Title: Potential for efficiency improvement of four-stroke marine diesel gensets by utilisation of exhaust gas energy

Authors: Dimitrios T. Hountalas; Georgios C. Mavropoulos; Christos Katsanos; Stavros Daniolos; Iosif Dolaptzis; Nikolaos Mastorakis

Addresses: Internal Combustion Engines Laboratory, Thermal Engineering Department, School of Mechanical Engineering, National Technical University of Athens, 9 Heroon Polytechniou St., Zografou Campus, 15780 Athens, Greece ' Internal Combustion Engines Laboratory, Thermal Engineering Department, School of Mechanical Engineering, National Technical University of Athens, 9 Heroon Polytechniou St., Zografou Campus, 15780 Athens, Greece ' Internal Combustion Engines Laboratory, Thermal Engineering Department, School of Mechanical Engineering, National Technical University of Athens, 9 Heroon Polytechniou St., Zografou Campus, 15780 Athens, Greece ' Minerva Marine Inc., 141-143 Vouliagmenis Avenue, Voula, Athens, 16673, Greece ' Minerva Marine Inc., 141-143 Vouliagmenis Avenue, Voula, Athens, 16673, Greece ' Minerva Marine Inc., 141-143 Vouliagmenis Avenue, Voula, Athens, 16673, Greece

Abstract: In the present paper, it is examined the potential application of a Rankine cycle exhaust gas heat recovery system which recovers and utilises energy from the exhaust gas of four-stroke marine diesel auxiliary unit before it is released to the atmosphere, increasing thus its total efficiency. For this purpose, a thermodynamic simulation model of the Rankine bottoming cycle is used. Heat utilisation is initially considered only from the main exhaust gas stream after the T/C turbine. As reference for the investigation are used the values from the official shop tests at various loads ranging from 25% up to 100%. From these using the Rankine cycle simulation model, it is investigated the potential for increase of generated cycle power output and optimisation of its efficiency. In addition, it is examined the effect of working media by considering steam and an organic. The results derived reveal that there exists a significant potential for fuel saving by utilisation of exhaust gas energy of auxiliary engines installed on commercial vessels.

Keywords: Rankine cycle; four-stroke diesel engines; heat recovery; exhaust gas; engine efficiency; marine engines; diesel auxiliary units; thermodynamics; simulation; modelling; auxiliary engines; commercial vessels.

DOI: 10.1504/IJGW.2016.077910

International Journal of Global Warming, 2016 Vol.10 No.1/2/3, pp.133 - 157

Received: 02 Sep 2014
Accepted: 28 Jan 2015
Published online: 22 Jul 2016 *

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