Analysis of Various Opening Configurations of a Second-Generation Virtual Natural Lighting Solutions Prototype

Abstract

To address the absence of natural light in working spaces, virtual natural lighting solutions (VNLS) can be promising. VNLS are systems that artificially provide lighting as well as a realistic outside view with properties comparable to those of real windows and skylights. This article discusses the evaluation and analysis of various opening configurations of a second-generation VNLS prototype, which features an array of light emitting diode (LED) tiles coupled with a line of linear LED fixtures with adjustable color temperatures that provide direct light. Simulation using Radiance was performed and validated with the measurement results. Various possibilities of placing the prototypes inside the test room were investigated in Radiance to determine the effect on space availability and visual comfort. Based on the comparison of seven configurations of two prototypes with equal total opening size, it was found that nearly all configurations tested yielded a space availability of 100% with a criterion of 200 lx and where space availability is defined as the percentage of points on a horizontal grid that meet or exceed the target illuminance. Taking 300 lx as the criterion, two openings on each short wall facing each other (configuration 2) and four openings on a long wall (configuration 5) yielded space availabilities of more than 90%. Taking 500 lx as the criterion, configurations 2 and 5 yielded space availabilities between 25% and 50%. The highest uniformity (E min /E avg ) was achieved under configuration 2 (0.59), whereas the maximum daylight glare probability (DGP) values under all configurations were between 0.25 and 0.30. Our simulation results suggest that the space availability in a private office can be optimized by placing a VNLS prototype on each short wall facing each other or by placing two on a long wall.

Mitigation of even harmonics in the Fourier components of vertical illuminance around a reference point

“…If installing windows in such positions is not possible due to space or architectural limitation, some vertical luminous displays 14,15 may be applied on the walls or partitions instead. Another practise can be combining downlight luminaires with window(s) on one fac¸ade; the downlighter may be dimmed or adjusted to match 92% of the maximum planar illuminance received from the window(s), in order to minimise the resulting even harmonics.…”

Sustainable Design Optimization Tool for Prototypical Buildings in Hot Arid Climate Using Analytical Hierarchy Process

“…Considering daylighting, numerous sources addressed the issue of optimizing design features towards achieving the best daylighting performance. Such design features included: (1) Window and opening design [1][2][3]; (2) Solar control devices [4]; (3) Optimal positioning and of lighting shelves using scale modelling and computer assessment [5,6]; and (4) Building shape, including façade and ceiling shape and characteristics [7][8][9]. Other authors focused around simulation and isolation of daylighting in a wide variety of space types using computer-aided tools, with the aim to assess daylighting performance using software tools [10][11][12][13][14][15][16].…”