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 How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas
11.12.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht What makes corals sick?
11.12.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Midwife and signpost for photons

11.12.2017 | Physics and Astronomy

How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas

11.12.2017 | Earth Sciences

PhoxTroT: Optical Interconnect Technologies Revolutionized Data Centers and HPC Systems

11.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>