Peltier-Seebeck effects are opposite side of the same coin - a long-understood property for converting heat into electricity or electricity into the absence of heat (cooling). Used in everyday products like the valve in gas appliances or the type of cooler that runs on 12 volts.
See http://en.wikipedia.org/wiki/Thermoelectric_effect
Since well over half of the gas we burn in our cars turns into waste in the form of heat, this could be significant. Anything that improves the efficiency of thermoelectric materials is cool...or the opposite.
These devices are generally extremely inefficient. That’s why they are used where simplicity is paramount. they are “rugged”, but they don’t last forever generally due to thermal fatigue (these materials aren’t all that physically sturdy and the electrical bonding generally fails first).
I think it would take a 5x improvement in efficiency to get them out of the niche that they are in now, and that might be flat impossible without violating the laws of physics and thermodynamics - but then, it would be great to be proven wrong.
“Peltier-Seebeck effects”
About 12 years ago I picked up an portable 12v Igloo cooler/warmer chest using that effect and it worked pretty good. During 90 degree weather in Chicago the ice cube tray formed ice cubes and kept the frozen food in a stable state. It also used a hell of a lot less juice than a normal refridge would. The only problem was that it created a lot of RFI when using the 120 ac/ 12v dc transformer when used in the apartment. Still have it in storage.