Cool roofs, cool off the Earth

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When we hanging clothes, of course, dark-colored clothing such as black, brown and dark blue will be the first dry than bright colors like white. Why? Because dark colors can absorb sunlight radiation in large numbers in comparison with bright colors. It was also applicable to various facilities such as asphalt and concrete reference, so that when we’re on top of paved roads will feel hotter than when we are on the road which not using asphalt, but both were under the same blazing sun.

Based on these simple facts, a scientist from Lawrence Berkeley National Laboratory, Dr. Art Rosenfeld, find solutions to cope with the heat that is often a problem because it raises the sunlight radiation in large numbers. Temperature on the surface that the concept of earth cooling through a color change on the roofs of houses.
Assistance through the roof surface temperature changes is also a big influence on life in urban areas. Because the urban environment depends on the cooling shade of trees and shade, so the area covered by asphalt in urban areas will be like a shelter and giant heat absorption. Consequently, exactly at noon the temperature in urban areas is 10 degrees hotter than the place that has lots of big trees and shade. This phenomenon is by Dr. Rosenfeld called the ‘heat island effect’.

According to Dr. Rosenfeld, the perfect solution for urban areas is through the roof discoloration on skyscraper buildings. If you paint your roof with a white color instead of black, sunlight will be reflected back to space, not stored in the building. That’s because the white surface has a level of “albedo” (power of reflection) is higher than the black surface.

What is surprising is that apparently the practice of changing the weather through the roof of this house has been known for centuries ago by the inhabitants of the Mediterranean. This can be seen from the design of ancient cities in the hills of Greece. Currently, the roofs of buildings in urban areas represent 20% of the total surface area. If all the roofs in urban become white, the temperature in urban areas can be reduced to 1-1.5 degrees.
For the modern metropolitan city, whitens the roof has many benefits, such as:

1 – Lower surface temperature will make the city more comfortable and safer place to live, either indoors or in the neighborhood. When the Chicago city in the U.S. heat wave in 1995 made 739 people died. Most of the victims came from those who live in buildings with a roof black.

2 – The roof of the cooler can reduce the effects of climate change. In addition to directly reduce carbon emissions through energy savings, the effect of “albedo” of the white roof can prevent trapping heat that would enhance the greenhouse effect and global warming.

3 – The roof of the cooler can reduce the amount of energy required to cool the room. By changing into a white roof, building owners and occupants can save on electricity costs by 15%.

Based on his research, Dr. Rosenfeld found that if all the roofs of buildings in urban areas were painted white, it would be an effort to reduce carbon emissions by 24 million tons. This equates to get rid of 300 million cars off the road every year for 20 years!

Another added value of this rooftop cooling process can be combined with energy cells and solar-powered heater that is currently a trend in environmental preservation.

As proof of the theory, High Desert Government Center in California, has applied this concept to be able to meet 70% of the building’s energy needs from solar power. It works!

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