Feel the heat ... thermal computer could be powered by body heat.


Heat is the great enemy of modern electronics - it can spawn errors and fry components.

But now scientists have turned heat to their advantage by creating devices that run on heat instead of electricity. The advance could lead to thermal computers that run off of body heat or other waste heat from our surroundings.

A heat current is simply the flow of energy from a hotter object to a colder object. Imagine heating a metal pipe at one end: Heat flows from the hot end to the cold end, and at every point along the pipe the temperature diminishes.
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In physics terms, there's a "uniform temperature gradient." The heat takes this simple path because the pipe conducts the same amount of heat in every place and in every direction.

Yet materials don't have to conduct heat so simply. If you stacked alternating sheets of a material that conducts heat and another that insulates it, the heat would be conducted more freely sideways than in the top-to-bottom direction.

Electrical engineers are familiar with this principle: It's the same one that makes resistors, one of the most common electrical components, conduct more when wired in parallel than when wired in series. The breakthrough of the new research is to tailor composite materials so that their thermal conduction is not just side to side or top to bottom, but in a direction that changes throughout.