EnviroInfo 2013 Approach for the practical application of

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1 Introduction, The interests of societies change along its evolution and development The history of the human race. shows that in our cultures what prevails is immediate gratification and not future planning and perhaps. that is why they sometimes face its unquestionable degradation Our culture is not an exception The. necessity of change in our mentality of our way of life of industrial activity and economical interaction is. necessary to avoid the level of human suffering and ecological degradation and to ensure a sustainable. development But despite the knowledge of these intentions for over 30 years we are still far away from. global sustainability Niembro Garc a 2008, Once the need for sustainable development is established one of the challenges on the way to. sustainability is the development of tools in order to measure and improve the efficiency and the. sustainability of processes and products, The combination of Life Cycle Assessment LCA and exergy analysis provides an additional impact. category to LCA in order to apply exergy as an indicator for energy efficiency and resource quality. demand B sch et al 2007 The calculation of exergy indicators within branch oriented networks enables. one to perform an Exergy Benchmarking Through the comparison of the exergy indicators between. companies belonging to the same branch arises a Best Practice of the branch which acts as an enhancer. of the Learning from the best process At this point the enterprises can identify the best practices in the. field of the material and energy use and implement measurements for the improvement of their own. processes or products, The obtained exergy data of processes taking place in the network enterprises can contribute to the. complementation of the already existing exergy database In many studies that consider the exergy. concept they stress the necessity of a database of exergy values for basic processes to fill data gaps and to. maintain data consistency B sch et al 2007, 2 Starting Point ReMo Green Energy Efficiency for Small and Medium.
sized Enterprises SME in Berlin, The Project ReMo Green is carried out in the framework of energy efficiency enterprise networks. Energy efficiency networks have been known for over 30 years This idea comes from Switzerland. where the first of its kind was founded in 1987 with the aim of reducing the energy consumption and. consequently the energy costs In Germany the first energy efficiency network was established in 2002. and currently there are about 25 active regional networks all over the country. The new approach of the ReMo Green project is the establishment of energy efficiency enterprise. networks with a branch specific oriented proceeding in order to provide the SMEs with more rigorous. comprehensive and efficient support for the increase of energy efficiency Due to the great variety of. industrial processes it is not possible to develop a single standard of procedures to increase the energy. efficiency that would be available for all the SMEs Because of this this project develops branch specific. reference models which are valid for SMEs of the same branch These reference models are an Energy. Efficiency Reference Modell and a Reference Standard Software for Energy Efficiency The. compilation of energetic data and the measurement of energetic values are essential for the development. of these models And these data together with the enterprise network structure is proposed in this paper as. a starting point for the implementation of exergy analysis in the network enterprises. The comparison of both approaches the energetic and the exergetic one could be very interesting and. useful for a better interpretation of the results Through such a comparison it is possible to determine. which method is more suitable for the analysis of production processes and which of them shows the more. realistic saving potential, The project ReMo Green is a complex and ambitious project in which come into play a number of. know how carriers that provide the enterprises not only the know how but also experience information. training and motivation for energy efficiency themes All of these activities are guaranteed without. Copyright 2013 Shaker Verlag Aachen ISBN 978 3 8440 1676 5. compromising the financial resources of the enterprises because it is a funded project The coordination. and the development of the whole project correspond to the IMBC GmbH3. 3 Description of the exergy approach in the framework of branch oriented. enterprise networks, The following describes an approach for the application of the concept of exergy for the improvement of. the efficiency of processes within enterprises of the same branch These exergy analyses are the first step. of a procedure which is aimed at combining the exergy based methods and LCA in order to consider the. sum of exergy of the energetic and material resources consumed in all the processes involved in the whole. life cycle of the products that are produced in the network enterprises. The schematic representation of the methodology is shown below. Schematic Representation of the exergy approach in the framework of enterprise networks. The beginning of this approach and its framework is the creation of solid and good organised branch. oriented enterprise networks The selection of branches with an intensive consumption of material and. energetic resources has already been made by ReMo Green The advantage of applying this approach in. the companies participating in the ReMo Green project is the availability of the collected data and the. The IMBC GmbH Institute for Information Management develops concepts for IT based sustainable solutions in the area of. environmental computer science for more than 8 years. Copyright 2013 Shaker Verlag Aachen ISBN 978 3 8440 1676 5. possibility of making use of the network structure But this approach could be applied of course with. more required time to new enterprise networks of other branches. The network promotes the active collaboration between the companies and its engagement with a. sustainable development With the support of institutions contributing the know how and management. capacities all the actions taking place within the network benefit the economic environmental and social. situation of the enterprises, The approach starts with the application of the exergy analysis to the production processes and products. within the enterprise This would correspond to an LCA in terms of exergy within the physical boundaries. of the company which is understood as Gate to Gate LCA In this phase values of exergy related to. industrial processes are calculated These data form the primary database of exergy values and are a source. for gate to gate Life Cycle Inventory LCI information Jim nez Gonz lez et al 2000. Within the exergy analysis the exergy losses and the exergy efficiency are calculated In order to make. appropriate improvement decisions these values are analysed together with the exergy flow diagrams of. the processes carried out within the companies These values can be considered as exergy indicators. which can be used for the realization of an Exergy Benchmarking Through the comparison of these. exergy indicators the optimization potential of the participant enterprises is revealed and the energetic. quality of the resources is improved The cooperation of enterprises in branch oriented networks is very. important to the obtainment and use of exergy life cycle data in the operational context. The boundaries of the exergy analysis are expanded to include the contribution of all the intermediate. processes from the natural resources to the desired product through the application of the Cumulative. Exergy Consumption CExC Analysis, The next step is to include the use phase of the product and its recovery or disposal Thus the whole.
