Turning off the frig at night will just make it work twice as long the next day, you won't save anything.
as for how much heat it takes to freeze 1 gallon of ice from 80 degree water.
Power output can also be expressed in kcal/sec, ie, 1 kilowatt=1 kj/sec=.2388 kcal/sec, or 860 kcal/hr.
since a gallon is ABOUT (ABOUT) 4000 grams it takes 4000 x 40 cals to get it to 32 degrees, then it takes 120 cal/gram x 4000 to freez it.
since it takes 480,000 calories to freez the ice in one gallon that is about 1/2 a kilowatt hour. or about 2 cents in our electricty costs of 4 cents per kilowatt hour.
so the heat put out of the fridge in the back is about like running a 500 watt heater for one hour.
why would you want to push that outside?
That is free heat.
or a 1000 wat heater for thrity minutes?
also. bringing in 1 gallon of ice water after it froze outside will cool your fridge and thenn the water by 1/2 kilowatt, which means your house has to run 500 watts for one hour to make up for each gallon of ice you bring in from the outside.
this is my two cents worth (Pun intended.
so if you bring in the ice already frozen, your heater in the house willl run two cents more by the end of the day, and if you freeze the ice in the fridge, the fridge will run two cents more each day.
One way or another your going to use the two cents. you save nothing.
but that is just my two cents.
MAKING and MELTING ICE takes an ENOURMOUS amount of power, but bringing it in from outside gains you nothing but it would extend the lif of your fridge for one hour for each gallon you bring in and shortens the heater life by about 10 minutes.
That is a significant decrease in freezer run time and it is nioticeable, but there are no cost savings, except stronger arms and exercise for you, and a more silent fridge with a heater that runs about ten minutes longer which you probably wouldnt notice.