O impacto do ofuscamento no (DES) uso da luz natural em ambientes do tipo escritório em baixa latitude

Abstract

External window shading is not enough for the occupants of air-conditioned office buildings to maintain the curtains and blinders opened, to enjoy daylighting, exterior view, environment comfort, and natural ventilation eventually, at low latitudes, such as Natal-RN (latitude -5.8; longitude -35.3). The current thesis assessed this problem to characterize the causes of the window's obstruction with internal devices. Firstly, a sample was selected, with 102 occupants distributed in 57 office rooms of four buildings designed with external window shading. The occupants' perception and behavior concerning the daylight, internal shading devices, and artificial light were assessed using questionnaires, notes, and photos during field auditory. Secondly, glare assessment was refined with 11 occupants of nine office rooms that interact with the internal shading device daily. A conducted questionnaire, notes in forms and photos, and measurements characterized the light performance that led to close the internal shading devices, including intermediary positions, and after closed. The illuminance and luminance measures and the glare indexes such as daylight glare probability (DGP), daylight glare index (DGI), and luminance ratios in three fields of vision (30°, 60°, and 90°) were compared with the occupants' opinions. The indexes were calculated through HDR images, generated, and calibrated through Photosphere software (WARD, 2019b), resized through HDR scope (KUMARAGURUBARAN ,INANICI, 2012), Glare Analysis (WIENOLD, 2018), and Wxfalse color (BLEICHER, 2015). The results demonstrated the excess of brightness as the main obstacle to the daylight use and exterior view due to the lighting discomfort. Indeed, most occupants close the internal shading devices because the external shading is not enough to reduce the sky brightness in the occupants' field of view, the computer screen brightness reflection, the reflect brightness by surroundings, and brightness and/or heat due to the direct daylight.