Earlier quoted context omitted.
When there's no airflow in the refrigerator, then it takes a long time to chill food, the reverse of how a blast chiller can chill food really quickly by moving lots of air. But maybe the water chills the air to make up for this, IDK. It would be interesting to experiment.
It's like pre-loading your refrigerator/freezer with a sack of ice. If your power goes out long enough for your food to spoil, what will you do? Well, maybe you'll go buy some sacks of ice to throw in there until the power turns back on. Ok, if you have the space to spare, why wait for the failure to go fetch the emergency ice? Just fill the empty space with ballast water and you're ahead of the problem. Once the the…
You want something that has a thaw point way below your foods thaw point - add salt t your ice.