BUILDING SHADING | MIDDLE EAST Shade from adjacent buildings on high-rise projects could have a huge impact on reducing energy cost and carbon emissions in warm climates, says Muhammad Omer Safder, who has modelled a 40-storey tower in the Middle East to show the potential savings IN THE SHADE S hading of the built environment has the potential to be one of the more significant decarbonising strategies and a driving force towards net zero carbon buildings. Integrated systems, such as brise soleil or horizontal overhangs, can provide shade that reduces solar heat gains and, subsequently, building cooling loads. Adjacent buildings also offer shade that can reduce the amount of cooling required. This article will look at the effect on cooling loads of shading on a high-rise building from adjacent high-rise towers and shading systems. In our study, we modelled a 40-floor high-rise office building in Abu Dhabi, UAE (ASHRAE climate zone 1A, B) with conditioned floor area of 57,900m2, and analysed the impact of adjacent buildings shade on the cooling load of the object building. (See Figures 1 and 2.) Building geometry and its energy model were built using Integrated Environmental Solutions (IES) applications ModelIT and ApacheSim. The energy simulation was performed using the Abu Dhabi annual weather file provided by the IES software library. A high-rise building model with and without shade was considered to evaluate the impact on cooling load and annual electrical energy consumption. The effect of recessed shade was also considered in the form of an external horizontal overhang (see Figure 2). Shade on the east and west orientation of the building envelope (Figure 2) reduced the cooling load to 5.8% compared with a building without shade. The recessed shade further reduced cooling load to 6.62% of the building. Saving on the use of cooling system equipment such as chillers, pumps and HVAC distribution fans reduces the annual electricity consumption from 4,361,933kWh to 3,980,192kWh. If the average cost per kWh of electricity is $0.10 (0.08), the annual operating cost difference would be $38,175 (30,472.81). Over the course of the projects operation for 10 years, the building will save AED 1.402 million (304,728.12) in electricity costs. This strategy, implemented at master planning level, could have an enormous impact on energy savings. Holistic design approach in architecture Figure 1: Adjacent buildings offer shade on east and west orientation The shading effect varies for each project depending upon the distance from surrounding buildings, height of adjacent buildings, and layout. External overhangs on glazing reduces the direct solar radiation into the space and can be particularly effective on the south orientation. Similarly, fixed external shade needs to be evaluated based on the building orientation and impact on daylighting design. It is important to include the architectural external shade design for the perimeter zone thermal load calculations for correct air conditioning equipment sizing. A passive shading strategy plays a significant role in achieving sustainability rating system credits, such as Estidama (Abu Dhabi Urban Planning Council). This strategy will help to achieve the requirements for credits in the Estidama building design tool, such as 48 November 2022 www.cibsejournal.com CIBSE Nov 22 pp48-49 Shading Middle East.indd 48 21/10/2022 16:24