Quote:
Originally Posted by cthermo
Like all heat pumps, the efiiciency gets worse as the difference in temperatures gets greater. If you are trying to heat cabin air using outside air at only 10 C degrees cooler then the Peltier is very efficient giving numbers like above. If the outside air is 30 degrees cooler, then the efficiency drops because the peltier can only pump 25 watts at that point, so 25 + 60 = 85 watts of heat. Heating becomes less than 100% efiicient between 50 and 60 degrees delta T (difference in temp of hot and cold faces of TEC). Thats when resistive heaters would be more practical.
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I'm a little confused, you said it becomes [Bold] less then[/Bold] 100% efficient, a resistive wire would put out heat at 100% efficient, correct? so it sounds like you are saying that if it's 50C cooler outside then what want the hot side of the plate to be that I would at that point be using the peltier as only a resistive plate, getting one watt of heat out for every watt of energy in? or is it that at those lower temps some of the heat loss would be to the cold side as well giving me a net loss.