Experimental investigation of a cryogenic-enhanced ORC for battery and fuel-cell waste-heat recovery in marine hybrid propulsion

“Abstract

This study experimentally investigates the recovery of ultra-low-grade waste heat from marine hybrid propulsion systems using a micro-scale cryogenic-enhanced ORC. The proposed system integrates battery and PEMFC cooling-water loops as heat sources, while cryogenic cold energy representative of liquid-hydrogen (LH₂) regasification is utilised as the heat sink. Battery thermal-management experiments were conducted on a representative lithium-ion battery module at coolant inlet temperatures of 15 °C and flow rates of 0.75–3 L/min. Measured discharge rates of 0.5C to 3C showed that battery waste heat alone provides only a limited temperature driving force for power recovery. A dedicated cryogenic-enhanced ORC test rig was then evaluated over 52 steady-state operating points by varying the heat-source water inlet temperature from 15 to 75 °C at a constant flow rate of 12 L/min and adjusting the R410A working-fluid mass flow rate between 10 and 16 g/s, with a fixed liquid-nitrogen flow rate of 40 g/s. When only battery waste heat (≤30 °C) was available, the maximum expander power and net power were approximately 266 W and 156 W, respectively, with a cycle isentropic efficiency of about 2.6%. In contrast, the availability of higher-temperature PEMFC waste heat increased the maximum expander power to approximately 645 W and the net power to about 510 W, with a maximum cycle isentropic efficiency of 7.3% at 75 °C. The results demonstrate that integrating PEMFC waste heat with cryogenic cold energy enables effective waste-heat-to-power conversion in LH₂-based marine hybrid propulsion systems, whereas battery waste heat alone yields limited performance.”

 

The full article is accessible via:

https://doi.org/10.1016/j.enconman.2026.121665

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