scholarly journals Improving the Efficiency of Green Roofs Using Atmospheric Water Harvesting Systems (An Innovative Design)

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 546
Author(s):  
Behrouz Pirouz ◽  
Stefania Anna Palermo ◽  
Michele Turco
Keyword(s):  
Arid Regions ◽  
Green Roof ◽  
Noise Pollution ◽  
Green Roofs ◽  
Dry Season ◽  
Solar Panels ◽  
Harvesting Systems ◽  
Mediterranean Regions ◽  
The Mediterranean ◽  
The Arid Regions

Conventional green roofs, although having numerous advantages, could place water resources under pressure in dry periods due to irrigation requirements. Moreover, the thermal efficiency of green roofs could decrease without irrigation, and the plants could get damaged. Therefore, this study aims to improve the efficiency of conventional green roofs by proposing a new multipurpose green roof combined with fog and dew harvesting systems. The analysis determined that the average water use of green roofs in the summer (in humid regions) is about 3.7 L/m2/day, in the Mediterranean regions about 4.5 L/m2/day, and in arid regions about 2.7 L/m2/day. During the dry season, the average fog potential in humid regions is 1.2 to 15.6 L/m2/day, Mediterranean regions between 1.6 and 4.6 L/m2/day, and arid regions between 1.8 and 11.8 L/m2/day. The average dew potential during the dry season in humid regions is 0.1 to 0.3 L/m2/day, in the Mediterranean regions is 0.2 to 0.3 L/m2/day, and in the arid regions is 0.5 to 0.7 L/m2/day. The analysis of the suggested multipurpose green roof combined with fog/dew harvesting systems, in the summer, in three different climates, show that fog harvesting could provide the total water requirement of the green roofs, and that dew harvesting by PV (photo-voltaic) panels could provide 15 to 26% of the water requirements. Moreover, it could show a higher thermal impact on the building, higher efficiency in stormwater management, less dependence on the urban water network, and greater efficiency in decreasing urban air, water, and noise pollution. Finally, the novel green roof system could consume less water due to the shaded area by mesh and solar PVs and maximize the utilization of the roof area, as solar panels could be applied on the same green roof.

scholarly journals Selecting Potential Moss Species for Green Roofs in the Mediterranean Basin

Urban Science ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 57 ◽  
Author(s):  
Ricardo Cruz de Carvalho ◽  
Zulema Varela ◽  
Teresa Afonso do Paço ◽  
Cristina Branquinho
Keyword(s):  
Climate Change ◽  
Mediterranean Basin ◽  
Vascular Plants ◽  
Green Roof ◽  
Green Roofs ◽  
Potential Candidate ◽  
Moss Species ◽  
The Mediterranean ◽  
The Mediterranean Basin ◽  
Selection Of

Green roofs are important infrastructures to address the effects of climate change in urban areas. However, most studies and applications have been done in cooler and wetter regions of the northern hemisphere. Climate change will lead to more extreme weather events, such as increased drought and decreased precipitation with intense flash rain events. Increase desertification is expected especially in the Mediterranean Basin, where in summer, radiation and temperature are high and water is scarce. Therefore, while vascular plants increase water consumption in green roofs during warmer periods, mosses present themselves as potential candidates due to their poikilohydric nature, responding to the environmental availability of water, completely drying out and recovering upon rehydration. Although criteria for the selection of vascular plants adapted to the Mediterranean and suitable for green roofs have been developed, no information is available regarding the selection of mosses based on scientific criteria. Here we propose selection criteria for moss species based on ecological preferences according to Ellenberg’s values and help to define moss traits suitable for a nonirrigated, nature-based green roof that tolerates the Mediterranean climate. The main result is a table of potential candidate mosses that can be either used as standalone or in conjunction with vascular plants to decrease water usage and/or manage stormwater through an easily applicable selection methodology. For green roof practitioners, we proposed that acrocarpous mosses exhibiting turf/cushion life forms and colonist or perennial life strategies best fit the requirements for such a green infrastructure in extreme climate regions with scarce water resources.

scholarly journals Improving the noise reduction by green roofs due to solar panels and substrate shaping

2018 ◽  
Vol 25 (3) ◽  
pp. 219-232 ◽  
Author(s):  
Timothy Van Renterghem
Keyword(s):  
Noise Reduction ◽  
Insertion Loss ◽  
Sound Pressure ◽  
Road Traffic ◽  
Green Roof ◽  
Green Roofs ◽  
Road Traffic Noise ◽  
Back Side ◽  
Solar Panels ◽  
Sound Pressure Levels

