1,720,968 research outputs found
Development of a standard for thermal energy and smart heat metering applications
No full textThe research activity described in this thesis is concerned with the development and characterization of a standard for thermal energy and with the study of innovative applications and measuring solutions for smart heat metering. After an initial overview on the current state of the art and regulations for direct thermal energy measurement devices and heat accounting systems, the activities related to the development and the metrological characterization of the Italian standard of thermal energy, carried out at the Istituto Nazionale di Ricerca Metrologica (INRIM), are presented and discussed. INRIM, according to its responsibilities as National Metrological Institute (NMI), realizes the primary standards for the basic and derived units of the International System of Units (SI) and ensures the operation and maintenance of such standards, providing the national metrological traceability to the SI. Along this line, the development and the characterization of the national standard for thermal energy is fundamental in order to ensure the metrological traceability of thermal energy measurements, which is achieved through an unbroken sequence of calibration steps, each characterized by its corresponding uncertainty. Such a metrological activity is essential for the provision of accurate measurements of the thermal energy exchanged by heat conveying fluids in a number of applications, contributing significantly to the improvement of the efficiency of energy systems and processes. The INRIM national standard for thermal energy has gone through deep changes since 2011, when extensive renovation works have been planned and carried out to improve its features and performances. Thus, a metrological analysis of the system was required to assess the quality of measurements, through the investigation of all the uncertainty contributions affecting the main measurement outputs of the system: water mass and volume flow rate and thermal energy. In particular, the activities related to the development and characterization of the national standard for thermal energy were focused on the set up of a new measurement system for testing and calibrating direct heat meters in experimental conditions close to the actual operating ones, the automatization of the whole measuring process and the evaluation of the uncertainty associated to the INRIM thermal energy standard. According to the Supplement 1 of the Guide to the expression of Uncertainty in Measurement (GUM), the evaluation of the uncertainty has been carried out by means of the Monte Carlo method, which allows evaluating the probability distribution of the measurands from the probability density functions associated to the input quantities of the measurement model. In order to evaluate and confirm the metrological capabilities of the INRIM measurement system and method with respect to other NMIs' laboratories worldwide, a pilot study on the comparison between national standards for thermal energy has been organized with the PTB Heat and Vacuum department in Berlin (Working Group 7.52, New Methods for Thermal Energy Measurement). Such an activity has been detailed from the design of the test plan for the comparison, to the discussion of the results of the first round of tests carried out at INRIM. The experimental plan has allowed observing and analyzing the effect of fluid temperature on the volume flow measurement provided by the electromagnetic flow meter used as transfer standard for the comparison. Since flow meters are typically calibrated at ambient flow conditions, understanding and quantifying the temperature effect on volume flow measurement is important, in particular, for heat metering applications. Furthermore, the analyses of two innovative measuring solutions for the non-invasive flow rate and temperature measurement in pipe flows, which can be effectively applied to thermal energy measurement, are presented and discussed. The first is related to the combined measurement of flow rate and temperature in liquid pipe flows by the clamp-on transit-time ultrasonic technique. In particular, the feasibility and the accuracy of such a non-intrusive measuring solution for the simultaneous measurement of flow rate and temperature has been analyzed by modelling the ultrasound propagation in a typical clamp-on sensor for a wide set of simulated measuring conditions. From the results of the numerical simulation, it has been possible to observe how the temperature dependent acoustic refraction of ultrasound beams can affect the accuracy of these sensors, in particular, in terms of non-intrusive temperature measurement. The second measuring solution is related to the proposal of a direct heat metering technique, based on the non-invasive measurement of the fluid flow rate circulating through a generic heat exchanger, exploiting the correlation between fluid velocity and internal heat transfer coefficient in forced pipe flows. A preliminary thermal fluid dynamic analysis has been carried out for different simulated operating conditions, in order to get a first evaluation of the feasibility and the accuracy of this non-invasive measuring technique. One of the most important application fields for heat metering devices is the measurement of thermal energy consumptions in buildings. In such a context, the fair heat cost allocation among the residents of multi-apartments and multi-purpose buildings with central heating systems, based on the accurate measurement of the actual individual thermal energy consumptions, represents an effective tool to promote energy saving and improve energy efficiency, as declared by the European Directive 2012/27/EU, recently implemented in Italy by the Decree 102/2014. Anyway, in many cases, i.e. in outdated central heating systems with vertical hot water distribution networks (rising main central heating plant configuration), the accurate measurement of individual thermal energy consumptions by means of the measures of flow rate and temperature difference of the heat conveying fluid (direct heat metering) may be neither feasible nor affordable because of installation and economic constraints. In these situations, indirect methods for the estimation of individual heat consumptions or innovative heat accounting solutions should be applied, providing their compliancy to at least one of the current technical standards for heat metering or heat cost allocation. Along this line, a novel heat cost allocation method for apartment buildings has been proposed and validated. Such a heat accounting method is particularly suitable for central heating systems characterized by room heating radiators connected to vertical hot water distribution networks and provides the indirect estimation of individual thermal energy consumptions without the need of temperature measurements at radiator heating surfaces. The proposed heat cost allocation method is based on the hydraulic modelling of hot water distribution networks, which allows estimating the water flow rates circulating through each radiator from the measurement of the overall water flow rate in the circuit and the corresponding head loss. The novel indirect heat accounting method has been validated at the INRIM central heating system test facility, a unique laboratory, consisting of 40 fully-instrumented water radiators equipped with a SI-traceable direct heat meter each and connected to an automatically reconfigurable hydraulic circuit, which allows testing indirect heat cost allocation methods in experimental conditions very close to those in the field
The INRIM thermal energy standard
No full textIn 2009, INRIM opened a research activity to plan the design and the realization of an innovative Thermal Energy Standard. The paper presents the main features of the new national standard and the innovative measurement approach adopted in order to faithfully simulate the real operating conditions of direct heat meters. An overview of the measurement procedure and the first experimental results for assessing the metrological performances of the thermal energy standard are given
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
A full-scale thermo-hydraulic simulator for the characterization of building heat cost allocation methods
Full text linkAn innovative heat accounting method for apartment buildings, named EcoThermo, based on the estimation of water flow rates at each radiator by thermo-hydraulic modelling of the hot water distribution system, has been developed in the framework of the EU Programme FP7-SME-2012. In order to validate this approach and to compare it with conventional Heat Cost Allocators (HCA), a full-scale thermo-hydraulic simulator has been recently built at INRIM. This INRIM test facility represents a real-scale hot water heating system consisting of a gas-fired boiler and 40 radiators of different characteristics, mimicking a four-story residential building. Each radiator is equipped with an electromagnetic flow meter and a pair of short-stem Pt100 PRTs immersed in the water flow for inlet and outlet water temperature measurement, such that the radiator thermal output can be determined by direct metering, providing an accurate reference value against which indirect allocation methods can be compared and assessed. The paper describes in detail the INRIM thermo-hydraulic simulator, highlighting its design features and metrological capabilities and discussing key results of the investigations carried out so far on different heat accounting approaches. The accuracy of the EcoThermo model has also been assessed against direct heat metering and HCA approach
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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