Design of Balcony from the Point of View of Daylighting

Abstract

Balconies are horizontal overhanging structures whose main function is a connection between interior and exterior space. Moreover, they increase an area of a room and they also can have a presentable, architectural and aesthetic purpose. There are a lot of requirements on the balconies, for example the requirements on static properties, thermal bridges, railings or fire safety. From the point of view of building physics, we can consider the balcony as the fixed shading construction which can reduce overheating in a shaded room during the summer but on the other hand the balcony can influence visual comfort in the room in a negative way. This article presents a comparison and an evaluation of the daylight factor in the rooms which are shaded by balconies. The influence of the balconies on the daylight factor is assessed in dependence on a length of the balcony (a balcony overhang) and dimensions of the room which the balcony shades.

Decision-making pathways to daylight efficiency for office buildings with balconies in the tropics

“…Figure 9a, however, illustrated an interesting cut-off point for design decision-making as balcony depths below 1.0 m had, in the majority of cases, sDA values falling within the preferred threshold whereas balcony depths above 1.0 m would tend to have sDA values falling, on average, within the accepted threshold. As expected from Al-Sallal et al [13], Kim and Kim [11], Gábrova [14], Xue et al [12] and Dahlan et al [15,16], the addition of balconies was determinant in reducing the ASE (Figure 9b). However, this study identified that balconies deeper than 1.5 m will achieve null ASE and therefore are optimum to avoid glare and overheating due to direct solar radiation.…”

“…The mean and median values for both solar orientations were classified as sDA acceptable and ASE tolerable, although the West façade resulted in higher levels of ASE, possibly due to the fact that the number of occupied hours in the afternoons is higher than in the mornings. The use of balconies wider than the windows (ratio of balcony width to window width = 2) decreased the daylight performance (Figure 12a) but also prevented glare (Figure 12b), echoing results found by [11,13,14]Al-Sallal et al [13]. The ratio of balcony width to window width of 1 and 2 showed similar performance for ASE, with most part of the cases classified as null, reinforcing the importance of having balconies with full window width.…”

“…Room width and depth were investigated simultaneously by changing balcony and window positions from the front and back façades to side façades, as displayed in Figure 4, reflecting the most common floor plan proportions for mixed-mode office spaces in São Paulo [22]. As confirmed by Gábrova [14], results clearly showed that the shallower the room, the better the daylight performance. More than 50% of the front balcony cases (room depth 5.5 m) were classified as sDA preferred, while only 29% of the side balcony cases (room depth 7 m) achieved this threshold.…”

“…Results presented by Al-Sallal et al [13], Kim and Kim [11] and Gábrova [14] through daylight simulations showed that the presence of balconies increased daylight uniformity and decreased glare and illuminance levels in the indoor environment. Gábrova [14] stated that the use of balconies increased daylight uniformity up to 55% inside the room. Al-Sallal et al [13] showed that a 3-meters wide balcony was able to eliminate glare inside the room.…”

“…Kim and Kim [11] stated that balconies 3 and 6-meters deep decreased illuminance levels by 18% and 46%, respectively. Gábrova [14] showed that balconies 0.75, 1.0, 1.25 and 1.5-meters deep decreased illuminance levels by 20%, 25%, 30% and 35%, respectively. Xue et al [12] and Dahlan et al [15,16] investigated the impact of balconies on the luminous performance of residential buildings through field measurements and questionnaires applied to the occupants.…”