ATTENTION TO THE OVERHEATING IN CURTAIN WALL

Introduction

In public buildings, the energy consumption caused by curtain wall accounts for more than 50% of the entire building[1], which means the facade thermal performance is the key factor for the energy-saving design of public buildings.

The two main parameters in the thermal performance of the curtain wall are U-factor (heat transfer coefficient) and SHGC (solar heat gain coefficient). So far, the typical building energy-saving design strategy is to reduce the U-factor and SHGC of the curtain wall to achieve lower heating and cooling energy consumption.

Normally, in addition to U-factor and SHGC, the curtain wall design should also include the condensation analysis under winter condition to avoid indoor condensation problem. In 2015, Singapore began to study the impact of insulated fenestration on energy saving and thermal comfort in tropical and subtropical climates [2], which brings another issue regarding the overheating in curtain wall. Subtropical regions such as Hong Kong is recommended to design and avoid indoor overheating due to the high solar irradiance in summer.

This paper selects Shenzhen, which has a similar summer climate to Hong Kong, as the boundary condition, uses THERM software of Lawrence Berkeley National Laboratory to conduct thermal analysis for typical curtain wall systems, and discusses the overheating protection for curtain walls.