has been built in Modena and is actually working. Key words Wind driven ventilation, stack, air flow, energy, pressure.
I. Introduction
The energy saving and the use of renewable energies inside the buildings is the principal argument of the new “Parliament and European Council executive on the energetic efficiency in building”, which sets the lowest objectives in terms ofenergetic efficiency of the buildings with an integrate approach. This approach takes in account not only the quality of the thermal insulation but also the kinds of system used, the possibility of cogeneration, the use of integrative energies, the natural ventilation systems and others.
Therefore, it’s important to evaluate the strategies to highly limit the needs of energy using not only passive techniques to optimize the contribution due to the climatic agents but also using materials and technologies which guarantee an high-level of performances in terms of thermal insulation and comfort. With this point of view the realization of the school cooling system, afier a wind and climatie study on the area, gives the chance to use wìnd energy through particular air stacks. Therefore, the study has been focused to reach an efficient “free cooling” which gives the possibility to remove the heat inside the rooms.
Ventilation is changing of air in enclosed space. In domestic buildings the primary ventilation method is renewable in the form of air infiltration and natural ventilation through windows and openings [1]. Natural ventilation uses the natural forces of wind pressure and stack effect to aid and direct the movement of air through buildings. The pressure differences inside and outside the building will drive airflow. Stacks effects are caused by temperature difference between the inside and the outside of buildings. This effect is dominant during periods of low wind speed and decreases in summer period when temperature differences are minimal. Several authors investigated about ventilation techniques. Khan showed a classification of wind driven ventilation types with their application and their typical airflow rates [2].

In the past to dissipate exhaust air into the atmosphere, chimneys were used and at their top were placed