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Modellazione numerica di sistemi complessi per la simulazione dell'efficienza energetica e dell'impatto ambientale dei processi industriali.
No full textOggetto del lavoro di tesi è lo sviluppo di metodologie numeriche per l’analisi delle prestazioni di sistemi e tecnologie che possono essere applicate a qualsiasi processo industriale per il miglioramento dell'efficienza energetica e la riduzione dell’impatto ambientale.
Lo studio si è focalizzato sull'implementazione di strumenti e modelli numerici specifici per indagare le prestazioni di sistemi/tecnologie che possono portare l'industria verso un settore prossimo ad impatto ambientale zero. L'ottimizzazione della soluzione, studiare la sua integrazione nei processi industriali esistenti e valutare la fattibilità economica sono alcuni degli obiettivi delle metodologie numeriche sviluppate.
I modelli numerici sviluppati in questo studio consentono di analizzare i benefici ottenuti dall'applicazione dei sistemi di recupero del calore di scarto (WHRS) nei processi industriali; il recupero del calore disperso nell'ambiente è una delle leve per migliorare l'efficienza energetica dei processi produttivi.
Lo studio si basa su due diverse metodologie numeriche: modellazione a parametri concentrati e distribuiti (0D/1D) e approccio CFD (analisi fluidodinamica computazionale -3D).
La tesi riporta anche una validazione numerico-sperimentale; infatti, i modelli numerici sono stati applicati a casi reali per testarne la loro affidabilità, confrontando i dati sperimentali con i risultati numerici.
Il primo approccio numerico, ovvero parametri concentrati e distribuiti, è stato utilizzato per sviluppare un modello che permette di simulare l'applicazione di un impianto di recupero di calore di scarto in un processo industriale; l'idea è di recuperare il calore contenuto nei gas emessi in atmosfera e di riutilizzare l'energia termica recuperata nei processi industriali. Di conseguenza, aumenta l'efficienza del processo e diminuiscono le emissioni di anidride carbonica.
La modellazione numerica 0D/1D consente di prevedere il comportamento fluidodinamico del sistema di recupero del calore e i benefici ottenuti da questa soluzione in termini di miglioramento dell'efficienza energetica e in termini di riduzione dell'impatto ambientale per il processo industriale.
Il modello 0D/1D comprende l'intero sistema di recupero del calore costituito dal circuito primario e secondario e da tutti i componenti principali (tubazioni, valvole, pompe ecc ecc...). Inoltre, è stata sviluppata una libreria specifica per la simulazione della strategia di controllo del sistema di recupero di calore di scarto.
Il modello numerico sviluppato è stato applicato ad un vero e proprio test case per analizzare l'applicazione del WHRS ad un processo industriale ceramico. Il WHRS è stato installato nello stabilimento situato nel distretto ceramico in Emilia Romagna e i dati sperimentali raccolti hanno dimostrato le capacità numeriche del modello.
La modellazione CFD, ovvero il secondo approccio, è stata applicata per studiare il comportamento fluidodinamico del singolo componente, ovvero il recuperatore di calore. Il modello numerico sviluppato fornisce il comportamento termico del sistema in termini di temperatura, pressione e distribuzione di velocità; è inoltre possibile stimare la potenza termica recuperata dall'unità.
A seconda delle dimensioni del sistema, possono essere prese in considerazione diverse strategie per la simulazione dei recuperatori di calore per ridurre la potenza computazionale richiesta dalla simulazione. In questo lavoro di ricerca vengono presentati due modelli numerici differenti.
Infine, viene presentato un modello numerico CFD per la simulazione del fenomeno del fouling negli scambiatori di calore. Viene utilizzato un modello multifase lagrangiano e nell'analisi vengono considerati i contatti delle particelle e la meccanica di adesione-rimbalzo.
I modelli numerici CFD implementati dimostrano di prevedere con precisione i risultati ottenuti sia con misurazioni su casi di test reali che con correlazioni teoriche.The objective of this thesis is the development of numerical methodologies for the accurate performance prediction of systems and technologies that can be applied to any industrial process for its energy efficiency enhancement and environmental footprint reduction.
Numerical modelling of the complete energy systems can be a key design tool to investigate the potential solutions to improve the performance of the considered system.
The aim of this research work is the implementation of specific tools and numerical models for investigating the performance of systems/technologies that can bring the industry towards a near-zero discharged sector. Analysing the solution optimization, studying the integration in the existing industrial processes and evaluating the economics of the design are some of the goals of the numerical methodologies developed.
The numerical models of this thesis deal with analysis of the benefits gained by the application of waste heat recovery systems (WHRS) in industrial processes; the recovery of heat that is wasted into the environment is one of the levers to enhance the energy efficiency in industrial processes.
The study relies on two different numerical approaches: lumped and distributed parameter modelling (0D/1D) and computational fluid dynamic approach (3D).
The thesis encompasses also a numerical-experimental validation; indeed, the numerical models have been applied to real test cases to test the capabilities of the computational tools and the results have been compared with experimental data for the models’ validations.
The first numerical approach, i.e. lumped and distributed parameter, has been used to develop a model that investigates the application of a WHRS in an industrial process; the idea is to recover the heat contained in the exhaust stream and to re-use the recovered thermal energy in the industrial processes in order to decrease their carbon emissions and increase process efficiencies.
The transient 0D/1D numerical modelling is able to predict the fluid dynamic behaviour of the heat recovery system and the benefits gained by this solution in terms of energy efficiency enhancement and in terms of environmental impact reduction for the industrial process.
