An self-adaptive cascade smart window capable of adjusting indoor light and thermal environment for building energy conservation

Abstract

The performance improvement of windows has a great need for development in terms of energy saving and carbon reduction, as their energy consumption is up to 30 % of the total energy consumption of the building. The window with phase change material (PCM) improves the thermal inertia of the window and thus reduces the energy consumption of air conditioning. However, the application effect of window with single PCM was limited by the leakage of PCM with the state of melted and the poor natural lighting. Therefore, a self-adaptive cascade phase-change window (PCMWⅢ) composed of three kinds of flexible-shaped PCM was proposed in this study. The experiments were carried out to compare the thermal performance of PCMWⅢ and conventional PCM window (PCMWⅠ). The results indicated that the indoor peak temperature of the model house with PCMWⅢ was 4.74 °C lower than that with PCMWⅠ under constant irradiation condition. The indoor temperature of the model house with PCMWⅢ exhibited a 2 °C temperature decrease compared with PCMWⅠ under the case of outdoor dynamical weather. Furthermore, a mathematical model of the cascaded PCM window was developed. The total energy consumption (including cooling load and lighting electrical load) was as the optimization goal to optimize the structure of PCMWⅢ. The simulation results showed that when the area ratio of SPCM-19, SPCM-25 and SPCM-28 was 3:1:5, the light and thermal performance of optimized PCMWⅢ showed excellent effect with the total energy consumption reduction of 15.03 % compared with PCMWⅠ. The proposed cascade phase-change smart window can provide reference for the development of PCM windows.