Numerical simulation of natural convection for raised-ceiling rooftop heated from below

Abstract EN

Attic design has a significant impact on buildings' energy performance thus making investigation of its thermal performance characteristics imperative.

Raised-ceiling is among the common complex attic configuration found in pitched-roof buildings.

In this study, natural convection inside a raised-ceiling rooftop heated isothermally from the base wall (ceiling) is numerically investigated at a certain pitch angle range while keeping the enclosure base-length unchanged.

The results show that the roof pitch and the kinks on the ceiling have a strong influence on the heat and fluid flow patterns.

At low roof pitch, high heat transfer rate between the cold and hot walls leads to a multi-cellular flow structure.

The number, size and strength of the counter-rotating cells change with the pitch angle.

The kinks caused air velocity to double for every 15° increase in the roof pitch.

The rate of convective heat transfer is enhanced with decreasing value of the aspect ratio.