Assessment on Passive Cooling Techniques to Improve Steel Roof Thermal Performance in Hot Tropical Climate

Abstract

In African hot tropical climate countries, due to climate and the unsuitability of construction materials, building’s indoor environment remains over the thermal comfort acceptable limit over long periods of time during the year. Among the building envelope components, roof is a critical part that is highly susceptible to solar radiation. Solutions like passive cooling and low energy consumption systems are not explored enough in those countries. These techniques and systems can be used to meet a large part of the cooling needs and reduce the overheating period in buildings, but their applicability depends on the climate zone. In this paper, investigations were conducted to determine their potential to improve steel roof performance for free running buildings under tropical climatic conditions. The case studies are two configurations (with and without attic) of typical steel roof in Burkina Faso. Using dynamic simulation, we have evaluated the impacts of radiant barrier, insulation, cool paint and ventilation for two configuration of roofing. For both configurations, high reflective solutions perform very well. It also appears that the attic case due to its actual configuration (shape and design) and to the climate conditions ventilation does not perform very well. These results can help building actors during the design process.