scholarly journals The GREENROOF module (v7.3) for modelling green roof hydrological and energetic performances within TEB

2013 ◽  
Vol 6 (6) ◽  
pp. 1941-1960 ◽  
Author(s):  
C. S. de Munck ◽  
A. Lemonsu ◽  
R. Bouzouidja ◽  
V. Masson ◽  
R. Claverie
Keyword(s):  
Water Content ◽  
Green Roof ◽  
Green Roofs ◽  
Model Interaction ◽  
Drainage Layer ◽  
Extensive Green Roof ◽  
Hydrological Characteristics ◽  
Drainage Layers ◽  
The Impact

Abstract. The need to prepare cities for climate change adaptation requests the urban modeller community to implement sustainable adaptation strategies within their models to be tested against specific city morphologies and scenarios. Greening city roofs is part of these strategies. In this context, the GREENROOF module for TEB (town energy balance) has been developed to model the interactions between buildings and green roof systems at the scale of the city. This module, which combines the ISBA model (Interaction between Soil Biosphere and Atmosphere) and TEB, allows for one to describe an extensive green roof composed of four functional layers (vegetation – grasses or sedums; substrate; retention/drainage layers; and artificial roof layers) and to model vegetation-atmosphere fluxes of heat, water and momentum, as well as the hydrological fluxes throughout the substrate and the drainage layers, and the thermal fluxes throughout the natural and artificial layers of the green roof. TEB-GREENROOF (SURFEX v7.3) should therefore be able to represent the impact of climate forcings on the functioning of green roof vegetation and, conversely, the influence of the green roof on the local climate. An evaluation of GREENROOF is performed for a case study located in Nancy (France) which consists of an instrumented extensive green roof with sedums and substrate and drainage layers that are typical of this kind of construction. After calibration of the drainage layer hydrological characteristics, model results show good dynamics for the substrate water content and the drainage at the green roof base, with nevertheless a tendency to underestimate the water content and overestimate the drainage. This does not impact too much the green roof temperatures, which present a good agreement with observations. Nonetheless GREENROOF tends to overestimate the soil temperatures and their amplitudes, but this effect is less important in the drainage layer. These results are encouraging with regard to modelling the impact of green roofs on thermal indoor comfort and energy consumption at the scale of cities, for which GREENROOF will be running with the building energy version of TEB – TEB-BEM. Moreover, with the green roof studied for GREENROOF evaluation being a type of extensive green roof widespread in cities, the type of hydrological characteristics highlighted for the case study will be used as the standard configuration to model extensive green roof impacts at the scale of cities.

scholarly journals The GREENROOF module (v7.3) for modelling green roof hydrological and energetic performances within TEB

2013 ◽  
Vol 6 (1) ◽  
pp. 1127-1172 ◽  
Author(s):  
C. S. de Munck ◽  
A. Lemonsu ◽  
R. Bouzouidja ◽  
V. Masson ◽  
R. Claverie
Keyword(s):  
Green Roof ◽  
Green Roofs ◽  
Building Envelope ◽  
Local Climate ◽  
Extensive Green Roof ◽  
Hydrological Characteristics ◽  
Drainage Layers ◽  
Evaluation Exercise ◽  
Climate Forcings ◽  
The Impact

