Ventilated roofs as a tool for improving the internal environment of animal houses in hot summer climates

摘要

The paper illustrates the results of experimental tests carried out on different types of roofs, with an impermeable fibre-cement cover, fitted with or without air interspaces, with and without insulating material, with the different layers at variable thickness. In the first phase the performances of four roof types were analysed, at varying inclinations, positioned on the sheds of 1 m X 2.2 m. In a second phase the performances of four types of roof at the same slope were analysed, positioned ona single 1 m X 8.2 m structure. The surface temperature values corresponding to the various layers were measured, as well as the speed and temperature values of the air in the cavity, the solar radiation, and the speed, direction and temperature of the external air. The tests were carried out both in the summer and winter periods, in order to measure the effectiveness of the roof both in hot and cold climatic conditions. A first simplified theoretical model was then created to determine the thermal performance of the roof according to various constructive characteristics. The results show that roofs with ventilated interspaces offer interesting possibilities for limiting high temperatures inside the buildings especially since they favour the dispersionof heat at night.