Sunfrost refrigerators are the most efficient ones out there.
Here are the specs on a typical model:
Energy Consumption : 585-845 Whr / day (42-58 Amp Hours)
DC, 20 kWh / month, 249 kWh / year
Annual Energy Cost: $21
Capacity: 16 cu. ft.
Dimensions: 62.5″ H, 34.5″ W, 27.75″ D
Weight: 300 lb. (44 cu ft. volume)
Available from: Alternative Energy Store