Experimental Analysis of the Performance of Light Shelves in Different Geometrical Configurations Through the Scale Model Approach

Abstract

Daylight plays a significant role in achieving energy saving and comfort in buildings. It is in accordance with the human circadian rhythms and allows the best visual conditions in work environments and residential buildings. Recently, numerous researchers have focused their attention on the performance of technological devices able to increase natural light availability in interior areas of buildings. Among them, light shelves are commonly used with the aim of improving the depth of daylight penetration, trying to reduce the nonuniform diffusion of light entering from vertical windows. In this paper, the authors propose six different configurations of an internalexternal light shelf and analyse their performance using the experimental scale model approach under real sky. Although the method is not very accurate as deduced from literature on this topic, the authors still demonstrate its usefulness in examining different geometric configurations of light shelves. In fact, even if the results highlight inaccuracies in the method used, which are accentuated under direct sun light, they are useful for considerations in the comparative analysis, particularly in regard to data logged under partially completely cloudy skies albeit with the awareness that light shelves' effectiveness is improved under direct sun light. Despite its limits, the method is simple to use and can be considered efficient in allowing the authors to carry out considerations regarding the performance of the system analysed. Among the six different configurations proposed two seem to be the most efficient and are characterized by the presence of an internal highly reflecting surface applied on the ceiling and an external one with two different inclination angles (10° and 20°).

Effective Use of Daylight in Office Rooms

“…From which we can conclude the inadmissibility of using WFR to assess the daylighting of rooms. In studies [3,16,27,[49][50][51][52][53][54][55][56][57], WWR was used to summarize the results, that is, the ratio of the TSBE area (STSBE) to the internal area of the TSBE in the BE in which it is installed. The height of the investigated room is 3 m.…”

A New Trend for Indoor Lighting Design Based on A Hybrid Methodology

“…Research [43] motivated the researchers to discuss the effective use of combination of LED products to reduce insect attraction. Authors in [4,44] tried to increase natural light availability, where authors of [4] supposed six different configurations of an internal/external light shelf and they advise the most two efficient models. Authors of [45] gave advisements to lighting designers, road authorities, etc.…”

“…Improving efficiency and reducing energy consumption are essential for sustainable grids [1]. The building sector is considered as one of the most sectors that consumes energy standing about 30-32% from the total energy productions, where the lighting loads consume between 5% to 20% in residential loads and up to 30% in commercial buildings [2][3][4]. For instance, in Europe, it represents about 14% of all energy consumption, while this ratio is around 19% of worldwide energy consumption.…”

“…For instance, in Europe, it represents about 14% of all energy consumption, while this ratio is around 19% of worldwide energy consumption. In special loading types, for example the retail sector, it may reach up to 80% of the energy used [2][3][4]. Therefore, many researchers are seemingly interested in decreasing the consumed power in lighting sections with various methods/algorithms.…”

“…The cost of light source "T26", E£: .99 £ = 552.749 $ (41) The cost of light source "TC", E£:( ) = 66 �18 + 20000 � 0The hybrid method optimal desgins 4.1.1 4…”