Johnson thermo-electrochemical converter
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Solution Overview
Problem
Johnson Thermo-Electrochemical Converter (JTEC) systems face reliability issues due to pressure loss caused by molecular hydrogen diffusion across membranes, limiting their operational efficiency and utility.
Innovation Solution
The implementation of additional Membrane Electrode Assembly (MEA) cells on the low temperature side and a controller to monitor and compensate for pressure differential losses, ensuring continuous hydrogen circulation and maintaining the operating pressure differential by pumping additional hydrogen when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Membrane Electrode Assembly cells are used to convert heat energy to electrical energy, then power generation efficiency is improved, but pressure loss occurs due to molecular hydrogen diffusion across membranes
Solution Approach 1:
The patent converts the harmful effect of hydrogen diffusion (which causes pressure loss) into a beneficial effect by using the diffusion-driven potential difference to drive electrical current through an external load. The diffusion that was previously a source of inefficiency becomes the driving force for power generation in the electrochemical cell.
Solution Approach 2:
The patent implements a feedback mechanism where the pressure differential caused by hydrogen diffusion is continuously monitored and used to regulate the electrochemical reactions. The system adjusts the electrical current and heat input to maintain optimal pressure differential, ensuring that the diffusion-driven pressure loss is converted into maximum electrical power while preventing excessive pressure imbalance.
2Productivity
If additional MEA cells are added to compensate for pressure loss, then operational efficiency is maintained, but device complexity increases
Solution Approach 1:
The patent divides the electrochemical conversion system into multiple discrete Membrane Electrode Assembly cells arranged in series. Each cell independently handles a portion of the hydrogen diffusion and electrical current generation, allowing the system to compensate for pressure loss by adding or removing individual cells without redesigning the entire system. This modular approach maintains operational efficiency while managing device complexity through standardized, replaceable units.
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 solution effectively compensates for hydrogen diffusion-induced pressure loss, maintaining efficient operation and increasing the pressure differential, thereby enhancing the JTEC system's performance and extending its operational capabilities.
Implementation Method 1
a non-porous membrane capable of conducting ions of the working fluid
Implementation Method 2
porous electrodes positioned on opposite sides of the non-porous membrane that are capable of conducting electrons
Implementation Method 3
Electrical work is performed as the pressure differential across the electrolyte separator forces molten sodium atoms through the electrolyte. The sodium is ionized upon entering the electrolyte, thereby releasing electrons to the external circuit.
Implementation Method 4
Johnson Thermo-Electrochemical Converter (JTEC) systems face reliability issues due to pressure loss caused by molecular hydrogen diffusion across membranes
Data Source
Figure 1
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Figure 4~5
AI summary
An electrochemical direct heat to electricity converter having a first electrochemical cell comprising a first plurality of membrane electrode assemblies and a second electrochemical cell comprising a second plurality of membrane electrode assemblies. A controller configured to (i) monitor a pressure of the first electrochemical cell and a pressure of the second electrochemical cell, (ii) determine an extent of loss of pressure differential resulting from molecular diffusion of the working fluid through the proton conductive membranes, and (iii) actuate the first electrochemical cell to pump an additional amount of the working fluid to the high pressure side when the pressure differential drops below a predetermined value.