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| SciFi movies and pathetic misconceptions of tech failing for the story line. |
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| AVGresponding:
--- Quote from: BrianHG on May 06, 2023, 01:05:57 pm --- --- Quote from: AVGresponding on May 06, 2023, 11:10:18 am ---TEMs are pretty inefficient, 6% or so for commercially available stuff, NASA are achieving on the order of 20% in their most advanced TEGs. --- End quote --- Do you have your acronyms backwards? Maybe something has changed in the last 5 years or so... TEGs, like the ones on the Voyager space probes, which operate on the Seebeck effect, can only achieve maximum 6% efficiency in the best of cases. The latest tech Stirling generators which use a magnet piston floating in helium as a lubricant can achieve 20% efficiency under optimum circumstances. However, this tech is not usually labeled today as TEG. It is possible to get even better efficiency with a normal Stirling engine, however, you will now have moving and rotating components which will wear out needing maintenance every few years. --- End quote --- Yes, I could have been more clear in explaining the difference between a TEM and the general TEG term, thanks. I think it depends who you ask as to whether Stirling engines are labelled (correctly or otherwise) as TEGs (in this specific context), I would tend to agree it's perhaps not the most accurate way to do it. I suppose it's an easy/lazy oversimplification since they effectively turn heat into electricity. |
| coppercone2:
--- Quote from: David Hess on May 05, 2023, 09:25:56 pm --- This reminds me of current efforts to make more efficient electric motors and motor controllers for electric vehicles. Both are already pretty efficient, so there is not much to be gained there. --- End quote --- Just don't underestimate how many of those things there are out there. The number of motors working vs small efficiency gain = HUGE Smaller motors in weirder form factors are the future I think. I think that is where the 'wow' is going to come from if we see what motors look like in 100 years. Gearbox elimination/reduction too. I can imagine something like instead of a motor attached to the shaft its gonna be like a sleeve that you put over a shaft that bolts onto something one day. Like slip this 2 inch thick piece of steel over the shaft and connect some wires to it and it is a car. Or just like bearings that are actually motors. It's gotta go some where eventually that is cool. Maybe we will see the procedure being instead of replacing the belt and motor bearings, it will just be like 'replace this small integrated car propulsion ASIC the size of a large ball bearing with a 300A plug on it'. |
| BrianHG:
--- Quote from: AVGresponding on May 06, 2023, 01:13:26 pm --- --- Quote from: BrianHG on May 06, 2023, 01:05:57 pm --- --- Quote from: AVGresponding on May 06, 2023, 11:10:18 am ---TEMs are pretty inefficient, 6% or so for commercially available stuff, NASA are achieving on the order of 20% in their most advanced TEGs. --- End quote --- Do you have your acronyms backwards? Maybe something has changed in the last 5 years or so... TEGs, like the ones on the Voyager space probes, which operate on the Seebeck effect, can only achieve maximum 6% efficiency in the best of cases. The latest tech Stirling generators which use a magnet piston floating in helium as a lubricant can achieve 20% efficiency under optimum circumstances. However, this tech is not usually labeled today as TEG. It is possible to get even better efficiency with a normal Stirling engine, however, you will now have moving and rotating components which will wear out needing maintenance every few years. --- End quote --- Yes, I could have been more clear in explaining the difference between a TEM and the general TEG term, thanks. I think it depends who you ask as to whether Stirling engines are labelled (correctly or otherwise) as TEGs (in this specific context), I would tend to agree it's perhaps not the most accurate way to do it. I suppose it's an easy/lazy oversimplification since they effectively turn heat into electricity. --- End quote --- The Seebeck effect turns a difference in temperature directly into electricity. The Sterling engine turns a difference in temperature to expand and compress a gas. That change in density of the gas is used to move a piston or turbine. This is basically a thermal motor/engine. That engine's motion is used to move a magnet or coil to generate electricity like any conventional alternator. |
| David Hess:
--- Quote from: coppercone2 on May 06, 2023, 01:32:56 pm ---Smaller motors in weirder form factors are the future I think. I think that is where the 'wow' is going to come from if we see what motors look like in 100 years. Gearbox elimination/reduction too. --- End quote --- Getting higher power density is a different matter. And there higher efficiency is required because it becomes more difficult to remove waste heat. This would matter for an aircraft, but not so much in a traction application. |
| coppice:
--- Quote from: David Hess on May 05, 2023, 09:25:56 pm ---This reminds me of current efforts to make more efficient electric motors and motor controllers for electric vehicles. Both are already pretty efficient, so there is not much to be gained there. --- End quote --- I think they are mostly trying to make electric motors for cars more efficient to simplify the cooling requirements in a confined space. Even if you have 99.9% efficiency, moving to 99.99% would eliminate 90% of your waste heat. :) The efficiency of current electric cars varies quite a bit, but I don't think that has a lot to do with the motor efficiency. |
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