1,720,970 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
Energy and emissions analysis of next generation electrochromic devices
No full textThe impact of buildings on the environment, energy consumption and climate change is significant, as
they use a large amount of resources across their life-cycle. Since windows play an important role in the
overall energy and environmental performance of buildings, emerging technologies are focused on the
optimization of these building components. Among window design technologies, electrochromic (EC)
devices have received growing interest for their ability to dynamically manage the daylight and solar
energy entering buildings. Near-infrared switching electrochromic (NEC) glazed windows use a novel EC
window technology that is able to continuously provide high transparency while modulating solar heat
gains. This study evaluated the manufacturing phase of NEC windows to understand if their use phase
performance comes at acceptable manufacturing burdens. This study also identified which constraints
are connected to the market shift to the novel technology, which can provide the research community
with useful information to better design the technology as it develops. A comparative “cradle-to-gate”
energy and emissions analysis was carried out between NEC and conventional EC windows.
The obtained results for the Global Warming Potential of the conventional EC device was 85 kg CO2-
eq/m2 and the Cumulative Energy Demand was 1680 MJ-eq/m2
. Results for the NEC device were found to
be 50 kg CO2-eq/m2 and 1050 MJ-eq/m2
, with the reduction primarily due to replacing the energy
intensive thin film deposition used in conventional EC with a solution-based coating process. Finally,
when an entire window is modeled (EC device, frame, glazing and sealing), the difference over conventional
EC, in terms of primary energy consumption, ranged for the whole window manufacturing
from 15% to 21%, depending on the material of the frame
Life Cycle Analysis in the construction sector: guiding the optimization of conventional Italian buildings
No full textLife Cycle Assessment (LCA) is a widely known methodology for “cradle to grave” investigation of the environmental impacts of products and technological lifecycles; however, this methodology has not been yet broadly used as an eco-design tool among the practitioners of the building sector. We applied LCA on three conventional Italian buildings – a detached residential house, a multi-family and a multi-story office building . Our analysis includes all the life stages, from the production of the construction materials, to their transportation, assembling, lighting, appliances, cooling- and heating-usages during the operating phase, to the end of life of all the materials and components. We found that the operation phase has the greatest contribution to the total impact (from 77% of that of the detached house, up to 85% of the office building), whereas the impact of the construction phase ranges from about 14% (office building) to 21% (detached house). We carried further analyses to evaluate the influence of various optimizations of the buildings, e.g., more efficient envelopes and facilities, on the entire life cycle of the three buildings. In addition, we propose a methodological approach, which can contribute to the acceptance of LCA as a tool in the eco-friendly design of buildings, especially those buildings whose impact during the construction phase needs to be carefully checked, such as Nearly Zero Energy Buildings
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
Benchmarks for environmental impact of housing in Europe: Definition of archetypes and LCA of the residential building stock
Full text linkThis study describes the results of Life Cycle Assessment (LCA) applied to 24 statistically-based dwelling archetypes, representative of the EU housing stock in 2010. The aim is to quantify the average environmental impacts related to housing in Europe and to define reference values (baseline scenario) for policies development. The average environmental impacts have been calculated taking into consideration the number of dwellings (clustered per typology, year of construction and climate zone) related to each representative model. System boundaries include production, construction, use (energy and water consumption), maintenance/replacement, and end-of-life phases of each dwelling. The environmental life cycle impact assessment was carried out using the ILCD method. EU average annual environmental impact per person, per dwelling, and per m2 were calculated. Results show that the average life cycle greenhouse gases emissions related to housing per person per year are 2.62 t CO2eq and related to a representative dwelling per year are of 6.36 t CO2eq. The use phase (energy and water consumption) is the most relevant one, followed by the production and the maintenance/replacement phases. Single-family houses are responsible for the highest share of impacts related to housing in Europe. The same type of building has different impacts in different climatic zones, due to the differences in the need for space heating. In general, electricity use and space heating are the activities that contribute more to the overall impacts. The final results could be used as a baseline scenario for testing eco-innovation scenarios and setting targets toward impact reduction
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
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