Cooperative energy management for a cluster of households prosumers

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThe increment of electrical and electronic appliances for improving the lifestyle of residential consumers had led to a larger demand of energy. In order to supply their energy requirements, the consumers have changed the paradigm by integrating renewable energy sources to their power grid. Therefore, consumers become prosumers in which they internally generate and consume energy looking for an autonomous operation. This paper proposes an energy management system for coordinating the operation of distributed household prosumers. It was found that better performance is achieved when cooperative operation with other prosumers in a neighborhood environment is achieved. Simulation and experimental results validate the proposed strategy by comparing the performance of islanded prosumers with the operation in cooperative modePeer ReviewedPostprint (author's final draft

Plataforma wireless per a la informatització de les pràctiques dels laboratoris d'enginyeria química de l'EUETIB

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Data-based fault detection in chemical processes: Managing records with operator intervention and uncertain labels

Developing data-driven fault detection systems for chemical plants requires managing uncertain data labels and dynamic attributes due to operator-process interactions. Mislabeled data is a known problem in computer science that has received scarce attention from the process systems community. This work introduces and examines the effects of operator actions in records and labels, and the consequences in the development of detection models. Using a state space model, this work proposes an iterative relabeling scheme for retraining classifiers that continuously refines dynamic attributes and labels. Three case studies are presented: a reactor as a motivating example, flooding in a simulated de-Butanizer column, as a complex case, and foaming in an absorber as an industrial challenge. For the first case, detection accuracy is shown to increase by 14% while operating costs are reduced by 20%. Moreover, regarding the de-Butanizer column, the performance of the proposed strategy is shown to be 10% higher than the filtering strategy. Promising results are finally reported in regard of efficient strategies to deal with the presented problemPeer ReviewedPostprint (author's final draft

Professionals educats per un desenvolupament humà i sostenible

Donat un problema d’enginyeria, la sostenibilitat no n’és una finalitat, és una restricció que cal que satisfaci la solució d’aquest problema. Altrament, la solució sempre seria no fer res, tornar a les cavernes. És per això que la sostenibilitat no és ni pot ser mai una assignatura sinó una competència transversal que han d’adquirir totes les persones que es formen en les diferents disciplines de per a la solució de problemes.Peer Reviewe

Què hi anem a fer al laboratori?

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Contribució a l'estudi de la modelització i l'optimització de l'operació de plantes químiques multipropòsit de funcionament discontinu