The 0D/1D model includes the entire heat recovery system which consists of the primary and secondary circuit, and all the main components (piping, valves, pumps etc etc...). In addition to this, a specific library has been developed for the simulation of the control strategy of the WHRS.
The numerical model developed has been applied to a real test case for investigating the application of the WHRS to a ceramic industrial process. The WHRS has been physically installed in the ceramic facility located in the ceramic district of Emilia Romagna and the experimental data gathered in this test case demonstrated the numerical capabilities of the model.
The CFD modelling, i.e., second approach, has been applied for investigating the fluid dynamic behavior of the single component, i.e., heat recovery unit. The numerical model developed provides the thermal behavior of the system in terms of temperature, pressure, and velocity distribution; the thermal power recovered by the unit can be also estimated.
Depending on the size of the system, different strategies for the simulation of the heat recovery units can be considered to decrease the computational effort of the simulation. In this research work, two numerical models are presented.
Finally, a CFD numerical model for the simulation of the fouling phenomenon in heat exchangers is presented. A Lagrangian multiphase model is used, and the particle contacts and the sticking-rebound mechanics are considered in the analysis.
The implemented CFD numerical models demonstrate to predict accurately the results obtained with both measurements on real test cases and theoretical correlations
IWAYS - Recycling of Heat, Water and Material across Multiple Sectors: Ceramic, Chemical and Steel Industry
Get PDFIn the framework of the iWAYS project, a synergy between energy and water reclamation and exploitation is addressed by means of the development and the installation of a wide array of technologies in three different industrial sectors: ceramic tile manufacturing, aluminium fluoride production and steel tubes manufacturer. The aim of the project is the creation of customized and integrated systems to achieve a substantial reduction in the thermal waste and in the freshwater consumption; this is the principal challenge the iWAYS project is solving by developing a set of technologies capable of recovering water and energy from challenging exhaust streams for productive use in the industrial processes. iWAYS systems will then treat steam condensate to meet the water quality requirements of each industrial process, while the recovered heat will be used to reduce primary energy consumption. iWAYS will recover additional materials from flue gas such as valuable acids or particulates, improving the production’s raw material efficiency and reducing detrimental emissions to the environment. The iWAYS technology will provide a reduction in the freshwater consumption greater that the 30% in each industrial case; with regards to the energy recovery, iWAYS will recover 6 GWh/y in the ceramic sector, more than 5 GWh/y in the chemical scenario and approximately 1 GWh/y in the steel sector. The iWAYS solution will have a payback lower than 5 years.Bioekonomikos tyrimų institutas / Bioeconomy Research InstituteVytauto Didžiojo universitetas / Vytautas Magnus UniversityŽemės ūkio akademija / Agriculture Academ
Economic assessment of an integrated waste to energy system for an urban sewage treatment plant: A numerical approach
Get PDFThe economic assessment of an integrated anaerobic digestion and gasification system for the exploitation of the residues from an urban sewage treatment plant is carried out. The obtained bio-fuels are used in a cogeneration unit to produce both electric and thermal energy. The analysis focuses on the water treatment plant of a touristic town, characterized by a highly variable number of inhabitants. Therefore, the amount of input biomass for the integrated plant results remarkably time dependent and the design accounts for the transient nature of the input. The performance of the integrated system is modelled by developing an ad-hoc dynamic library for the simulation of the energy conversion systems under the OpenModelica open source platform. The system's performance and economic assessment are modelled by means of equations and correlations that calculate the components' behaviour on a time dependent basis. The simulation demonstrates that the final wastes to landfill decrease by a 73% improving significantly the environmental impact of the plant. Furthermore, the proposed integrated system is able to produce the 25% of the electric energy required for the plant operation. Thus, the payback period of the integrated plant results to be lower than 3 years
CFD analysis of a full-scale ceramic kiln module under actual operating conditions
Get PDFThe paper focuses on the CFD analysis of a full-scale module of an industrial ceramic kiln under actual operating conditions. The multi-dimensional analysis includes the real geometry of a ceramic kiln module employed in the preheating and firing sections and investigates the heat transfer between the tiles and the burners’ flame as well as the many components that comprise the module. Particular attention is devoted to the simulation of the convective flow field in the upper and lower chambers and to the effects of radiation on the different materials is addressed. The assessment of the radiation contribution to the tiles temperature is paramount to the improvement of the performance of the kiln in terms of energy efficiency and fuel consumption. The CFD analysis is combined to a lumped and distributed parameter model of the entire kiln in order to simulate the module behaviour at the boundaries under actual operating conditions. Finally, the CFD simulation is employed to address the effects of the module operating conditions on the tiles’ temperature distribution in order to improve the temperature uniformity as well as to enhance the energy efficiency of the system and thus to reduce the fuel consumption
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
ADLnet: A 1d-CNN for Activity of Daily Living Recognition in Smart Homes
No full textHuman activity recognition (HAR) systems enable continuous monitoring of human behaviours in several areas, including activity of daily living (ADL) detection in ambient intelligent environments. The extraction of relevant features is the most challenging part of sensor-based HAR. Feature extraction influences algorithm performance and reduces computation time and complexity. However, the majority of current HAR systems rely on handcrafted features that are incapable of handling complex activities, especially with the influx of multimodal and high-dimensional sensor data. Over the last few decades, Deep Learning has been considered to be one of the most powerful tools to handle huge amounts of data. Thus, we developed ADLnet, a One-Dimensional Convolutional Neural Network (1d-CNN) for recognizing ADLs in Smart Homes, as part of an ambient assisted living framework to provide assistance to elderly inhabitants. We propose an innovative method to scan and classify time-series sensor data such as the CASAS dataset, which has been used for the training/validation/testing process. Testing results show very high performance
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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