This invention introduces a self-sustaining desalination system powered directly by tidal energy. By coupling a hydrokinetic turbine to a centrifugal reverse osmosis module, it converts tidal motion into high-pressure water flow without electricity, achieving efficient, low-cost freshwater production for off-grid coastal and island regions.
Access to clean water remains a challenge for off-grid and coastal communities where electricity infrastructure is limited or expensive. Conventional seawater reverse osmosis (RO) systems depend on powerful electric pumps and grid power, while renewable-powered alternatives typically rely on energy conversion from mechanical to electrical power, resulting in efficiency losses. Existing closed-circuit RO designs suffer additional inefficiencies due to brine mixing and pressure losses. A direct, efficient, and modular desalination system that eliminates electrical conversion is needed to provide sustainable freshwater production in remote and resource-limited areas.
This invention directly couples a tidal turbine to a centrifugal reverse osmosis (CRO) system via a mechanical gearbox, eliminating the need for electrical power conversion. The tidal turbine drives a high-speed cylindrical membrane module that generates radial pressure for desalination. A small pre-pump raises feedwater pressure to the osmotic threshold, after which the CRO stage provides the remaining 20–30 bar required for seawater desalination. The design leverages centrifugal shear to reduce membrane fouling and achieves water recovery rates above 50% while minimizing energy losses and system complexity. Computational simulations and pilot-scale tests demonstrate stable turbine–membrane coupling and near-thermodynamic-limit desalination efficiency.
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• Direct mechanical coupling eliminates energy conversion losses
• Achieves near-thermodynamic-limit desalination efficiency
• Continuous, predictable operation using tidal flow without energy storage
• Reduces fouling and scaling via centrifugal shear and short retentate channels
• Delivers high water recovery (≈50%) in a compact modular unit
• Reduces capital and maintenance costs by eliminating electrical systems
• Scalable for diverse coastal and maritime installations
• Freshwater supply for remote coastal and island communities
• On-board desalination for offshore platforms and maritime vessels
• Sustainable aquaculture and coastal industry water treatment
• Process water generation for coastal hydrogen and renewable energy plants
• Rapid-response desalination for disaster relief and emergency deployments
• US Provisional Patent Application 63/541,849 – Filed September 30, 2023
• US Utility Patent Application 18/900,088 – Filed September 27, 2024, Published US 2025/0108331 A1 (Filed)
Lab validation and pilot prototype testing underway – Computational modeling and small-scale experiments demonstrate turbine–CRO coupling efficiency and stable performance. TRL ~4–5.
This technology is available for licensing.
Strong potential for coastal infrastructure developers, NGOs, and renewable desalination system integrators seeking scalable, off-grid, and low-cost water purification technologies.
Simulation data, prototype design parameters, and preliminary field performance data available upon request.