Passive design strategies for curtain wall system in subtropical office buildings in China considering multi-sensory comfort

In subtropical urban environments where glass building curtain walls predominate in the high-rise office construction, the building envelope plays an important role in determining energy use and comfort level within the building. This work formulates passive design concepts to the high rises office building in the subtropical China through a systematic evaluation of four common envelope types, namely, single-layer curtain walls, single-layer curtain walls with shading, double-layer curtain walls, and continuous shading with enclosure structures. Based on representative subtropical climate condition as a typical example of the subtropics in China, a parametric analysis is conducted using various comfort performance criteria including thermal comfort hours, useful daylight illuminance (UDI), and visual quality. EnergyPlus and Radiance performance simulations identified the optimum parameter spaces in each envelope type: for single-layer curtain walls, 565–591 comfortable hours could be achieved annually with glass U-values ranging from 1.7–3.2 W/m²K of glass U-value and window-to-wall ratios of 0.40–0.60; the single-layer curtain walls with shading had the best performance overall, providing 599–601 comfortable hours. After eliminating designs that fail to achieve adequate visual performance with average interior visibility ratio > 40 %, this work provides evidence-based design guidelines for curtain wall systems that maintain a balance between thermal comfort, quality of daylighting and aesthetics. The evidence-based design measures described in this paper are useful to architects and engineers intending to optimize the building envelope design within the subtropical climate, addressing the gap of theoretical knowledge and practical application to sustainable high-rise construction.