Solar and lighting transmission in complex fenestration systems with perforated solar protection systems

Abstract

Santiago de Chile is a city with a semi-arid climate, with prolonged periods of high temperature and solar radiation. In recent years, in this city, office buildings have been built with high window to wall ratio (WWR) facades. 65% of the office buildings built in the period 2005-2014 have a WWR higher than 60%. Only 5% of these buildings showed an efficient glazed façade solar protection device. One of these systems corresponds to an exterior textile solar protection. This type of systems, together with the perforated screens, could be effective solutions for the solar protection of glazed facades, reducing the cooling energy consumption of buildings, without risking the visual comfort of the occupants. The objective of this research is to evaluate the solar transmission and lighting of seven perforated solar protection systems. Three of these systems correspond to external textile solar protections, and the remaining four are perforated metallic screens. The evaluation was carried out by applying an experimental protocol in two different calorimeters that simulate an office space. In one of the calorimeters, the solar protection systems are installed while the other is used as a reference without any solar protection system. Measurements were made with illuminance sensors and pyranometers. The horizontal illuminance sensors from Konica Minolta (T10) were installed outdoor and at different points inside the calorimeters. Near the facade, vertical indoor and outdoor pyrometers were installed (Kipp Zonnen, CMP11 and Sp Lite 2). The measurements on the north facade are made in summer on clear days. The measurements showed a reduction in solar transmission of 82.1% (metallic screen, 40% drilling) to 94.7% (cloth, 3% drilling) and from 70.8% to 95.4% in the transmission of lighting respectively.