Okay , 2% difference in energy doesn't sound like much.
With more context, I am interested in industrial personnel cooling systems which consist of a small backpack or belt-worn bag that has a little battery powered pump and a 'reservoir' that you put ice cubes or a frozen water bottle in - wthe ice cubes or bottle is surrounded by coolant, and it pumps the coolant through tubing in a shirt or pants like this;
To keep the bags or belts from becoming burdensome to wear they only hold a small amount of frozen substance which is reportedly good for 1-2hrs of good cooling effect.
Anyway, I was envisioning setting up a crew with the shirts and a small freezer and battery swap station to change-out their bottles and batteries. It seems common residential style deep-freezes are usually capable of around 0 to -10F ( 0 to -23C) operation so I assume this is what the system manufacturer is basing the cooling time off of. I was just trying to think if modifying the freezer or buying a more specialty freezer that will pull lower temps would translate to significantly longer "cooling time" for the guy wearing the system.
Ideally you could pull more like a solid 2.5 hours of cooling even on the hottest days because workers would be on breaktime by then anyway so it would be a natural time to swap equipment out after break.
