Comparison

Comparison Standard MONO-cell electrolyser and the patented Spirig® MULTI-cell electrolyser
Why is the worldwide patented multiple-electrolysis cell design far superior to the old known mono-cell electrolysers?

Electrolysis follows the basic electro-physical law of Faraday. Regardless of the nature of the electrode materials or electrolytic fluids used it says: To produce 100 litres of a mixture of hydrogen and oxygen a current of 165 Ampere DC must flow for one hour through the electrolytic cell from the positive to the negative electrode and it decomposes 54,6 gramm of water.


The dc voltage across the cell to force the 165 Amp through the cell now depends entirely on the electrode material, electrolytic fluid composition and on the geometric size of the cell. A high temperature level of the electrolyte fluid exponentially increases the electrode corrosion effects. The surface area and the distance between the two electrodes with the electrolytic fluid in between defines the cell resistance. The electrolytic fluid is compared with the material of the electrode a bad conductor.

The electrolyte will heat up by the high electrolysis current of e.g. 165 Amp rapidely and start boiling which as a consequence feeds high humidity and electrolytic fluid contaminations into the hydrogen-flow.
Designers have tried to optimize this basic single cell design, but the most negative point of the very high dc current (165 amp per 100 litres/hour) needed to get a technically feasible and acceptable gas output could not be eliminated as it is a basic physics law in single cell designs. If the necessary dc current could be cut in half or even to one tenth then the heat losses created in the electrolyte fluid would be reduced by a factor 4 or even 100! Heat losses increase with the square (power of two) of the current. Often mono-cells are termed as water cookers with gas output.

The patented multiple electrolysis cell design of Spirig reduces the high electrolysis currents by a factor of ten or more, but increases the number of cells by that factor. This sounds like logical solution, but the complexity of such an arrangement, if realized by ordinary pot cell design (pot + cover with electrodes) would be too complicated and too expensive. The patented Spirig multiple-cell design is an elegant design allowing multiple cell combinations with a minimum of seals and a minimal complexity of the required gas volumes and electric connections to pass the currents from one cell to the next without creating excessive by-pass (stray) currents lost for gas production.

Comparison

  Multi-Cell (Spirflame®) Single-Cell
Electric Energy Consumption Low High. For the same gas volume the energy consumption of a single-cell design is about 3-times more than the patented Spirflame®
Number of Electroysis Cells 11, 22, 55 or over 100 cells. This depends on the requested maximal gas rate of the specific Spirflame® model. Each individual cell can produce maximal 10 liter gas per hour. 1 "pot" cell
Electrolysis Current 15 Amp DC maximal 165 Amp DC to produce 100 liter of gas per hour
Electrolysis Voltage Each cell between 1.8 to 2.2 V DC total cell stack dc voltage is number of cells multiplied by single cell dc voltage. Cell needs between 3 to 7 V DC to "squeeze" the very high dc current level through the electrolyte fluid.
Heat Losses Low, because there is only a small max. 15 ampere dc current Very high, because of the very high dc current needed. A 10-fold increase in dc current means a 10x10=100-fold increase in heat losses. Losses increase to the power of 2 (square) with the current intensity.
Energy Efficiency High, because of low heat losses Low, because of high heat losses.
Gas Rate Potential 500 liter/hour per generator module or higher without need for water cooling Around 70 liter/hour maximal gas rate are a realistic limit for non-continous operated single-cell generators.
Continous Operation 100% duty industrial full power operation was the design target and is met by the patented principle. Permanent operation at full power output causes electrolyte to start boiling, contaminate the gas with caustic pottash aerosols and high water vapour content.
Operation Temperature of Electrolyte Fluid Safe level of +45 °C as demanded by the German Industry Norm (DIN) 32508 is not exceeded Will pass without extra artificial water cooling the critical temperature level of 45 °C within approx 30 minutes.
Quality of Gas Clean mixture of hydrogen and oxygen with minimal contaminations removable for automated microflame applications by special disposable gas filters. Corrosive electrolyte aerosols (fog) and humidity present in gas. Can be filtered-off, but consumption of filters costly.
Flame Flash-Back Filters The clean gas does not influence such protective devices, eg stainless steel mesh filters. Pores of filter cartridges tend to soon clog.
Overpressure Safety Protection Various sequenced electronic and electric excess pressure safety guards would shut-off the ac energy supply in a worst case condition to the system permanently and would need a manual re-set. Various grades of safety protections
also advisable but the sensors might
be influenced by the corrosive fogs
Other Safety Protections The housing base is designed as a fluid sump to trap spills of corrosive fluid in the extreme rare case of a leak. No such leak protection known.
Materials All parts are made in high quality stainless steel design to avoid any risk of chemical attacks. Stainless steel also used.