Reverse Electrodialysis Cell With Thermal Salinity Regeneration

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Solution Overview

Problem

Existing reverse electrodialysis systems face limitations in practical location constraints due to the need for continuous salt and fresh water sources and are susceptible to contamination, while closed-loop systems require energy-intensive salinity gradient regeneration.

Innovation Solution

A reverse-electrodialysis system with a regeneration system that uses a heat source to transfer thermal energy, precipitate and reintroduce salt into the saline solutions, maintaining the salinity gradient and generating electrical power through controlled membrane permeability and heat management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If open-loop RED battery is used, then continuous salt and fresh water sources are required, but this limits practical locations and increases contamination risk

Engineering Contradiction:

Improvelocation flexibilityVSAvoidcontamination risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system uses itself to regenerate the salinity gradient by precipitating salt from the dilute solution and reintroducing it to the concentrated solution, eliminating the need for external water sources and reducing contamination risk

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system changes the temperature parameter of the dilute solution to precipitate salt, then changes it back to dissolve the precipitated salt into the concentrated solution, thereby regenerating the salinity gradient without external water sources

Inventive Principle:

Principle #35Parameter changes

2Reliability

If closed-loop RED cell is used, then ongoing regeneration of salinity difference is required, but this is energy intensive and inefficient

Engineering Contradiction:

Improvecontinuous operationVSAvoidregeneration energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system utilizes phase transition of salt between dissolved and precipitated states by controlling solution temperature, enabling regeneration of the salinity gradient without energy-intensive processes

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The system regens the salinity gradient using the concentrated solution itself as the regeneration medium, eliminating the need for external energy inputs typically required for salt rejection in closed-loop systems

Inventive Principle:

Principle #25Self-service

3Quantity of substance

If heat pump is used to precipitate salt from dilute solution, then thermal energy is removed, but this requires energy input for cooling

Engineering Contradiction:

Improvesalt precipitationVSAvoidheat pump energy consumption

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The system combines the cooling function with the salt precipitation function into a single process, where removing thermal energy from the dilute solution simultaneously achieves both cooling and salt precipitation without requiring separate energy inputs

Inventive Principle:

Principle #5Merging (Combining)

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

This approach enables efficient and continuous generation of electrical power from thermal energy, reducing the need for continuous water sources and minimizing contamination risks, while optimizing energy use and system efficiency.

Implementation Method 1

remove (by the heat pump) thermal energy from the dilute saline solution, causing the dilute saline solution to precipitate a salt

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Implementation Method 2

transfer thermal energy to the concentrated saline solution, causing the precipitated salt to dissolve in the concentrated saline solution

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 3

the first membrane selectively allows cations to migrate toward the cathode and the second membrane selectively allows anions to migrate toward the anode, causing a voltage difference between the cathode and the anode

Methodology Applied

Scientific EffectIon migration: Electrophoresis

Implementation Method 4

passing a salt solution and fresh water through a stack of alternating cation and anion exchange membranes. The chemical potential difference between the salt and fresh water generates a voltage over each membrane

Methodology Applied

Scientific EffectOsmosis: Osmosis

Data Source

PatentUS20250023082A1Reverse electrodialysis cell and methods of use thereof

Publication Date: 2025.01.16 NANA RAHUL S

AI summary

A method of generating electrical power or hydrogen from thermal energy is disclosed. The method includes separating, by a selectively permeable membrane, a first saline solution from a second saline solution, receiving, by the first saline solution and/or the second saline solution, thermal energy from a heat source, and mixing the first saline solution and the second saline solution in a controlled manner, capturing at least some salinity-gradient energy as electrical power as the salinity difference between the first saline solution and the second saline solution decreases. The method further includes transferring, by a heat pump, thermal energy from the first saline solution to the second saline solution, causing the salinity difference between the first saline solution and the second saline solution to increase.