Will an ice cooler (standard Igloo/Rubbermaid type plastic ice cooler with lid) perform better over time on a hot summer day if you periodically drain the water from melted ice? I say keep the water in there, since when you drain the ~32 degree water you are effectively replacing that volume with ambient air and thus accelerating the melting of more ice. My brother-in-law insists the cooler will last longer (keep the beer colder longer) if you drain the water. He cites the second law of thermodynamics to support his argument; however, he hasn’t articulated exactly how.
Please help me answer this question of great importance.
Ice at 32 degrees will absorb 144 BTU’s per pound to melt. Water at 32 degrees will absorb approx 1 BTU per pound to change one degree. A mixture of Ice and water should be at 32 degrees.
Heat flows through the ice chest’s walls into the mixture. The melting of the Ice will keep the mixture at 32 degrees.
Draining off the water and only leaving Ice will slow down the heat transfer. The same amount of heat will flow through the walls of the ice chest. the walls not being completely in contact with the ice will have a temperature increase. With a larger delta T a sllightly smaller amount of heat transfer will occure (not really enough to count but some). But the air that displaces the water will be at outside temperature and need cooling.
Also unless the Ice is in complete contact with the walls the temperature inside the chest will increase slightly. Only the air in direct contact with the ice will be at 32 degrees. Therefore your drinks can increase in temperature. Where as before they were sitting in water at 32 degrees with full contact.
Me If it is drinks I never drain the water unless I am putting in new Ice and need the room. If it is food stuff that I do not want soaked I drain.
This sounds like the worlds simplest home science experiment. Two coolers full of ice and beer, one cooler has the drain plug open. Open two beers every hour and measure the temperature of the beer. Make it the cheap stuff if you’re just doing it for science.
Take a second cooler full of dry ice and chuck in a few chunks every few hours if you are out and about for a couple of days and you have the room for the extra box.