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[en] The concept of sustainability was developed from thermodynamic properties applied to complex adaptive systems. The origins of the perception about sustainable development and limitation in its application to analyze the interaction between a system and its surroundings were described. The properties of a complex adaptive system were taken as basis to determine how a system can to be affected by the resources restriction and irreversibility of the processes. The complex adaptive system was understood using the first and second law of thermodynamics, generating a conceptual framework to define the sustainability of a system. The contributions developed by exergy were shown to analyze the sustainability of systems in an economic, social and environmental context
[es]El concepto de sustentabilidad fue desarrollado a partir de propiedades termodinamicas aplicadas a sistemas adaptativos complejos. Los origenes de la percepcion sobre el desarrollo sustentable y la limitacion en su aplicacion para analizar la interaccion entre un sistema y su entorno fueron descritas. Las propiedades de un sistema adaptativo complejo fueron tomadas como base para determinar como un sistema puede ser afectado por la restriccion de recursos e irreversibilidad de los procesos. El sistema adaptativo complejo fue comprendido utilizando la primera y segunda ley de la termodinamica, generando un marco conceptual para definir la sustentabilidad de un sistema. Los aportes desarrollados por la exergia fueron mostrados para analizar la sustentabilidad de sistemas en un contexto economico, social y ambiental
[en] The technologies developed from 1973 on rational use, conservation and efficiency in the use of energy updated in a framework of sustain ability energetic and environment protection, it has not taken into account the concepts of quality of energy within of any energetic system (Source - Technology - Final Use), neither the favorable economic and technical implications of adopting the concepts of the Exergy and of exegetic efficiency, derivatives from the Second Law of the Thermodynamic, those which should be included as methods in the environmental and economic technical evaluations of an energetic system. This article presents the basic development of the concepts referenced from the Zero Law of the Thermodynamic, illustrating with examples the advantages to incorporate them as valuation and comparison parameters
[en] Exergy analysis is made of three components of an integrated wind energy to hydrogen fuel cell: wind turbine, fuel cell (PEMFC) and electrolyzer (PEM). The methodology used to assess how affect the second law efficiency of the electrolyzer and the FC parameters as temperature and operating pressure and membrane thickness. It develop methods to evaluate the influence of changes in the air density and height of the tower on the second law efficiency of the turbine. This work represents a starting point for developing the global availability analysis of an integrated wind / hydrogen / fuel cells, which can be used as a tool to achieve the optimum design of the same. The use of this system contribute to protect the environment
[en] Ecology is no more a descriptive and self-sufficient science. Many viewpoints are needed simultaneously to give a full coverage of such complex systems: ecosystems. These viewpoints come from physics, chemistry, and nuclear physics, without a new far from equilibrium thermodynamics and without new mathematical tools such as catastrophe theory, fractal theory, cybernetics and network theory, the development of ecosystem science would never have reached the point of today. Some ideas are presented about the importance that concept such as energy, entropy, exergy information and none equilibrium have in the analysis of processes taking place in ecosystems
[en] In order to know the blast furnace thermic state, the thermic exergy can be used, which considers the temperatures level of the process. The magnitude analysis of thermic exergy for blast furnace operation using pulverized coal, natural gas and oxygen injection by tuyeres, shows that natural gas injection is less effective than pulverized coal and enriched blast with oxygen simultaneous injection. (Author) 6 refs
[en] This paper presents the results of the continuity in a research process carried out at the Center for Energy and Environmental Technologies Studies, belonging to 'Marta Abreu' Central University of Las Villas, related to obtaining models for the determination of caloric powers and chemical exergy contained in any solid combustible element of biomass origin. The main formulations known in the literature are presented, as well as the results obtained by the authors to represent the lower caloric power and the chemical exergy in terms of elemental composition (C, H, O, N, and S). The formulations obtained correlate with the samples considered between 5% and 15% for the higher caloric power, and between 1,3% and 2,4% for chemical exergy. Based on these correlations, this study provides the relationship between higher caloric power and chemical exergy as a function of the elemental composition of C, H, O, N, and S in the fuel masses that will be used in biomass thermoelectric power stations (TPS) in process of construction in the country. (author)
[en] An exergetic analysis of a centralized system of air conditioning, based on a vapor compression refrigeration cycle, appears in this article. The investigation allows to calculate the irreversibilities (exergy destruction) in the main components of the refrigeration cycle as well as to evaluate the sensitivity of this indicator when the operating conditions changes. As main result the most sensible components of the cycle are identified, information that will be useful in order to define strategies of operation focused to the power efficiency increase.
[en] The present work constitutes a proposal of procedures of conceptual engineering in the studies of preinvestment in systems of combined heating, cooling and power, CHP, CCHP, cogeneration or trigeneration, applied to the tertiary sector. These procedures are regulated in the Decree Law 237/2015, in general form as regulation for investment processes, without dealing with the characteristic issues of this kind of projects, relative to the peculiar fact that in them the feasibility directly depends upon thermodynamic concepts as well as to the precepts of the economy, so it is more rational to apply the Thermoeconomics methods, in particular the theories of the exergy and exergoeconomic costs and the corresponding modeling and optimizing methods for this type of systems. The proposals are illustrated with a real case study which, as a project, is still in the phase of preliminary studies. (author)
[en] The work shows the energy and exergy evaluation of the combined cycle Energas Boca de Jaruco, which consists of five gas turbines 30 MWh five heat recovery steam OTSGs type and a steam turbine of 150 MW. This evaluation is performed without additional burning and for different percentages of utilization of these burners. The results allow to have a criterion of the efficiency of the system with and without supplementary burned, which can define strategies most appropriate system operation. (full text)
[en] A Unrefined sugar consumption in Colombia is the greatest in the world and its production is one of the main agricultural activities of national economy. In spite of this, the use of energy resources in this sector has been inefficient, causing the need to use additional fuels to bagaze, such as wood and rubber for compensating the energy inefficiency (Velasquez et al., 2004). For this reason alternative design proposals have emerged for unrefined sugar productive systems, which have been based in energy considerations, without counting on the quality of the different energy forms involved in the processes. In this work an exergy analysis of the more representative sugar mills designs is developed. It has been found that although significant improvement in energy efficiency is observed by introducing technological modifications (Velasquez et al., 2004), it has not happened the same with the exergy efficiency, which is significantly low for all the systems analyzed. This result is to be expected, because in the process low temperature thermal energy is used, condition imposed by the sugar cane juice evaporation.