Comparison of passive cooling techniques in improving thermal comfort of occupants of a pre-fabricated building

Abstract

Pre-fabricated composite buildings are proposed as sustainable sheltering and housing solutions fordeveloping countries. This work compares different passive cooling techniques of shading, natural ventilation, cool painting and increase in thickness of interior gypsum plaster for these buildings to tackleoverheating in hot climates. The studied techniques are measured and compared in terms of indoor airtemperature by calculating four indicators of maximum, minimum, average of highest 5% and averageof lowest 5% temperatures as well as thermal comfort of the occupants based on two acceptability ratesof ASHRAE 55 and three acceptability limits of EN 15251 standards in three climates: Porto, Nairobiand Mumbai. The findings of this comparison bring insights into the effectiveness of passive coolingtechniques, that can be highly beneficial at design level. Results point out improvements by all studied techniques, even if these quantitatively depend on the presence of the occupants and the choiceof the performance indicators. Finally, further indicators such as stored heat, solar radiation heat gainand surface temperature are analyzed, to explain causes and effects associated with studied passivecooling techniques. Results of these comparisons pointed out that the combined implementation of alltechniques combined is effective enough to provide thermal comfort of the occupants during almost allannual occupancy in Nairobi measured by acceptability rate of 80% of ASHRAE 55 and Category III of EN15251.