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Increasing energy efficiency in buildings is a crucial topic, especially in those EU countries where almost 50% of the final energy consumption is used for space heating and cooling, of which 80% is used for buildings. This study presents a model and a tool that can be used to evaluate energy consumption and to identify retrofitting strategies and renewable energy sources with the aim of reaching energy and climate targets in order to improve energy security, competitiveness and sustainability in a territory. In a previous research, a 'top-down engineering' model was applied for a number of 1 km 2 districts in the city of Turin (IT) to evaluate the residual potential of buildings that could be connected to the district heating network. In this work, the energy-use model has been improved by considering applications to urban areas of different dimensions, and an urban energy atlas for the Turin building stock has been defined with the support of a Geographical Information System. The model has been validated by comparing the results of an energy balance calculation with energy consumption data of three consecutive heating seasons over an area of about 40 km 2 in which 500,000 inhabitants live.

Energy resilience can be reached with a secure, sustainable, competitive, and affordable system. In order to achieve energy resilience in the urban environment, urban-scale energy models play a key role in supporting the promotion and identification of effective energy-efficient and low-carbon policies pertaining to buildings. In this work, a dynamic urban-scale energy model, based on an energy balance, has been designed to take into account the local climate conditions and morphological urban-scale parameters. The aim is to present an engineering methodology, applied to clusters of buildings, using the available urban databases. This methodology has been calibrated and optimized through an iterative procedure on 102 residential buildings in a district of the city of Turin (Italy). The results of this work show how a place-based dynamic energy balance methodology can also be sufficiently accurate at an urban scale with an average seasonal relative error of 14%. In particular, to achieve this accuracy, the model has been optimized by correcting the typological and geometrical characteristics of the buildings and the typologies of ventilation and heating system; in addition, the indoor temperatures of the buildings—that were initially estimated as constant—have been correlated to the climatic variables. The proposed model can be applied to other cities utilizing the existing databases or, being an engineering model, can be used to assess the impact of climate change or other scenarios.

There is growing attention to the use of greenery in urban areas, in various forms and functions, as an instrument to reduce the impact of human activities on the urban environment. The aim of this study has been to investigate the use of green roofs as a strategy to reduce the urban heat island effect and to improve the thermal comfort of indoor and outdoor environments. The effects of the built-up environment, the presence of vegetation and green roofs, and the urban morphology of the city of Turin (Italy) have been assessed considering the land surface temperature distribution. This analysis has considered all the information recorded by the local weather stations and satellite images, and compares it with the geometrical and typological characteristics of the city in order to find correlations that confirm that greenery and vegetation improve the livability of an urban context. The results demonstrate that the land-surface temperature, and therefore the air temperature, tend to decrease as the green areas increase. This trend depends on the type of urban context. Based on the results of a green-roofs investigation of Turin, the existing and potential green roofs are respectively almost 300 (257,380 m2) and 15,450 (6,787,929 m2). Based on potential assessment, a strategy of priority was established according to the characteristics of building, to the presence of empty spaces, and to the identification of critical areas, in which the thermal comfort conditions are poor with low vegetation. This approach can be useful to help stakeholders, urban planners, and policy makers to effectively mitigate the urban heat island (UHI), improve the livability of the city, reduce greenhouse gas (GHG) emissions and gain thermal comfort conditions, and to identify policies and incentives to promote green roofs.

In the past, to make the city liveable, the urban morphology has always be considered taking into account the climate, the buildings' density and characteristics, the type of inhabitants and their social condition. On the contrary, recently in the urban planning process the morphological aspects are no more included even if they influence the energy consumption, the thermal comfort of the urban spaces and the district air quality. Moreover, the socio-economic conditions of inhabitants might strongly affect the lifestyle choice and behavior of building occupants and thus, the probability of success of urban planning measures for energy conservation. The present study aims to: 1) identify the correlation between thermal energy consumption for space heating and urban variables and 2) investigate the role of socio-economic variables in energy savings potential. The city of Turin is suitable for these analyses because it is characterized by different urban forms and urban spaces and by various characteristics of the population. By using a GIS tool, the district 3, chosen as a case study, has been divided into different urban textures considering their urban and socio-economic characteristics. The results of this study show that the measured energy consumption of single building depends on the physical building features (f.i. thermal insulation level, the compactness, the energy system efficiency etc.) but also on the urban form and the streets' orientation. Another important result is that the social and economic situation of inhabitants has a relevant role in the success of sustainable policies. These conclusions may support urban planners in the definition of new urban areas with some "preliminary" energy savings measures at no cost and in formulating tailored policies according to socio-economic conditions from district to district.