Thermal Energy Consumption of a SMES Cooled by Liquid Hydrogen in a Fuel Cell-Battery System

Abstract

The use of liquid hydrogen ($\text{LH}_{2}$) in fuel cell-powered ships has been studied. However, directly heating $\text{LH}_{2}$ to the operating temperature of the fuel cell requires considerable energy consumption. The heat generated from AC losses in superconducting magnetic energy storage (SMES) during operation must be promptly removed by the refrigeration system. $\text{LH}_{2}$ is considered a promising superconducting refrigeration medium. Therefore, this paper establishes a $\text{LH}_{2}$ -fuel cell-SMES electric-thermal integrated system, wherein $\text{LH}_{2}$ is utilized for SMES refrigeration and as a fuel supply for the fuel cell. The system's refrigeration and fuel supply demands were determined by calculating the SMES AC losses and the fuel cell hydrogen consumption under three different energy management strategies. The preliminary heating of $\text{LH}_{2}$ is achieved through SMES refrigeration, followed by expansion work and heat generated by the fuel cell to meet the operational conditions required by the fuel cell. Results indicate that under the equivalent consumption minimization strategy (ECMS), the fuel cell achieves the lowest hydrogen consumption, albeit with the highest overall system energy consumption. The AC loss optimization Strategy A minimizes SMES AC losses, reducing the load on the refrigeration system but increasing hydrogen consumption. Strategy B optimally balances SMES AC losses and fuel cell hydrogen consumption, resulting in fuel cell hydrogen consumption nearly identical to that under ECMS, significantly lower than under Strategy A, and with overall system energy consumption lower than that under ECMS.