The building aspect ratio for an energy efficient green network design

The new paradigm of smart city includes the topics of land consumption and climate change adaptation thus bringing to the fore the role of open spaces system in the strategic development of urban areas (Gill et al., 2007; Gargiulo & Zucaro, 2015). In this context, the study of different characteristics of urban settlements and the focus on the relationship between full and empty urban spaces, could provide an important set of information for an energy saving based design of open spaces (Jones et al., 2001; Papa et al., 2014). In particular, within the relations between the elements composing the urban physical space, green spaces play a major role thanks to the many positive effects they produce on the urban environment. Vegetation, in fact, in addition to being a key component of quality of life, has an important role to make cities more sustainable and resilient, through the so-called "oasis effect", significant for reducing the energy consumption due to the use of air conditioning in summer (Coronel & Alvarez, 2001; Zhang et al., 2014). This paper intends to propose a methodology for measuring the impact of the green areas in different types of urban fabric, in terms of temperature mitigation and energy consumption reduction in order to contribute to the scientific debate on the definition of new instruments able to integrate climate and energy aspects in the design of green space networks. This work, in particular, represents a development of a previous research aimed at effectively localizing, dimensioning and distributing green spaces, starting from data related to a heterogeneous urban pattern for density and presence of green in the municipality of Naples. The variable of building aspect ratio, related to the geometry of the road network, was inserted in the calculation parameters, thus achieving, through the use of a thermal simulation software, the incidence of solar radiation on the main facades of the buildings and its rated thermal input for air conditioning of indoor environment. The obtained data were integrated, through the GIS system, with the results of the previous study creating a useful decision support tool to test the effectiveness of the green network system in the analyzed urban context, and to strategically define the areas to place new vegetation elements, both punctual (green spaces) and linear (tree rows).