Want to build an HHO fuel cell but not sure what type to choose? While most cells will generate some HHO, there can be an enormous difference in output from one to another – so it’s important to get the design right.
HHO is created by electrolysis: electricity conducted through water between two charged poles, or electrodes. The substance and form of the electrodes can vary, although they must be made of an inert metal, preferably stainless steel. The four basic electrode designs are described below.
The type of electrode that is easiest to build – and one of the most popular – consists of two or more wires wrapped in a spiral around a support mechanism. Unfortunately it is also the least effective, as so little metal (maybe a few square inches) is actually exposed. The the amount of HHO gas that can be generated directly relates to the surface area of the electrodes.
The second kind of electrode is made out of steel mesh, similar to the mesh you would use for screen doors or windows. The mesh is cut to fit into a container and stacked in various configurations. Each layer must be insulated from the others – if the layers contact each other, they can cause a short. This type of electrolyzer makes a lot of bubbles but is not very impressive in terms of the density of HHO gas produced.
Plate designs are the most widely used and the most efficient. Because of their large surface area, plate electrodes have the highest conversion of energy to Hydrogen and Oxygen, while wasting very little energy in the form of heat. High quality stainless steel plates are corrosion resistant, which is why they are used in industry to generate vast quantities of gas.
Tube designs are second in efficiency to metal plates. The tubes may be placed in a ring Stanley Meyer-style or stacked concentrically, one onside another. The problem with tubes is that their maximum usable area is going to be limited by the smallest tube. Tubes, along with spirals, are also prone to overheating.
Those are the four main types of electrodes. There are also two different styles of fuel cells: wet and dry. In a wet cell, the plate stack (or other type of electrode) is completely immersed in electrolyte solution. In a dry cell, the stack is not immersed. Instead, the solution is housed in an external reservoir and gravity fed through holes that have been drilled into the plates.
Both styles of cell have good and bad design points. Recently a third style of cell been developed that seems to combine the best aspects of wet and dry cells. Generally speaking, in this hybrid type the cell container serves as the reservoir but the electrolyte remains below the top of the plates.
As you can see there is no definitive version of an HHO fuel cell, which means it can be difficult knowing exactly which type to build. Using plans that have been developed by experts and tested over and over again can certainly save a lot of time. The most important thing is to just get started, and reap the amazing benefits than an HHO cell can provide.