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Environ Dev Sustain (2009) 11:971988 DOI 10.1007/s10668-008-9162-3
Mehmet Kanoglu Ibrahim Dincer Yunus A. Cengel
Received: 29 February 2008 / Accepted: 19 June 2008 / Published online: 10 July 2008 Springer Science+Business Media B.V. 2008
Abstract In this paper, some key aspects and denitions of exergy are presented, and practical examples are given in order to highlight its usefulness in design, analysis and performance improvement for various types of energy processes for better environment and sustainable development. The relations between exergy, sustainability and environmental impact are illustrated to show how improving the performance of the process through exergy efciency affects the environmental impact and sustainable development. Both exergy and energy efciencies for various systems/processes are also studied for comparison purposes.
Keywords Exergy Energy Efciency Performance Environment and sustainability Nomenclaturecp Specic heat (kJ/kg K)
COP Coefcient of performance
E Energy (kJ)
Ex Amount of exergy (kJ) Exdestroyed Exergy destruction (kJ)
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Ex Rate of exergy (kW) h Enthalpy (kJ/kg)
Readers should send their comments on this paper to: [email protected] within 3 months of publication of this issue.
M. Kanoglu
Department of Mechanical Engineeering, University of Gaziantep, 27310 Gaziantep, Turkey e-mail: [email protected]
I. Dincer (&)
Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, Canada L1H 7K4e-mail: [email protected]
Y. A. Cengel
Department of Mechanical Engineeering, University of Nevada, Reno, Reno, NV, USA e-mail: [email protected]
Exergy for better environment and sustainability
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m Mass (kg)
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m Mass ow rate (kg/s)
N Mole number (kmol)
P Pressure (kPa)
Q Amount of heat transfer (kJ)
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Q Rate of heat transfer (kW) s Entropy (kJ/kg K)
Sgen Entropy generation (kJ/K)
T Temperature (kJ/kg)
Taf Adiabatic ame temperature (K)
u Internal energy (kJ/kg)v Specic volume (m3/kg) V Volume (m3)
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V volume ow rate (m3/s)
W Amount of work (kJ)
_
W Rate of work or power (kW)
Greek lettersgth Thermal efciencygex Exergy (second-law) efciency w Flow exergy (kJ/kg)
1 Introduction
The science of thermodynamics is built primarily on two fundamental natural laws, known as the rst and the second laws. The rst law of thermodynamics is simply an expression of the conservation of energy principle. It asserts that energy is a thermodynamic property, and that during...