Thermal performance of different types of roof in a naturally ventilated building in the warm and humid climate of Vijayawada

Abstract

The building sector in India consumes over 30% of the total electricity produced in the country
annually. A passive building strategy can reduce energy consumption by 40 to 60%. The roof is the primary
cause for heat gain into the building, which results in thermal discomfort in naturally ventilated buildings
and increases the cooling load in an air-conditioned building. Unfortunately, due to lack of awareness, the
roof is given the least importance during building construction. Therefore, this paper is an attempt to study
different roof types and compare their thermal performance. For a base case, a naturally ventilated building
in Vijayawada, with a conventional RCC roof, was monitored for 8 hours of the active period, and the
results were analyzed in Design-Builder Software (dynamic energy simulation software). To find the
effectiveness of different roof types, Metrics such as Temperature Difference Ratio (TDR), and and
Maximum Temperature Difference (MTD) of each were compared. The study provides a hierarchy of
thermal performance of nine different roof types. It was found that of all the different roof types, a double
roof with cool roof provided the best performance to improve the thermal performance of the building