The effect known as "heat island”Concerns urban areas, in fact it seems that the temperature in the city is higher than in the surrounding regions that are not yet urbanized. The difference in temperature can be significant, homes and offices consume a lot of electricity, thus increasing emissions greenhouse gases and therefore the temperature.
New York City is trying to reverse this trend by using science as an ally. Many New York City buildings have dark-colored roofs because they have been asphalted or covered with bitumen and other building materials famous for their waterproofing capabilities, strength, and ease of application. Unfortunately, dark roofs are a problem because they increase the effect "urban heat island“.
Dark roofs absorb too much solar heat and increase the temperature of the surrounding spaces, including the interior of the building. In response to the increase in internal temperature of the building, the residents of the city tend to turn up the air conditioning and operate other devices to cool the rooms. In this way energy expenditure increases, increases thegreenhouse effect and also the outside temperature.
The phenomenon is not a characteristic of daytime hours, even at night the temperature can rise by as much as 7 degrees. Thanks to tests conducted by NASA, a solution could be observed. On July 22, 2011, the dark buildings in New York City reached a temperature of 77 degrees centigrade. On the contrary, buildings that had clear coatings or of particular materials had one temperature only 52 ° C cooler. Well 25 degrees less.
The material that carpeted the coolest buildings in NYC was being tested. The mayor of New York has started a program to fight the global warming lowering carbon emissions by 30% by 2030. A low-cost coating material was used with this program.
Dark surfaces absorb sunlight and heat, whereas light materials reflect light without retaining heat. The white material used for the cladding of New York buildings is a low cost roofing material, the price is only 50 cents per square foot. Furthermore, the installation of these covers is extremely simple: the official NASA report states that there is no need for special training and that it is an easy-to-apply material.
Why is ease of application important? Consumers are very often reluctant to make a change because it involves a large money expense. With a low-cost, easy-to-apply material, the user is encouraged to "DIY labor”Thus replacing, the old asphalt cover, with the new more ecological and more covering efficient because it keeps the house cooler. NASA studies the effect "urban heat island"To better understand what are the most practical strategies to be implemented in the city to deal with the problem of solar heating.
edited by Anna De Simone