Heat Integration of Liquid Hydrogen-Fueled Hybrid Electric Ship Propulsion System

Abstract

This study introduced the methodology for integrating ethylene glycol/water mixture (GW) systems which supply heat energy to the liquid hydrogen (LH2) fuel gas supply system (FGSS), and manage the temperature conditions of the battery system. All systems were designed and simulated based on the power demand of a 2 MW class platform supply vessel assumed as the target ship. The LH2 FGSS model is based on Aspen HYSYS V11 and the cell model that makes up the battery system is implemented based on a Thevenin model with four parameters. Through three different simulation cases, the integrated GW system significantly reduced electric power consumption for the GW heater during ship operations, achieving reductions of 1.38% (Case 1), 16.29% (Case 2), and 27.52% (Case 3). The energy-saving ratio showed decreases of 1.86% (Case 1), 21.01% (Case 2), and 33.80% (Case 3) in overall energy usage within the GW system. Furthermore, an examination of the battery system's thermal management in the integrated GW system demonstrated stable cell temperature control within +/- 3 K of the target temperature, making this integration a viable solution for maintaining normal operating temperatures, despite relatively higher fluctuations compared to an independent GW system.