We tested an ice-less cooler that claims to keep cold beverages as cold as an ice chest, but without using ice.
The product is called “The Chill Chest”.
To test the product, we let 30 chilled water bottles chill in the Chill Chest.
We also put 30 chilled bottles of water in a cooler with a bag of ice.
After allowing the Chill Chest and the cooler to sit for 4 hours, the water in the Chill Chest maintained its cold temperature and was actually a tad cooler than the ice chest.
This study was commensurate with other studies I have seen.
The general belief is to have the Chill Chest as full as possible with beverages that are very cold to start with.
You can purchase the chill chest on line for about $20.