COOL CHIPS PLC, GIBRALTAR, HAS REVEALED that quantum mechanical electron tunneling was the mechanism used by its wafer-thin discs to produce cooling ( AW&ST Jan. 14, p. 425). When an electric current is applied to one side of the chip, electrons "tunnel" across the 1-10-nanometer gap separating the two sides. The flow of electrons heats the receiving side, while the gap insulates the cooling side from conductive heating. Cool Chips reports that prototypes have demonstrated a tunneling current exceeding 10 amps over a wafer area of approximately 9 sq. cm. Theoretically, the heat flux for flat electrodes is nearly 5,000 watts per sq. cm., according to the company, which says the devices are designed to operate at 70-80% of maximum theoretical efficiency, but are less than 10% of the size and weight of compressors. Applications could range from avionics cooling to consumer in-car coolers. Prototype development to demonstrate high output efficiency is expected to take at least a year.

©June 24, 2002, The McGraw-Hill Companies Inc.