An Introduction to the Concept of Exergy And
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Energy Efficiency and Economy-Wide Rebound Effects: a Review of the Evidence and Its Implications
Renewable and Sustainable Energy Reviews xxx (xxxx) xxx Contents lists available at ScienceDirect Renewable and Sustainable Energy Reviews journal homepage: http://www.elsevier.com/locate/rser Energy efficiency and economy-wide rebound effects: A review of the evidence and its implications Paul E. Brockway a,*, Steve Sorrell b, Gregor Semieniuk c,d, Matthew Kuperus Heun e, Victor Court f,g a School of Earth and Environment, University of Leeds, UK b Science Policy Research Unit, University of Sussex, UK c Political Economy Research Institute & Department of Economics, University of Massachusetts, Amherst, USA d Department of Economics, SOAS University of London, UK e Engineering Department, Calvin University, 3201 Burton St. SE, Grand Rapids, MI, 49546, USA f IFP School, IFP Energies Nouvelles, 1 & 4 avenue de Bois Pr´eau, 92852, Rueil-Malmaison cedex, France g Chair Energy & Prosperity, Institut Louis Bachelier, 28 place de la Bourse, 75002, Paris, France ARTICLE INFO ABSTRACT Keywords: The majority of global energy scenarios anticipate a structural break in the relationship between energy con Energy efficiency sumption and gross domestic product (GDP), with several scenarios projecting absolute decoupling, where en Economy-wide rebound effects ergy use falls while GDP continues to grow. However, there are few precedents for absolute decoupling, and Integrated assessment models current global trends are in the opposite direction. This paper explores one possible explanation for the historical Energy-GDP decoupling close relationship between energy consumption and GDP, namely that the economy-wide rebound effects from Energy rebound improved energy efficiency are larger than is commonly assumed. We review the evidence on the size of economy-wide rebound effects and explore whether and how such effects are taken into account within the models used to produce global energy scenarios. -
Exergy Accounting - the Energy That Matters V
THE 8th LATIN-AMERICAN CONGRESS ON ELECTRICITY GENERATION AND TRANSMISSION - CLAGTEE 2009 1 Exergy Accounting - The Energy that Matters V. Fachina, PETROBRAS 1 Exergy means the maximum work which can be Abstract-- The exergy concept is introduced by utilizing a extracted from a control volume. Also it is the maximum general framework on which are based the model equations. An energy quantity which can be made useful after discounting exergy analysis is performed on a case study: a control volume the irreversible losses. Finally, exergy means a physical, for a power module is created by comprising gas turbine, chemical contrast level between a control volume and its reduction gearbox, AC generator, exhaustion ducts and heat nearby surroundings. regenerator. The implementation of the equations is carried out Now considering the economical realm, Fig. 1 can be by collecting test data of the equipment data sheets from the respective vendors. By utilizing an exergy map, one proposes translated as follows: the reversible losses as either business both mitigating and contingent countermeasures for maximizing productivity losses or refundable taxes; the irreversible ones the exergy efficiency. An exergy accounting is introduced by as either nonrefundable taxes or inflation; the right arrows as showing how the exergy concept might eventually be brought up product and service values; the left ones as product and to the traditional money accounting. At last, one devises a unified service investments. approach for efficiency metrics in order to bridge the gaps A word of advice: a control volume means either a between the physical and the economical realms. physical or logical reality subset bounded by our observation. -
Finite-Time Thermodynamic Model for Evaluating Heat Engines in Ocean Thermal Energy Conversion
