A new affordable and quick experimental device for measuring the thermo-optical properties of translucent construction materials. (November 2020)

• Record Type: Journal Article
• Authors: Hamada Fakra, Damien Ali; Alfonso José, Blázquez Recio; Murad, Nour Mohammad; Gatina, Jean Claude
• Is Part Of: Journal of building engineering. Volume 32(2021)
• Publication Date: 2020-11
• Subjects: Optical reflectance -- Optical transmittance -- Optical absorbance -- Thermal conductivity -- Low-cost device -- Experimentation -- Heat transfer -- Polycarbonate; Building -- Periodicals; 690.05
• DOI: 10.1016/j.jobe.2020.101708
• Languages: English
• ISSNs: 2352-7102

Abstract

Abstract: The knowledge of thermo-optical properties of building materials is an essential factor for studying human comfort inside the building. Experiments are generally used to determine these properties. Each thermo-optical coefficients (i.e. the thermal conductivity, optical reflectance, transmittance and absorbance of the materials) can be measured separately by various devices. However, considering the new and complex materials that are emerging, for example, the translucent materials, the existing measuring instruments are finding it challenging to characterize these coefficients correctly. In this article, a new experimental device based on a spherical environment is proposed. The proposed system is capable of measuring the optical reflectance, transmittance, absorbance, and the thermal conductivity of homogeneous and innovative construction materials over a short experimental duration. The measurement protocol, the physical laws associated with the new experimental device, and the calibration tests of the measuring sensors are described. Furthermore, an application test based on a known reference, a polycarbonate construction material, is described in detail to prove the ability of the device to correctly measure these thermo-optical property coefficients. The results obtained show a relative error The results obtained show a relative error around of +/- 5%. Comparisons of the absolute error with the test results from the experimental device proposed by ASTM International (formerly the American Society for Testing and Materials) show that the maximum errors contributed by the new system described in this work to perform these measurements are generally acceptable. For the polycarbonate material, we obtained the following relative errors: 4.5% for the thermal conductivity, 4.7% for the optical reflectance, 0.56% for the optical transmittance and 1.78% for the optical absorbance. Highlights: New method to characterize the thermo-optical properties of translucent material. New experimental device for measuring the thermo-optical properties of construction material. The low-cost conception of thermo-optical measurement device and validation of the system. Reduction of the experimental duration.