Preliminary studies of a cool roofs' energy-rating system in Italy

Abstract

Energy saving in the building sector is one of the key issues to achieve environmental targets at national and European Union (EU) levels. Although characterised by a large number of different climatic conditions, Italy energy policies were aimed at reducing the energy consumption related to space heating in buildings, neglecting space cooling. The recent EU Directive for the State Members is to assess the energy quality of buildings taking into account all the relevant energy uses. Cool roofs are an old concept merged with new technologies that play a crucial role in the energy balance of buildings especially at Mediterranean latitudes. Reducing the solar gains thanks to a high solar reflectance, cool roofs tend to decrease the cooling demand and increase the thermal comfort. Energy rating and labelling are a quick solution to compare energy-related products. This paper presents the first studies aimed at the definition of an energy-rating scheme for cool roofs, starting from product properties and reaching building performances. Energy simulation results were used to find out simple linear regressions, expressing the energy performance of the building as a function of the roof's radiative properties and measuring the performance of the cool roof product.

Relating microclimate, human thermal comfort and health during heat waves: An analysis of heat island mitigation strategies through a case study in an urban outdoor environment

“…-Case A: present configuration of the site; -Case B: the asphalt is replaced by a concrete pavement (The Asphalt Institute, 1984;Russel and Lenz, 2013) with a higher albedo coefficient and a lower thermal capacity (Table 6); -Case C: the configuration is characterized by a roof albedo of 0.66 (Pisello, Cotana, Nicolini, & Brinchi, 2013), which is 0.31 units higher than that of the present configuration. The choice to evaluate this solution is due to the increasing interest towards cool roofs (Zinzi, Carnielo, & Federici, 2014;Pisello, Pignatta, Castaldo, & Cotana, 2014;Rosso et al, 2015;; -Case D: this configuration has a wider urban vegetation area, about 9% with respect to the present configuration. This choice derives from the study of who during their research in Toronto, Canada, examined the effects of an increase in the vegetation coverage ratio of 10% on the microclimate; -Case E: this is a combination of the three previous mitigation strategies of the Urban Heat Island (UHI) with the implementation of cool roofs, cool pavement and a wider urban vegetation area;…”

Thermal impact of a redeveloped area on localized urban microclimate: A case study in Rome

“…In the last years, many studies aimed at assessing the impact of building energy consumption mitigation techniques on UHI, such as green roofs [21,22] and cool materials [23][24][25][26]. They are materials (paving, roofs and walls) characterized by a high solar reflectance and thus by surface temperatures sensibly lower than a conventional material; moreover, their high infrared emissivity value allows to emit and dissipate the stored heat towards the sky during night-time hours.…”

Energy Performance and Thermal Comfort of a High Efficiency House: RhOME for denCity, Winner of Solar Decathlon Europe 2014

“…The methodology studied by De Lieto Vollaro et al [15] is based on two validated calculation tools: TRNSYS and RETScreen. This approach allows an analysis of feasibility, and it starts with the building energy demand analysis, conducted under dynamic conditions through TRNSYS software [16][17][18][19][20][21][22][23][24][25][26][27][28]. Simplified methodologies, characterised by semi-stationary conditions, cannot faithfully reproduce the variation of climatic conditions and inertial properties of the structures [29].…”