entropy Article Finite-Time Thermodynamic Model for Evaluating Heat Engines in Ocean Thermal Energy Conversion Takeshi Yasunaga * and Yasuyuki Ikegami Institute of Ocean Energy, Saga University, 1 Honjo-Machi, Saga 840-8502, Japan; [email protected] * Correspondence: [email protected] Received: 14 January 2020; Accepted: 11 February 2020; Published: 13 February 2020 Abstract: Ocean thermal energy conversion (OTEC) converts the thermal energy stored in the ocean temperature difference between warm surface seawater and cold deep seawater into electricity. The necessary temperature difference to drive OTEC heat engines is only 15–25 K, which will theoretically be of low thermal efficiency. Research has been conducted to propose unique systems that can increase the thermal efficiency. This thermal efficiency is generally applied for the system performance metric, and researchers have focused on using the higher available temperature difference of heat engines to improve this efficiency without considering the finite flow rate and sensible heat of seawater. In this study, our model shows a new concept of thermodynamics for OTEC. The first step is to define the transferable thermal energy in the OTEC as the equilibrium state and the dead state instead of the atmospheric condition. Second, the model shows the available maximum work, the new concept of exergy, by minimizing the entropy generation while considering external heat loss. The maximum thermal energy and exergy allow the normalization of the first and second laws of thermal efficiencies. These evaluation methods can be applied to optimized OTEC systems and their effectiveness is confirmed. Keywords: finite-time thermodynamics; reversible heat engine; normalized thermal efficiency; maximum work; exergy; entropy generation 1. -
Exergy As a Measure of Resource Use in Life Cyclet Assessment and Other Sustainability Assessment Tools
resources Article Exergy as a Measure of Resource Use in Life Cyclet Assessment and Other Sustainability Assessment Tools Goran Finnveden 1,*, Yevgeniya Arushanyan 1 and Miguel Brandão 1,2 1 Department of Sustainable Development, Environmental Science and Engineering (SEED), KTH Royal Institute of Technology, Stockholm SE 100-44, Sweden; [email protected] (Y.A.); [email protected] (M.B.) 2 Department of Bioeconomy and Systems Analysis, Institute of Soil Science and Plant Cultivation, Czartoryskich 8 Str., 24-100 Pulawy, Poland * Correspondance: goran.fi[email protected]; Tel.: +46-8-790-73-18 Academic Editor: Mario Schmidt Received: 14 December 2015; Accepted: 12 June 2016; Published: 29 June 2016 Abstract: A thermodynamic approach based on exergy use has been suggested as a measure for the use of resources in Life Cycle Assessment and other sustainability assessment methods. It is a relevant approach since it can capture energy resources, as well as metal ores and other materials that have a chemical exergy expressed in the same units. The aim of this paper is to illustrate the use of the thermodynamic approach in case studies and to compare the results with other approaches, and thus contribute to the discussion of how to measure resource use. The two case studies are the recycling of ferrous waste and the production and use of a laptop. The results show that the different methods produce strikingly different results when applied to case studies, which indicates the need to further discuss methods for assessing resource use. The study also demonstrates the feasibility of the thermodynamic approach. -
Energy Energy Science and Technology Has Been a Primary Driver of Human Progress for Centuries, and Intensive Energy Use Is Essential to Industrialized Society
Sustainability Brief: Energy Energy science and technology has been a primary driver of human progress for centuries, and intensive energy use is essential to industrialized society. Our energy infrastructure is the foundation that makes almost all commercial activity and modern home life possible. The growth and proliferation of this energy web over the last century has enabled both economic growth and improved quality of life. Along with those advantages and benefits, however, have come increasingly apparent costs, consequences, and risks. Because industrialized civilization depends so heavily on this energy infrastructure, failures or consequences of that infrastructure have a huge impact with economic, social, and environmental implications. The subject of Sustainable Energy addresses the impacts and vulnerabilities of our energy infrastructure, and focuses on reducing the emerging risks in our current approach so as to ensure the continued availability of reliable, cost-effective energy and the quality of life that depends upon it. These risks include the threat of supply disruptions, economic hardship imposed by rising energy costs, environmental impacts, public health issues, social equity issues, and threats related to either man-made (e.g. terrorist) or natural (e.g. extreme weather) causes, among many others. New Jersey citizens and businesses already bear the costs and consequences of our current energy infrastructure, and these impacts are likely to increase over time. Ensuring the long term sustainability of New Jersey’s -