Abstract. The need to prepare cities for climate change adaptation requests the urban modeller community to implement within their models sustainable adaptation strategies to be tested against specific city morphologies and scenarios. Greening city roofs is part of these strategies. In this context, a GREENROOF module for TEB (Town Energy Balance) has been developed to model the interactions between buildings and green roof systems at the scale of the city. This module allows one to describe an extensive green roof composed of four functional layers (vegetation – grasses or sedums, substrate, retention/drainage layers and artificial roof layers) and to model vegetation-atmosphere fluxes of heat, water and momentum, as well as the hydrological and thermal fluxes throughout the substrate and the drainage layers, and the thermal coupling with the structural building envelope. TEB-GREENROOF (v7.3) is therefore able to represent the impact of climate forcings on the functioning of the green roof vegetation and, conversely, the influence of the green roof on the local climate. A calibration exercise to adjust the model to the peculiar hydrological characteristics of the substrates and drainage layers commonly found on green roofs is performed for a case study located in Nancy (France) which consists of an extensive green roof with sedums. Model results for the optimum hydrological calibration show a good dynamics for the substrate water content which is nevertheless under-estimated but without impacting too much the green roof temperatures since they present a good agreement with observations. These results are encouraging with regard to modelling the impact of green roofs on thermal indoor comfort and energy consumption at the scale of cities, for which GREENROOF will be running with the building energy version of TEB, TEB-BEM. Moreover, the green roof studied for GREENROOF evaluation being a city-widespread type of extensive green roof, the hydrological characteristics derived through the evaluation exercise will be used as the standard configuration to model extensive green roofs at the scale of cities.

scholarly journals A New Method to Determine How Compaction Affects Water and Heat Transport in Green Roof Substrates

2019 ◽  
Vol 9 (21) ◽  
pp. 4697
Author(s):  
Victoria Sandoval ◽  
Francisco Suárez
Keyword(s):  
Porous Media ◽  
Water Content ◽  
Heat Transport ◽  
Green Roof ◽  
Green Roofs ◽  
Transport Processes ◽  
Heat Fluxes ◽  
Soil Fraction ◽  
Substrate Properties ◽  
The Impact

Although compaction affects water and heat transport processes in porous media, few studies have dealt with this problem. This is particularly true for substrates, which are artificial porous media used for engineering and technological solutions, such as in vegetated or green roofs. We propose a methodology to study the effect of substrate compaction on the characterization of physical, hydrodynamic and thermal properties of five green roof substrates. The methodology consists in a parametric analysis that uses the properties of a substrate with known bulk density, and then modifies the substrate properties to consider how compaction affects water and heat fluxes. Coupled heat and water transport numerical simulations were performed to assess the impact of the changes in the previous properties on the hydraulic and thermal performance of a hypothetical roof system. Our results showed that compaction reduced the amplitude of the fluctuations in the volumetric water content daily cycles, increasing the average water content and reducing the breakthrough time of the green roof substrates. Compaction changes the thermal behavior of the green roof substrates in different ways for each substrate due to the dependence of the air, water and soil fraction of each substrate.

scholarly journals A preliminary Study on The Use of PET Bottle Waste as The Green Roof Drainage Layer for Thermal Insulator

2021 ◽  
Vol 881 (1) ◽  
pp. 012054
Author(s):  
A Munir ◽  
Irfandi ◽  
Muslimsyah ◽  
Abdullah
Keyword(s):  
Solar Radiation ◽  
Green Roof ◽  
Green Roofs ◽  
Ambient Air ◽  
Sustainable Urban Development ◽  
Heat Gain ◽  
Drainage Layer ◽  
Roof System ◽  
Pet Bottles ◽  
The Impact

Abstract The phenomenon of urban heat island (UHI) and global warming are significant issues now in relation to sustainable urban development. The application of green roofs is an intention to weaken the impact of UHI by reducing heat gain on the building surface that is emitted to the environment. In addition, green roofs also reduce heat transmission from solar radiation received by the roof to the indoor. Utilization of plastic bottle waste from PET (Polyethylene Terephthalate) will cut down the weight of the green roof system, which also develops the heat resistance value of the roof. This research is an initial study that suggests a green roof application that is more environmentally friendly with the principle of reusing PET waste as a sustainable building material to increase thermal resistant of the system. The analysis concentrates on describing the thermal behavior of the green roof system with the inclusion of PET bottles as a drainage layer. The investigation was carried out by preparing a cubical model of 60cm x 60 cm x 60 cm with a green roof system. Thermal performances were assessed by measuring the temperature of each layer of the green roof using thermocouple wire. The environmental variables measured were solar intensity, ambient air temperature, and air humidity, where the sensors placed close to the models. This analysis demonstrates the influences of green roofs in reducing solar radiation heat. Even though the decreasing of room temperature between the models was not significantly different, this initial results show that, by introducing PET, still display a further performance in reducing heat gain from solar radiation. However, it is necessary to adjust the evaluation models. Heat accumulation in room raised the indoor temperature to be higher than the roof temperature, so that the behavior of the green roof with the purpose of PET is not obviously distinguishable. A trial model with ventilation opening will release heat from enclosed space and it could evaluate clearly the rate of heat flow from the roof.

