sleat@aat.UUCP (10/28/84)
[Apologies if this is a duplicate. Local evidence suggests the first posting never made it out of this system.] >I'm not sure that "thermal diodes" is the correct term, but I recall >hearing a few years ago about the development of semiconductor devices >that acted as heat pumps or refrigerators. Pass a current through >them and one end got hot, while the other got cold. I think some >company actually tried marketing a portable refrigerator using these. >Does anybody know where I could get some specs on these devices, or >buy some of them? >-- >Jan Wolitzky, AT&T Bell Laboratories, Murray Hill, NJ; (201) 582-2998 You might try: Cambridge Thermionic Corporation 445 Concord Ave. Cambridge, MA 02238 617-491-5400 I have an old data sheet (ca. 1979) for their model 801-1029-01-00-00 "Ceramic Module". Basic spec's are: Max Temp Difference >60degC Max Current 9 Amps Nominal Voltage 0.7Vdc Hot Side Temperature 50degC (max?) Max Heat Pumping Cap >3.3 Watts Max operating Temp 125degC The unit is a rectangular block approx .2 x .3 x 1 inches, with two 18awg pigtail leads. Heat is transferred across the .2 inch dimension (i.e., from one .3" x 1" surface to the other). The energy transfer rate, at a fixed current, is of course inversely proportional to the temperature difference. The given transfer capacity of 3.3 Watts is at 9 Amps with a delta-T of 0. From the rather cryptic performance curves given, it looks like you get about 0.2W across with 9 Amps at a delta-T of 50degC. Below 5 Amps, transfer rate is approxi- mately linear with current. Above that it begins to fall off (as resistance effects begin to dominate, I suspect), the slope reaching zero at about 9 Amps. Above 9 Amps, the slope goes negative. Nowhere on the data sheet does it mention that this is a semiconductor device, though the leads are color coded for polarity and the 0.7V suggests a semiconductor junction breakdown voltage. I believe that this exploits a phenomenon other than the Peltier effect, though my recollection on such matters is hazy at best. Any denizens of net.physics care to elucidate? Michael Sleator Ann Arbor Terminals {aatpdx, cbosgd, mb2c, psu-cs, uofm-cv}!aat!sleat