1,720,974 research outputs found
On time-alignment of weather data in Building Performance Simulation
Full text linkWhile simulating complex systems, information exchange among components is one of the most important aspects. A specific kind of information is that related to weather data. The format of
the climatic data diffusely used in Building Performance Simulation tools (BPSts) contains information about weather variables which are different from each other as far as concern their nature and timing. They have a statistical origin and, in the majority of the cases, are provided on an hourly basis. Given this inhomogeneity and hourly time base, care had been taken to manage their timing and different approaches are today’s in use by BPSts. Furthermore, when the building involves complex components and control strategies, sub-hourly simulation are needed to understand the efficiency of the enquired system. This necessity has led to the implementation of even more different interpolation routines. The capability of these interpolation routines to represent weather conditions that change much more frequently than shown on an hourly basis is here investigated. Besides, BPSts are today used also at operational time, as predictive tools for control strategies and/or Fault Detection and Diagnosis. In this scenario, the statistical validity of climatic data is not anymore sufficient, while their variability profile, recorded with high frequency, and their correct interpretation/synchronization (integral values vs instantaneous values), might became relevant. In this article will be presented a review of the choices implemented by two well-known software, such as TRNSYS 17 and EnergyPlus 8.4.0, to handle weather data and further considerations will be made upon possibilities offered or denied by this choices when different components are involved in the simulation
Ventilation Pre-heating Effectiveness of a PCM Solar Air Collector with Ventilated Window System
No full textParameters that affect PMV in schools
No full textIt is widely accepted that the indoor environmental quality may strongly affect human’s health, comfort, and productivity. This is especially true in case of school environments, as children are physically still developing and, in comparison to healthy adults, will suffer the consequences of a poor indoor environment earlier. Consequently, IEQ in schools is a very investigated topic also due to the close relationship with building energy performances. From the thermal comfort perspective, the assessment of comfort conditions is usually carried out by means of the PMV and the PPD indices. Unfortunately, the peculiarities of school environments (e.g wide classrooms, the absence of HVAC systems, the kind of activity and clothing) require high care to obtain a reliable analysis. Based on a large experience since almost 20 years by the Italian research team InEQualitES (Indoor Environmental Quality and Energy Saving), this paper is addressed to the main criticalities related to the thermal comfort assessment in schools. Particularly will be discussed the calculation of a sole PMV/PPD value to be attributed to the same classroom in the presence of more measurement positions, the effect of insulation value and, finally, how PMV index has to be used in non-air conditioned environments
Introducing distributed solar thermal power in small-scale district heating systems
No full textDistrict Heating Systems (DHS) connected to distributed solar collectors may contribute in reaching, especially in areas with high population density, the target of 50% of the heat demand for domestic hot water, space heating and cooling provided by renewable sources, which will be mandatory in Italy, from January 1, 2017, for new and deeply renovated buildings. By means of a software platform, developed by the Energy Efficiency Department of ENEA, a small-scale district heating system located in a suburb in the Municipality of Bologna (Italy) and including residential buildings, schools, public buildings and a commercial building and heated by gas boilers was simulated. The introduction, in the simulated DHS, of one or more solar thermal fields integrated on the roofs of the buildings was studied, and sensitivity analysis on the effect of the number and the size of the solar fields on the energy and economic performance of the DHS was carried out. The energy performance of the DHS integrated with the solar fields reaches its optimum in the configuration that maximizes the local self-consumption of the produced solar energy. Using the DHS as a vector to share solar energy, the increase in the thermal losses of the DHS can be considered acceptable in the configurations with a solar production equal to or lower than the domestic heat water loads plus the heat losses of the whole DHS in summer
Experimental analysis of PCM heat exchanger in ventilated window system
No full textIn this paper a new ventilated window with a PCM heat exchanger is proposed. In winter, the heat exchanger
works as a solar collector to store heat for pre-heating of the ventilated air. In summer, it works in cooperate with
night ventilation to pre-cool the ventilated air. In this work, the prototype of the heat exchanger is built and tested
experimentally. The PCM heat capacity measured by differential scanning calorimetry DSC is used to help
understand the phase change processes. The PCM temperature at different heights in both melting and freezing
processes is measured. Moreover, the PCM temperature with different air flow rates is measured and compared.
The results show that clear phase change is observed in both melting and freezing processes. The experiment with
different air flow rates shows that the increase of air flow rate improves the heat exchange rate, but the improve
rate is decreased gradually
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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