scholarly journals Seismic Performance of a Green Roof Structure

2021 ◽  
Vol 13 (8) ◽  
pp. 4278
Author(s):  
Svetlana Tam ◽  
Jenna Wong
Keyword(s):  
Green Roof ◽  
Time History ◽  
Green Roofs ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Roof Structure ◽  
Nonlinear Time History Analyses ◽  
Vegetated Roofs ◽  
Nonlinear Time History ◽  
The Impact

Sustainability addresses the need to reduce the structure’s impact on the environment but does not reduce the environment’s impact on the structure. To explore this relationship, this study focuses on quantifying the impact of green roofs or vegetated roofs on seismic responses such as story displacements, interstory drifts, and floor level accelerations. Using an archetype three-story steel moment frame, nonlinear time history analyses are conducted in OpenSees for a shallow and deep green roof using a suite of ground motions from various distances from the fault to identify key trends and sensitivities in response.

scholarly journals Hydrologic Performance of an Extensive Green Roof under Intensive Rain Events: Results from a Rain-Chamber Simulation

2021 ◽  
Vol 13 (6) ◽  
pp. 3078
Author(s):  
Elena Giacomello ◽  
Jacopo Gaspari
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Green Roofs ◽  
International Standards ◽  
Dimensionless Number ◽  
Runoff Coefficient ◽  
Retention Performance ◽  
Extensive Green Roof ◽  
Rain Events ◽  
Hydrologic Performance

The water storage capacity of a green roof generates several benefits for the building conterminous environment. The hydrologic performance is conventionally expressed by the runoff coefficient, according to international standards and guidelines. The runoff coefficient is a dimensionless number and defines the water retention performance over a long period. At the scale of single rain events, characterized by varying intensity and duration, the reaction of the green roof is scarcely investigated. The purpose of this study is to highlight how an extensive green roof—having a supposed minimum water performance, compared to an intensive one—responds to real and repetitive rain events, simulated in a rain chamber with controlled rain and runoff data. The experiment provides, through cumulative curve graphs, the behavior of the green roof sample during four rainy days. The simulated rain events are based on a statistical study (summarized in the paper) of 25 years of rain data for a specific location in North Italy characterized by an average rain/year of 1100 mm. The results prove the active response of the substrate, although thin and mineral, and quick draining, in terms of water retention and detention during intense rain events. The study raises questions about how to better express the water performance of green roofs.

scholarly journals State-of-the-Art Green Roofs: Technical Performance and Certifications for Sustainable Construction

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 69 ◽  
Author(s):  
Alejandra Naranjo ◽  
Andrés Colonia ◽  
Jaime Mesa ◽  
Heriberto Maury ◽  
Aníbal Maury-Ramírez
Keyword(s):  
Environmental Assessment ◽  
State Of The Art ◽  
Green Roof ◽  
Green Roofs ◽  
Assessment Method ◽  
Assessment System ◽  
Sustainable Construction ◽  
Runoff Water ◽  
Technical Performance ◽  
The Impact

