1,720,957 research outputs found
L’analisi del ciclo di vita degli edifici esistenti
No full textThe residential sector is one of the most energy-intensive sectors of a country and energy efficiency in buildings is crucial in order to achieve the goal of reducing by 20% the EU energy consumption by 2020. The regulatory framework, both at European and National level, emphasizes more and more this need, requiring performance limits increasingly stringent. Within this context, the analysis and the optimization of the energetic and environmental performance of existing buildings becomes a key issue. This paper aims to present how the Life Cycle Assessment (LCA) methodology, that allows the measurement of the environmental impact of products and services across all life cycle stages, could be used to achieve this goal. The results of various case studies are shown and a methodological approach is proposed as a guideline for LCA of existing buildings, demonstrating its real potential in this applications
Development of a greenhouse gas accounting GIS-based tool to support local policy making - Application to an Italian municipality
No full textClimate change is the issue of the century and, according to Agenda 21, local actions are essential to impact global mitigation of greenhouse gases (GHG) emissions (“think globally, act locally”). However, in order to plan and implement effective, sustainable actions, local authorities need detailed information on their GHG emissions and their sources. This paper presents the work that led to the development of a GIS-based tool for local GHG accounting, which provides data for local decision-makers in an innovative manner different from traditional GHG inventories. The original aspects of the study are the geo-referencing of all results and the possibility of calculating all emissions (carbon sources) and removals (carbon sinks) with input data of different accuracy
Comparative analysis of solar power technologies through Life Cycle Assessment approach
No full textThrough the Life Cycle Assessment (LCA) approach, a comparative environmental analysis was carried out to evaluate both photovoltaic (PV) and concentrated solar power (CSP) technologies. The analysis was performed on the basis of the same key parameters (location, solar radiation, etc.), considering three different power plants: a PV plant with polycrystalline Silicon modules, a Parabolic Through CSP plant (PT-CSP) and a Central Tower CSP plant (CT-CSP). All the plants are equipped with solar tracking systems. Manufacturing processes of materials and components of the power plants, their transportation, the operation and the end of life of the power plants themselves are considered, while construction activities, maintenance and dismantling activities are omitted. The functional unit chosen is 1 kWh of electricity produced by the plant and the following key indicators were calculated to make the comparison: Greenhouse Gases (GHG) emissions over a 100 years time horizon and Energy Payback Time (EPT). The analysis shows an overall impact of the PV plant significantly higher than both CSP plants: GHG emissions for PV plant are equal to 34.4 gCO2eq/kWh, while for PT-CSP and CT-CSP the values are, respectively, 20.6 gCO2eq/kWh and 14.2 gCO2eq/kWh. The trend in results is the same for EPT, in fact it results 2.1 years for PV, 1.2 years for PT-CSP and 0.7 for CT-CSP. The results are also in agreement with the data reported in literature
Life Cycle Assessment of electricity production from renewable energies: review and results harmonization
No full textA signifi cant number of Life Cycle Assessment (LCA) analyses of renewable energy technologies is
available in the literature, even though there is a lack of consistent conclusions about the life cycle
impacts of the different technologies. The reported results vary consistently, according to the size and
the technology of the considered plant, thus limiting the utility of LCA to inform policy makers and
constituting a barrier to the deployment of a full awareness on sustainable energies. This variability in
LCA results, in fact, can generate confusion regarding the actual environmental consequences of
implementing renewable technologies. The article reviews approximately 50 papers, related to more
than 10 0 different case studies regarding solar energy (Concentrated Solar Power, Photovoltaic), wind
power, hydropower, and geothermal power. A methodology for the harmonization of the results is
presented. The detailed data collection and the results normalization and harmonization allowed a more
reliable comparison of the various renewable technologies. For most of the considered environmental
indicators, wind power technologies turn out to be the low end while geothermal and PV technologies
the high end of the impact range where all the other technologies are positioned
Evaluation of the optimal geometry of air cooled condensers for concentrated solar power plants through the LCA approach
No full textConcentrated Solar Power (CSP) is an emerging technology for environmental-friendly power generation. Almost all existing CSP plants currently use Water Cooled Condensers, but an increasing use of Air Cooled Condensers is predictable, because of limited water supplies and high costs of cooling water; furthermore, there are several projects to develop CSP plant in desert areas. The MACCSol research project (Development and verification of a novel modular air cooled condenser for enhanced concentrated solar power generation), funded under the EU 7th Framework Programme, provides an innovative modular dry cooling approach. During the design phase, that is currently undergone, a typical Modular Air Cooled Condenser (MACC) module 2X2 m has been defined; it uses fans of 1m in diameter and it could be equipped with three different kinds of tube bundle geometries: circular finned, plate finned and continuous finned. This paper describes how the Life Cycle Assessment can be used as an eco-design tool to identify the optimum tube bundle among the above mentioned geometries. The analysis was performed supposing the MACC operating in a reference CSP plant, for 15 years, considering a total of seventeen different tube bundle geometries, eight different MACC sizes and two transportation scenarios
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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