An Empirical Study of a Passive Exterior Window for an Office Building in the Context of Ultra-Low Energy

Abstract

As the energy crisis continues to intensify and with increasing awareness of global climate change, the issue of high energy consumption and emissions in buildings is garnering more attention. Windows have significant research value and importance as pivotal components in the development of ultra-low-energy buildings. This study presents a proposal for a passive exterior window considering the climatic conditions prevalent in the hot summer and cold winter zone of China. Firstly, an experimental platform was established outside a standard office to conduct tests and analyze the indoor thermal environment for four different scenarios in the summer and winter by comparing a passive room (PR) and non-passive room (NPR), respectively. The human apparent temperature was calculated based on the collected thermal environment data and subsequently evaluated. Lastly, the indoor environmental temperature (IET), window surface temperature (WST), and apparent temperature (AT) data were subjected to non-linear fitting regression analysis using Origin software. The primary aim of this analysis was to examine the impact of the passive exterior window on the indoor thermal environment and establish the feasibility of implementing such a window in the hot summer and cold winter zone of China. The results showed that: (1) in the summer, the IET and WST in the PR exhibited reductions of 0.8 °C and 0.6 °C, respectively, under ventilated conditions compared to the NPR; (2) in the winter, the IET and WST of the PR remained lower compared to those of the NPR (however, the temperature differential between the IET and WST in the PR amounted to 6.8 °C and 7.7 °C, respectively, while the corresponding disparity in the NPR was 8.1 °C and 9.3 °C); and (3) regarding the AT, during summer ventilation, the PR exhibited a substantial reduction of up to 3.5 °C in comparison to the NPR. Moreover, in the context of winter, the time for indoor human thermal perception to reach a comfortable level was extended by 0.5 h. Future investigations will delve into the influence of passive exterior windows on building energy consumption, and this research can provide a practical reference for energy-efficient design and retrofitting of exterior windows in the region.