The urban fabric largely consists of acoustically rigid materials. This not only affects sound pressure levels in streets, but also how sound propagates towards the back side of a building or to connected urban canyons. A green roof is a practical solution to have roof absorption, mitigating diffracting sound waves. Flat green roofs were shown to provide roughly 3 dBA urban road traffic noise reduction relative to a common flat rigid roof. Although already relevant, it has been numerically studied in this work how the green roof insertion loss of flat roofs can be further increased. Solar panels on green roofs were found to significantly decrease sound pressure levels at the shielded building facade, up to 5 dBA on top of the insertion loss of granular substrates. Polyurethane foam slabs as green roof substrates provide relevant shielding when placed on a series of hollow trapezium-like cores of sufficient height.

scholarly journals Water balance study on green roof in Brazil

2020 ◽  
Vol 4 (4) ◽  
pp. 141-144
Author(s):  
Calheiros Herlane Costa ◽  
Silva Fernanda Gomes Gonçalves ◽  
Costa Luisa Silva ◽  
Silva Matheus Lins Macedo
Keyword(s):  
Water Balance ◽  
Rainy Season ◽  
Green Roof ◽  
Green Roofs ◽  
Dry Season ◽  
Water Retention Capacity ◽  
Water Runoff ◽  
Retention Capacity ◽  
Balance Study ◽  
Recovery Capacity

The present study aims to investigate the water balance in conventional and green roofs and also to monitor the development of peanut grass (Arachis repens Handro), relating the type of vegetation cover or not with its water retention capacity and, consequently, to obtain the coefficient of runoff for each scenario tested. The scenarios tested were: (1) conventional collection surface with fiber cement tile, (2) green roof structure with substrate and no plant, and (3) planted green roof. The rains incident on the roof were obtained for the city of Itajubá, in Minas Gerais, by the curve of i-d-f with 5min of duration and 5years of return period according to the recommendation of NBR 10844 (ABNT,1989). The volumes of storm water runoff and drained from the bottom of the roofs studied were collected in calibrated graduated containers. It was concluded that: the peanut grass showed satisfactory development and high recovery capacity; the peanut grass took only 1½ month to cover the entire roof; the coefficient of runoff of the green roof for intense rainy season was on average 0.569 and in the dry season it was 0.003. While the conventional roof presented average surface runoff coefficient of 0.995 for the rainy season and 0.901 for the dry season; the component of the green roof that contributed most to the rainwater retention was the substrate. Therefore, attention should be paid to the choice of substrate so that it can adequately grow the plant, retain rainwater and not contaminate the bottom drainage water of the roof that can be used for less noble uses.

scholarly journals Environmental factors of energy saving for buildings with green roofs at Russian cities

2020 ◽  
Vol 175 ◽  
pp. 14021
Author(s):  
Elena Sysoeva ◽  
Andrey Benuzh ◽  
Margarita Gelmanova ◽  
Aleksey Bogachev
Keyword(s):  
Green Roof ◽  
Noise Pollution ◽  
Green Roofs ◽  
Ecological Efficiency ◽  
Scientific Justification ◽  
Area Increase ◽  
Urban Heat ◽  
Overall Resistance ◽  
Roof Design ◽  
Resistance To Heat

Green roofs can increase the energy efficiency of the coating by lowering the temperature of the roof in the summer, and in winter - by possibly increasing the overall resistance to heat transfer of the coating. In addition, they reduce the volume and intensity of runoff due to the moisture saturation of the substrate and the processes of total evaporation, improve the microclimate of the urban area: increase air humidity, soften the effect of the urban heat island, reduce noise pollution, significantly reduce the volume and density of dust massesin densely built-up areas of large megacities. Experimental and analytical researches are needed to create a methodology for scientific justification of the ecological efficiency of the green roof design and the district model, to confirm the need and possibility making of a green roof in the II climatic zone of Russia, taking into account the temperature difference (up to 50 °C) in summer and winter seasons.

