The Rojases at Green Power Science, in Florida, give us more info on the pot-in-pot refrigerator. They highlight the need to be aware of your surrounding humidity levels. If the humidity is above 75%, they note, the zeer pots won’t work because they require evaporation to work and that’s a no-go when it is very humid out.
I was pretty blown away by this project.
Mikey and Wendy live on an off-grid, homestead in New Mexico (see their Holy Scrap Homestead blog). As such, they were looking for more efficiency from their appliances. Mikey has come up with a temperature controller that has allowed them convert a small chest freezer into a refrigerator and so downsize from their full-size fridge that cost them a lot in energy and was underutilized.
The temperature controller can also be used to regulate temperature for stuff like tempeh and yoghurt making, incubation, heat pads, raising bread dough, and controlling the temperature on simple crockpots and on hot plates for tasks like candy-making. There are a lot of possible uses.
The design and instructions on how to build it are “open source” in other words, free, off his website but he also sells kits to build it yourself and already completed units from there, as well.
Here is Mikey talking about the controller and what he was able to do with it. BTW, I don’t know Mikey or Wendy and they haven’t asked me to blog this. Just stumbled across this and thought it should be shared.
Here’s Wendy making yoghurt using the device:
Wendy using the temperature controller to make tempeh:
Mikey raising bread dough.
Besides the temperature controller, Mikey has other useful open source projects.
This video shows the science behind the pot-in-pot refrigerator, aka the Zeer pot. Pot-in-pot refrigeration is ancient technology that has been revived with a lot of success in Saharan Africa and rolled out to other developing regions. In those countries small farmers use the pots to store produce for market.
Here in North America, we could use it as a picnic/drinks cooler, to free up fridge space, to save on electricity, during an emergency or if we live off-grid and electrical refrigeration isn’t an option.
This is cheap, pretty easy-to-apply technology and gives you a cooler without the ice. My wish would be for someone to produce interlocking unglazed ceramic cubes or low rectangles so that this solution would be easier to fit into a kitchen or pantry. I know from what I’ve read that the pots have to be unglazed for the device to work – since it is cooling through evaporation through the porous pottery.
I am curious about what affects how quickly the pot cools (the presenter seemed to suggest that the temperature around the Zeer is a factor) and how long the effect lasts.
The Real Know How 