It's reefer madness day at TreeHugger! *. Another great idea to save on refrigeration costs, as long as it is still cold outside, is the Freeaire system, which asks the question: why pay money to refrigerate when cold is free in winter? In a typical convenience store, half the energy consumed is used for refrigeration. The Freeaire can save 90% of the electricity for 150 days of the year; furthermore the fridge equipment lasts much longer as it is barely used throughout the winter. A microprocessor controls a fan and and damper to monitor the temperature of the cooler and the air, and bring in as much outside air as required to keep the temperature stable. The inventor acknowledges that there " may be still out on whether there will be less cold and snow in the future, but even if there might be less cold outside air around in fifty years, that's no reason to act in a way to make it happen! " ::Freeaire via ::The Ugliest Blog on the Intarweb
*(reefer is short for refrigerated van, its not what you think)
See also Justin's post on chest refrigerators.