1,720,954 research outputs found
Dynamic simulation of Ground-Coupled Heat Pumps (GCHPs): insights on the economic convenience and on the environmental benefits
No full textGround-Coupled Heat Pumps (GCHPs) allow to achieve noticeable reduction of primary energy consumption, of CO2 emissions, and operational costs of Heating, Ventilation and Air Cooling (HVAC) systems. The large installation expense is a strong barrier to their diffusion; however, GCHPs can be economically convenient in a number of contexts. We present a study which identifies such cases, based on integrated building-HVAC-GCHP dynamic simulations carried out with the software TRNSYS. Three building types were simulated, with very different schedules - a detached house, a hotel, and an office building – considering, for each of them, the case of a highly-insulated and a lowly-insulated envelope by adopting, respectively, the transmittance values typical of brand-new and Sixties’ buildings. To take into account climate conditions, 6 locations were chosen ranging from warm Mediterranean (Seville) to cold Scandinavian climate (Stockholm). The results of simulation allow to identify key parameters which influence the economic viability of GCHP systems, such as peak power demand and full-load equivalent operating hours. As shown in the results, geothermal heat pumps covering the whole heating demand are almost unfeasible without public subsidies, since the reduction of operational cost is not sufficient to cover the difference in the initial expense compared to a gas boiler. An exception is represented by hotels, due to their intense use of the heating system. To reduce the initial investment, hybrid heat pump-gas boiler configurations can be adopted, where the HP is installed to cover the base demand and a backup gas boiler is used to cover peaks. In this way, a cheaper heat pump can be installed, although covering a large share of the heating demand with renewable heat from the ground. The ratio between electricity price and fuel price is another driving parameter, since it influences the saving margin and hence the payback time of installing a heat pump. Payback times can dramatically be decreased acting on the electricity price, e.g. reducing taxes.
Finally, we analysed the effectiveness of incentives granted for different energy refurbishment interventions to avoid CO2 emissions, finding that GCHP (and, in particular, hybrid GCHP) are much more effective than interventions on the building envelope, such as window replacement
Assessment of Energetic, Economic and Environmental Performance of Ground-Coupled Heat Pumps
Full text linkGround-coupled heat pumps (GCHPs) have a great potential for reducing the cost and climate change impact of building heating, cooling, and domestic hot water (DHW). The high installation cost is a major barrier to their diffusion but, under certain conditions (climate, building use, alternative fuels, etc.), the investment can be profitable in the long term. We present a comprehensive modeling study on GCHPs, performed with the dynamic energy simulation software TRNSYS, reproducing the operating conditions of three building types (residential, office, and hotel), with two insulation levels of the building envelope (poor/good), with the climate conditions of six European cities. Simulation results highlight the driving variables for heating/cooling peak loads and yearly demand, which are the input to assess economic performance and environmental benefits of GCHPs. We found that, in Italy, GCHPs are able to reduce CO2 emissions up to 216 g CO2/year per euro spent. However, payback times are still quite high, i.e., from 8 to 20 years. This performance can be improved by changing taxation on gas and electricity and using hybrid systems, adding a fossil-fuel boiler to cover peak heating loads, thus reducing the overall installation cost compared to full-load sized GCHP systems
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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