Electricity from waste heat

Considering how much waste heat there is in various industrial processes, this is BIG news.  Consider that only 20% of the energy in your gas tank is converted into motion down the road—the rest is waste heat.  Consider that a very good electrical generating power station only converts 40% of the energy in coal into electricity—the rest is waste heat.

Remember, anything that passes the tests of thermodynamic efficiency will have a positive impact on the real economy.

Congratulations to all who made this work—if even only at the university lab stage.

Silicon semiconductors to convert heat into power

German scientists have found that enriched silicon nanoparticles can turn waste heat into electricity. The silicon semiconductors are even cheap to produce.

Creating power from heat can be quite an ordeal.

• First, steam is converted into pressure.
• The pressure is then sent through turbines or piston systems.
• There, kinetic energy is created.
• And that in turn produces electric power with the help of generators.

But scientists from the University of Duisburg-Essen have found a short cut.

Gabi Schierning from the university's Center for Nanointegration has developed silicon semiconductors that can convert heat directly into power.

The silicon semiconductors work like solar cells - but instead of using the sun as an energy source, they use heat.

This is nothing new. However, existing methods are based on very rare and expensive materials or use the soft metal, lead, which is harmful to the environment. In some cases lead can be harmful for people, too.

Schierning says the energy yielded using existing methods has also been far too low for wider usage. So she pinned her hopes on nanotechnology.

"This can remarkably boost efficiency," she said.

Schierning starts with tiny silicon nanoparticles - but to enhance their conductivity, she enriches them with other elements.

Technically speaking, the silicon is "doped."

To do this, the scientists at the University of Duisburg-Essen use phosphorus and boron.

Silicon, phosphorus and boron can all be produced cheaply.

Schierning cites this as a major factor. She says it could help establish the new technology in a range of applications. For instance, it could be used to recycle waste heat which is otherwise emitted into the environment.

"There's enough waste heat," Schierning says, "whether it's in the chemical industrial sector or in the car industry."

A combined heat-solar cell could even replace the alternator in a car. more