The "green coat" is able to make houses cooler in summer, with a difference of 3 degrees, and save up to 15% in the bill. These are the results of the pilot project that Enea (the National Agency for New Technologies, Energy and Sustainable Economic Development) is conducting at the Casaccia Research Center.
"We have created a plant wall based on an extensive roof-garden system and on a self-supporting structure positioned 50 cm from the wall of the School of Energies, where we carry out training courses" - explains Carlo Alberto Campiotti of the Unit Department for 'energy efficiency - "Then we began the study of the interactions between green coverings, energy flows, the microclimate and internal comfort, diversifying the plant species".
The 'system of plants' installed on walls and roofs-terraces was able to create a real insulating pad around houses and condominiums. In this way the vegetation is able to mitigate the temperature peaks during the summer, capturing a large part of the solar energy which does not directly affect the surface of the building; moreover it is able to dissipate through the evapotranspiration of plants (up to 1 liter of water per day per square meter) a large amount of thermal energy, which otherwise would be absorbed by the building and released as heat inside the building. home.
"In summer, this system of vegetation allows to reduce up to 15% of energy for cooling - emphasizes Campiotti - while in winter the saving for heating reaches 10% thanks to the chimney effect between the wall and the vegetable blanket; in practice, a natural ventilation that removes moisture from the external walls and reduces the thermal dispersion of the building ".
In addition to improving the thermal-acoustic insulation and living comfort for the single dwelling, these solutions also have advantages for the entire urban context: green roofs and walls, in fact, contribute considerably to the reduction of the 'heat island' effect ', which during the summer can cause a peak of the electrical load between 3 and 8% for each additional degree of temperature. Furthermore, less use of climate control means less greenhouse gas emissions such as CO2, methane, fluorinated and water vapor.
Addressing the green roofs, terraces and walls of individual houses and condominiums also means reducing the effects of the so-called 'water bombs' - the roofs and terraces in fact represent 20% of the total area of the cities and cover them with vegetation would allow to absorb until 50% of rainwater by regulating its flow into the city's water system - in addition to improving air quality.
"For many sectors in distress of our economy, including that of construction, new perspectives of recovery are opening up - continues Campiotti - thanks also to the introduction of the green bonus with the last Budget Law, a new fiscal incentive that allows to recover 36% of expenses up to 5 thousand euros, incurred for the green housing of individual houses and parts of condominiums, an intervention that could also contribute to the increase in the value of the building itself ".
In September, at the School of Energies of the Research Center ENEA Casaccia, the Department of Energy Efficiency of ENEA will organize a course on the cultivation of the most suitable vegetable essences for green coverings. The training is free and is aimed in particular at agronomists, land surveyors, architects, biologists and graduates in natural sciences.