The folks at Low Tech Magazine are here again, this time with a solar powered coffee maker. Lest you think of a large parabolic mirror with a pot at its focus, in this case the device is much more friendly. It’s a table-top appliance that relies upon a 100 W 12 V panel for its operation.
They make the point that an electric coffee pot requires at least 300 W to work, so what’s the secret? In this case, insulation, as a standard moka pot is placed within a nichrome heating element set in mortar and surrounded by cork. On the outside are tiles, though they appear largely ornamental and the write-up suggests you could experiment with other materials to serve as an enclosure.
It appears to be an effective coffee maker, with the significant caveat that it’s hardly fast. In full sunlight the first pot takes over an hour to brew, with subsequent ones once it’s up to temperature being somewhat faster. But you can’t argue with the idea of free power, even if your favourite caffeinated beverage may now take a while to appear.
We like this idea, despite its slow brewing. We’ve featured Low Tech Magazine before, not least in their solar powered oven.
I came across this website a few years ago and immediately fell in love with the idea of a solar powered web server. Sadly I forgot the name of the website and didn’t really attempt to search it.
Thanks for reminding me [Jenny], I now have a nice addition to my reading list
In a perfect world with a solar panel that doesn’t have loss and a perfect insulation, it would take 8 minutes and 22 seconds, based on a 3 cup (150ml) mokka pot and the 100W panel.
With a warm mortar slab, which is mentioned, it takes 20 minutes. It’s only the first one that takes over an hour. Now, 20 minutes vs 8 minutes, with a solar panel that won’t be 100% effective, that’s actually pretty reasonable.
The two biggest improvements I can find are, covering the top and a much better insulation. Quality ceramic fiber blankets for example, with an outer coating for the fibers. Make a cover on it to cover the top and that solar panel might be able to produce coffee much faster. It’s also generally advised to start out brewing with hot water, reducing the time even more.
Very interesting article.
Solar powered coffee roaster.