Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ASU researcher outlines strategies to curb urban heat island

22.02.2010
Protect yourself from the summer sun is good advice to children who want to play outside on a hot summer day and it is good advice to cities as a way to mitigate the phenomenon known as urban heat island.

For children, a hat, long sleeves and sun block provide protection. For cities, it might be canopies, additives to construction materials and smarter use of landscaping that helps protect it from the sun, said Harvey Bryan, an ASU professor of architecture.

Bryan presented several possible strategies a city could use to help it fight urban heat island (UHI) in a presentation he made at the annual meeting of the American Association for the Advancement of Science, held in San Diego, Feb. 18 – 22. Bryan's presentation, "Digital Simulations and Zoning Codes: To Mitigate Urban Heat Island," was presented on Feb. 21 in a session on Urban Design and Energy Demand: Transforming Cities for an Eco-Energy Future.

Urban heat island is a phenomenon experienced by large cities, especially those located in desert areas, where the constant heat of the day is absorbed by the buildings, pavement and concrete. The result is a rise in nighttime low temperature for a city's core from the stored heat of the day.

The higher nighttime temperatures mean more cooling is required for residents' comfort, resulting in increased power demand and potentially more greenhouse gases emitted. Phoenix, where summer nighttime temperatures often do not go below 90 F, is a classic example of the UHI, Bryan said.

Citing work he participated in about a year ago – with Daniel Hoffman, an ASU professor of architecture and Akram Rosheidat, an ASU doctoral student – which focused on ways of improving pedestrian comfort in downtown Phoenix, Bryan outlined several methods a city can employ that will help alleviate the UHI. Shade, not surprisingly, is one of the prime tools.

"Canopies to shade streets and sidewalks keep the concrete and asphalt cooler," Bryan explained. "Interestingly, sidewalks in downtown Phoenix during the early 1900s were canopied."

Bryan said another key aspect is being smart on material choices for the canopies.

"In addition to shading devices, color and thermal properties are also important considerations," Bryan said. "Lighter colors are best for any surface in the Valley. You also have to consider the heat capacity of the materials – denser material will absorb heat during the day and are slow at re-emitting at night."

In areas that cannot be canopied, Bryan said material additives use could play an important role. Phoenix, for example, has a large number of parking lots and streets that constantly absorb daytime heat.

"Introducing additives, like crumb rubber to asphalt and concrete, are ways of reducing heat capacity at the surface and making for a better nighttime profile," he said.

"The important part is to look at materials performance more than just during the daytime. We need a 24-hour profile to see how materials absorb heat during the day and how they emit it during the evening. We then look for materials that are reflective during the day and highly emitting during the evening."

All of this points to modeling as an important tool in mitigating UHI.

"It comes down to how we model the downtown and how we look at various scenarios with different materials using models that accurately simulate the radiative phenomena," Bryan explained. "Most cities have never used such powerful tools to find solutions to UHI."

Source: Harvey Bryan, (480) 965-6094

Media contact: Skip Derra, (480) 965-4823; skip.derra@asu.edu

Skip Derra | EurekAlert!
Further information:
http://www.asu.edu

Further reports about: ASU PHOENIX UHI construction material greenhouse gas heat capacity

More articles from Earth Sciences:

nachricht Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>