Passive Cooling Strategies for High Thermal Performance Buildings in Hot Climate

Urban development in many parts of the United Arab Emirates (UAE) has significant impacts on the environment. The use of glazed façades that exposed to the hot climate of the UAE has increased in popularity. This modern architectural pattern increases the operational costs and energy consumption due to the higher solar gain. Thus, improving the ecological performance of building industry in the UAE and minimizing/preventing the negative impact of urban development on the natural environment are the main concerns for building engineers, developers and stakeholders seeking for environmentally friendly buildings in the country. Throughout the world, passive cooling strategies have been developed to overcome this major drawback of glazed facades. Passive cooling techniques such as thermal mass, wind-towers, and courtyards can already be found within the traditional architectural fabric of UAE like Bastikia and Shindagha districts in Dubai. It is also applied to modern urban development such as Madinat Jumeirah in Dubai. Other cooling passive strategies, including the use of Double Skin Façades, vegetated green wall and Plant-Shaded techniques are also applied to reduce the heat-gain effects. Recently, the use of passive cooling techniques have been adopted within Abu Dhabi building codes to maintain the new vision of the UAE towards building sustainability. This paper investigates different alternatives of passive cooling strategies for reducing cooling load of contemporary buildings design in extremely hot climate of UAE. These techniques include Vegetated living wall (VLW), Plant-shaded wall (PSW), and Vertically Integrated Greenhouse (VIG). The study demonstrates the potential benefits of passive cooling strategies not only to minimize the negative impact on the natural environment, but also to reduce the cooling load and the air-conditioning cost. The experimental results of the study show that Vegetated and plant-shaded strategies can reduce peak time indoor air temperature by at least 5 °C during the hot summer period, and reduce the peak air conditioning energy demand by up to 20% in case of using vegetated living walls, and 18.5% in the case of using plant-shaded walls.