Sangmin Ji, a Ph.D. candidate at Gyeongsang National University, wins the Excellence Award (Technology category) of the “Future Ocean Science and Technology Award”

▸Design and evaluation of a boil-off-gas reliquefaction system for ammonia carriers transporting the eco-friendly marine fuel ammonia

▸Demonstrated energy efficiency and economic viability through refrigeration-cycle optimization… contributing to carbon-neutral shipping technology

Sangmin Ji, a Ph.D. candidate in Professor Jinkwang Lee’s lab in the Department of Mechanical Convergence Engineering, College of Engineering, Gyeongsang National University (GNU; President Jinhoe Kwon), received the Excellence Award (Technology category) of the “Future Ocean Science and Technology Award” at the “2026 Joint Conference of the Korean Society of Ocean Engineers.”

The “Future Ocean Science and Technology Award,” established by the Ministry of Oceans and Fisheries and the Council of Korean Marine Science and Technology Societies to identify and commend outstanding graduate-student presenters in marine science and technology and to support the growth of early-career researchers, is conferred at the nation’s largest marine science and technology academic event, jointly organized by multiple societies including the Korean Society of Ocean Engineers.

This research outcome was published in the international journal in refrigeration and thermal engineering, the International Journal of Refrigeration (SCIE), volume 170 (2025), under the title “Design and thermodynamic evaluation of onboard NH3 BOG re-liquefaction systems for ocean-going NH3 carriers.”

Ph.D. candidate Sangmin Ji and Professor Jinkwang Lee served as lead authors, with co-authors Master’s student Sejun Park (Gyeongsang National University), Dr. Younggyun Seo (Korea Research Institute of Ships and Ocean Engineering, KRISO), and Dr. Minsu Choi (KAIST).

He earned the honor for research that designed and evaluated an onboard reliquefaction system that returns naturally vaporized boil-off gas (BOG) to liquid on an 88,000 m3-class Very Large Ammonia Carrier (VLAC) transporting ammonia (NH3), an eco-friendly carbon-free marine fuel.

A key feature of this study is the quantitative comparison of two approaches—the vapor-compression refrigeration cycle and the Linde–Hampson refrigeration cycle—from thermodynamic and economic perspectives. Using a hybrid optimization method combining SQP and BOX algorithms, Ji minimized the specific energy consumption (SEC) required to reliquefy a unit of BOG. Economic analysis based on system life-cycle cost (LCC) identified the Linde–Hampson system as superior in both energy efficiency and economic performance. These findings are expected to serve as foundational data for the development of ammonia carriers and the realization of carbon-neutral shipping.

Advisor Professor Jinkwang Lee said, “This award is a valuable result recognizing our lab’s capabilities in BOG reliquefaction and refrigeration-cycle optimization, core technologies for ammonia carriers,” and added, “I expect Ph.D. candidate Sangmin Ji, who excellently carried out a difficult research process, to continue to grow into a key talent contributing to the advancement of eco-friendly ship technologies.”

This award is regarded as recognition of research excellence in the design and optimization of refrigeration cycles for efficiently reliquefying boil-off gas (BOG) generated during the marine transport of ammonia carriers, and as a demonstration of research competitiveness in the dissemination of eco-friendly carbon-free marine fuels and in ammonia marine transport technologies.

Photo caption: Sangmin Ji, Ph.D. candidate, Department of Mechanical Convergence Engineering, College of Engineering, Gyeongsang National University

This page is provided via AI machine translation. Some inaccuracies may occur. For official purposes, please refer to the original document.