Shipboard applications of heat pumps and thermal energy storage under dual carbon targets: Opportunities and challenges

In response to China's carbon peaking and carbon neutrality goals—commonly referred to as the “dual carbon” strategy—and the International Maritime Organization's emission reduction targets, shipboard energy systems face the dual challenge of high carbon emissions and low efficiency. Traditional thermal management technologies struggle to adapt to the dynamic marine environment, characterized by fluctuating temperatures and variable energy demands. The integration of heat pumps and phase change materials (PCMs) presents a promising solution, offering efficient heat recovery and thermal storage. However, current heat pump systems remain constrained by large temperature variations, limited space, and stability issues under marine conditions. Among PCMs, paraffin-based materials are the most widely used due to their thermal stability, safety, and cost-effectiveness, despite their low thermal conductivity. Among system configurations, embedded Heat Pump–PCM systems show significant advantages in space-limited environments such as ships, while parallel configurations provide greater flexibility for variable load conditions. Through case studies in waste heat recovery, battery thermal management, and cabin air conditioning, the system's energy-saving potential and feasibility are evaluated. A comprehensive performance assessment framework is proposed, incorporating coefficient of performance, thermal storage efficiency, and life cycle cost, providing technical insights for the development of green, efficient, and intelligent ship energy systems.