15 Evaluating on Exergy Analysis of Refrigeration
International Journal of Engineering & Applied Sciences (IJEAS) Vol.4, Issue 4(2012)15-25 EVALUATING ON EXERGY ANALYSIS OF REFRIGERATION SYSTEM WITH TWO-STAGE AND ECONOMISER Bayram Kılıç 1* , Osman İpek 2, Sinan U ğuz 3 1Bucak Emin Gülmez Vocational School, Mehmet Akif Ersoy University, Bucak, 15300, Burdur, Turkey 2Engineering&Architecture Faculty, Mechanical Engineering, Süleyman Demirel University,32260,Isparta, Turkey 3Bucak Zeliha Tolunay Applied Technology and Management School, Mehmet Akif Ersoy University, , Bucak, 15300, Burdur, Turkey *Corresponding Author: E-mail: [email protected] Recived: 26 December 2012 Abstract In this study, the first and second law analysis of vapor compression refrigeration cycle with two-stage and economiser were carried out. R134a was used in system as refrigerant. The necessary thermodynamic values for analyses were calculated by Solkane program. The coefficient of performance (COP), exergetic efficiency ( ηex) and total irreversibility rate of the system in the different operating conditions were investigated for this refrigerant. As a result, the highest coefficient of performance value and exergy efficiency value was obtained in the condenser temperature 25 oC and evaporator temperature 5 oC in the refrigeration system with two-stage and economiser. The highest irreversibility value was obtained in the condenser temperature 45 oC and evaporator temperature -15 oC in the refrigeration system. Keywords: Refrigeration system, COP, exergy analysis, two-stage. 1. Introduction Single-stage compression process can give quite satisfactory results for the evaporation temperatures until -15 oC in vapor compression refrigeration cycles of condensation temperatures is not too high. However, the capacity of cooling cycle together with the coefficient of performance rapidly decreases in working conditions are very low evaporation temperatures. -
Second Biennial Conference of the United States Society for Ecological Economics
Second Biennial Conference of the United States Society for Ecological Economics May 22-24, 2003 Prime Hotel and Conference Center Saratoga Springs, New York co-sponsored by Gund Institute for Ecological Economics Rensselaer Polytechnic Institute Dept. of Economics Santa-Barbara Family Foundation University of Vermont School of Natural Resources U.S. Society for Ecological Economics President John Gowdy Rensselaer Polytechnic Institute President-Elect Secretary-Treasurer Barry Solomon Joy Hecht University of California, Santa Cruz New Jersey Sustainable State Institute Executive Directors Susan and Michael Mageau Institute for a Sustainable Future Board Members at Large Jon Erickson Brent Haddad University of Vermont University of California, Santa Cruz Valerie Luzadis Karin Limburg SUNY College of Environmental SUNY College of Environmental Science & Forestry Science & Forestry Student Board Member Caroline Hermans University of Vermont Second Biennial USSEE Conference Planning Committee Jon Erickson, Chair University of Vermont Graham Cox Josh Farley Rensselaer Polytechnic Institute University of Vermont Rich Howarth Susan Mageau Dartmouth College Institute for a Sustainable Future Valerie Luzadis Trista Patterson SUNY College of Environmental Science University of Maryland & Forestry Roy Wood Kodak, Inc. SECOND BIENNIAL CONFERENCE OF THE UNITED STATES SOCIETY FOR ECOLOGICAL ECONOMICS CONFERENCE SUMMARY Thursday, May 22 Morning 9:00 Registration Opens 11:30 Concurrent Session 1 Afternoon 1:00 Refreshments 1:30 Concurrent Session 2 3:00 -
Sustainability Indicators for the Use of Resources—The Exergy Approach
