Title: Why Emergy- and Exergy Analysis are non-commensurable methods for the assessment of energy conversion systems

Authors: Enrico Sciubba

Addresses: Department of Mechanical and Aeronautical Engineering, University of Roma 1, La Sapienza, via Eudossiana 18, 00184, Rome, Italy

Abstract: The paper discusses a fundamental incompatibility between Emergy- (|EMA|) and Exergy (|EXA|) Analysis. Both approaches quantify the resource consumption of physical systems by applying space- and time integrated energy input/output methods. A detailed theoretical analysis and two specific examples show that at least one of the claims made by EMA practitioners is based on a misinterpretation of the exergy accounting practices, that the claim that ||emergy is embodied exergy|| is inconsistent with EMA procedures, and that if these procedures were amended to correctly account for exergy flows, EMA would resemble Szargut|s Cumulative Exergy Content method and/or Extended Exergy Accounting.

Keywords: exergy analysis; emergy analysis; extended exergy accounting; energy conversion.

DOI: 10.1504/IJEX.2009.026676

International Journal of Exergy, 2009 Vol.6 No.4, pp.523 - 549

Available online: 22 Jun 2009

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