A good friend of mine works with a non-profit charity called
S.A.F.E. where they are looking to expand their cold food storage capacity for perishable foods grown in community gardens. Long story short, she informed me that they were going to build a large walk-in refrigerator using a modified window AC unit with a programmable after market thermostat called the
CoolBot shown in the image below. The project has a $1000ish price tag that is not overly optimistic. Industrial units with a similar capacity cost as much as a new economy car or more, but also I have read that many of these units actually require more electricity than the DIY systems interestingly enough. Its a simple device, merely fooling a standard wall unit by heating the temperature sensor.
Homesteaders, Small Farms
There is a lot of appeal in building large cool storage units for food storage. An advantage in how the CoolBot or any similar product (if any) is that maintenance costs are minimal with the simplicity of the design. I posted a video uploaded by a small farmer presenting his build.
Portable Units
The video below was a project completed from UNC which demonstrates a portable system using the same concept.
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