What explains the big difference?
Cold air likes to go down. When you open a fridge door, the cold air pours out at the bottom. When you open a chest, it stays in the chest.
Also, a freezer probably has better insulation than a fridge to begin with, since it's designed to hold bigger temperature differential.
There's a number of people experimenting with converting chest freezers to chest fridges using an external thermostat. Apparently, these can be extremely efficient - people are reporting 10-20% of your 1.1kwH/day number.
Of course, the typical downsides of a chest freezer apply to a chest fridge - they're typically much more limited in size compared to their upright counterparts due to ergonomics, and the larger they are, the more difficult they are to fully utilize.
But they're a lot better than no fridge at all.