"Bright — the new black", or cool roofs in New York City Facts
Every century cities become more and more dark. Has become a tradition to make a roof of black materials, like tar and asphalt are waterproof, dense, flexible and easy-to-work materials. From the point of view of the urban environment and the climate is more appropriate setting of bright white roofs, which are called "striking new black." In New York, has performed the first attempt to change the existing law. Innovation should not only reduce the heat of summer, but also electricity bills. Research scientist at Columbia University Stuart Gaffin was published March 7, 2012 in the electronic weekly newspaper Environmental Research Letters.
July 22, 2011 the temperature of dark surfaces absorb light of New York's roofs, reached 76 degrees Celsius. On this day, it was found a record number of energy use. In a break with such indicators was at 55 degrees, recorded on the roof with a white coating. On average in New York every summer for about 14 days of temperature readings exceed 32 degrees Celsius, but in a few decades will be the inhabitants of the metropolis in this heat for a month.
Project to date white roofs is the cheapest and most effective way to reduce carbon dioxide emissions by 30% by 2030. Creating white roofs requires two synthetic membranes established professionals, and white coating, overlay their own. The cost of the membranes between 15 and 28 dollars per 0.09 square meters. Cover is well maintained for at least 4 years of use.
Urban masses with asphalt, metals and dark buildings absorb more sunlight than natural sites (forests, fields, mountains covered with snow), as the latter have a higher reflectivity. Absorption cities unthinkable huge amount of heat leads to the formation of so-called "urban heat islands" where temperatures of cities is much higher than the temperature in the surrounding areas of these cities.
The problem of heat conceals not only excessive energy use and carbon emissions, it also affects the quality of the air, and thus endanger the health of people in extreme heat. In recent years, architects, cities increasingly take account of these factors, suggesting introduce a "living" roof covered with plants, or do white coating.