The use of green walls in sustainable urban context: with reference to Dubai, UAE

Abstract

The impact of urban development on the natural environment generates unique challenges to architects and engineers seeking passive design strategies in hot and humid climates such as those in Dubai. They are collaborating to design new buildings that are energy efficient, environmentally friendly, and architecturally significant. Passive cooling design techniques, which are recognized mainly in the old Dubai, are energy efficient and can be considered as a good alternative to mechanical cooling systems. Green roofs and façades are passive techniques and add more benefits not only for reducing the energy demand of buildings, but also for providing environmental benefits, including visual relief, accessible green space, and improving air quality. In recent years, greening systems have been practised in many hot cities, including greening directly on to roofs and walls, greening the cavity between walls, and incorporating greening systems within the construction of the wall. Green roofs are frequently used in cities like Dubai; however, practising green wall technology is still new despite its great benefits.Based on the climatic condition of Dubai, this paper attempts to reduce energy consumption in buildings by adopting passive cooling strategies in the sustainable urban context of Dubai. The growing interest in incorporating vegetated green walls into sustainable building is highlighted. To achieve the aim of the study, the following objectives have been covered: to investigate the use of passive cooling strategies in Dubai; to enhance the energy performance by reducing the cooling loads and therefore identifying the optimal parameters for building skins; and to draw guidelines for architects, planners and developers to demonstrate the potential benefits of green wall technology. In this context various issues, including the urban development of Dubai, sustainability, passive cooling techniques, and the performance of green walls, are to be considered.

Green Facades and Living Walls—A Review Establishing the Classification of Construction Types and Mapping the Benefits

“…Living walls NSP Living walls have also been shown to reduce noise [14] Living walls NSP Acoustical insulation that is far better (up to 30 dB) than that of exposed wall [26] Living walls NSP Reduces outside noise and vibration (up to 40 dB) [25] Living…”

“…Thermal performance, as a benefit of green facades and living walls, depends on many factors, and some of them include climate, building skin type, and density of plant coverage. Through careful incorporation of shading, insulation, and vegetation, heat can be blocked and indoor temperatures reduced by 10 • C, while vegetation as a heat buffer can reduce energy consumption for up to 20% [26]. Early experiments measuring the thermal effects of climbing plants on building facades in summer demonstrated less than 1 • C reduction in the ambient air temperature [29].…”

“…As Timur and Karaca explain, "living walls provide a noise buffer which significantly reduces outside noise and vibration (up to 40 dB) inside the building and its close area" [25] (p. 598). The degree of sound insulation depends mainly on the depth of the growing media, the type of plants, materials used for the structural components of the living wall system, and the layer of air between the plants and the wall [26]. One type of living wall, known as a landscape wall, was specially designed and described as noise intervention on Ibiza, Spain by Urbanarbolismo [40].…”

“…Their usage can reduce climatic stress on building facades, prolong the life of buildings, and reduce cost for the painting materials [93]. Haggag [26] states that VGS can indeed prolong the life of existing facades if waterproof panels are used and separated a layer by air, as this can protect a building from wind, solar radiation, and rain, can allow moisture to escape, and can also contribute to the reduction of expansion and contraction of building materials. Wong et al adds to this discussion and explains that: "by limiting the diurnal fluctuation of wall surface temperatures, the lifespan of building facades is prolonged, slowing down wear and tear as well as savings in maintenance cost and the replacement of facade parts" [28] (p. 663).…”

“…Descriptive studies about VGS benefits could be found, but the benefits in those studies were simply described, and not measured or empirically tested [13,14,26,27]. A smaller number of studies contained specific measurements for an analyzed benefit [28][29][30].…”