Solid State Fridge? | Green Energy News

March 23, 2003 – Vol.7 No.52

SOLID STATE FRIDGE?

Run an electric current through two dissimilar conductors and one end gets hot, the other cold. It’s known as a thermocouple. And the reverse is true too. Heat a thermocouple and a flow of current is created. It’s an age old concept that still intrigues researchers and product designers.

Unfortunately, thermocouples aren’t very efficient, but they could get better with nanotechnologies

While the cold end of a thermocouple is already used in some consumer products such as mini-refrigerators and climate-controlled car seats, scientists hope that the now-inefficient technology could be improved to make to make full-sized, solid-state refrigerators that could replace the machines we now have.

Scientists at RTI International in North Carolina have a successful prototype thermocouple that makes use of nano-scale materials that could - with improvements - be used for refrigeration, or in reverse, for power generation.

The prototype, a chip about the size of a postage stamp, is comprised of about 1000 layers of nano-scale films of thermoelectric materials squeezed between two thin crystals. In testing, the chip cooled a solid block of steel from 79 degrees to 64 degrees in about two minutes - cooling much faster than conventional refrigeration. Each layer of the alternating stack of semiconductors is only a few tens-of-billionth of a centimeter thick.

Improvements in efficiency are needed, but researchers who developed the chip in only 18 months, think efficiency can be improved by 2-3 times. Visit RTI at http://www.rti.org/ .