Multi-Stage Power Control for Solar EDR Desalination
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Solution Overview
Problem
Desalination systems face challenges in efficiently utilizing time-varying renewable energy sources like solar power, leading to the need for oversized equipment or energy storage, which is costly and impractical in resource-constrained regions.
Innovation Solution
A control system that dynamically allocates time-varying electric power between multiple processes, including electrochemical desalination and pumping, using real-time and predictive controllers to maximize instantaneous and future production, minimizing the need for oversized equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oversized photovoltaic panels are used to produce sufficient electric power during morning and evening time periods, then sufficient electric power availability is improved, but system cost increases
Solution Approach 1:
The EDR system operates with dynamically adjustable voltage and flow rate that adapt to real-time solar power availability. The controller continuously modifies operating parameters to match the time-varying photovoltaic output, enabling the system to function effectively with standard-sized panels rather than requiring oversized equipment.
Solution Approach 2:
The system changes its operating parameters (voltage, current, flow rate) based on the time of day and solar irradiance levels. By adjusting these parameters dynamically, the system optimizes power utilization across different solar conditions without requiring excess generating capacity.
2Reliability
If large batteries are used to store electric energy produced during mid-day for use during periods of low or no solar irradiance, then sufficient electric power availability is improved, but system cost increases
Solution Approach 1:
The system employs dynamic control of voltage and flow rate to adapt to solar power fluctuations throughout the day. This dynamic operation eliminates the need for large battery storage by continuously optimizing power usage to match solar availability, thereby reducing reliability concerns without increasing system cost.
Solution Approach 2:
The EDR system maintains continuous operation during daylight hours by dynamically adjusting parameters to utilize available solar power. This continuous adaptive operation ensures productive use of solar energy without interruption, eliminating the need for battery storage to bridge gaps between generation and consumption.
3Productivity
If the voltage applied to the membranes is increased to increase the production rate of desalinated water, then productivity is improved, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts voltage and flow rate based on real-time solar power availability and system conditions. This dynamic optimization ensures that voltage is increased only when solar power is abundant, maximizing productivity during peak solar periods while avoiding excessive energy consumption during lower irradiance periods.
Solution Approach 2:
The controller uses feedback from solar power measurements and system performance to continuously optimize voltage and flow rate settings. This feedback mechanism ensures that voltage increases translate to proportional productivity gains without wasteful energy consumption, maintaining optimal efficiency across varying operating conditions.
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 effectively utilizes renewable energy by optimizing power allocation, reducing the required battery capacity by up to 90% and enhancing energy efficiency, making it cost-effective for resource-constrained areas.
Implementation Method 1
Solar-powered photovoltaic panels and wind mill electric generators provide logical power sources for EDR systems
Implementation Method 2
EDR is an electrically driven desalination process, in which ions move across ion exchange membranes
Data Source
AI summary
A control system includes one or more levels of control of power and energy. At one level, a first controller optimally divides power between two or more processes, to maximize instantaneous production, for a given amount of currently available power. In the case of EDR desalination, electric power is optimally divided between ion exchange membranes and pumps to maximize instantaneous production of desalinated water for a given amount of available electric power. Optionally, at another level, a second controller divides time-varying power between the processes fed by the first level controller and an energy storage unit, based on a prediction of future power availability and a function. In the EDR case, power generated by a photovoltaic array is divided between the EDR desalination process and a battery, based on a prediction of future PV power availability and a function, to ensure reliable water production in the future.