Fridge0: An Open Source Solar Refrigerator

One of the biggest challenges anyone determined to live off the grid has to face is refrigeration. Traditional systems devour energy and aren't very eco-friendly, so the most common solution is to hack until you reach the desired goal. The Fridge0 design uses solar power, a freezer turned into a fridge, and a thermal mass that acts as a cold battery. There is plenty of DIY here, especially on the software side, but I guess that doesn't scare you…

A hack that shows up repeatedly on YouTube involves horizontal freezers and converting them into regular refrigerators by completely replacing their thermostat. The reason for this is none other than efficiency. Under solar configurations, wasting energy is a real madness, and in general terms, “freezers that don't freeze” do a better job.

Then there are completely off-grid solutions that include their own battery banks, but the cost skyrockets very quickly. So… what alternatives exist? The Fridge0 project by Joey Hess is one of the most interesting. In relaxed terms, Fridge0 is a “cold battery”, meaning it only runs for the time needed to keep its thermal mass at the right temperature. That means a Fridge0 can go three or four days at a time (depending on the size of the mass) as a passive fridge, without drawing external power.

One of the fundamental elements that makes Fridge0 possible is its computer-based control. The system needs to know if there is enough solar energy to switch the freezer on, and turn it off at the right time, avoiding food from freezing. For that it uses a CubieTruck (one of the many alternatives to the Raspberry Pi), which also works as a router and server. All the necessary software is open source, but you will have to fight quite a bit with its documentation (or rather, the lack of it).

Personally, I think the “cold battery” concept is the most striking thing about Fridge0. Despite all the discussions on the subject, using water is still faster and cheaper. Joey Hess's Fridge0 has a thermal mass of 17 gallons of water, about 64.3 liters. That takes away a third of the available space in the freezer, but consider the benefits: it reduces the time the freezer has to stay on, lowers the battery requirements in the circuit (the Fridge0 doesn't need them, but the rest of the off-grid platform does), and cuts the final cost.

In short, an advanced project for prepper adventurers and anyone who decides to live more efficiently. The only problem is the documentation. The Fridge0 page acts as a kind of wiki, but the material tends to be scarce. You may want to get in touch with Joey if you decide to reproduce it; however, don't forget this is DIY. There is always room to improvise, replace, and optimize.

Official site: Click here