Richard J Kinch wrote:

... How much energy would we save if we kept ice trays in a baggie?

A significant amount compared to the bogus Energy Star efficiency ratings,
butat about $1/day total to run a real refrigerator in a real household
environment, I don't know that it is enough to justify the nuisance. I do
know it is enough to demonstrate the absurdity of Energy Star.

My ice cube trays hold 0.796 pounds of water. Freezing one from 60 F takes
(60-32+144)0.796 = 137 Btu, ie 0.04 kWh of heat. A fridge with a COP of 3
could move that with 0.013 kWh worth 1.3 cents at 10 cents/kWh. Know anyone
who freezes 1/0.013 = 75 ice cube trays per day? :-)

The trays have about 4"x10" of ice surface. Over a month, they might lose
1/4" of depth in my frost-free freezer. How much does that cost?

Polyethylene bags, by the way, are not very effective vapor barriers...

Foil helps, aluminum helps, but

http://www.devicelink.com/mpb/archive/98/09/005.html

says 100 in^2 of "low-density polyethylene" loses about 0.4 grams of water
per day per mil (0.001") of thickness at 40 C (104 F), with 0% RH on one
side and 35% on the other. A graph shows how this decreases linearly with
inverse (1000/T(K)) temperature. How much would that cost?

EERE/DOE say a 6 mil poly film vapor barrier has 0.06 perms, ie 1 ft^2
transmits 0.06 grains of water vapor per hour (out of 7000 grains per pound)
with a 1" Hg differential pressure at 73.4 F. How much would that cost?

Nick