An integrated computational method for calculating dynamic thermal bridges of building facades in tropical countries

Abstract

Identifying thermal bridges on building façades has been a great challenge for architects, especially during the conceptual design stage. This is not only due to the complexity of parameters when calculating thermal bridges, but also lack of feature integration between building energy simulation (BES) tools and the actual building conditions. For example, existing BES tools predominantly calculate thermal bridges only in steady state without considering the temperature dynamic behaviour of building outdoors. Consequently, relevant features such as thermal delay, decrement factor, and operative temperature are often neglected, and this can lead to miscalculation of energy consumption. This study then proposes an integrated method to calculate dynamic thermal bridges under transient conditions by incorporating field observations and computational simulations of thermal bridges. More specifically, the proposed method employs several measurement tools such as HOBO data logger to record the actual conditions of indoor and outdoor room temperature and thermal cameras to identify the surface temperature of selected building junctions. The actual datasets are then integrated with the simulation workflow developed in BES tools. This study ultimately enables architects not only to identify potential thermal bridges on existing building façades but also to support material and geometric exploration in early design phase.

Key words： Thermal bridges; Dynamic calculation; Thermal delay; Cooling load; Computational design method