Experimentation with freezer

Turned on my new freezer for the first time and it works great.  Just for kicks, I put a 2 liter Dr. Pepper bottle filled with water, and let it freeze inside there in order to test it's effectiveness at cooling.  It froze up pretty good.  I got to wondering about how much energy it took to freeze a bottle like that.

The BTU measurement gives a good idea.  It is defined as about 1055 joules.  If a bottle weighs about 2 pounds, and if each pound requires 1 BTU  in order to cool it 1 degree Farenheit, the to drop it from 72 to 32 degrees is 40 degree temperature drop.  That means that 40 BTU per pound times 2 lbs equal 80 BTU.  Then, take that 80 BTU and multiply it by 1055 joules to get  84400 joules.

Thus, since there are about 3.6 million joules in a kilowatt hour, then divide 84.4k joules into that and get 0.023 kilowatt hours to cool 1 Dr. Pepper bottle down to freezing.  Pretty cool alright.

About 50 of these bottles would take a kilowatt hour of electricity, then.  It probably wouldn't work out exactly like that, but it could be a good approximation.

This led me into a lot of thinking about how to cool down in the desert at da Ranch.  Instead of spending all that money on an air conditioner, I wonder if I could cool down by recirculating cool water ( with frozen Dr. Pepper bottles inside an Igloo ice chest ) through a cooling pad.  To cool down, just sit down on the cool pad and it the water will circulated through it.  It picks up heat from da butt and cools you off.   At the same time, it heats the water and melts the ice in da Dr. Pepper bottles.  After awhile, all the ice melts and the cooling effect stops.  How long would that last?  Depends upon how much energy needs to be exchanged, I'd say.

That could be in combination with a small swamp cooler could do the trick.  Only would cost about 250 more for the cooler.  Swamp coolers need air exchange to work, but da toilet needs it too.  Bwah, hah, hah.

I'll place this one on the off-the-grid construction sub series.

Update:

Found an error in the calcs.  It should be 4.4 lbs for the 2 liter bottle.  Perhaps more.  Each liter weighs a kilogram, which weighs 2.2 lbs.  So, it should be closer to 20 bottles per kilowatt-hour.  Unless there's another error, that number may be close to being right.

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