Energy-efficient window retrofit for existing high-rise residential buildings with the consideration of mutual shading

Abstract

Upgrading the window glazing can help minimize the energy consumption through a reduction of solar heat gain in summer or indoor heat loss in winter. On the other hand, the mutual shading caused by surrounding high-rise buildings could affect the energy performance of the window glazing. In hot climate, mutual shading could further reduce the solar heat gain. In cold climate, overshadowing lowers the solar heat gain in winter resulting in greater demand for space heating. To explore the most energy-efficient window glazing for different climates, it is imperative to integrate mutual shading with window retrofit measures when evaluating the thermal performance of a building. This study applies a computer-based simulation program known as DesignBuilder to assess the building performance. The energy model is based on a typical high-rise residential building, and four common double energy-efficient glazing alternatives were employed in lieu of single clear glass. The results show that the optimum window retrofit solution vary with different climatic conditions and there are different choices for upgrading window glazing in the same building with and without the consideration of mutual shading due to the mutual shading effect on the energy use.