Today the main objectives of a sustainable building, from the perspective of the environment, are to reduce global warming, reduce the emission of pollutants, reduce the heat island effect, and reduce the use of energy for air conditioning, while maintaining the comfortable conditions of the rooms during the summer.
Urban Heat Islands
The urban heat islands are a problem of our times, typical of highly urbanized areas.
Because solar irradiation, the roofs of buildings and road surfaces heat up and become very hot.
The buildings and the asphalt release heat to the air, day and even at night.
Because of that the air temperature remains at least 4 ÷ 5 ° C higher than the surrounding countryside.
The high temperature accelerates the processes which generate photochemical smog and the various pollutants that form it (+1 ° C = 5% ozone) and induces the increase of energy consumption for air conditioning (+1 ° C = 3% consumption).
What is a Cool Roof
The Cool Roof is a cover with a high ability to reflect incident solar radiation and a high value of emissivity in the infrared. All this allows the roof to return to the atmosphere, by means of thermal radiation, most of the absorbed fraction.
The Cool Roof is characterized by a low surface temperature, even in direct sunlight.
The Cool Roof is based on the use of techniques to control heat with the use of high solar reflectance and high thermal emittance materials, which have the ability to maintain fresh roof.
What is the Solar Reflectance
The solar reflectance is the property of a material to reflect the solar radiation.
A surface provided with high solar reflectance remains fresher, because it reflects most of the incident solar radiation. Light colors, especially white, have a high solar reflectance.
The solar reflectance is expressed by a value from 0 to 1 or in%.
What is the Thermal Emissivity
The Thermal Emissivity is the ability of a material to dissipate heat.
A surface provided with high thermal emissivity remains fresher as possesses the ability to effectively dissipate heat to the environment. The MBDP polymer-bitumen membranes have a high thermal emissivity.
The emissivity is expressed with a value between 0 to 1 or in%.
What is the SRI (Solar Reflectance Index)
SRI is the solar reflection index. It is calculated according to the Standard ASTM E1980 and considers the effect of both the solar reflectance and thermal emissivity. It varies between 0% (black color reference) and 100% (reference white color) and can be greater than 100%. The higher the SRI value, the lower the surface temperature.
Advantages of cool Roof
There are many advantages of a Cool Roof cover:
– Improvement of the interior condition of the building in summer
– Saving energy for summer cooling of the interior of the building
– Overall building energy efficiency improvement
– Reduction of heat island
– Improvement of the dimensional stability of the roofing systems and the underlying structures (minor movements, expansion, cracks, etc.).
– More effective retention over time of the characteristics of the waterproof roofing systems, thanks to the low surface temperatures and of less stress.
Novaglass solutions for the Cool Roof
Reflect the summer sunlight is the best way to increase your home comfort and reduce air conditioning costs. Thanks to Novaglass solutions for the Cool Roof, fresh and reflective roof, all this is possible!
Novaglass offers waterproof cool roof systems, all certified by EELab – Energy Efficiency Laboratory at the University of Modena and Reggio Emilia.