Heat-Pump RED Cell for Closed-Loop Salinity Gradient Regeneration
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Solution Overview
Problem
Existing reverse electrodialysis systems require continuous sources of salt and fresh water, are susceptible to contamination, and have inefficient regeneration processes.
Innovation Solution
A method and system that utilize a selectively permeable membrane to separate saline solutions, transfer thermal energy using a heat pump, and employ regeneration processes like salt decomposition, electrodialysis, and membrane distillation to maintain a salinity gradient in a closed system, generating electrical power and hydrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If open-loop RED battery is used, then continuous sources of salt and fresh water are required, but this limits practical locations and increases susceptibility to contamination
Solution Approach 1:
The system divides the water source into two separate streams: a fresh water source and a salt water source. These segmented streams are processed through separate filtration and treatment systems before being combined in the RED battery, allowing the system to be deployed in locations where natural salinity gradients exist without direct contamination between streams
Solution Approach 2:
The patent introduces intermediate processing systems including filtration units, pasteurization systems, and chemical treatment chambers as mediators between the natural water sources and the RED battery. These intermediaries remove contaminants while preserving the essential salinity difference, enabling deployment in previously unsuitable locations
2Reliability
If closed-loop RED cell is used, then continuous regeneration of salinity difference is required, but this is energy intensive and inefficient
Solution Approach 1:
The patent merges the RED power generation system with a separate thermal energy system. The two systems share common infrastructure including heat exchangers, pumping systems, and control mechanisms. The thermal system provides waste heat to the RED system and receives cooling demand, creating a synergistic relationship that reduces overall energy consumption for salinity gradient maintenance
Solution Approach 2:
The system uses the salinity gradient itself to drive parts of the regeneration process. The natural osmotic pressure and chemical potential differences between concentrated and dilute streams are harnessed to drive mixing processes and heat transfer operations, reducing the need for external energy input for regeneration
3Stability of the object's composition
If thermal energy is transferred to saline solutions, then salinity gradient can be maintained, but energy consumption increases
Solution Approach 1:
The system employs periodic thermal cycling where heat is applied to the concentrated salt water stream in alternating phases with cooling phases. This periodic thermal action maintains the salinity gradient by preventing excessive mixing while minimizing continuous thermal energy input. The cyclic heating and cooling creates temperature differences that drive natural convection and enhance mass transfer efficiency
Solution Approach 2:
The patent utilizes phase transitions of water (liquid-vapor-liquid) in the thermal energy transfer process. Water is evaporated from the concentrated stream, the vapor is condensed, and the phase change process is used to transfer thermal energy efficiently while maintaining the salinity difference. The latent heat of vaporization and condensation provides intense heat transfer with minimal energy loss
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 efficiently generates electrical power and hydrogen by maintaining a salinity gradient in a closed loop, reducing contamination risks and energy consumption, and enhancing regeneration efficiency.
Implementation Method 1
separating, by a selectively permeable membrane, a first saline solution from a second saline solution
Implementation Method 2
transferring, by a heat pump, thermal energy to the first saline solution and/or the second saline solution
Implementation Method 3
capturing at least some salinity-gradient energy as electrical power
Implementation Method 4
capturing at least some salinity-gradient energy as electrical power
Implementation Method 5
heating the spent dilute solution to decompose the salt to make at least one gaseous product
Implementation Method 6
generating the third saline solution by membrane distillation
Implementation Method 7
regeneration process selected from the group consisting of: salt decomposition, electrodialysis, membrane distillation, evaporation
Data Source
AI summary
A method and a system 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. The method and system may include a regeneration process, such as membrane distillation, forward osmosis, electrodialysis, salt evaporation and/or salt decomposition.