Re: Solar Steam Generator
If built correctly, it has the potential to outperform photovoltaic panels ("solar cells") of identical surface area (not counting the mounting frame or engine/generator). If I recall correctly, the current technologies convert between 7% and 23% of the energy hitting them into electricity, depending on materials. For example, the flexible backpack or roll-up units trade convenience over efficiency. I don't remember the efficiency of solar heating, but I think that it is closer to 50%-60%. You are starting out with twice as much harvested energy for the same size collection area, but with the published design you have friction losses in the "steam engine," the belt drive, and the permanent magnet generator/alternator in addition to the battery charging losses either system would have.
When all is said and done, you may get as much usable power out of a photovoltaic array with the same surface area as the dish contraption, and with much less maintenance. Also, to get maximum power, you would need to keep re-aiming the dish all day to follow the solar arc. Sunlight hitting a "solar cell" at an angle other than perpendicular still produces power at a reduced percentage. Sunlight hitting a fixed dish at an off angle moves the focused hot spot somewhere other than on the surface of the author's black can.
I do appreciate seeing people think "outside the box," though. A purpose-built integrated collector together with an azimuth tracking dish support may be much more efficient than the science project described. I recall seeing design ideas for using external combustion Stirling engines powered by solar reflectors in Popular Science as far back as 40 years ago.
I don't think the author actually built what he was describing. I would expect to see photos if he had a working model.
Plus, size matters. The amount of power gathered depends on the area of the device collecting the sunlight. An old 12-foot back yard dish would have 16 times the collection surface area compared to the 3-foot dish mentioned in the materials list, and would be a much better choice for a practical project.
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.