On a Cool Coating for Roof Clay Tiles: Development of the Prototype and Thermal-energy Assessment

AbstractClay tiles are the most common roof covering in Italian buildings, in particular in traditional residential buildings. Given the important role of the roof characteristics for building energy efficiency and indoor thermal comfort conditions, innovative solutions for improving the thermal-energy performance of such diffused roof element has become a key research issue. In this view, cool roof applications represent an effective solution to this aim. The present work deals with the analysis of innovative coatings for traditional clay tiles, aimed at increasing their "cooling" potential. Several pigments with the sodium silicate as binder are tested in terms of reflectance and emittance, which mainly determine the cool roof performance. Additionally, the year-round performance of the proposed tile is evaluated when applied to a single family residential building located in central Italy. The developed cool roof solution is characterized by the same visual appearance of traditional "natural brick" color tiles, while the solar reflectance is higher than natural terracotta tile by 13%. Therefore its thermal performance is optimized in order to reduce the roof overheating and the consequent energy requirement for cooling. Results of dynamic simulation of the case study building show how the proposed tile is able to decrease the number of hours when the indoor operative temperature of the attic is higher than 26°C by 18%, while the same effect in lowering the indoor temperature below 20°C in winter is less than 1%. Therefore, the proposed solution could be considered as an interesting strategy for new buildings or for traditional roof retrofitting, without producing any significant architectural impact, even in traditional or historic buildings, where more invasive solutions are too difficult to be implemented

Lignin as co-product of second generation bioethanol production from ligno-cellulosic biomass

Abstract To improve the economic viability of the biofuel production from biomass, it is of increasing importance to add value to the lignin produced as a bio-residue. Moreover, to meet the goal to replace 30% of fossil fuel by biofuels by 2030, a huge amount of lignin will soon be produced. The first major step involved to add value to the unconverted lignin is its separation from other biomass constituents to give high purity lignin. In this current work, extraction of lignin from a bio-residue (containing ca. 40% lignin) from second generation bioethanol production is presented. The biomass chosen is Arundo donax L. (or giant reed), which is non-food plant, can tolerate a wide variety of ecological conditions with all types of soils, and has increasingly importance as raw material for industrial purposes as a source of fibers alternative to wood, which availability is decreasing. Slightly different extraction procedures are investigated. Methods used are simple, mild, safe, and avoid destruction of fiber content in the bio- residue, with the final aim to valorize all fractions of the bio-residue, which is an essential step to make biofuel production to be cost effective. Lignins extracted are characterized by morphological analysis, using Scanning Electron Microscopy, SEM, and in terms of thermal behavior -using thermo gravimetric analysis TGA- which is critical for determining suitability of the lignin for polymer composite preparation with improved thermomechanical performance. The method judged as the best of the three leads rapidly to extraction of lignin free from fibers and ash, with thermal behavior suitable for composite preparation