Green roof systems, a technology which was used in major ancient buildings, are currently becoming an interesting strategy to reduce the negative impact of traditional urban development caused by ground impermeabilization. Only regarding the environmental impact, the application of these biological coatings on buildings has the potential of acting as a thermal, moisture, noise, and electromagnetic barrier. At the urban scale, they might reduce the heat island effect and sewage system load, improve runoff water and air quality, and reconstruct natural landscapes including wildlife. In spite of these significant benefits, the current design and construction methods are not completely regulated by law because there is a lack of knowledge of their technical performance. Hence, this review of the current state of the art presents a proper green roof classification based on their components and vegetation layer. Similarly, a detailed description from the key factors that control the hydraulic and thermal performance of green roofs is given. Based on these factors, an estimation of the impact of green roof systems on sustainable construction certifications is included (i.e., LEED—Leadership in Energy and Environment Design, BREEAM—Building Research Establishment Environmental Assessment Method, CASBEE—Comprehensive Assessment System for Built Environment Efficiency, BEAM—Building Environmental Assessment Method, ESGB—Evaluation Standard for Green Building). Finally, conclusions and future research challenges for the correct implementation of green roofs are addressed.

The biodiversity of temperate extensive green roofs – a review of research and practice

2016 ◽  
Vol 62 (1-2) ◽  
pp. 44-57 ◽  
Author(s):  
Christine Thuring ◽  
Gary Grant
Keyword(s):  
Green Roof ◽  
Green Roofs ◽  
Ecological Design ◽  
Ecological Research ◽  
Extensive Green Roof ◽  
Research And Practice ◽  
Climatic Regions ◽  
History Of ◽  
Research To Policy ◽  
Extensive Green Roofs

From its beginnings in Germany in the twentieth century, a thriving extensive green roof industry has become established in many countries in temperate climates. Based upon the success of the industry, and with an expectation that this technology will be adopted in other climates, this review of the ecological research of extensive green roofs aims to evaluate the application of this knowledge. The modern extensive green roof is the product of research in the 1970s by German green roof pioneers; the selection of suitable species from analogue habitats led to green roof vegetation dominated by drought tolerant taxa. The commercial success of extensive green roof systems can be attributed to engineering and horticultural research, to policy mechanisms in some places, and to a market that encourages innovation, and the origins in ecological design are now easily overlooked. Some of the work reviewed here, including the classification of spontaneous roof vegetation into plant communities, is not widely known due to its confinement to the German literature. By re-visiting the history of the extensive green roof and reviewing the ecological research that has contributed to our understanding of it, the intention is, for this paper, to inform those considering green roofs in other climatic regions, to apply an ecologically informed approach in using local knowledge for developing installations that are suited to the bioregion in which they occur. Finally the paper considers some future directions for research and practice.

scholarly journals Lessons from New York High Line Green Roof: Conserving Biodiversity and Reconnecting with Nature

Urban Science ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Kawar Salih ◽  
Zaid O. Saeed ◽  
Avar Almukhtar
Keyword(s):  
New York ◽  
Urban Design ◽  
Urban Expansion ◽  
Green Roof ◽  
Green Roofs ◽  
Urban Spaces ◽  
Climate Change Research ◽  
Study Approach ◽  
High Line

The concept of sustainable urban design has appeared in different perspectives to minimize and reduce the negative impacts of urban expansion in terms of climatic and environmental drawbacks. One of the undeniable approaches of sustainable urban design is the adoption of green urban roofs. Green roofs are seen to have a substantial role in addressing and resolving environmental issues in the context of climate change. Research investigations have indicated that green roofs have a remarkable impact on decreasing rainwater runoff, reducing the heat island effect in urban spaces, and increasing biodiversity. Nevertheless, green roofs in urban spaces as a competent alternative to nature remains a standing question. To what extent can green roofs mimic the biodiversity that is seen in nature? Moreover, to what level is this approach practical for achieving a tangible reconnection with nature, or so-called biophilia? This study attempts to discuss the essence and impact of green roofs in urban spaces based on a case study approach. The study reflected lessons from the New York High Line Green Roof regarding biophilia and biodiversity in this case study. It concludes with key lessons that can be transferred to other urban spaces with similar settings.

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