Thermal comfort of multiple-skin facades in warm-climate offices

摘要

A multiple-skin facade is an envelope construction that consists of two transparent surfaces separated by a cavity. The extra skin can reduce both cooling demand in summer and heating demand in winter. Solar radiation entering through the outer skin on the south face of the building will heat the air in the cavity. Depending on whether there is a demand for heating or cooling, this preheated air can either be drawn into the interior spaces or ventilated out of the building.These kinds of systems can be varied, depending on the arrangement of the air cavity section. Some examples of variations are the shaft-box window, the corridor facade, the multi-storey double-skin facade, and the box-window facade. The advantages of the double-skin facade are that it provides acoustic insulation, thermal insulation, and reduction of the effects of wind pressure; this approach allows natural or fan-supported ventilation and the possibility of rehabilitating existing single-skin facades by the addition of a second skin. The disadvantages of the system are its higher cost, the lack of practical information on fire protection, reduction of available space for offices, and less room-to-room or floor-to-floor sound insulation. In this study, the authors chose to conduct a parametric study for warm climates to provide a design aid for architects and designers. The parameters studied were the width of the cavity between the double skins, the area of the openings, the height of the buildings, the height of the transparent chimney added to the top of the south double facade, and the arrangements of open and closed openings. The effects of these parameters on airflow within the building and levels of thermal comfort were studied.