Spectral transmittance changes in a PCM glass block affected by an artificial radiation source

Abstract

Adaptive principles based on latent thermal energy storage together with its optimal modulation of optical properties in transparent façade systems represent one of the challenging solutions for reducing the energy consumption of buildings. Properly incorporated phase change material (PCM) may be a potential technique for passive solar system applications. This study focuses on the analysis of PCM’s optical changes on innovative building envelope components. A stable radiation source that most closely approximates the conditions of sunlight is essential for the characterization of new solar thermal systems. Hence the intensity and spectral distribution of the light source are the most important factors corresponding to natural sunlight. This contribution stems from previous experimental research focused on the investigation of the changes in the transparency of the PCM material, which is the result of the phase transformation from solid to liquid and vice versa under radiation exposure. The main challenge is to characterize the spectral optical properties in the PCM glass system. Accordingly, optical changes were analyzed experimentally using the spectrometry method. The measurements are based on a comparison of clear and PCM-filled glass blocks, affected by artificial radiation in a laboratory. The results revealed that PCM glass block may act as near-infrared absorbing and at the same time a highly transparent system in the visible region compared to the conventional air-based systems.