Building energy and exergy analysis of the light-weight roofs compared with the traditional ones in different climates

Abstract

A significant research gap exists concerning the thermal properties of lightweight roofs, as extensive investigations have predominantly focused on their mechanical characteristics. However, there is a notable dearth of studies addressing the thermal behavior of lightweight roof systems. The comprehension of thermal properties in lightweight roofs is of paramount importance, as it enables the promotion of energy-efficient design practices. The absence of comprehensive research in this domain constrains the optimization of thermal insulation mechanisms within lightweight roof constructions. Consequently, this hinders developments aimed at reducing energy consumption in buildings. To bridge this research gap, this study investigates the thermal performance of two lightweight roofs called waffle slab and bubble deck in three different climates, and compare them with conventional cement block roofs. Results revealed that Valencia had the lowest heating load due to its moderate climate, while Denver showed the minimum cooling load due to colder temperatures. The bubble deck roof outperformed other roofs in terms of heat loss reduction, achieving an average of 76% in winter and 41% in summer. Additionally, the bubble deck roof demonstrated the best overall efficiency (72% on average) and improved thermal comfort during summer, with lower energy consumption. Exergy analysis showed that the bubble deck roof significantly reduced input and output exergy, indicating its superior energy conservation capabilities compared to waffle slab and cement block roofs. These findings emphasize the potential benefits of lightweight roofs, particularly the bubble deck, in enhancing energy efficiency and occupant comfort.