CIRP Encyclopedia of Production Engineering

2014 Edition
| Editors: The International Academy for Production Engineering, Luc Laperrière, Gunther Reinhart

Energy Efficiency

  • Joost Duflou
  • Christoph Herrmann
  • Sami Kara
Reference work entry


Energy efficiency is the ratio between the useful energy output and the energy input of a thermodynamic system.

Theory and Application


The energy efficiency metric originates from the early development of thermodynamic cycles, such as the steam engine and internal combustion engine. However, the metric can be applied to any thermodynamic system. It serves as a performance criterion of the corresponding system. Figure 1 illustrates a generic energy flow diagram of a thermodynamic system, with the system boundary shown by the dashed line.
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  4. Tanaka K (2008) Assessing measures of energy efficiency performance and their application in industry. IEA information paper. International Energy Agency, FranceGoogle Scholar

Copyright information

© CIRP 2014

Authors and Affiliations

  1. 1.Centre for Industrial Management, Department of Mechanical EngineeringKU LeuvenHeverlee - LeuvenBelgium
  2. 2.TU BraunschweigBraunschweigGermany
  3. 3.School of Mechanical & Manufacturing EngineeringThe University of New South WalesSydneyAustralia