Aquest treball de tesi s'adreça a la indústria de procés químic d'operació discontínua tot i que també pot resultar profitós per altres situacions de fabricació per lots. Aquests tipus d'indústries són molt variats i s'inclouen en sectors com el de la química fina, el farmacèutic, l'agroalimentari i, en definitiva, l'elaboració d'especialitats. La seva importància econòmica rau tant en el seu significatiu volum de producció com en l'alt valor afegit que sovint tenen els productes.L'objecte de l'estudi és la gestió dels recursos de fabricació i l'optimització de l'operació de la planta per tal d'ajustar la producció resultant als requeriments de la demanda. La natura discontínua i dinàmica dels processos que hi tenen lloc reclama la presa de decisions en termes d'assignació de tasques a equips (reactors, filtres i altres aparells), de seqüenciació de productes i temporització de les operacions. Es tracta, doncs, d'un problema de programació d'activitats.El primer pas vers la solució d'aquest problema és la modelització del sistema estudiat. Aquest treball proposa un model d'operació detallat que inclou, a més de la compartició per part dels diferents productes de recursos generals (temps, equips, serveis...), aspectes més específics de la indústria química. Són les necessitats de transferència i emmagatzamatge de productes, tant intermedis com acabats, de natura molt probablement fluïda. I són també, les tasques de preparació i neteja que, depenent de la seqüència de productes, cal aplicar als equips emprats.La modelització de l'emmagatzemament també considera la possible inestabilitat de certs intermedis i la conseqüent limitació de l'espera abans de ser processats. De fet, la modelització incorpora un nou esquema conceptual que permet la segmentació de les receptes dels diferents productes en sèries de tasques lligades als intermedis estables. Llavors, la descripció d'un programa d'operacions complex mitjançant una sèrie d'ordres de fabricació d'aquests intermedis proporciona una notable simplificació del problema que redueix el número de restriccions a considerar i facilita el procediment d'optimització.L'optimització mitjançant mètodes rigorosos ja establerts només resulta indicada per problemes molt simples en comparació amb el que es planteja en aquest treball. És per això que s'ha desenvolupat una metodologia heurística general que permet abordar aquest problema patró sota les diferents circumstàncies de cada cas particular. En una primera part es procedeix a la generació d'alternatives de producció considerant els casos possibles i eliminant els ineficients sota una sèrie de criteris preestablerts. Aquestes alternatives s'expressen com seqüències de fabricació d'intermedis estables i posteriorment poden ser millorades sota diferents objectius bé manualment o bé emprant mètodes sistemàtics.La validació de la metodologia proposada és possible gràcies a la comparació amb casos de la literatura. En proposar exemples de major complexitat, la utilització de mètodes estocàstics es demostra molt eficient per resoldre problemes per als quals és difícil trobar regles de solució. Llavors, la validació d'aquest casos és possible estadísticament.En conclusió, d'aquest treball en resulta una metodologia general i flexible que s'adapta a la majoria de característiques d'un tipus de problemes que, de moment i en última instància, han de ser resolts de manera particular. La seva complexitat continua reclamant la nostra intuïció.This thesis concerns batch chemical process industries, although it may be of interest in other batch processing areas. This kind of industry is diverse and includes a variety of sectors such as fine chemicals, pharmaceuticals, food and agriculture industry and speciality manufacturing. The economical significance of this industrial activity resides on both, its large production volume and its high added value. The thesis is aimed at studying the management of limited resources and the optimization of plant operation in order to have the production meet the demand requirements. The inherent discontinuous and dynamic nature of this kind of processes needs decision-making in terms of unit-to-task assignment (reactors, filters and other apparatuses), in terms of product sequencing and in terms of operation timing. The first step towards the solution of this problem is system modelling. This work proposes a detailed operation model that includes the general sharing of resources (time, equipment, utilities, etc.), as well as more specific aspects related to the chemical industry. These aspects are the special needs for material transfer and storage, both final and intermediate, which are likely to be of fluid nature. Additionally, these aspects also include the special set-up and cleaning tasks that the equipment units require depending on the sequence of tasks performed.Storage modelling also considers the different stability of the intermediate substances and the resulting limitation of the waiting time before processing. Thus, the modelling incorporates a novel conceptual framework allowing the segmentation of the recipes into different series of tasks defined by the stable intermediate products. Hence, the description of a complex operation schedule by a sequence of production orders related to these intermediate products allows a significant problem simplification, which results in the reduction of the number of constraints to be considered and enhances the performance of the search. Optimization via established rigorous methods is only suitable for problems simpler than those addressed in this thesis. This is the reason for the development of a general heuristic methodology. The first part generates production alternative paths through an enumerative procedure that eliminates inefficient options according to given pre-established criteria. These alternative paths are characterized as production sequences of storable intermediate products that are next improved regarding different objective functions either manually or automatically.The validation of the proposed methodology is achieved through a comparative study using cases reported in the literature. For those more complex cases, the use of stochastic methods has demonstrated to be very effective when scheduling rules are not available. For these cases, the assessment and validation is achieved through statistical analysis.In conclusion, this thesis results in a general and flexible methodology that accommodates the most of the features of a kind of scheduling and planning problems that finally require particular solution strategies. The more complex the problem, the more the human intuition is to some extend still required

