Développement d’une méthode d’évaluation des propriétés radiatives et isolantes d’un matériau destiné aux enveloppes extérieures de bâtiments

Abstract

While heatwaves are increasing in intensity and frequency because of climate change, they are exacerbated in urban areas by the urban heat island (UHI) phenomenon. In particular, the absence of vegetation and the concentration of construction materials in buildings and roadways lead to the absorption and retention of heat within the urban area, threatening the health of residents. Among the solutions for adapting urban areas to extreme heat is the use of so-called "cool" coatings for buildings. These coatings have radiative properties that enable them to reduce heat absorption in the building envelope, while facilitating the release of absorbed heat to the outside air. However, in regions with hot summers and cold winters such as Quebec (Canada), it is essential to complement the application of these coatings with insulation measures. Furthermore, the development of exterior building claddings with such radiative and insulating properties is slowed by the need to characterize each of their thermal properties individually. It is therefore essential to provide industries with an adaptable experimental method for efficiently assessing the overall thermal behavior of their products. This research project presents a method for assessing the radiative and insulating performance of materials intended for exterior building cladding, using common equipment: a heat lamp, expanded polystyrene insulation, a thermal camera and thermocouples. The main heat transfers experienced by a building façade were reproduced and monitored using temperature trends at different points on the material studied. In addition, a case study was integrated into this research and analyzed using the method developed. This involved a composite material based on polyurethane and fiberglass. This material was coated with nine different paints, whose radiative properties were analyzed using the experimental method. The results showed that the method enables materials to be distinguished qualitatively according to their potential to contribute to UHI. It also enabled the observation of surface aspects that influence heat absorption: color and roughness. All experimental results were compared with numerical simulations. These required characterization of all the input data, i.e., the imposed and induced heat transfer flows, as well as all the thermal properties of the materials involved in these heat transfers. The results showed that experiments and simulations were highly correlated, suggesting that all the radiative and insulating properties of interest were correctly observed during the experiments.

Date	2 Nov 2023
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Éric Lachance-Tremblay (Supervisor) & Diego Ramirez-Cardona (Co-supervisor)