Performance Assessment of Rooftop Greenery System in an Institutional Building in Subtropical Climate in Australia

摘要

Energy consumption in Building sector is one of the major contributors to Australia's stationary energy greenhouse gas emissions. The greening of buildings is essentially one of the ecological measures. Green roofs have been around for centuries as used on domestic houses in Northern and Western Europe. There has been significant development of extensive green roofs in Western Europe and North America in last two decades mainly through retrofitting to existing buildings. In comparison with other developed countries, Australia has been slow in adapting green roofs. The main reason is lack of relevant and reliable research to provide confidence in the economic and environmental benefits of green roofs. Beside that green roof's design and performance varies with each region, orientation, structure and microclimate. Because of this uncertainty and lack of tested exemplars, designers and developers hesitate to use them. The objective of this paper is to analyze the performance of an extensive green roof by modelling using DesignBuilder Energyplus; state of the art Building simulation software, on an institutional building in Rockhampton, Queensland (Australia) for cost saving in cooling energy. The result showed that an energy saving of up to 6% can be achieved for a four storied building in subtropical Queensland (Australia).