At 09:56 AM 9/8/2009, Rocket J Squirrel wrote:
>It takes a pretty long exposure to warm air to raise the temp of a
>can of beer even a couple degrees.

Oh, right, well, I understand that the stuff in the fridge doesn't
warm up much when I open the door.  That's not what I was concerned
about.  I understand I'm making my fridge more efficient by storing
many more BTUs of cold per cc in my 3.5-litre water jug than if I
just left air in there.

What I'm concerned about is the loss of the cold AIR that inevitably
fills the space between the bananas and the bottle of salad dressing.

When you open the door of a stock fridge to cool off your toes, how
many grams of propane or millwatts of electricity does it take to
cool the warm air that replaced the cold air that flowed out?  (As
opposed to just leaving that cold air inside, as the top-opening
fridge mostly does.)

I have done that calculation, but, as you say ...

>... we hear the reefer's compressor kick in, but it is responding
>only to the temperature of the air ...

That's my whole concern.  I'm not worried about the milk spoiling.