Sergio Usón

Application of Thermoeconomics to Industrial Ecology

Industrial Ecology involves the transformation of industrial processes from linear to closed loop systems: matter and energy flows which were initially considered as wastes become now resources for existing or new processes. In this paper, Thermoeconomics, commonly used for the optimization and diagnosis of energy systems, is proposed as a tool for the characterization of Industrial Ecology. Thermoeconomics is based on the exergy analysis (Thermodynamics) but goes further by introducing the concepts of purpose and cost (Economics). It is presented in this study as a systematic and general approach for the analysis of waste flow integration. The formulation is based on extending the thermoeconomic process of the cost formation of wastes in order to consider their use as input for other processes. Consequently, it can be applied to important Industrial Ecology issues such as identification of integration possibilities and efficiency improvement, quantification of benefits obtained by integration, or determination of fair prices based on physical roots. The capability of the methodology is demonstrated by means of a case study based on the integration of a power plant, a cement kiln and a gas-fired boiler.

Thermoeconomic Evaluation of Biomass Conversion Systems

The chapter presents the application of thermoeconomics to the analysis of a sample biomass energy conversion system. Thermoeconomics is aimed at the analysis, optimization and diagnosis of energy conversion systems; it is based on the concept of exergy which is constantly gaining more popularity among engineers and researchers, and the concept of cost. The case study chosen for demonstrating the usefulness of the methodology concerns an integrated biomass gasification and utilization system with an atmospheric fluidized bed gasification unit and a gas turbine unit fed with the produced gas. Definition of fuel and product flows allows one to identify key components responsible for conversion of the largest amounts of exergy. Further concepts of thermoeconomics, such as exergy cost and its formation process allow one to determine the quality of each component of the plant. Attention is paid to the explanation of methodology rather than to particular technological issues, which are explained in the cited references, and are also subject of other chapters of this book.

Fundamentals of Exergy Analysis

Conservation laws are important tools in analysis of thermal processes. In engineering practice, substance conservation law and energy conservation law are commonly used. Exergy analysis based on first and second law of thermodynamics are still rarely applied in engineering and industrial practices. Demonstration of its potential to examine the imperfection of thermodynamic processes, evaluation of efficiency of resources transformation as well as to measure ecological effects is one of the main aims of this book. Thus, in this section, fundamentals of first, second law and exergy analysis are presented. In Chap. 3, two examples illustrating the rules of exergy balances are included. They present energy and exergy evaluation of steam boiler and steam heat-and-power plant (CHP).

Exergo-ecological Assessment of Multi-generation Energy Systems

This chapter provides three examples illustrating the usefullness of the concepts of exergy, exergy cost and thermo-ecological cost. The first example is related to exergo-ecological evaluation of adsorption chiller system. System consisted of cogeneration, solar collector and adsorption chiller are analyzed using the concept of thermo-ecological cost. The second example is devoted to thermo-ecological assessment of combined cold-heat-and-power plant CCHP plant supported with renewable energy. The aim of this analysis is to apply the exergo-ecological analysis for selected CCHP trigenaration system based on two renewable resources (biogas/solar radiation). The third example concerns the recovery of exergy from pressurized natural gas. The recovery system comprises a two-stage turbine expander integrated with a co-generation module. The example demonstrates the usefulness of exergy analysis, which, in contrast to energy analysis, provides tools to indicate and quantify the origin of the generated electricity. Finally, the studied case provides a numerical example for the calculation of unit exergy cost and of the thermo-ecological cost along the productive structure of the system.

Theory of Exergy Cost and Thermo-ecological Cost

The aim of the chapter is to introduce thermoeconomics and thermoecology, which are methodologies based on exergy and cost. After introducing thermoeconomics, the concept of exergy cost and a theory that enables its calculation is presented. Exergy cost of a flow within a system is the amount of exergy resources consumed by that system that are needed for producing the flow. Afterwards, symbolic thermoeconomics is presented in detail; this is a matrix-based methodology that enables not only the calculation of exergy cost, but also other relevant issues such as the effect of residues and the detailed analysis of exergy cost formation. In a following section, thermoecological cost is presented; this cost is also based on exergy but has the main differences that it only takes into account non-renewable exergy resources and considers also the effect of emissions of harmful substances. Finally, a methodology for connecting thermoecological cost with symbolic thermoeconomics is presented. Simple examples have been introduced along the chapter in order to show the capabilities of the proposed approaches. Furthermore, the concepts and formulae introduced will be applied in later chapters of the book.

