Parametric Thermal Simulations of an Airflow-Screen Façade System

Abstract

Energy-saving performance is required for building façades, and high-performance window systems, such as double-skin and airflow windows, are being considered as viable alternatives. However, those systems are costly owing to the increased number of glazing panes. Therefore, an airflow-screen façade system (AFS) that combines glazing, a blind, and a roller shade can be a viable solution. The design issues of AFS are the backflow to the indoor side and the effect of natural convection on indoor airflow when exhaust fans are not in use during holidays and at nighttime. However, only few studies exist on the annual thermal behavior of AFS. In this study, based on the thermal load calculation program NewHASP, a simulation model of AFS was built using a thermal node solar heat gain model and a ventilation network model. Sensitivity analysis of the maximum and annual thermal load were performed with the following parameters of the AFS: roller shade airtightness, glazing type, blind slat angle control system, window orientation, and exhaust fan air volume. The results of the sensitivity analysis indicate that the maximum and annual thermal loads were the most sensitive to were the direction the window faces and the airtightness of the roller shade.