Peltier TEC

Best you start with a google search. This will give you links to the basics of Peltier devices as well as what is currently available on the market to purchase.

Greenweld show a 40 x 40mm peltier drawing 3.9A maximum. Your parameters would be much less than maximum but would depend on how efficiently you can sink the heat away.

You are also going to need a fan on the hot side heat sink. Convection alone will not properly cool the assembly.

This free software from Melcor will help you in your analysis.

I would have to see the specs for your specific Peltier device to give you that info, but typical devices are about 5-10% efficient. That means at the high end of this range you will need 10 watts of power for one watt of cooling. Here are some basic units for doing your calculations;

1 Watt = 3.4129 BTU/hr

1 BTU is the amount of energy needed to change one pound of water by one degree Fahrenheit.

So, if what you are cooling is 5lbs and you want it cooled by 45 degree Fahrenheit (25C = 45F) in one hour you would need to provide 659.2 Watts of electricity.

Note - these calculations are all done on the high side of the efficiency range. Peltier devices have a sweet spot for efficiency and their effectiveness drops off if you push them past that.

-Doug