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A comment on Ultralight lithium-sulfur batteries for electric airplanes. Parent comment

Re:Ultralight lithium-sulfur batteries for electric airplanes by zkms on Wednesday August 19, 2020 @05:15PM (#24216621)
> you are bound by the Carnot efficiency, which is at most 35% no matter what(in reality more like 20% or so)

Internal-combustion engines are not limited by the Carnot efficiency; see page 4 of these slides. In fact, latest-generation Priuses gets almost 40% thermal efficiency on the gasoline engine, and large diesel engines -- thanks to lean combustion (favorable ratio of specific heats for the gases that push on the piston), no throttling losses, higher compression ratio -- do even better.

https://www.energy.gov/sites/prod/files/2014/03/f8/deer11_ed...

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Re:Ultralight lithium-sulfur batteries for electric airplanes by evilos on Wednesday August 19, 2020 @07:57PM (#24218325)
Not parent commenter (and non mechanically inclined person), but I skimmed through the slides and it seems like a lot of the efficiency increasing techniques involve recapturing lost energy in the form of converting waste heat to electric energy.

Does the 40% for Prius include energy recapturing techniques?

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