Sustainability 2012, 4, 1867-1878; doi:10.3390/su4081867 OPEN ACCESS sustainability ISSN 2071-1050 www.mdpi.com/journal/sustainability Article Sustainability Indicators for the Use of Resources—The Exergy Approach Christopher J. Koroneos 1,*, Evanthia A. Nanaki 2 and George A. Xydis 3 1 Unit of Environmental Science and Technology, Department of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechneiou Street, Zografou Campus, 15773 Athens, Greece 2 University of Western Macedonia, Department of Mechanical Engineering, Bakola and Sialvera, 50100 Kozani, Greece; E-Mail: [email protected] 3 Technical University of Denmark, Department of Electrical Engineering, Frederiksborgvej 399, P.O. Box 49, Building 776, 4000 Roskilde, Denmark; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +30-210-772-3085; Fax: +30-210-772-3285. Received: 17 July 2012; in revised form: 25 July 2012 / Accepted: 2 August 2012 / Published: 20 August 2012 Abstract: Global carbon dioxide (CO2) emissions reached an all-time high in 2010, rising 45% in the past 20 years. The rise of peoples’ concerns regarding environmental problems such as global warming and waste management problem has led to a movement to convert the current mass-production, mass-consumption, and mass-disposal type economic society into a sustainable society. The Rio Conference on Environment and Development in 1992, and other similar environmental milestone activities and happenings, documented the need for better and more detailed knowledge and information about environmental conditions, trends, and impacts. New thinking and research with regard to indicator frameworks, methodologies, and actual indicators are also needed. -
Energy and Exergy Analyses of Angra 2 Nuclear Power Plant
2017 International Nuclear Atlantic Conference - INAC 2017 Belo Horizonte, MG, Brazil, October 22-27, 2017 ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR – ABEN ENERGY AND EXERGY ANALYSES OF ANGRA 2 NUCLEAR POWER PLANT João G. O. Marques, Antonella L. Costa, Claubia Pereira, Ângela Fortini Universidade Federal de Minas Gerais Departamento de Engenharia Nuclear – Escola de Engenharia Av. Antônio Carlos Nº 6627, Campus Pampulha, CEP 31270-901, Belo Horizonte, MG, Brasil [email protected], [email protected], [email protected], [email protected] ABSTRACT Nuclear Power Plants (NPPs) based on Pressurized Water Reactors (PWRs) technology are considered an alternative to fossil fuels plants due to their reliability with low operational cost and low CO2 emissions. An example of PWR plant is Angra 2 built in Brazil. This NPP has a nominal electric power output of 1300 MW and made it possible for the country save its water resources during electricity generation from hydraulic plants, and improved Brazilian knowledge and technology in nuclear research area. Despite all these benefits, PWR plants generally have a relatively low thermal efficiency combined with a large amount of irreversibility generation or exergy destruction in their components, reducing their capacity to produce work. Because of that, it is important to assess such systems to understand how each component impacts on system efficiency. Based on that, the aim of this work is to evaluate Angra 2 by performing energy and exergy analyses to quantify the thermodynamic performance of this PWR plant and its components. The methodology consists in the development of a mathematical model in EES (Engineering Equation Solver) software based on thermodynamic states in addition to energy and exergy balance equations. -
Exergy Analysis As a Tool for Addressing Climate Change
European Journal of Sustainable Development Research 2021, 5(2), em0148 e-ISSN: 2542-4742 https://www.ejosdr.com Research Article Exergy Analysis as a Tool for Addressing Climate Change Marc A. Rosen 1* 1 Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario, L1G 0C5, CANADA *Corresponding Author: [email protected] Citation: Rosen, M. A. (2021). Exergy Analysis as a Tool for Addressing Climate Change. European Journal of Sustainable Development Research, 5(2), em0148. https://doi.org/10.21601/ejosdr/9346 ARTICLE INFO ABSTRACT Received: 1 Oct. 2020 Exergy is described as a tool for addressing climate change, in particular through identifying and explaining the Accepted: 3 Oct. 2020 benefits of sustainable energy, so the benefits can be appreciated by experts and non-experts alike and attained. Exergy can be used to understand climate change measures and to assess and improve energy systems. Exergy also can help better understand the benefits of utilizing sustainable energy by providing more useful and meaningful information than energy provides. Exergy clearly identifies efficiency improvements and reductions in wastes and environmental impacts attributable to sustainable energy. Exergy can also identify better than energy the environmental benefits and economics of energy technologies. Exergy should be applied by engineers and scientists, as well as decision and policy makers, involved in addressing climate change. Keywords: exergy, climate change, environment, ecology, energy impacts. Exergy can also identify better than energy ways to INTRODUCTION improve environmental benefits and economics. Consequently, many researchers suggest that the impact of The relationship between energy and economics, such as energy use on the environment, the achievement of increased the trade-offs between efficiency and cost, has almost always efficiency, and the economics of energy systems are best been important. -
