The maritime sector is facing increasing pressure to improve energy efficiency and reduce greenhouse gas emissions under the International Maritime Organization (IMO) strategy and, in parallel, regional regulatory frameworks. A significant share of the fuel energy converted onboard ships is rejected as waste heat through exhaust gases and cooling circuits. Waste Heat Recovery Systems (WHRS) represent an effective pathway to reduce fuel consumption; how- ever, their potential is often limited by the temporal mismatch between waste heat availability and onboard thermal demand. In this context, Thermal Energy Storage (TES) can act as a buffer to decouple heat recovery from heat utilization.