Green Roofs and Greenpass

Abstract

The United Nations have identified climate change as the greatest threat to human life. As current research shows, urban areas are more vulnerable to climate change than rural areas. Numerous people are affected by climate change in their daily life, health and well-being. The need to react is undisputed and has led to numerous guidelines and directives for urban climate adaptation. Plants are commonly mentioned and recommended as one key to urban climate adaptation. Due to shading of open space and building surfaces, as well as evapotranspiration, plants reduce the energy load on the urban fabric and increase thermal comfort and climate resilience amongst many other ecosystem services. Plants, therefore, are described as green infrastructure (GI), because of the beneficial effects they provide. Extensive green roofs are often discussed regarding their impact on thermal comfort for pedestrians and physical properties of buildings. By means of Stadslab2050 project Elief Playhouse in Antwerp, Belgium, a single-story building in the courtyard of a perimeter block, the effects of different extensive green roof designs (A and B) on the microclimate, human comfort at ground and roof level, as well as building physics are analyzed and compared to the actual roofing (bitumen membrane) as the Status Quo variant. For the analyses and evaluation of the different designs the innovative Green Performance Assessment System (GREENPASS®) method has been chosen. The planning tool combines spatial and volumetric analyses with complex 3D microclimate simulations to calculate key performance indicators such as thermal comfort score, thermal storage score, thermal load score, run-off and carbon sequestration. Complementary maps and graphs are compiled. Overall, the chosen method allows to understand, compare and optimize project designs and performance. The results for the Elief Playhouse show that the implementation of green roofs serves a slight contribution to the urban energy balance but a huge impact on the building and humans. Variant B with entire greening performs better in all considered indicators, than the less greened design Variant A and the actual Status Quo. Variant B will probably bring a greater cost/benefit than Variant A and is thus recommended.

The Combination of Building Greenery and Photovoltaic Energy Production—A Discussion of Challenges and Opportunities in Design

“…GI also offers many other benefits such as noise reduction, stormwater retention and dust-particle filtering. Green infrastructures help to increase biodiversity by providing habitats for plants and animals as well as improving the urban microclimate [12,13]. Building greenery (the implementation of green roofs and green facades on buildings) is one type of green infrastructure.…”

Design Concept for a Greened Timber Truss Bridge in City Area

“…Current research gives evidence on numerous micro-climatic effects, specifically of green facades and their positive impact on urban and household temperature and energy balance [27][28][29]. Trees with high crown or leaf area densities and vegetation with exhaustive coverage on buildings have great significance in terms of shading traffic areas and building surfaces [30][31][32].…”

The Impact of Green Roofs on the Parameters of the Environment in Urban Areas—Review

“…Concrete is a common material in manufacturing pavers used on the surfaces of roads and footpaths, and also quite common in flat roofs; steel and aluminum are the preferred materials in urban infrastructures, such as fences, railings, road signs, elements of traditional roofs, e.g., flashings, or ventilation chimneys. Analyses of urban areas with the most representative buildings in Central and Eastern Europe are, therefore, to be carried out using geographical information systems (GIS) in order to identify the areas made of different materials and to determine the roof area for the future green roof Analyses of urban areas with the most representative buildings in Central and Eastern Europe are, therefore, to be carried out using geographical information systems (GIS) in order to identify the areas made of different materials and to determine the roof area for the future green roof construction [54,55]. Such information will make it possible to model the influence of green roofs on the reduction of the urban heat island effect by determining the area of a specific temperature (depending on the material it is made of).…”

“…The green roof also benefits the thermal insulation of the building interior [56]. In flats located on the topmost floors, under green roofs, the demand for cooling energy decreases from 10% to 40% (depending on the climatic conditions and the building structure) [53][54][55][56][57][58][59]. In buildings without air conditioning, the temperature on the topmost floors may be about 2 • C lower than in buildings with traditional roofs [43,60,61].…”