Degradation and mineralization of Bisphenol A by the photo fenton process

Bisphenol A (BPA; 2,2-bis (4-hydroxyphenyl) propane) is an industrial organic chemical basically used in the plastics industry as a monomer for producing epoxy resins and polycarbonates [1,2]. It is also a well-known endocrine disruptor agent that contaminates surface waters even at low concentration [3]. Unfortunately, BPA cannot be entirely removed from water solutions by conventional treatments. Additionally, in some cases, such treatments can lead to a series of by-products with higher endocrine disrupting effect [4]. Advanced Oxidation Processes (AOPs), among them the Fenton and photo-Fenton processes, are efficient methods for BPA photodegradation [1]. However, they are energy-intensive processes and their cost is ought to be improved by reducing the reaction time as well as the consumption of reagents. In this work, the Fenton and the photo-Fenton degradation of BPA (0,5 L, 30 mg L-1) was addressed. The process efficiency was evaluated under different H2O2 and Fe(II) initial concentrations (2,37-6,41 mM H2O2 and 1,42·10-2-3,92·10-2 mM iron salt), while other variables were fixed (pH=3, 25ºC, UV light source). The treatment performance was assessed for a series of assays from a factorial design and was quantified in terms of the decay rate of total organic carbon (TOC) and the total conversion attained, according to a pseudo first order kinetics [5-6]. The performance of the mineralization may be characterized by determining the two parameters of the model, ¿max (or [TOC]8) and k, which can be obtained by fitting the model to the experimental data under the least squares criterion. The results were plot k in front to identify different clusters and the conditions which produces higher mineralization ratesPostprint (published version

Towards automatic construction of domain ontologies: Application to ISA88 and assessment

Process Systems Engineering has shown a growing interest on ontologies to develop knowledge models, organize information, and produce software accordingly. Although software tools supporting the structure of ontologies exist, developing a PSE ontology is a creative procedure to be performed by human experts from each specific domain. This work explores the opportunities for automatic construction of domain ontologies. Specialised documentation can be selected and automatically parsed; next pattern recognition methods can be used to extract concepts and relations; finally, supervision is required to validate the automatic outcome, as well as to complete the task. The bulk of the development of an ontology is expected to result from the application of systematic procedures, thus the development time will be significantly reduced. Automatic methods were prepared and applied to the development of an ontology for batch processing based on the ISA88 standard. Methods are described and commented, and results are discussed from the comparison with a previous ontology for the same domain manually developed.Postprint (published version

Mixed-integer-linear-programming-based energy management system for hybrid PV-wind-battery microgrids: Modeling, design, and experimental verification

© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksMicrogrids are energy systems that aggregate distributed energy resources, loads, and power electronics devices in a stable and balanced way. They rely on energy management systems to schedule optimally the distributed energy resources. Conventionally, many scheduling problems have been solved by using complex algorithms that, even so, do not consider the operation of the distributed energy resources. This paper presents the modeling and design of a modular energy management system and its integration to a grid-connected battery-based microgrid. The scheduling model is a power generation-side strategy, defined as a general mixed-integer linear programming by taking into account two stages for proper charging of the storage units. This model is considered as a deterministic problem that aims to minimize operating costs and promote self-consumption based on 24-hour ahead forecast data. The operation of the microgrid is complemented with a supervisory control stage that compensates any mismatch between the offline scheduling process and the real time microgrid operation. The proposal has been tested experimentally in a hybrid microgrid at the Microgrid Research Laboratory, Aalborg University.Peer ReviewedPostprint (author's final draft

Evolution of project-based learning in small groups in environmental engineering courses

This work presents the assessment of the development and evolution of an active methodology (Project-Based Learning –PBL-) implemented on the course “Unit Operations in Environmental Engineering”, within the bachelor’s degree in Environmental Engineering, with the purpose of decreasing the dropout rate in this course. After the initial design and implementation of this methodology during the first academic year (12/13), different modifications were adopted in the following ones (13-14, 14-15 & 15-16) in order to optimize the student’s and professor’s work load as well as correct some malfunctions observed in the initial design of the PBL. This active methodology seeks to make students the main architects of their own learning processes. Accordingly, they have to identify their learning needs, which is a highly motivating approach both for their curricular development and for attaining the required learning outcomes in this field of knowledge. The results obtained show that working in small teams (cooperative work) enhances each group member’s self–learning capabilities. Moreover, academic marks improve when compared to traditional learning methodologies. Nevertheless, the implementation of more active methodologies, such as project-based learning, in small groups has certain specific characteristics. In this case it has been implemented simultaneously in two different groups of 10 students each one. Such small groups are more heterogeneous since the presence of two highly motivated students or not can vary or affect the whole group’s attitude and academic resultsPeer Reviewe