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I am not sure if this is the best place to put this, but if I'm in the wrong place please tell me where I can go. So I know a peltier module is not the most efficient, however my goal is to make a hand warmer / cooler with a petlier module. My operating temperatures will be around 60f to 90f, nowhere near the max of most peltiers. My first question is can it be powered by a small battery? Second, would I need a heatsink with this kind of temperatures that I want to produce and if it's required, is there any passive cooling I can use without being thick? Third, is this idea practical?

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For heating, it would be practical. There are battery powered coats that are currently on the market. A peltier module pumps heat, plus makes a heat; so you get more heat than electricity you put in. So instead of getting 100% heat from electricity in a resistive heater, you are getting 150% heat (for example) from electricity in a heat pump (peltier module in this case).

A heatsink will increase the efficiency by allowing more heat to be pumped. Lots of variables, but lets say an increase from 150% to 180%. Add a fan to that heatsink and say an increase from 180% to 200%. I would recommend starting with a heatsink at least, and increasing or decreasing the chosen voltage to achieve your desired temperature. If you have a 12v module, start with something around 6 volts. Remember not to drain lipo batteries too low and to watch battery chemistry or you could damage them or start a fire.

Good luck!

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  • $\begingroup$ So heating with a petlier module is very efficient, but what about cooling efficiency assuming if I had a moderate heatsink? Also, with a petlier module if I reverse the direction of electricity, I can switch the sides of the petlier module right? $\endgroup$ Jan 15 '17 at 18:36
  • $\begingroup$ Also, if my temperatures were more extreme, what would happen to the efficiency? For example the outside temperature was like 10f or 100f? $\endgroup$ Jan 15 '17 at 18:50
  • $\begingroup$ Yes reverse polarity will switch the direction of heat pumping. Cooling is around lets say 50% efficient when coupled with a heatsink and fan. Obviously, large temperature differences reduce that efficiency. Remember your fan and heatsink have to be sized to pump the heat being moved by the module and the waste heat being generated. $\endgroup$
    – ericnutsch
    Jan 16 '17 at 19:51
  • $\begingroup$ So without a heatsink or a fan, what does the efficiency reduce to? $\endgroup$ Jan 16 '17 at 20:53
  • $\begingroup$ I am just estimating numbers from my experience using them. Your mileage may vary... there are lots a variables here. You can contact a peltier module manufacturer for more information or do some experimental measurement on your own. tetech.com/peltier-thermoelectric-cooler-modules $\endgroup$
    – ericnutsch
    Jan 17 '17 at 0:50

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