Breakthrough in Converting Heat Waste to Electricity: nanocrystals of rock salt into lead telluride

[Elmore Furth]

Here is a potentially new technnology that could convert 10 to 15 percent of the waste heat into electricity.

ScienceDaily (Jan. 18, 2011) — Researchers at Northwestern University have placed nanocrystals of rock salt into lead telluride, creating a material that can harness electricity from heat-generating items such as vehicle exhaust systems, industrial processes and equipment and sun light more efficiently than scientists have seen in the past.

The material exhibits a high thermoelectric figure of merit that is expected to enable 14 percent of heat waste to electricity, a scientific first. Chemists, physicists and material scientists at Northwestern collaborated to develop the material. The results of the study are published by the journal Nature Chemistry.

"It has been known for 100 years that semiconductors have this property that can harness electricity," said Mercouri Kanatzidis, the Charles E. and Emma H. Morrison Professor of Chemistry in The Weinberg College of Arts and Sciences. "To make this an efficient process, all you need is the right material, and we have found a recipe or system to make this material."

Kanatzidis, co-author of the study, and his team dispersed nanocrystals of rock salt (SrTe) into the material lead telluride (PbTe). Past attempts at this kind of nanoscale inclusion in bulk material have improved the energy conversion efficiency of lead telluride, but the nano inclusions also increased the scattering of electrons, which reduced overall conductivity. In this study, the Northwestern team offers the first example of using nanostructures in lead telluride to reduce electron scattering and increase the energy conversion efficiency of the material.

Breakthrough in Converting Heat Waste to Electricity: Automotive, Chemical, Brick and Glass Industries Could Benefit from Discovery
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[wildflower]

1. Could this work on the heat generated in landfills?

I worry a lot about landfills and what we are to do with them as they continue to grow.

[TheMadMonk]

3. Much better idea for landfill.

http://en.wikipedia.org/wiki/Plasma_arc_waste_disposal

[lfairban]

2. ?

. . . dispersed nanocrystals of rock salt (SrTe). . .

I thought rock salt was Sodium Chloride, (NaCl) not Strontium Telluride.

[Thor_MN]

8. One would think a site named Science Daily would have writers that would know

the difference between Strontium Telluride and rock salt. Likely what happened is that someone who knew what they were talking about mentioned that Strontium Telluride has a rock salt structure (cubic symetrical crystals) and the person writing took that to mean that is WAS rock salt.

Sad, really.

[Ready4Change]

4. Coating for the back of PVs?

PV panels get warm, and would work better if kept cooler. Would coating their backs with this both generate more electricity from the waste heat and provide cooling?

[caraher]

5. I don't think so

The example they gave was harvesting waste heat from a (presumably incandescent!) light bulb. I think you really want something with a much higher temperature than you'd get just from PV "waste" heat. Thermoelectric materials can be used either for temperature regulation or as current sources, and basically the amount of current is related to the amount of thermal energy transferred across the device. If you have a relatively small temperature difference you're simply not going to drive a lot of current, and it probably won't make economic sense to try to harvest that energy this way. You probably want to look at things a few hundred degrees above ambient temperature rather than a few tens of degrees.

[Ready4Change]

7. AH, ok.

More like a cars exhaust and/or area around the catalytic converter?

[opihimoimoi]

6. #12 checking in