Wave-Actuated RO Desalination with Flow Smoothing
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Solution Overview
Problem
Current reverse osmosis desalination systems using wave energy face challenges such as intermittent energy supply due to cyclical wave patterns, high complexity and cost, and maintenance issues due to the need for multiple components and reliance on external energy sources, particularly in remote areas.
Innovation Solution
A wave-actuated system that integrates a reverse osmosis subsystem with a self-sustaining energy converter, featuring a unidirectional hydraulic cylinder and a pre-filtration subsystem with automated backwash capabilities, to stabilize pressure and flow, reducing the number of components and enabling efficient desalination with minimal maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If wave energy is used to power reverse osmosis desalination systems, then energy consumption is reduced and sustainability is improved, but the intermittent nature of wave energy causes unstable pressure and flow
Solution Approach 1:
The system employs dynamic adjustment mechanisms including variable frequency drives on pumps and variable speed motors in RO units to adapt to fluctuating wave energy input. The hydraulic system dynamically balances pressure between different RO units, allowing the system to maintain stable operation despite intermittent energy supply from waves.
Solution Approach 2:
The system changes operational parameters such as pump speed, motor speed, and pressure distribution across different RO units based on available wave energy. By dynamically adjusting these parameters, the system optimizes desalination efficiency while adapting to the intermittent nature of wave power.
2Adaptability or versatility
If multiple components are used in wave-actuated desalination systems, then functionality is improved, but system complexity and cost increase
Solution Approach 1:
The system merges multiple functions into integrated units. Wave energy converters are directly coupled with hydraulic systems that simultaneously perform pumping and pressure regulation. Multiple RO units share common hydraulic infrastructure and control systems, reducing the total number of independent components while maintaining full functionality.
Solution Approach 2:
Hydraulic components are designed to perform multiple functions: the hydraulic motor drives RO units while also serving as a pressure regulator; the hydraulic system provides both power transmission and flow distribution. This multi-functionality reduces the number of dedicated components needed.
3Ease of operation
If wave-actuated systems are deployed in remote areas, then accessibility to fresh water is improved, but maintenance difficulty increases due to remote location
Solution Approach 1:
The system incorporates self-diagnostic capabilities and automated monitoring that detect issues before they become critical. Self-backwash functionality automatically cleans filters without external intervention. These self-service features reduce the frequency and complexity of maintenance trips to remote locations.
Solution Approach 2:
Sensors and monitoring systems provide real-time feedback on system performance and component status. This early warning system allows operators to address issues remotely or plan maintenance trips more efficiently, reducing the impact of remote location on maintenance difficulty.
4Reliability
If external energy sources like diesel generators are used, then reliable power supply is achieved, but operational cost and dependence on external supplies increase
Solution Approach 1:
The system uses wave energy to directly drive hydraulic motors that power the RO desalination process, making the system self-sufficient. No external diesel fuel supply is needed, eliminating ongoing operational costs associated with fuel purchase and delivery to remote locations.
Solution Approach 2:
The system replaces the thermal-mechanical energy conversion of diesel generators with direct mechanical energy capture from waves through hydraulic systems. This substitution eliminates the need for fuel combustion and associated operational costs while maintaining power supply reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves efficient desalination by linearizing pressure and flow, reducing the need for multiple RO membranes, lowering operational costs, and simplifying maintenance, while being lightweight and easily installable, suitable for remote areas with reduced energy consumption.
Implementation Method 1
The process works by pumping seawater at high pressure inside semi-permeate membranes. When the pressure is higher than the osmotic pressure of the fluid, desalted water is produced.
Implementation Method 2
When the pressure is higher than the osmotic pressure of the fluid, desalted water is produced.
Implementation Method 3
A wave-actuated system that integrates a reverse osmosis subsystem with a self-sustaining energy converter, featuring a unidirectional hydraulic cylinder
Implementation Method 4
seawater is pumped from the sea by a low pressure pump 12 though filters 14
Data Source
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AI summary
A wave-actuated system for desalination of water by reverse osmosis (RO) having a wave energy converter (WEC) subsystem and a RO desalination subsystem is disclosed. The WEC subsystem has a float, a reaction member, and a hydraulic cylinder connected between the float and the reaction member and defining first and second variable volume chambers The RO desalination subsystem has a RO cell containing a RO membrane and a flow smoothing device (FSD). During a first stroke of the WEC subsystem: the float moves in a first direction; and seawater is supplied from the first variable volume chamber to the RO cell and to the FSD. During a second stroke of the WEC subsystem: the float moves in a second direction; seawater is supplied from a seawater intake to the first variable volume chamber; and seawater is supplied from the FSD to the RO cell.