A refrigerator consisting of a simple air compressor (which can be made from a food can, some bicycle rubber, and bike valves), a soft drink bottle as a pressure vessel, and a simple pressure release valve (probably based around magnets from a computer hard drive).
The compressor can be driven by pretty much anything, such as a small wind turbine, a motor run from a solar panel or the mains/battery, even by hand if necessary.
Air is compressed into the plastic bottle up to 2-3 bar, at which point it is released by the valve and due to adiabatic expansion rapidly cools. This now cold air enters into an insulated box = refrigerator.
The system can be further optimised by recycling the displaced cool air from the box to cool the plastic bottle, as well as a small amount of water to cool the compressing air internally.
The valve will be settable in terms of pressure and therefore temperature, and the system should be able to easily maintain internal temperatures around 0 C.
Due to the rapid cooling of the air, water will be produced as a by-product which can be collected. The system in an averagely humid environment should produce about 5-10 liters of drinking water per day.