

The pizza’s ready, and the open oven is making the kitchen feel cozy and warm.
A research team from the University of Colorado Boulder is working on how to convert that surplus heat to electricity.
Cue the development of tiny antennas – so-called ‘rectennas’ – which are significantly finer than human hair. Inside, optical rectangles capture light and heat, which a diode converts into electric current.
In an initial experiment, a network of 250,000 antennas was arrayed on a hot plate, capturing 1% of the heat.
With improvements, the technology might mean heat can be harvested from chimneys or bakery ovens.
It might even be possible to capture heat in space that’s deflected back from white walls on earth.