… than a wet-cell? Not automatically.
Efficiency depends largely on the design of the electrolyzer, power supply, electrolyte, electrolyte density, electrolyte temperature, etc. These design parameters are largely independent of whether an electrolyzer is a ‘wet-cell’ or a ‘dry-cell’.
Efficient designs are optimized for the application. There are far too many electrolyzer design variables to discuss them all and the ramifications of each here. However, if building electrolyzers, keep in mind:
General Efficiency Considerations:
1. Don’t assume that any particular electrolyte or concentration is the best. Test each electrolyte with various concentrations until you find the optimum for your electrolyzer design. The main two electrolytes are NaOH (sodium hydroxide) and KOH (potassium hydroxide). We prefer NaOH because in our electrolyzer designs NaOH is 30% more efficient than KOH.
2. Wide plates tend to be more efficient than tall ones. You need to remove the bubbles from the plates as fast as possible, because wherever there is a bubble, there is inactive plate area. That is the one advantage of the wire-wound design of the ‘jar’ cell from Water4Gas.
3. Electrolyzers tend to run more efficiently when hot (reduces electrolyte resistance). There will be an optimum temperature for any given electrolyzer, electrolyte and electrolyte density; it’s best to be able to control the temperature.
4. Because electrolyte lowers resistance when the temperature rises, you need to deal with an effect I call ‘amperage-runaway’. Learn about efficient ways to control amperage-runaway (see HyZor Technology book). MOST power supply designs ‘out there’ are using technologies we abandonded decades ago.
5. It’s VITAL to use an electrolyzer design that does not allow electricity to ‘bypass’ the plates.This was never an issue in the original Faraday cell designs because the electrolyzer was just ONE cell.But in the various ‘series-cell’ designs, it becomes an issue. If electricity bypasses the plates (through the electrolyte or electrolyte foam), then you lose gas production (and wattage efficiency). So you want to ‘force’ the electricity to go through the cell/plate/cell/plate, etc. by making that ‘path’ less resistance.Again, this consideration is specific to series-cells, it doesn’t matter if it’s ‘wet’ or ‘dry’ design.
Dry-cell specific Considerations:If you do use a ‘remote reservoir’, here are a couple of design tips to raise efficiency.
1. Designs with pumps tend to eliminate the ‘surging’ that happens in convection cells. Be sure to use a pump large enough to remove the bubbles from the cells ASAP. If this is done, excellent results can be achieved with narrow plate spacing. Of course this also means a larger reservoir, because the bubbles need to be removed from the fluid before re-entering the electrolyzer. Perhaps a vortex could help.
2. Design for even flow of electrolyte through all cells, unrestricted exit of the liquid/gas mixture from the top of the cell-pack (like these people did, click) to the reservoir and DO NOT allow the electrolyte from any cell to mix with any other cell’s electrolyte until the electrolyte is well away from the electrolyzer (to prevent electricity from bypassing cells).
For the world’s most efficient and practical (as far as we know) electrolyzer designs, read our Brown’s Gas books 1 and 2, the HyZor Technology book and watch Brown’s Gas videos 2 and 3. Then ask us about Pressure Relief tubes, Gridplates and the Barbell neutralzone.
Our HyZor, as currently designed, could be considered to be a compact hybrid ‘wet/dry- cell’ wherein the bulk of the electrolyte is separate from the (dual) electrolyzers.
I have not yet seen a dry-cell or wet-cell that can match or exceed the efficiencies of our current HyZor design, which have achieved 20+ MMW.
Q ~ Is a dry-cell more efficient?
… than a wet-cell? Not automatically.