Contributions to the energy management of industrial refrigeration systems: a data-driven perspective

Nowadays, energy management has gained attention due to the constant increment of energy consumption in industry and the pollution problems that this fact supposes. On this subject, one of the main industrial sectors, the food and beverage, attributes a great percentage of its energy expenditure to the refrigeration systems. Such systems are highly affected by operation conditions and are commonly composed by different machines that are continually interacting. These particularities difficult the successful application of efficient energy management methodologies requiring further research efforts in order to improve the current approaches. In this regard, with the current framework of the Industry 4.0, the manufacturing industry is moving towards a complete digitalization of its process information. Is in this context, where the promising capabilities of the data-driven techniques can be applied to energy management. Such technology can push forward the energy management to new horizons, since these techniques take advantage of the common data acquired in the refrigeration systems for its inner operation to develop new methodologies able to reach higher efficiencies. Accordingly, this thesis focuses its attention on the research of novel energy management methodologies applied to refrigeration systems by means of data-driven strategies. To address this broad topic and with the aim to improve the efficiency of the industrial refrigeration systems, the current thesis considers three main aspects of any energy management methodology: the system performance assessment, the machinery operation improvement and the load management. Therefore, this thesis presents a novel methodology for each one of the three main aspects considered. The proposed methodologies should contemplate the necessary robustness and reliability to be applicable in real refrigeration systems. The experimental results obtained from the validation tests in the industrial refrigeration system, show the significant improvement capabilities in regard with the energy efficiency. Each one of the proposed methodologies present a promising result and can be employed individually or as a whole, composing a great basis for a data-driven based energy management framework.Avui en dia la gestió energètica ha guanyat interès degut a l'increment constant de consum per part de la indústria i els problemes de contaminació que això suposa. En aquest tema, un dels principals sectors industrials, el d'alimentació i begudes, atribueix bona part de percentatge del seu consum als sistemes de refrigeració. Aquests sistemes es veuen altament afectats per les condicions d'operació i habitualment estan formats per diverses màquines que estan continuament interactuant. Aquestes particularitats dificulten l'aplicació exitosa de metodologies d'eficiència energètica, requerint més esforços en recerca per millorar els enfocs actuals. En aquest tema, amb l'actual marc de la Indústria 4.0, la indústria està avançant cap una digitalització total de la informació dels seus processos. És en aquest context, on les capacitats prometedores de les tècniques basades en dades poden ser aplicades per a la gestió energètica. Aquesta tecnologia pot impulsar la gestió energètica cap a nous horitzons, ja que aquestes tècniques aprofiten les dades adquirides usualment en els sistemes de refrigeració per el seu propi funcionament, per a desenvolupar noves metodologies capaces d'obtenir eficiències més elevades. En conseqüència, aquesta tesi centra la seva atenció en la recerca de noves metodologies per a la gestió energètica, aplicades als sistemes de refrigeració i mitjançant estratègies basades en dades. Per abordar aquest ampli tema i amb el propòsit de millorar l'eficiència dels sistemes de refrigeració industrial, la present tesi considera els tres aspectes principals de qualsevol metodologia de gestió energètica: l'avaluació del rendiment del sistema, la millora de l'operació de la maquinària i la gestió de les càrregues. Per tant, aquesta tesi presenta una metodologia nova per a cadascun dels tres aspectes considerats. Les metodologies proposades han de contemplar la robustesa i fiabilitat necessàries per a ser aplicades en un sistema de refrigeració real. Els resultats experimentals obtinguts dels tests de validació fets en un sistema de refrigeració industrial mostren unes capacitats de millora significatives referent a l'eficiència energètica. Cadascuna de les metodologies proposades presenta un resultat prometedor i pot ser aplicada independentment o juntament amb les altres, formant una bona base per un marc de gestió energètica basat en dades

TIEG: basic information of the research group

This paper presents a summary of the main activities of research group TIEG (Terrassa Industrial Electronics Group). The group objectives are basically focused on four main areas, i.e. Electromagnetic Compatibility (EMC) in power systems ; EMC in integrated circuits ; power electronics for energy management ; power electronics for motion controlPeer Reviewe

