TS Golden Bear in Vallejo, California (California State University Maritime Academy photo)

Waste Heat Recovery on the Training Ship Golden Bear

By Eric Hahn, Faculty Associate – Research, Energy Academic Group

NAVAL POSTGRADUATE SCHOOL (NPS) faculty made a recent visit to California State University Maritime Academy, Cal Maritime, to research waste heat recovery (WHR) for energy efficiency on surface ships.

Energy Efficiency and Navy Combat Power

The capacity to integrate future high-power weapons demands ship energy systems that support the maximum operational reach and lethality that warfighters can apply. Common renewable energy technologies are not feasible due to spatial constraints and survivability considerations. However, WHR system retrofits have shown potential.

Why WHR?

There are theoretical limits on the performance of heat engines. “Heat engines” receive heat (often from fuel combustion), convert some heat to work (usually in the form of a rotating shaft), then reject the remaining heat to the environment. Theoretical limits on thermal efficiency establish that a heat engine will not convert all received heat into work. However, the rejected or “waste” heat can be recovered for another “low end” heat engine to receive.

WHR Research and Analysis

The recent tour of Cal Maritime's 500-foot Training Ship Golden Bear featured its Organic Rankine Cycle (ORC) WHR system. NPS professor Andres Larraza leads research and analysis efforts analyzing WHR system approaches, like ORC and others. The objective: determine the best options, feasibility, and barriers to improved operational capabilities and implementation. Professor Larraza and LT Denzel Reina, USN—a graduate student studying mechanical engineering at NPS—are considering how WHR systems could be included in future ship design as well as in retrofit to existing ships. Alternative WHR systems, including thermoelectric and thermoacoustics technologies, are also being studied.

LEARN MORE
Email Eric Hahn at ehahn1@nps.edu