Design and Analysis of a Passive Lighting Device for a Sustainable Office Environment in Hot-Arid Climate Conditions

Abstract

Visual comfort in office spaces improves not only productivity and wellbeing but also satisfaction and energy efficiency of the buildings. The objective of this research is to study the effect of one of the transporting daylighting systems (Anidolic Integrated Ceiling ‘AIC’) on the enhancement of the luminous interior environment and energy saving in office building through objective and subjective evaluations. The quantitative study was performed by measurement of the illuminance values in the physical model (1:4) under local luminous climate in two scenarios (with and without ‘AIC’) and by numerical simulation to calculate the daylight autonomy. The qualitative evaluations were achieved by using a field survey composed of four questions related to pleasantness, level of light and artificial lighting needs. Experimental study shows that the AIC offers high levels of illumination in quantitative terms result in moderate values of Daylight Factor (2% - 4%). Simulation results showed that more than 88% of energy consumption for electrical lighting can be saved. Subjective evaluation results indicate that in the test model (with AIC), 67% of participants felt more pleasant with the luminous environment, 74.19% considered that the level of light is sufficient and only 08 of 31 subjects need to use artificial lighting.

Curve Optimization for the Anidolic Daylight System Counterbalancing Energy Saving, Indoor Visual and Thermal Comfort for Sydney Dwellings

“…Saadi et al (2022) analyzed passive daylighting using Anidolic Integrated Ceiling (AIC), enhancing interior luminance and energy saving in offices located in a hot, arid climate. They reported a 2-4% increase in Daylight Factor, 88% saving in lighting electricity, and 67% lighting satisfaction [11]. Wittkopf et al (2006) simulated AIC and achieved 21% and 26% savings in building energy for Singapore and Sheffield, respectively, as well as more than 20% savings in lighting energy [12].…”

“…With the same idea as the light shelf [22], an Anidolic Daylighting System (ADS) uses a perfect non-imaging [23] parabolic mirror using a white or reflective metal [4] and acts as a solar concentrator [13]. As a good option for tropical regions [6,19,[23][24][25], the ADS captures light flux and then distributes the diffuse component of daylight [23] over a wider indoor area and "creates a more balanced daylight distribution throughout the space" [14] as a universal passive solution to improve deep indoor spaces' daylight illuminance and energy efficiency [11,12,22,[24][25][26]; it brought occupants' high satisfaction with the lighting environment [6] and "confirmed the superior services" [13].…”

“…The ADS can enhance indoor visual comfort under a high luminous sky by providing a congenial luminous environment, keeping a more homogeneous daylight distribution, and reducing discomfort glare probability [28]. The ADS does not provide indoors with excessive indirect sunlight, which causes glare and overheating under a sunny sky [11], while an integrated ADS can improve indoor luminous performance by a higher Daylight Factor (DF) and work plan illuminances (at the rear part of the room) and improve Daylight Autonomy (DA), not at the expense of visual comfort [13]. Anidolic shelves used in urban districts can increase DF compared to conventional double glazing, even up to 1.7 times in the deeper parts of the room; this increase was the value of the reference case [13,27].…”

“…More recent attention has focused on the provision of daylight in the rear part of indoor spaces (i.e., core daylighting) in designing sustainable buildings [6]. Especially during the cooling season, when the sun is high, deep rooms experience uneven daylight distribution that identifies additional artificial lighting which leads to the overuse of electricity [11]. Passive daylighting systems which are affordable and require minimum maintenance can provide indoor daylight and ventilation simultaneously [4] and increase daylight homogeneity.…”

“…Non-imaging optics including mirrors and light guides are used for solar concentrators in daylighting systems for the purpose of efficient collection and redistribution of the diffuse sunlight [13]. Light pipes and anidolic integrated ceilings are the most frequently used systems in buildings [11]. Anidolic collectors, which are effective for daylight collection and redistribution [13], by redirecting sunlight towards the back of the room by reflecting the sun rays from the ceiling underside [4,14], can increase daylight illuminance level.…”