Effect of PCM thickness and melting temperature on thermal performance of double glazing units

The phase change material (PCM) applied in the glazing unit is an effective approach to decrease the building energy consumption and improve the utilization efficiency of solar energy, which makes a better thermal performance of glazing. In the present work, thermal performance of a PCM-filled double glazing unit with different thickness of phase change material in winter was investigated numerically in the cold area of Northeast China with the melting temperature 14-16 °C, 16-18 °C and 18-20 °C. The validation of the calculation model with experimental data was accomplished, and a good agreement of the temperature field between simulations and experimental data can be found. Then effect of thickness and melting temperature of PCM on thermal performance of double glazing units was investigated and the relevant parameters were analyzed. The results show that the interior surface temperature increases by 158.7%, the total transmitted energy decreases by 109.1% and the transmitted solar energy decreases by 86.1% when PCM thickness is 50 mm, compared with its thickness 4 mm. With the increasing of PCM melting temperature, its utilization decreases. When the thickness increases from 4 mm to 30 mm, the liquid fraction increases, but the condition is reverse when it continues to increase to 50 mm. So considering all parameters, the thickness 12-30 mm and the melting temperature 14-16 °C is recommended in Northeast China.