1 April 2003
Running Hot And Cold(HKTDC Electronic Components & Parts, Vol 02,2003)
Vol 2, 2003
Running Hot And Cold
Miles Of Cables
|GI Co elements are finding an increasingly wide range of uses in such diverse applications as car refrigerators, water dispensers, dry boxes and the heat sinks of processors|
In the early days, elements made by GI Co went into car refrigerators, as the 12-volt battery was highly suited to the cooling module. Today, in addition to automobile use, the company's elements find their way into water dispensers and dry boxes, while a wider range of uses also looms.
"Until recently, the primary use of our elements was in car refrigerators, but now it is water dispensers," says manager Philip Chiu. "At least one maker of computer chips uses our elements for cooling by attaching them to the heat sinks of processors."
Depending on the country of use, elements are also known as thermoelectric cooling modules, heat pumps, Peltier elements (after the Frenchman Jean Peltier), micro-coolers or TE coolers (TECs). The Peltier effect, for example, makes it possible to produce a solid-state heat-pumping device that can transfer heat from one side of a solid crystalline plate to another.
Chiu says that GI elements are essentially an assembly of junction transistors, making use of tellurium and bismuth. "Tellurium's properties make this material an ideal bed for PN junctions, when a hot-cold difference is required, and forms the basis of our entire business," he explains.
Noting that the origins of the technology lie in equipment designed for space exploration and the military, he says GI has manufactured such elements since 1986.
"The technology originated in the US and soon found its way to the mainland, where it was adapted for military purposes. In those days, the army owned manufacturing facilities. Then, with the modernisation and opening up of the mainland, the army plants were gradually converted to produce consumer goods to earn hard cash," says Chiu.
With contacts with the military, he says he was ideally placed to take maximum advantage of the now-available technology. "GI used to produce transistor radios in Shenzhen in the 1970s," he recalls. "The army factories were nearby, and it was not uncommon to be in contact with each other. This was when the idea of GI getting into thermoelectric devices was first mooted."
He says that others entered the field as well, and that GI had to survive an early bout of competition that saw constant undercutting of prices. "We came through and have continued to flourish ever since," he says.
Precision tools at GI, such as cutters to slice up the chip material, are imported from the US and produce elements as small as 4 PN junctions.
The smaller types are finding new outlets such as medical equipment - for example in a pack applied to the skin. The hot and cold differentials - which can be finely controlled - have a blood pumping action that is useful following surgery instead of using medicines with possible negative side-effects.
Chiu says there is a bright future for elements as more and more applications are coming onto the market. "While we spend a lot of time studying new uses, we do not intend to make any end-products ourselves as that would put us in competition with our customers," Chiu adds. "We sell only the elements."
WRITTEN BY TONY HENDERSON
Unit C, 1/F
Lippo Leighton Tower
103 Leighton Rd