What does the level of performance indicated here likely mean in terms of the efficiency of, say, a thermal energy plant of some description? How far is the needle shifted for an end user?
Wiki also tells me that the best TEG modules currently lock in around 8%, so we're looking at like 10-11% at best with the new material.
So from a bulk scale electricity standpoint... the needle probably hasn't shifted at all. From a small scale? In the IoT like applications (as mentioned in the press release), that extra 30-40% is nothing to sneeze at.
Also, this seems to suffer the same problem that most high-zT thermoelectric materials do: the total power handling capability is too low to be worthwhile. From a large-scale waste heat recovery standpoint, you're probably better off with a less efficient solution that can actually handle a useful proportion of your total heat output.
You have some kind of error here: with T_c = T_h, not only does Wikipedia’s formula give 0% efficiency, but it must: any power at all generated with no temperature difference would make a perpetual motion machine.
Sorry, I was ignoring the left side (the T_h - T_c / T_h) part of the formula to see the relative change from changing zT from 2.5 to 5.0. Effectively I was looking at the relative efficiency of the high zT material in the limit as T_h approaches T_c. Which as you point out, drives the real individual efficiencies to zero. I was just trying to get the "best case" scenario.
Would also point out that for the IoT like applications, the assumption of T_c ~= T_h isn't so bad. For example, if you wanted something powered off residual body heat, you're looking at something like 293/310 = 0.945. For
For T_c=293 and T_h=303, you get efficiency = 1.4% for zT=5 and efficiency = 1.0% for zT=2.5. So about a 40% relative increase as OP calculated and negligible absolute change.
Improving from 1% to 1.4% is a huge improvement. It’s 40% more cooling for a given power input or 40% more power output for a given amount of heat consumed. Alternatively, it means you consume only 1/1.4 the resources to achieve your goal.
This does not imply that 1.4% efficiency is enough to be useful for most applications, of course.
The Peltier and Seebeck effects are so grossly inefficient that even an order of magnitude increase in efficiency doesn’t bring it into reason for basically any purpose. I’m not actually aware of any device ever made that uses the seebeck effect in any substantial way other than the little heat powered fans people put on wood stoves.
The peltier effect is just down right awesome, you put power in and now it’s cold!? Reality steps in at some point when you need to drive down the efficiency even further to get large differentials and ugh. They’re insane to deal with, any amount of thermal load worth speaking of means you have to use a phase change system.
It is very handy for camera sensors though and other scientific gear. There’s a world world of CCD sensors that act in a vacuum with peltier devices driving them below -30c to reduce the noise produced by the sensor.
> I’m not actually aware of any device ever made that uses the seebeck effect in any substantial way other than the little heat powered fans people put on wood stoves.
My camp cooler is powered by a 60W peltier. Plugs in to any automotive cigarette lighter. It will keep things refrigerator cold for as long as you want, and it's almost completely silent in operation. There's tons of different models on the market. FWIW.
You realise how inefficient they are when you load it full of warm beer and run it for a few days and the beer isn't even cool yet. From that 60 watts of input power, you only get ~4 watts of cooling, and with some leaking through the walls of the box, the time to cool down something of substantial mass can be weeks.
That's why you have to use a real fridge to do the work before starting the journey. And at that point, those electric fridges are only slightly more useful than a pile of ice packs.
A couple of watts of cooling is not even enough to overwhelm checking on the beer frankly. All peltier elements are effectively the same efficiency: atrocious.
Obviously, using pre-cooled drinks is better, but if I put in a 12 pack of some beverage, it will be fridge-cold within 24 hours. In practice, it's never been an issue.
>It will keep things refrigerator cold for as long as you want, and it's almost completely silent in operation.
that's more a function of the insulation , rather than the cooling ability. The wattage needed for 'thermal maintenance' is far lower than needed for actually removing heat from the system.
Peltiers' are kind of on the same scale of efficiency as using your car (on purpose) to cook food in the engine bay.
...and yet that is still useful enough to be the right answer for some products. For the camp cooler example, it means I don't have to waste precious space on ice packs, nor worry about water as ice melts. If I put in room temperature sodas, they will be cold within 24 hours, which is good enough to be useful. On cold days I can run it in reverse and have a hot drink at break time. And the cooler/heater itself barely adds any weight to the cooler itself.
As a side note, look up the book 'manifold destiny'. It's all about cooking with one's engine bay. An amusing read!
it works similar to a thermocouple. A normal thermocouple needs a voltage bridge to increase the voltage with a millions to get anything that can be read by a digital 5v meter. These materials don’t need that. And a couple of degrees could produce a workable voltage. But the title Of the article states that the material is meta stable, unsure if that means it will work for a couple of seconds then die. Also, vanadium is used which makes it quite costly.
The predominant use cases for this will be powering ultra-low power sensors. The higher power could enable better (longer range, higher bandwidth) radios in the sensors.
Wiki also tells me that the best TEG modules currently lock in around 8%, so we're looking at like 10-11% at best with the new material.
So from a bulk scale electricity standpoint... the needle probably hasn't shifted at all. From a small scale? In the IoT like applications (as mentioned in the press release), that extra 30-40% is nothing to sneeze at.