On Fri, 03 Aug 2007 10:28:16 -0000, "
wrote:

Wow - that's about 2-3 units a day just for a coolbox! I use about 3.5
units a day for everything - including a fullsize Bosch A-rated
fridge.

I think those coolboxes use Peltier cooling (a weird diode that gets
cool one side and hot the other when a current is passed through it).
Peltiers are very inefficient. http://en.wikipedia.org/wiki/Thermoe...ng#Performance
- says conventional refrigeration is many times more efficient.

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.

Their performance gets rapidly worse if the heat is not removed from
the hot side effectively enough, the temperature can rapidly go up and
cause melting of a cheap Chinese tat coolbox if the vents are covered
up in a car boot and it does nothing for your ice cream. With better
cooling (implies a more powerful noisier fan than the 12v plastic one
in a CCT Coolbox.) useful results can be obtained.

In serious applications they are handy for cooling small components
which aren't of themselves generating heat. An instrument we sold Ca.
1970 used them with success to cool an antibody chamber in an
Automated RadioImmunoassay Anayser.

DG