Numerical evaluation of the thermal performances of roof-mounted radiant barriers

TL;DR

This study evaluates the thermal performance of roof-mounted radiant barriers through dynamic simulations, comparing them to traditional insulation and analyzing the impact of airflow on thermal resistance.

Contribution

It introduces a thermo-aeraulic model to assess how airflow affects the thermal resistance of radiant barriers, providing a new mathematical relation.

Findings

Radiant barriers show improved thermal performance compared to traditional insulation.

Thermal resistance increases with airflow rate in the new model.

The proposed mathematical relation links airflow rate to thermal resistance.

Abstract

This paper deals with the thermal performances of roof-mounted radiant barriers. Using dynamic simulations of a mathematical model of a whole test cell including a radiant barrier installed between the roof top and the ceiling, the thermal performance of the roof is calculated. The mean method is more particularly used to assess the thermal resistance of the building component and lead to a value which is compared to the one obtained for a mass insulation product such as polyurethane foam. On a further stage, the thermal mathematical model is replaced by a thermo-aeraulic model which is used to evaluate the thermal resistance of the roof as a function of the airflow rate. The results shows a better performance of the roof in this new configuration, which is widely used in practice. Finally, the mathematical relation between the thermal resistance and the airflow rate is proposed.