Experimental measurements about harmonic current mitigation of electric vehicle battery chargers

The expected high penetration of battery chargers for electric vehicles (EV) in electric networks is foreseen as a potential problem for power quality. Battery chargers are nonlinear devices that inject harmonic currents and pollute network voltages. Thus, their harmonic emissions must be analyzed and reduced by harmonic mitigation techniques to avoid future problems. This paper analyzes and reports some real case measurements of harmonics injected by single- and three-phase battery chargers and their attenuation using line choke inductances.Postprint (published version

Effect of driver to gate coupling circuits on EMI produced by SiC MOSFETS

This work presents a study of the influence of different gate driver circuits on the switching behavior and EMI produced by SiC MOSFET devices used in a boost converter. The paper includes several simulations of switching behavior using different VGS voltage levels and different passive RCD (Resistance Capacitor Diode) circuits to interface the driver to the SiC MOS gate and several tests of conducted and radiated EMI for each one of the interface circuits. The paper also includes a comparison of both aspects (switching and EMI) when using different gate voltage levels. The study reveals that gate voltage has little impact on switching behavior and therefore on conducted and radiated EMI, while gate RCD coupling circuits have a noticeable impact. The EMI reduction, when using the adequate driver-gate circuit may be in the order of 10 dB at certain frequencies in the conducted band and up to 20 dB for certain frequencies in the radiated band.Postprint (author’s final draft

Poética del contraproyecto en la poesía de Jorge Urrutia

Delimitaciones, hasta el momento presente el último poemario publicado de Jorge Urrutia, apareció prácticamente a los veinte años de su primer libro de poemas, Lágrimas saladas (Caracas, 1966), al que siguieron Amor canto el primero (Málaga, 1967), Con la espada de mi boca (Barcelona, 1967) y La fuente como un pájaro escondido (Bilbao, 1968). Tras casi una década sin dar a luz nuevos libros de creación, con El grado fiero de la escritura (1977) y Del estado, evolución y permanencia del ánimo (1979) reiniciaría su andadura lírica, pero a través de una poética muy peculiar, en la que se inscribe asimismo su ya referido conjunto más reciente, Delimitaciones

Cartas inéditas de Margarida Xirgu sobre Benavente

La presente es la tercera oportunidad en que abundo en aspectos diversos de un epistolario inédito (1927-1932) de Margarida Xirgu. En la primera ocasión, di cuenta de la existencia de la serie de cartas de referencia, y publiqué tres de ellas. En la segunda, se estudiaron todas las misivas con datos relativos a García Lorca y a Rafael Alberti, y se dieron a conocer los fragmentos que los contenían. Ahora, y en sucesivos artículos, se tratará de aportar nuevos documentos inéditos sobre otras piezas teatrales y otros dramaturgos vinculados a la actriz en el período que se considera. De entre las diversas cartas ad hoc, se comentarán en este trabajo —y en su caso se editarán íntegramente— las que incluyen referencias a Jacinto Benavente, de modo que reservo para contribuciones posteriores las que aluden a los Quintero, Marquina, Jacinto Grau, etc

Nonlinear loads model for harmonics flow prediction, using multivariate regression

This paper describes a method for obtaining a model of a single or a set of nonlinear loads (NLL) connected to a certain point of an electrical network. The basic assumption is that the network supplying the NLL has significant series impedances and is disturbed by other parallel, random, and unknown neighbor loads, sharing part of the supply system with the NLL. The main interest for obtaining the model is its further use to predict the amount and flow of harmonic currents generated by the NLL, in the case of adding a filter to reduce the harmonics distortion. The modeling technique used in the paper is based on multivariate multiple outputs regression and leads to a set of equations giving the NLL behavior (one for each of the harmonic currents). The model is obtained from data taken at measuring point and is only valid to predict the NLL behavior when new loads are connected at this point. The modeling method was first tested with V, I data coming from simulations using a MATLAB-Simulink SimPowerSystems toolbox. Finally, the method has been validated using V, I data taken in a real installation with different neighbor loads and under different load conditions.Postprint (published version

In Memoriam

Manuel Ardit (1941-2013), Gregori M. Estrada (1918-2015), Joaquim Molas (1930-2015