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Thermal Behavior of Green Roofs Applied to Tropical Climate

DOI: 10.1155/2013/940386

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The main goal of this paper is to present results on an experimental field about the green roofs thermal behavior, compared to other traditional roof covering systems. On the one hand, it intends to describe shortly the constructive system of a green roof with a lightweight building system, which has a sustainable building materials character and, on the other, it worries with the water reuse and with the run-off delay. The main methodological procedure adopted to study the thermal behavior of green roof was installing thermocouples to collect surface temperatures and indoor air, later comparing them with existing prototypes in an experimental plot. The thermal behavior analysis of cover systems was assessed by a representative episode of the climate fact, based on the dynamic climate approach. The experimental results from internal air temperature measurements show that the green roofs applied to warm and dry climates also provide an interesting time lag with surface and internal air temperature reduction. 1. Introduction Across the country, the urbanization process has been problematic for the occurrence of several damages, for example, floods observed during the spring and summer, due to the concentration trend of consecutive rainy days. Green roofs have the potential to retain stormwater on the roof surface reducing the runoff effect by retaining part of the rainfall and distributing the runoff over a long-time period [1], consequently reducing the pollution of urban rainwater from runoff by absorbing and filtering pollutants [2] and lowering the thermal loading on buildings [3]. Other factors may be added to this issue as the increase of air temperature, at micro- and mesoclimatic scales; the increasingly visible role of urban heat islands and water shortages in big cities, so green roofs can help buildings to keep cool in summer; and also the reduction building’s energy consumption by direct shading, evaporative cooling, and additional insulation [4, 5]. The technology underlying green roof design is complex, but given the intrinsic benefits of green roofs, there has been a desire by architects to adopt this new technology. In city centres, where access to green space is negligible, green roofs create space where people can rest and interact with friends or business colleagues [3]. Green roofs provide a psychological benefit because of their appearance, which differs greatly from ordinary roofs. Therefore, aesthetic value is the most apparent benefit of vegetated roofs [6]. Consequently, green roofs are increasingly being incorporated as a

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