Sunday, April 19, 2009

Solar still phase III results - 2.25L, glass bottle project - on hold


After some weeks getting bar/restaurant people to save their empty beer and wine bottles and obediently shuttling them to school to be broken down in the electric concrete mixer, it turns out the fist-sized cobblestone we need to crush the bottles in the mixer throws off the rotation of the motor, producing a brrrr brrrrrrrr sound like we were sending the motor to the graveyard while it is still a somewhat new machine.

What to do now? We could crush the bottles by hand or use some other means to break them down or I always enjoyed the thought of trying to connect the motor to a bicycle – let people ride a bike to spin a metal concrete basin which would break bottles into shiny sand-sized particles. This would solve two problems at once – recycling empty glass bottles and saving their disappearing beach problem. Alas, it’s not smart to push the mixer until it burns out. Plus, I’m tired of the legwork. So be it.

Another project on standstill for various reasons is the solar still. This may partly explain my reluctance to update you all lately – results are weak. The third model distills about 2.25L/day, somewhere between the first and the second model.



Why? It could be because the surface area of the water is about half of the other two. Or you could say the pressure decreased with the open drain and freshwater catch tube. Whatever the reason, it was a huge blow to my ego when the results came through – I really thought we were onto something big.

In the last few days, a few other mechanical teachers have agreed to help build another model out of sheet metal. We’ll see how far we make it. But, judging from the about 10X shy production-cost ratio we’re at after the first three models, something in the back of my mind tells me if this country wants to get serious about solar desalination, it should look abroad and import. The Chinese are exporting probably-cheaply-made but very reasonably-priced solar desal units. I’ve also corresponded with several companies in Denmark and Switzerland who are ready to export large-scale units. So, while I thought a few lowly Peace Corps Volunteers and a group of Capeverdean students and teachers could invent something revolutionary from a grassroots effort from brief Internet research, conceding to globalization and forking out for the export for the yes, more educated research, may prove to be the better option. You best believe this message is being passed up the line.

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