Numerical And Experimental Investigation Of The Dynamic Heat Transfer Process Of Phase Change Material Filled Glass Window

The building energy consumption is huge in China, and building energy efficiency is an important part of sustainable economic development and energy conservation. Improving the thermal insulation effect of transparent envelope is significant to achieve building energy efficiency. The PCMW (double glazed window filled with phase change material) increases the heat capacity and thermal inertia of transparent envelope and has a significant cooling shifting effect, because phase change material has a large energy storage density.In order to investigate the thermal insulation performance of PCMW, the numerical models of PCMW and HW (hollow glass window) were built, and the dynamic heat transfer characteristics of them in the hot summer and cold winter area of China were investigated by numerical simulation. It was concluded that in the typical sunny summer day, the peak temperature on the interior surface of PCMW (glauber’s salt) reduced by 10.2℃, and the heat entered building through the PCMW reduced by 39.5% comparing with the HW. However, in the typical rainy summer day, typical sunny winter day and typical rainy winter day, the dynamic thermal performance of the PCMW was unsatisfactory as it cannot decrease the building energy consumption.The comparative experiment setup was built to verify the numerical models and investigate the thermal performances of PCMW and HW in summer. The experiments and numerical simulations in a typical sunny summer day were conducted, and the results were in good agreement. Then the thermal performances of PCMW (paraffin, MG29) were investigated, because the thermal performances of PCMW (glauber’s salt) was unsatisfactory in rainy summer day and the thermal performance of glauber’s salt was unstable. Results showed that comparing with HW, the peak temperature on the interior surface of PCMW (MG29) reduced by 2.6℃ and delayed 2 hours, the peak heat flux reduced by 30.2W/m2, and the heat entered building reduced by 39.5% in typical sunny summer day. The peak temperature reduced by 2℃ and delayed 1 hour, the peak heat flux reduced by 11.4W/m2, and the heat entered building increased by 4.9% in typical rainy summer day.In order to enhance the thermal insulation performance of PCMW and select the optimal phase change material for the hot summer and cold winter area of China, the effects of PCM1 s thermophysical parameters on the thermal performance of PCMW were investigated by FLUENT. Results showed that the thermal insulation and load shiffing effects of PCMW enhanced with the increasing fusion latent heat of PCM, and the optimal melting temperature of PCM was 25℃-31℃. Moreover, minimizaiton of temperature difference between liquid phase and solid phase could improve PCMW thermal performance.The effects of PCMW on the building energy consumption in the hot summer and cold winter area of China were researched by ENERGYPLUS. The nonlinear optical and thermal parameters of PCMW were treated as average values of integration. It was known that the annual energy consumption of the office building with PCMW reduced 1.77% comparing with HW, and reduced 3.47% comparing with SW (single glass window). The cooling load of the building with PCMW reduced 6.46% comparing with HW, and reduced 6.68% comparing with SW. The heating load of the building with PCMW increased 13.9% comparing with HW, and reduced 3.57% comparing with SW. In brief, the cooling and heating load shifting effects of PCMW were remarkable, and the energy saving potential was significant.