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In downtown Phoenix, cooler pavement for parking lots

By | May 31, 2011, 8:13 AM PDT

To battle the urban heat island effect, city officials in Phoenix have approved the installation of a 90,000-square-foot temporary parking lot made from “cool pavement” in the city’s downtown area.

The asphalt in the parking lot, which is located between First, Second, Taylor and Polk streets, is treated with a permanent solar reflective coating made by Emerald Cities.

The “Celadon Green” coating promises to reduce the surface temperature of asphalt by at least 30 degrees Fahrenheit on hot days — a phenomenon a desert city like Phoenix sees most of the year.

Installation began last Wednesday, with spray crews working by moonlight to treat the lot. It will be unveiled to the public on June 10.

If you’ve ever been to a major city during the summer, you’ll know that it’s no fun to walk the streets. With blackened asphalt used in streets, pavements and sidewalks absorbing copious amounts of sunlight as heat, a city’s grid quickly heats up.

In a southwestern city like Phoenix, well, that’s some serious heat: air temperatures to the tune of 115 to 118 degrees Fahrenheit, with blacktop temps pushing 170 degrees.

Aside from discomfort, the heat poses significant problems for sustainability and efficiency for a city. With air conditioners blazing, a city utility could quickly see demand top capacity, causing a brownout or blackout. The heat damages the asphalt itself, which is money lost for the city. The heat aggravates air pollution, causing additional health issues for susceptible residents such as children or the elderly. And it’s certainly doing no good for the sustainability goals of the city or private corporations headquartered there.

While urban planners have been working to reinstall green zones in the concrete jungle — grassy fields and trees do a great job at absorbing carbon dioxide, shading pedestrians and keeping pavements cool — it’s not enough.

We’ve seen porous pavements for water runoff control; now meet a street-savvy answer for heat. Manufacturer Emerald Cities says its coating — which uses Colloidal Nano Silica, superplasticizers and polymers and solar reflective pigments — solves the problem by lightening the color of asphalt.

It’s a bit like those new, light gray roof tiles you’ve seen at your local home improvement store. By reflecting the heat instead of absorbing it, your home’s temperature is more easily regulated, in both winter and summer.

In 2008, Energy secretary Stephen Chu said the following:

Changing surface colors in 100 of the world’s largest cities could save the equivalent of 44 billion tonnes of carbon dioxide — about as much as global carbon emissions are expected to rise by over the next decade.

Perhaps this treatment is the answer.

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Andrew Nusca

About Andrew Nusca

Andrew Nusca is the editor of SmartPlanet.

Andrew Nusca

Andrew Nusca

Editor

Andrew Nusca is editor of SmartPlanet and an associate editor for ZDNet. Previously, he worked at Money, Men's Vogue and Popular Mechanics magazines. He holds degrees from the Columbia University Graduate School of Journalism and New York University. He based in New York but resides in Philadelphia.

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Andrew Nusca

Andrew Nusca
Andrew Nusca does not hold any investments in the companies he covers.
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+3 Votes
+ -
"New" old technology.
Good city planners have been using that color pavement in urban tennis courts for decades to reduce the heat stress on players. I have 30-year-old courts near my parents house that color.

The cost and major durability issues around vehicle traffic were the reasons it was not used more often. Anything heavier than a golf cart caused unacceptable wear and it wore off quickly when tried in high traffic places like basketball courts.

Does this product address those issues?
Posted by Hates Idiots
31st May 2011
+3 Votes
+ -
great point.
and yes, it seems to. the biggest part of the product's pitch is its 'crack-free' durability.

unfortunately, all this means i'll always have to wear sunglasses to move about my blinding, future city.
Posted by andrew.nusca
31st May 2011
+1 Vote
+ -
"New" old technology
It is new technology using state-of-the-art nano-engineering which addresses all these issues and more - stronger, more skid resistant, cooler and mitigates GHG emissions. Has gone through 2 years rigorous testing (LBNL, MIT) and is LEED certified. It is not "paint"!
Posted by Billyjackson
10th Jun 2011
+1 Vote
+ -
Why not use whitewash?
For thousands of years, people living in mediterranean climates have been using an inexpensive and relatively non-toxic solution; a mixture of lime and binders called "whitewash". Look at the homes of any Greek island - think the color is mere coincidence? Alternatively, one could use concrete or perhaps adding titanium dioxide (again relatively non-toxic) to asphalt. This coating is probably quite expensive and who wants to add potentially toxic nano-particles and plasticizers (endcrine disrupters) into the environment?
Posted by ajrmd
31st May 2011
+1 Vote
+ -
TO2
It does have titanium dioxide and nano-cement - kind of the point - and whitewash for homes cannot be used on roads, parking lots etc. Maybe too expensive to paint your house with but certainly very cost-effective as a coating for asphalt regardless the other positive features of reducing temperature and GHGs (CO2, NOX)
Posted by Billyjackson
10th Jun 2011
+2 Votes
+ -
Convert the heat to energy
Surely, someone could figure out a way to convert the heat to energy.
Posted by slow poke
1st Jun 2011
+4 Votes
+ -
Hot Lots
Why not cover the parking lots and install solar panels on the roofs? That way you get shade and generate electricity!
Posted by willheornot
1st Jun 2011
+2 Votes
+ -
Sounds Expensive
Wouldn't it be cheaper to use concrete pavements, not only are they lighter in color, they last much longer and do not need sealcoating. This reduces heat generated in the air and waterbodies from stormwater runoff, as well as PAH's from the sealcoat. It's also a locally produced material, and requires less nighttime lighting, keeping patrons safer at night.
Posted by Cool Pavements
Updated - 1st Jun 2011
+1 Vote
+ -
How come I haven't heard?
I live in Phoenix, and read the newspaper, and check out the web pages of the local TV stations, and I have not seen a word about it, not even in my water bill. They usually put this kind of information in them. Would not mind some of it around my house.
Posted by halomar1970
1st Jun 2011
0 Votes
+ -
Green Pavement
Great! I think parking area being in a down area must need some special pavement, the idea of cooler pavement is amazing.
http://www.greenproindia.com/pavingtiles.php
Posted by zoyajack
17th Aug
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