life cycle of the product can be considered and assessed in terms of exergy resulting in an Exergy Life. Cycle Assessment ELCA, The steps of the procedure are explained in more detail separately in the following paragraphs. 4 Exergy analysis,4 1 The concept of exergy and exergy losses. The exergy concept is relatively young The term exergy was suggested for the first time by Zoran Rant. in 1956 Rant 1956 but the concept was developed by Josiah Willard Gibbs in 1873 Gibbs 1873 Exergy. is a measure of the maximum amount of useful energy that can be obtained when matter is brought to. equilibrium with its surroundings In other words exergy is defined as the maximum work or ability to. produce work during the process towards equilibrium Rant 1956 The concept of exergy incorporates. therefore both qualitative and quantitative properties of energy and has been developed to provide a. coherent and congruent quantification of the quality of an energy form Sciubba 2009. The only way to describe the concept of the energy quality is by using the second law of. thermodynamics In a world rapidly running out of fossil fuel the second law of thermodynamics may. well turn out to be the central scientific truth of the twenty first century Goodstein 1994 The second. law explains that the exergy is always conserved in a reversible process but is always consumed in an. irreversible process i e real processes On the other hand the first law of thermodynamics is the law of. energy conservation and says that energy cannot be created or destroyed only transformed In these. transformations the energy is converted into other forms of energy that are less suitable for the realization. of real processes In other words exergy is destroyed producing the loss of energy quality and. consequently the ability to produce work, The goal of the exergy analysis in this approach is the optimization of the production systems and. processes consuming energy and materials in two dimensions the quantitative and the qualitative. Copyright 2013 Shaker Verlag Aachen ISBN 978 3 8440 1676 5. The analysis of the exergy losses enables the localization of the improvement potential of the system. efficiency For real processes the exergy is never balanced this means that the exergy input is always. greater than the exergy output i e and this is due to the irreversibilities occurring during. the process The work of Mei Gong and G ran Wall Gong Wall 1997 called this type of exergy loss. exergy destruction The total exergy output consists of a utilized part and a non utilized part This. unused exergy output is called exergy waste Both of them are exergy losses Irreversibility is. considered as the wasted work potential or the lost opportunity to produce work. The exergy destruction is related to the entropy generated during the process and is given below. Gong Wall 1997, where is the temperature of the environment is the total entropy generated during the process. is the total exergy input is the total exergy output and is the exergy destruction of the. 4 2 Exergy calculation, For the calculation of exergy we have to establish the mass and energy balances and then to determinate.
the exergy contents of the in and outflows The exergy inputs and outputs of a system are matter heat. 4 2 1 Exergy of matter flows, The components of a matter exergy flow are the physical exergy the chemical exergy the kinetic. exergy and the potential exergy, The physical exergy of matter consist of mechanical and thermal exergy and it is due to temperature. and pressure differences with the environment It is calculated as the difference between the enthalpy. and the enthalpy of the environment minus the exergy loss defined in equation 1 Szargut 1988. The chemical exergy is due to the chemical composition of the substance and can be calculated on a. molar basis as, where is the Gibbs standard free energy liberated in the formation of the compound and are the. molar fraction of the th chemical elements of the compound Ayres 1998 The exergy of a lot of. elements were already calculated by Jan Szargut and can be used in the calculations Szargut et al 1988. The kinetic exergy is related with the velocity of the flow relative to the environment Van. Lier Woudstra 2005, The potential exergy is calculated as the difference of the potential energies of the matter and its. surroundings van Lier Woudstra 2005, Copyright 2013 Shaker Verlag Aachen ISBN 978 3 8440 1676 5.
4 2 2 Exergy of work flows, Since the exergy is defined as the maximum work potential the exergy of work is calculated as the work. itself van Lier Woudstra 2005,4 2 3 Exergy of heat flows. The maximum work potential of a heat flow is limited by the Carnot factor Cornelissen 1997. 4 3 Exergy efficiency, The calculation of exergy losses enables the detection of inefficiencies and therefore the determination of. the possible improvement potential of processes Once we have this information the logical approach. would be to improve the part of the system with higher exergy losses But taking into consideration that. every part of a system depends on each other the improvement of a single part may produce extra losses. in another That could lead to equal or larger total exergy losses in the improved process Gong Wall. The improvement of processes should be analysed in combination with the exergy efficiency and the. exergy flow diagrams to obtain better results, The exergy efficiency is usually defined as the utilized exergy divided by the used exergy Gong Wall. 1997 But there is more than one way to define these two concepts We use the approach of Mei Gong. and G ran Wall Gong Wall 1997 which is based on the following figure. Approach for the practical application of Exergy Analysis within branch oriented enterprise networks towards the realization of an Exergy Life Cycle Assessment ELCA Iria lvarez 1 Abstract Usually efficiency is defined in energetic terms without taking into account the quality of the energy Another way to analyse and optimise processes and systems is in terms of exergy The concept of

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