Influence of optical parameters on thermal and optical performance of multi-layer glazed roof filled with PCM

Phase change material (PCM) applied in the multi-layer glazed roof can cut down energy consumption and increase thermal comfort by improving its thermal storage capacity. In present work, a numerical model was developed to provide a tool to simulate the heat and light transfer process in a multi-layer glazed roof filled with PCM for developing engineering analyses, which was validated by experimental method. The influences of refractive index and extinction coefficients in solid and liquid states on thermal and optical performance of the glazed roof were investigated. The results show that the influences of solid and liquid refractive index on the interior temperature are smaller than that of solid and liquid extinction coefficients. Due to the convection process of air layer, the influences of the optical parameters of PCM in solid and liquid states on the temperature difference are both completely opposite. The liquid extinction coefficients on temperature decrement factor is bigger than other optical parameters, even the bigger liquid extinction coefficients may make the insulation effect of PCM invalid. The conclusions provide basic design parameters and novel design concept for the multi-layer glazed roof containing PCM.