Dynamics of Melting Process in Phase Change Material Windows Determined Based on Direct Light Transmission

Detailed analyses of melting processes in phase change material (PCM) glazing units, changes direct transmittance as well investigation refraction index were provided based on laboratory measurements. The main goal the study was to determine light versus time under constant solar radiation intensity and stable temperature surrounding air. experiment conducted a triple glazed unit with one cavity filled paraffin RT21HC PCM. installed special holder exposed from an artificial sun. vertical illuminance measured by luxmeters compared reference case transmittance. determined for whole period measurements when some specific artefacts identified theoretically explained values refractive indexes paraffins solid liquid state, glass. process PCM glass complex one, interreflections semi layers characterized different physical states (solid, or mushy). These optical phenomena caused nonuniformity transmittance, especially is mushy state. It revealed that cannot be treated linear function.