Investigation of cooling load reduction in buildings by passive cooling options applied on roof

Abstract

Performance of three passive cooling systems namely, water pond on roof, water jacket on roof and radiation shield on roof is assessed here experimentally and numerically. In each case a mathematical model of the building was developed by taking into account the time-varying conduction, convection and radiation heat loads as well as infiltration heating load, aiming to provide both an acceptable accuracy and reasonable computational time. The numerical results were then validated against the experimental data taken from a model house, which was build and tested in Shiraz, Iran. The experimental and numerical results indicate that the application of these passive cooling methods can reduce the cooling loads required during the summer considerably. Furthermore, to compare the performance of these techniques, the temperature inside the building and the cooling load required to maintain a constant temperature inside the building were calculated. The calculated results indicate that among the assessed passive techniques water pond and water jacket on roof have the best and the lowest performance, respectively.