Exergy analysis on non-catalyzed partial oxidation reforming using homogeneous charge compression ignition engine in a solid oxide fuel cell system Sechul Oh, Han Ho Song * Department of Mechanical & Aerospace Engineering, Seoul National University, Gwanak-gu, Seoul, South Korea article info Article history: Received 14 March 2017 Received in revised form 23 November 2017 Accepted 16 December 2017 Available online xxx Keywords: Exergy HCCI engine SOFC Reformer Comparison Topping cycle abstract Based on the recent improvements in high-temperature fuel cells, distributed power generation fuel cell system of small scale (~hundreds kilowatts) has been widely investigated. To improve the system efficiency, most developments focused on the fuel cell stack, but little was paid attention to the intrinsic exergy destructions at the other parts of a typical configuration. The main objective of this study is to investigate a feasibility of reducing the exergy destruction in the reforming process of fuel cell system, by using a homogeneous charge compression ignition (HCCI) engine as a replacement of existing reforming subsystems, i.e. steam methane reforming (SMR), partial oxidation (POX), or autothermal reforming (ATR), in a solid oxide fuel cell (SOFC) system. To do this, parametric studies with exergy analysis were conducted by using in-house 1-D SOFC and 0-D HCCI simulation models. In results, due to the work pro- duction from HCCI reforming engine in addition to the work of the fuel stack, it is demonstrated that HCCI-SOFC system has higher system efficiency than partial oxidation (POX) and autothermal reforming (ATR) systems, which use similar partial oxidation reaction for reformer operation. Furthermore, because of no requirement for catalyst, the HCCI system demonstrates wider operating range than that of POX and ATR systems. When compared to the steam methane reforming (SMR)-SOFC system, the HCCI-SOFC system has the lower total work but slightly higher exergetic system efficiency, mainly caused by large amount of heat exergy needed to operate endo- thermic reforming process in the SMR process. Based on our simulation data, the exergetic efficiency of the HCCI-SOFC system shows 6.0%, 2.1% and 0.4% higher than POX, ATR and SMR systems at the highest efficiency points of each strategy, while 5.5%, 5.8% and 3.8% higher than POX, ATR and SMR systems at 99% methane con- version points in each reformer, respectively. © 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. * Corresponding author. E-mail address: hhsong@snu.ac.kr (H.H. Song). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (2017) 1 e18 https://doi.org/10.1016/j.ijhydene.2017.12.090 0360-3199/© 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Oh S, Song HH, Exergy analysis on non-catalyzed partial oxidation reforming using homogeneous charge compression ignition engine in a solid oxide fuel cell system, International Journal of Hydrogen Energy (2017), https://doi.org/ 10.1016/j.ijhydene.2017.12.090