Contents lists available at ScienceDirect Sustainable Cities and Society journal homepage: www.elsevier.com/locate/scs Cool roofs and cool pavements application in Acharnes, Greece Dionysia – Denia Kolokotsa a, ⁎ , Gerassimos Giannariakis a , Kostas Gobakis a , Giannis Giannarakis b , Afroditi Synnefa c , Mat Santamouris c a Energy Management in the Built Environment Laboratory, Technical University of Crete Kounoupidiana, GR 73100 Chania, Greece b Section of Environmental Physics and Meteorology Group Building Environmental Studies Physics Department University of Athens, Athens Greece c Faculty of the Built Environment, University of NEW south Wales, Sydney, Australia ARTICLE INFO Keywords: Cool roofs Cool pavements Energy efficiency Thermal comfort ABSTRACT The continuously increasing urban temperature results to the well-known urban heat island phenomenon. Cool roofs and cool pavements are very promising mitigation techniques as they can be easily applied to new and existing buildings as well as urban spaces. In the present paper, the application of cool materials in the urban region of Acharnes municipality in Greece is described. Cool roofs in the form of ceiling tiles are installed on the rooftop of the municipality building while cool paving stones are used to replace conventional pavements. A series of monitoring activities are performed for the building and the urban region. Measurements of the outdoor meteorological conditions, the indoor thermal comfort of the case study building, the surface temperature of the roofs and pavements as well as thermal imaging are exploited for the analysis of the cool roofs and cool pa- vements’ performance. Thermal models using EnergyPlus and Envi-met are developed for the analysis of the cool roofs and cool pavements respectively. The overall study showed that the application of cool roofs results to 17% reduction in the annual cooling demand for the case study building while the surface temperature of the urban pavements is reduced by almost 10 K. 1. Introduction One of the main problems of urban life nowadays is the con- tinuously increasing urban temperature resulting to the urban heat is- land (Akbari et al., 2015; Santamouris, 2001)that causes an increase in air temperature in cities versus suburban areas. The air temperature increase has a direct effect on the energy demand of cooling during summer in cities (Santamouris and Kolokotsa, 2016). In addition, the ongoing growing urbanization rate, in fact, exacerbates the problem as natural vegetation is converted into structured urban areas (Radhi, Fikry, & Sharples, 2013). The urban heat island has been investigated by numerous re- searchers targeting to quantify the urban heat island intensity and the impact of the various technologies on urban heat mitigation and adaptation and energy consumption. For example, (Santamouris et al., 2001; Zoulia, Santamouris, & Dimoudi, 2009), evaluated the impact of urban heat island on the cooling demand of various building typologies in the Athens region. The research showed a 100% increase in the cooling needs and peak electricity demand in the urban region versus the periphery. Urban heat island mitigation techniques involve the incorporation of cool materials and green infrastructure within cities (Akbari and Kolokotsa, 2016; Ferguson et al., 2005; Magli, Lodi, Lombroso, Muscio, & Teggi, 2015). The change of urban surface albedo by the building materials and pavements creates a significant difference in the thermal balance of cities versus their surroundings. Building materials and pa- vements absorb solar and infrared radiation part of which is dissipated to the atmosphere resulting in an increase of the ambient temperature. Cool materials have higher solar reflectance and infrared emittance compared to conventional materials and therefore can dissipate the absorbed heat. Therefore cool materials can maintain lower tempera- tures compared to conventional building and paving materials (Gaitani et al., 2011; Santamouris, Synnefa, Kolokotsa, Dimitriou, & Apostolakis, 2008; Synnefa, Santamouris, & Akbari, 2007). Based on the above, the selection of buildings’ and pavements’ materials influences the energy consumption and indoor environmental quality of buildings as well as the users’ well-being in open spaces. Moreover, cool materials present some significant advantages since they can be easily applied to new and existing buildings. In addition, cool materials can extend the lifetime of the surfaces they are applied to (Karlessi and Santamouris, 2013; Santamouris, Synnefa, & Karlessi, 2011;Zinzi, 2010). To this end, many case studies are presented in the literature out- lining the impact of cool roofs and pavements in the urban heat island https://doi.org/10.1016/j.scs.2017.11.035 Received 25 July 2017; Received in revised form 22 November 2017; Accepted 25 November 2017 ⁎ Corresponding author. E-mail address: dkolokotsa@enveng.tuc.gr (D.–.D. Kolokotsa). Sustainable Cities and Society 37 (2018) 466–474 Available online 27 November 2017 2210-6707/ © 2017 Elsevier Ltd. All rights reserved. T