Hot town, summer in the city — it's nothing new, but ways to handle the heat, humidity, and stormwater haven’t changed much since the invention of the sewer system.
One solution offered by architectural researchers is known as a “green roof” — a roof covered in living, growing plants to soften the effects of heat, flooding, noise, and stormwater runoff.
Five platforms at the the Research and Demonstration Facility aat Virginia Tech in Blacksburg, Virginia, were used to test various depths of “green” roofing. The thickest growth is in the foreground, with unplanted growth material and finally reflective roofing material in the distance.
Elizabeth J. Grant, an assistant professor of architecture and design at Virginia Tech, will present ways for architects to determine the most effective depths of green roofing for stormwater control on Thursday at the International Conference on Building Envelope Systems and Technologies — also known as ICBEST — in Aachen, Germany.
“With growing numbers of people moving into cities, it is crucial to give architects and builders tools to make good decisions about green roofs,” Grant said. “These systems are on the rise not just because they represent a link to the natural world that is scarce in the city, but because they work. Extremes of temperature and rainfall are becoming unpredictable as climates change, and vegetated roofs help us build resilience in a rapidly changing world.”
With Kenneth Black and Jim Jones of the School of Architecture + Design, the team generated equations that can predict the effectiveness of vegetated roof installations to control stormwater runoff relative to temperature, humidity, and frequency of sunlight and rainfall.
Green roofs use the sun to transform water into water vapor, which provides cooling as a byproduct. In the same way, these vegetated roofs reduce stormwater runoff and flow rates, which in turn helps prevent sewers from overflowing and stream banks from eroding.
“Our research should give architects and designers justification that they are helping the environment by incorporating green roofs in their plans,” Grant said. “We are bridging the gap between science and design.”
The researchers built a variety of test platforms with depths of green roofing ranging from about 2.5 inches to 6 inches deep at the Research and Demonstration Facility managed by the College of Architecture and Urban Studies in Blacksburg, Virginia.
Alongside the platforms were a weather station and a rain gauge to measure rainfall, temperature, humidity, wind speed and direction, and solar radiation.
Of 74 rainfall events included in the study, all of the treatment platforms, including the unplanted, growing-medium-only roof, retained significantly more runoff than a white reflective roof membrane with no vegetation or growing medium used for comparison.
Deeper platforms hold more stormwater runoff, but overall green roofs retain about 50 percent of the stormwater compared with about 6 percent for the normal, flat roof.
Light colored roofs or reflective roof surfaces have also been mentioned as solutions to sweltering city temperatures, but recent studies warn that they may merely redistribute heat without reducing it, and they don’t address runoff problems as well as vegetated roofs.
The next step in the research is to analyze the data at five-minute intervals to compare the delays in runoff at the treatment platforms, which is important for understanding sewer-system loads and stream erosion.
Written by John Pastor
Katie Gehrt | Virginia Tech
NEST: building of the future is up and running
23.05.2016 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Designing buildings with a positive energy balance
18.03.2016 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH
A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.
The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...
Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.
The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...
In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.
In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...
Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices
Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.
When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene
In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...
24.05.2016 | Event News
20.05.2016 | Event News
19.05.2016 | Event News
27.05.2016 | Awards Funding
27.05.2016 | Life Sciences
27.05.2016 | Life Sciences