Design optimization of supercritical carbon dioxide (s-CO2) cycles for waste heat recovery from marine engines

Md. J. Hossain, Jahedul Islam Chowdhury, Nazmiye Balta-Ozkan, Faisal Asfand, Syamimi Saadon, Mohammad Imran

Research output: Contribution to journalArticlepeer-review

Abstract

The global climate change challenge and the international commitment to reduce carbon emission can be addressed by improving energy conversion efficiency and adopting efficient waste heat recovery technologies. Supercritical carbon dioxide (s-CO2) cycles that offer a compact footprint and higher cycle efficiency are investigated in this study to utilize the waste heat of the exhaust gas from a marine diesel engine (Wärtsilä-18V50DF, 17.55 MW). Steady-state models of basic, recuperated and reheated s-CO2 Brayton cycles are developed and optimised for net work and thermal efficiency in Aspen Plus to simulate and compare their performances. Results show that the reheated cycle performs marginally better than the recuperated cycle accounting for the highest optimised net-work and thermal efficiency. For the reheated and recuperated cycle, the optimized net-work ranges from 648–2860 kW and 628–2852 kW respectively, while optimized thermal efficiency ranges are 15.2–36.3% and 14.8–35.6% respectively. Besides, an energy efficiency improvement of 6.3% is achievable when the engine is integrated with an s-CO2 waste heat recovery system which is operated by flue gas with a temperature of 373 °C and mass flow rate of 28.2 kg/s, compared to the engine without a heat recovery system.
Original languageEnglish
Pages (from-to)1-44
Number of pages44
JournalJournal of Energy Resources Technology
Early online date29 Jan 2021
DOIs
Publication statusE-pub ahead of print - 29 Jan 2021

Keywords

  • Fuel Technology
  • Mechanical Engineering
  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Geochemistry and Petrology

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