Energy, Exergy, and Thermo-Economic Analysis of Renewable Energy-Driven Polygeneration Systems for Sustainable Desalination
processes Review Energy, Exergy, and Thermo-Economic Analysis of Renewable Energy-Driven Polygeneration Systems for Sustainable Desalination Mohammad Hasan Khoshgoftar Manesh 1,2,* and Viviani Caroline Onishi 3,* 1 Energy, Environment and Biologic Research Lab (EEBRlab), Division of Thermal Sciences and Energy Systems, Department of Mechanical Engineering, Faculty of Technology & Engineering, University of Qom, Qom 3716146611, Iran 2 Center of Environmental Research, Qom 3716146611, Iran 3 School of Engineering and the Built Environment, Edinburgh Napier University, Edinburgh EH10 5DT, UK * Correspondence: [email protected] (M.H.K.M.); [email protected] (V.C.O.) Abstract: Reliable production of freshwater and energy is vital for tackling two of the most crit- ical issues the world is facing today: climate change and sustainable development. In this light, a comprehensive review is performed on the foremost renewable energy-driven polygeneration systems for freshwater production using thermal and membrane desalination. Thus, this review is designed to outline the latest developments on integrated polygeneration and desalination systems based on multi-stage flash (MSF), multi-effect distillation (MED), humidification-dehumidification (HDH), and reverse osmosis (RO) technologies. Special attention is paid to innovative approaches for modelling, design, simulation, and optimization to improve energy, exergy, and thermo-economic performance of decentralized polygeneration plants accounting for electricity, space heating and cool- ing, domestic hot water, and freshwater production, among others. Different integrated renewable Citation: Khoshgoftar Manesh, M.H.; energy-driven polygeneration and desalination systems are investigated, including those assisted Onishi, V.C. Energy, Exergy, and by solar, biomass, geothermal, ocean, wind, and hybrid renewable energy sources. -
Energy Degradation and Ecosystem Development: Theoretical Framing, Indicators
Ecological Indicators 20 (2012) 204–212 Contents lists available at SciVerse ScienceDirect Ecological Indicators jo urnal homepage: www.elsevier.com/locate/ecolind Energy degradation and ecosystem development: Theoretical framing, indicators definition and application to a test case study ∗ Alessandro Ludovisi Dipartimento di Biologia Cellulare e Ambientale, Università di Perugia, Via Elce di Sotto, 06123 Perugia, Italy a r t i c l e i n f o a b s t r a c t Article history: During the last few decades, the so-called “maximum dissipation principle” has raised a wide debate as Received 21 May 2011 a paradigm governing the development of ecological systems. In the present contribution, after having Received in revised form 5 February 2012 discussed the meaning of the term energy degradation within the framework provided by the entropy Accepted 9 February 2012 and the exergy balance, it is suggested to distinguish three different facets of the phenomenon of the energy degradation, respectively dealing with the overall, system and environmental degradation. In Keywords: relation with ecological indication, the above classification shows that different types of indicators of Ecological indicators energy degradation can be defined, thus emphasising that a clear reference to the specific facet consid- Ecological orientors Entropy ered should be made in order to avoid ambiguous statements. The behaviour of several thermodynamic Exergy indicators, which include previously derived indices and a new set of entropy-based indicators, is exam- Lake Trasimeno ined along the seasonal progression in a lake ecosystem, and the effectiveness of the considered indicators in characterising the development state is evaluated by comparing their responses with the main succes- sional traits of the phytoplankton community.