On 03 Aug 2007 21:09:17 GMT, (Andrew
Gabriel) wrote:



The reason they are inefficient is mainly that the diode proper is
very thin and heat from the hot side leaks back to the cool side,
simply by conduction. However I don't know what their thermodynamic
efficiency is like.

At the temperature differentials you normally find in a fridge,
they consume about the same power that they pump, i.e. a 50W
peltier will pump about 50W too (giving off 100W from the hot side).
Compressor based refrigeration does very much better than this.
The inefficiency is not so much due to heat conduction as you imply,
just a 5-10% duty cycle will maintain the temperature difference when
there is no heat to pump across, so only 5-10% of the power is lost
to conduction.

Hmmmm,


BTW, it's not a diode -- peltier devices are a series of semiconductor
junctions

I bet they're not monodes ;-)

DG