Thermal performance of highly glazed office buildings in the tropics: Contradicting architectś expectations

The inadequacy of highly glazed facade office buildings has been debatable for decades due to their impact on the internal environment comfort and energy consumption. One of the consequences noticed in the 50′s decade was the thermal discomfort caused by the non-uniform thermal environment. Despite the glass technology developments since then, buildings with ordinary laminated glass and unknown thermal properties became commonly accepted in Brazil's most populated cities in the low latitudes, opposing primary design recommendations. This work discusses this context based on the short-term thermal assessment of five case studies in a warm and humid climate, assuming regular occupation. The combination of the walk-through audit with thermal monitoring at the centre of office rooms and next to the facade resulted in comparing air and operative temperatures, and the PMV index, under different environment configurations. Surface temperature measurements with thermographic photos complemented the thermal analyses. The case studies confirmed different simultaneous thermal sensations between perimeter and centre zones. The perimeter zones barely reach PMV 0.5, achieved by the users' adaptations that mitigated the thermal radiation from the facades, obstructing the windows with internal shades or avoiding the window view by changing the layout. Therefore, the extensive use of window obstructions compromises other indoor environmental aspects, such as daylighting and exterior view, contradicting the architects' expectations of a transparent glass building.