196,376 research outputs found
Pratiques médiatiques multiples dans les mobilisations italiennes contre la précarité
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On the relation between urban climate and energy performance of buildings. A three-years experience in Rome, Italy
No full textClimatic conditions strongly affect the energy performance of buildings, and due to the synergy between global climate change and the Urban Heat Island (UHI) effect, the climatic conditions inside and outside the city are highly different. However, weather data collected at airports are commonly used for building energy simulations and these data do not take into account real temperature distribution in cities. Many studies in the literature address the topic but mostly considering only a couple of urban and non-urban stations. In this paper, the urban climate in Rome, Italy, is analysed after monitoring of the air temperature and relative humidity in four selected neighbourhoods and one reference station from October 2014 until September 2017. Rome is characterised by a composite urban pattern and high variability of building types, of which the four selected areas are representative. The heating degree days decrease up to 18% and cooling degree days increase up to 157% in the urban area with respect to the rural reference and the area most affected by the UHI is the city centre. The UHI is more intense in summer than in winter (average increase between 0.7 °C and 1 °C); while the diurnal and nocturnal UHI depends on the season and the neighbourhood. Then, the energy performance of a representative apartment block and a typical office building was computed using the measured data. Regarding the predicted energy performance, comparing the four urban sites and the reference site, the UHI causes a reduction of heating consumption up to 21% in residential building and 18% in the office building. An increase of cooling consumption up to 74% is instead computed for the residential building and up to 53% for the office building. © 2018 Elsevier Lt
The Many Frames of the Precarious Condition. Some Insights from Italian Mobilization against Precarity
No full textThis chapter analyses the different frames that emerged during the mobilizations of precarious workers that occurred in Italy in the early 2000s, involving hundreds of thousands of protesters all over the country. In the past, workers’ movements had been rather homogeneous, representing workers who experienced very similar working and living conditions. In this sense, it was possible to speak about a rather homogeneous working class that developed mostly in the urban environment, around factories whose workers shared similar visions about themselves and their role in society. In advanced capitalistic societies, workers’ movements progressively lost their centrality in the struggles towards a more just society. At the same time, the trade unions, the institutional political actors that once represented them — also an outcome of workers’ movements — severely shrank in membership, with union density collapsing in the last decades. Workers, though, did not disappear from contentious politics. And neither did workers’ organizations, broadly conceived. Rather, they changed the way in which they engaged in protests, the organizational forms they selected to mobilize, and the discourses they elaborated around labour issues. This happened also because, despite the relevant heritage of unionism for workers, the very structure of the labour market changed dramatically in the past few decades
Atomistic Simulations of P(NDI2OD-T2) Morphologies: From Single Chain to Condensed Phases
No full textWe investigate theoretically the structure, crystallinity, and solubility of a high-mobility n-type semiconducting copolymer, P(NDI2OD-T2), and we propose a set of new force field parameters. The force field is reparametrized against density functional theory (DFT) calculations, with the aim to reproduce the correct torsional angles that govern the polymer chain flexibility and morphology. We simulate P(NDI2OD-T2) oligomers in different environments, namely, in vacuo, in the bulk phase, and in liquid toluene and chloronaphthalene solution. The choice of these solvents is motivated by the fact that they induce different kinds of molecular preaggregates during the casting procedures, resulting in variable device performances. Our results are in good agreement with the available experimental data; the polymer bulk structure, in which the chains are quite planar, is correcly reproduced, yet the isolated chains are flexible enough to fold in vacuo. We also calculate the solubility of P(NDI2OD-T2) in toluene and chloronaphthalene, predicting a much better solubility of the polymer in the latter, also in accordance to experimental observations. Different morphologies and dynamics of the oligomers in the two solvents have been observed. The proposed parameters make it possible to obtain the description of P(NDI2OD-T2) in different environments and can serve as a basis for extensive studies of this polymer semiconductor, such as, for example, the dynamics of aggregation in solvent
Assessment of construction cost reduction of nearly zero energy dwellings in a life cycle perspective
