Radiant glass façade technology: thermal and comfort performance based on experimental monitoring of outdoor test cells

Abstract

Fully glazed façades on commercial buildings have a significant impact on the thermal comfort of the occupants. Discomfort caused by thermal asymmetry can be addressed with a commercial glass curtain wall equipped with radiant glass (RG) technology. Such a wall acts as a heating system that uses radiant long-wave heat, and is fully integrated into the façade; the thermal performance of a glass curtain wall can be adapted according to occupant requirements.This study presents the results of an experimental campaign of tests conducted in outdoor test cells equipped with RG to assess the thermal and comfort performance of the façade. The study compares two identical cells in the same boundary under winter climate conditions: one (as reference) with a commercial low-e double glass façade and an HVAC heating system, and the other (as prototype) equipped with RG technology working entirely as the heating system. Comparisons between data gathered from outdoor cells were performed to investigate the thermodynamic performance, radiant and thermal asymmetry, operative and air temperatures, standards, and local indoor thermal comfort levels of both façades.This study demonstrated that using RG as a heating device can improve the level of thermal comfort by avoiding radiant asymmetry through a uniform distribution of radiant temperature, even along the perimeter zone in higher-glazed façades not subjected to external climatic conditions. The results suggests that operative and ambient temperatures can be lowered while maintaining thermal comfort.