Application of Thermo-economic Analysis (TEA) to Industrial Ecology (IE)

An example of ironworks is used to illustrate the application of thermo-economic analysis to industrial ecology. The case study analyzes the changes in blast furnace plant when part of the coke is replaced by coal. The application of direct exergy analysis apparently shows that the replacement has negative effects, which is contrary to experience. This problem can be overcome by performing thermo-economic analysis extended with the thermo-ecological cost of resources consumed by the plant. The approach allows one to quantify precisely how unit exergy cost is formed. Furthermore, a methodology for quantifying local savings (reduction of components’ irreversibility due to improvements in their operation) and plant savings (reduction of resources consumption) is presented and applied to the example, what points out clearly where resources savings appear and how this positive effect is extended in the productive chain.

Experiencia piloto de aula invertida para mejorar el proceso de enseñanza-aprendizaje en la asignatura de Termodinámica Técnica

Este trabajo ha sido financiado por medio de los proyectos de innovacion docente PIIDUZ_16_032 y PIIDUZ_16_165 (Programa de Proyectos de Innovacion Docente para Grupos de Profesores del Vicerrectorado de Politica Academica de la Universidad de Zaragoza).

Evaluación de la mejora del proceso de enseñanza-aprendizaje mediante la integración de objetos de aprendizaje reutilizables en un curso abierto OCW

En un contexto de Recursos Educativos Abiertos (REA), el concepto de Objetos de Aprendizaje Reutilizables (OAR), en formato digital y de caracter independiente y autonomo, resulta de gran interes para su uso en contextos educativos multiples como los cursos abiertos (OCW, por sus siglas en ingles). El objetivo de este trabajo es presentar los principales resultados obtenidos hasta la fecha en un proyecto de innovacion docente financiado por la Universidad de Zaragoza durante los cursos academicos 2015-16 y 2016-17 (Ref. PIIDUZ_15_079, 16_165 y 16_032). En este proyecto, se han creado 25 OARs en forma de videos docentes bajo licencias Creative Commons para mejorar los resultados de aprendizaje de cinco asignaturas en el campo de la Termodinamica y la Ingenieria Termica, que actualmente se imparten en tres titulaciones distintas. Para evaluar la mejora del proceso de ensenanza-aprendizaje obtenida mediante los videos, se han preparado y lanzado diferentes cuestionarios para los estudiantes. Hasta el momento, los resultados muestran que la mayoria de los estudiantes estan satisfechos con esta experiencia de innovacion. En este sentido, consideran que el uso de videos docentes ha mejorado su proceso de aprendizaje, aumentando su motivacion para estudiar y ayudandoles a entender los conceptos mas complejos. Keywords: OAR, OCW, REA, videos docentes, innovacion docente.

Anamnesis for Improving Thermoeconomic Diagnosis: The Case of a 3×350 MW Coal-Fired Power Plant

The aim of thermoeconomic diagnosis is to identify malfunctioning components in energy systems and to quantify the increment of fuel consumption due to each anomaly. Anamnesis, or the repetition of diagnosis along the time, allows to overcome error induced by measurement uncertainty. In this paper, a diagnosis system based on the diagnosis algorithm proposed by Correas [1] and implemented at Teruel 3×350 MW coal-fired power plant is presented and applied to the anamnesis for a period of several years. First, the plant and the diagnosis system structure are briefly described. Then, the diagnosis model is presented, including the definition of the free diagnosis variables, (independent causes of additional fuel consumption) and the system efficiency indicators (dependent variables). In the free diagnosis variables not only indicators of component efficiency are included but also set-points, ambient conditions and fuel quality. The system has been used by the power plant O&M staff for more than a year, and this experience has yielded important conclusions on how to design and implement such diagnosis systems. Afterwards, some results of the anamnesis performed by using this system are presented. It can be seen how the measurement uncertainty induces dispersion, so that the direct comparison of only two situations could lead to inexact conclusions.Copyright