EFFECT OF GREEN ROOF AGE ON RUNOFF WATER QUALITY IN PORTLAND, OREGON

2018 ◽  
Vol 13 (2) ◽  
pp. 42-54 ◽  
Author(s):  
Jarrett Okita ◽  
Cara Poor ◽  
Jessica M. Kleiss ◽  
Ted Eckmann
Keyword(s):  
Water Quality ◽  
Urban Areas ◽  
Water Retention ◽  
Green Roof ◽  
Green Roofs ◽  
Dry Season ◽  
Rain Event ◽  
Wet Season ◽  
Runoff Water

Green roofs have become a common method to increase water retention on-site in urban areas. However, the long-term water quality of runoff from green roofs is poorly understood. This study evaluated the water quality of stormwater runoff from a regular (non-vegetated) roof, a green roof installed 6 months previously, and a green roof installed 6 years ago in Portland, Oregon. Samples of runoff were taken during every rain event for 10 months, and analyzed for total phosphorus (TP), phosphate (PO3-4), total nitrogen (TN), nitrate (NO-3), ammonia (NH3), copper (Cu), and zinc (Zn). Runoff from the green roofs had higher concentrations of TP and PO3-4 and lower concentrations of Zn compared to the regular roof. Average TP concentrations from the 6-year old roof and 6-month old roof were 6.3 and 14.6 times higher, respectively, than concentrations from the regular roof, and average PO3-4 concentrations from the 6-year old roof and 6-month old roof were 13.5 and 26.6 times higher, respectively, compared to the regular roof. Runoff from the 6-month old green roof had higher concentrations of TP and PO3-4 than the 6-year old green roof during the wet season, but lower concentrations during the dry season. The 6-month old green roof installations where receiving waters are sensitive or impaired may need additional treatment methods to reduce phosphorus levels. As green roofs age, water retention decreases and phosphorus leaching increases during the dry season.

scholarly journals Hydrological Performance of Green Roofs at Building and City Scales under Mediterranean Conditions

2018 ◽  
Vol 10 (9) ◽  
pp. 3105 ◽  
Author(s):  
Ignacio Andrés-Doménech ◽  
Sara Perales-Momparler ◽  
Adrián Morales-Torres ◽  
Ignacio Escuder-Bueno
Keyword(s):  
Green Roof ◽  
Drainage System ◽  
Green Roofs ◽  
Hydrological Models ◽  
The Mediterranean ◽  
Dry Climates ◽  
One Year ◽  
The City ◽  
Mediterranean Conditions

Green roofs are one specific type of sustainable urban drainage system (SUDS); they aim to manage runoff at the source by storing water in its different layers, delaying the hydrological response, and restoring evapotranspiration. Evidence of their performance in the Mediterranean is still scarce. The main objective of this paper is to analyse the hydrological performance of green roofs at building and city scales under Mediterranean conditions. A green roof and a conventional roof were monitored over one year in Benaguasil (Valencia, Spain). Rainfall and flow data were recorded and analysed. Hydrological models were calibrated and validated at the building scale to analyse the hydrological long-term efficiency of the green roof and compare it against that obtained for the conventional roof. Results show that green roofs can provide good hydrological performances, even in dry climates such as the Mediterranean. In addition, their influence at the city scale is also significant, given the average runoff coefficient reduction obtained.

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 Addressing the Water–Energy–Food Nexus through Enhanced Green Roof Performance

2021 ◽  
Vol 13 (4) ◽  
pp. 1972
Author(s):  
Jeremy Wright ◽  
Jeremy Lytle ◽  
Devon Santillo ◽  
Luzalen Marcos ◽  
Kristiina Valter Mai
Keyword(s):  
Climate Change ◽  
Performance Optimization ◽  
Urban Areas ◽  
Stormwater Management ◽  
Green Roof ◽  
Green Roofs ◽  
Management Tool ◽  
Contributing Factors ◽  
Rainwater Runoff ◽  
Rain Events

Urban densification and climate change are creating a multitude of issues for cities around the globe. Contributing factors include increased impervious surfaces that result in poor stormwater management, rising urban temperatures, poor air quality, and a lack of available green space. In the context of volatile weather, there are growing concerns regarding the effects of increased intense rainfalls and how they affect highly populated areas. Green roofs are becoming a stormwater management tool, occupying a growing area of urban roof space in many developed cities. In addition to the water-centric approach to the implementation of green roofs, these systems offer a multitude of benefits across the urban water–energy–food nexus. This paper provides insight to green roof systems available that can be utilized as tools to mitigate the effects of climate change in urbanized areas. A new array of green roof testing modules is presented along with research methods employed to address current issues related to food, energy and water performance optimization. Rainwater runoff after three rain events was observed to be reduced commensurate with the presence of a blue roof retention membrane in the testbed, the growing media depth and type, as well as the productive nature of the plants in the testbed. Preliminary observations indicate that more productive green roof systems may have increasingly positive benefits across the water–energy–food nexus in dense urban areas that are vulnerable to climate disruption.

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