System Integration and Sea Trials of a Containerized Ocean Thermal Energy Conversion Prototype

Ocean Thermal Energy Conversion (OTEC) is a promising renewable energy technology for remote islands, offshore platforms, and maritime infrastructure, yet its commercialization is constrained by low cycle efficiency, high auxiliary energy demand, and the engineering challenges associated with large-scale seawater transport. This study presents the integration and experimental evaluation of a 20 kW class containerized OTEC prototype using R134a in a closed Rankine cycle. The working fluid circulates within the power-generation module, while warm surface seawater supplies the evaporator and cold deep seawater is pumped through an insulated intake pipe to the container-mounted condenser. The prototype integrates a radial-inflow turbine, stainless-steel heat exchangers, circulation pumps, and a programmable logic controller-based control system. Land-based commissioning tests, conducted at initial warm-to-cold-water temperature differences of approximately 20–25 °C, produced a peak electrical output of 11 kW in one run and approximately 5 kW for 11 min in another. Sea trials in the South China Sea recorded a peak electrical output of 16.4 kW and a cumulative power-generation duration of 4 h 47 min across separate runs. These results document the integration and short-duration operation of the prototype under offshore conditions and identify priorities for improved control and longer-duration testing.