Hydrogen experiment

Back at the beginning of August I set up an experiment to generate hydrogen gas using a 15W solar panel, two stainless steel electrodes, some old plastic bottles, wire and water. Over the months I was baffled as to why it was not producing hydrogen and why the water had turned orange. At one point I had added salt to the water in case 15W was not sufficient with well water to produce a reaction. That had the downside of also producing chlorine gas but I figured - it's outside about 20 feet from anybody and the chlorine would dissipate to meaningless quantities if indeed any quantity worth worrying about was produced.

Nothing happened so today I dismantled the hydrogen generator and retasked the solar panel to work with my solar water heater. In the case of the solar water heater, I suspect I need to do a redesign but that's what experimentation is all about. Experimentation is more fun than anything else.

The way I had it working was two dollar store stainless steel knives with ring connectors crimped onto the wires and the wires screwed to the knives using stainless steel self-drilling bolts. I had the anode inside a small water bottle with the cap on and holes in the bottom. That was inside the bottom of a 2-liter pop bottle with the top of another wedged on to to prevent evaporation of the water. The cathode was slipped outside the water bottle but inside the pop bottle. 

The rust colour had completely baffled me when it appeared. Having dismantled the setup, the bottles were thickly coated in rust and the stainless steel knives were covered in rust too.

The stainless knives look to be actual stainless steel. Where that huge quantity of rust came from is the wire ring connectors. As can be seen, the one from the anode is completely rusted away. The one to the cathode is barely hanging on.

So, the problem seems to have been an unforeseen electrochemical reaction that transformed some of the equipment from steel to iron oxide. That is an interesting situation as I'd been building the system cheaply and simply with my only expenditure being one dollar for the stainless steel knives. I dislike spending money on experiments, preferring to use what I have.

The solution would be a total redesign. The reason I have the anode and cathode separated is so that the hydrogen can be collected separately from the oxygen. I wanted the hydrogen for other experiments and other fun. For cooking I recall seeing somebody doing a similar thing using an old propane tank full of water. They were producing Brown's gas though which is quite hazardous. Brown's gas is oxygen and hydrogen gas together. It only becomes water when the hydrogen is burned in the presence of oxygen.

One of my thoughts had been that if hydrogen could be generated and collected in large enough quantities then aside from experiements, it could be used for cooking and water heating.

The solar water heater is another experiment that's more fun than practical. While they do work exceptionally well, done right, all I'm aiming for is proof of concept. To be "right" it would need black tubing, a black heat reflective backing and glass over the front to convert shortwave light to longwave light. In other words to make it hot inside the unit. The piping from the heating unit to the reservoir would need to be lagged. The reservoir needs also to be lagged. The alternative would be an immersion element and bigger solar panels. 

Going further, if the solar water heater was done well, the water heating would need no pump as the heating could be acieved by convective circulation. That is something well worth doing but which would really only be doable with a domestic installation.