No full textConcerning Nearly Zero Energy Buildings, it is important to guarantee energy efficiency, thermal comfort and indoor environmental quality, while keeping construction and operational costs low. In this framework, this paper explores the efficacy of applying different scenarios, for reducing construction costs of new nearly zero energy multi-family houses in a life cycle perspective. Conversely to the standard cost-optimal approach, a real Italian case study building was chosen. Alternative and unconventional combinations of solutions for envelope and technical systems were adopted. Calculations were performed in two Italian cities (Rome and Turin). Three types of analysis were developed thermal comfort, energy performance and financial calculation. Results of the thermal analysis show that the installation of active cooling to prevent summer overheating can be avoided by applying low-cost passive strategies. All the proposed low-cost scenarios (4 alternative scenarios in Rome and 5 in Turin)reached the highest grade of energy performance, with a reduction of the non-renewable primary energy consumption up to 46% compared to the base case in Rome and 18% in Turin. From the economic perspective, all the scenarios in the two climate zones allow both reductions in the construction costs, up to 26% in Rome and 15% in Turin, and a Net Present Value after 50 years up to 163 €/m2 in Rome and 158 €/m2 in Turin
Survey and solutions for potential cost reduction in the design and construction process of nearly zero energy multi-family houses
No full textWhile the day in which nearly zero energy buildings is quickly approaching, their construction cost remains higher than minimum requirements' ones, in this framework operates CoNZEBs (Solution sets for the cost reduction of new Nearly Zero-Energy Buildings) Project, funded EU Horizon 2020. This paper explores a critical point identified by the project: potential cost reductions in the design and construction process. Starting from current costs and assessed the lack of available data, a survey is carried out focusing on two main stakeholders: i) design and planning process actors; ii) construction companies and contractors. About 100 answers are collected within the participant countries (Denmark, Germany, Italy, Slovenia), providing insights about issues and potential solutions for the process cost reductions. The results show differences among countries in terms of expectations for the potentials solutions, mainly related to the national market characteristics. The survey also shows the critical issue of the increase for construction costs respect to the originally planned ones Another session presents the impact of exemplary solutions aimed at optimising the design and construction process costs; they are grouped in three categories: specific building envelope and energy system technologies, specific design solutions, innovative project management systems. Quantitative examples are provided for each category
On the relation between urban climate and energy performance of buildings. A three-years experience in Rome, Italy
No full textClimatic conditions strongly affect the energy performance of buildings, and due to the synergy between global climate change and the Urban Heat Island (UHI) effect, the climatic conditions inside and outside the city are highly different. However, weather data collected at airports are commonly used for building energy simulations and these data do not take into account real temperature distribution in cities. Many studies in the literature address the topic but mostly considering only a couple of urban and non-urban stations. In this paper, the urban climate in Rome, Italy, is analysed after monitoring of the air temperature and relative humidity in four selected neighbourhoods and one reference station from October 2014 until September 2017. Rome is characterised by a composite urban pattern and high variability of building types, of which the four selected areas are representative. The heating degree days decrease up to 18% and cooling degree days increase up to 157% in the urban area with respect to the rural reference and the area most affected by the UHI is the city centre. The UHI is more intense in summer than in winter (average increase between 0.7 °C and 1 °C); while the diurnal and nocturnal UHI depends on the season and the neighbourhood. Then, the energy performance of a representative apartment block and a typical office building was computed using the measured data. Regarding the predicted energy performance, comparing the four urban sites and the reference site, the UHI causes a reduction of heating consumption up to 21% in residential building and 18% in the office building. An increase of cooling consumption up to 74% is instead computed for the residential building and up to 53% for the office building
On the cost reduction of a nearly zero energy multifamily house in Italy: Technical and economic assessment
No full textTwo important issues concerning NZEB development are: from one side to guarantee specific heating-cooling balance for each climatic condition, taking into account thermal comfort and indoor environmental quality, and from the other side to enhance the reduction of construction and management costs, ensuring the fulfillment of NZEBs standard requirements. In this paper these two aspects have been analyzed. Numerical analyses under transient thermal conditions demonstrated that passive design (night ventilation and shadings) allow to minimize the overheating risk in summer season and consequently to avoid the installation of an active cooling system: up to 65% average cooling demand reduction can be obtained; 1.5 air change rate of night ventilation allowed to reduce the overeating risks to 16 hours only. Furthermore, the development of low-cost technical solutions in the construction phase guarantees up to 25% reduction of investment costs and high final savings, considering operational costs over the entire building life cycle (50 years). The Net Present Value of the four scenarios range from 63 €/m2 to 140 €/m
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