Experimental investigation of optical and thermal performance of a PCM-glazed unit for building applications

In present work, optical and thermal performances of a PCM-glazed unit were experimentally investigated compared with that filled with air, and the influences of solar irradiance, melting temperature and PCM layer thickness on three parameters were analyzed including the transmittance, the temperature difference between upper and bottom surfaces, and the interior surface temperature of the glazed unit. The results show that the thermal performance of glazed unit filled with PCM is improved compared with that of air, and transmittance of glazed unit is 50% when the PCM is liquid. Solar irradiance and PCM layer thickness both have effects on the optical and thermal performance of glazed unit, but the effect of melting temperature on thermal performance can be neglected. Increasing the PCM thickness can effectively decrease the heat loss of glazed unit filled with PCM, but the PCM thickness in the glazed unit is not beyond 16 mm considering the optical performance of glazed unit.