2 ms·
> the absolute best theoretical efficiency of this might be 70% While ICE are heat engines with a theoretical limit of 70%, they’re more specialised subsets de
by masklinn 4y ago
> the absolute best theoretical efficiency of this might be 70%
While ICE are heat engines with a theoretical limit of 70%, they’re more specialised subsets described by the Otto (gas) and Diesel (… diesel) cycles, which have a much lower theoretical maximum.
Just plugging the temperature ranges into Carnot will give you a Carnot limit of 50%, and using Otto will yield 46% (https://physics.stackexchange.com/a/98992 https://physics.stackexchange.com/a/98992).
Add in that gas engines are not spherical and into a vacuum (losses and delays) and you’re in the 30s.
- qikInNdOutReply 4y agoWrap the combustion engine with a heatpump to a small steam engine?
- osigurdson 4y agoIt isn't precisely "wrapped", but this is essentially how all natural gas fired generation facilities work. https://en.wikipedia.org/wiki/Combined_cycle_power_plant https://en.wikipedia.org/wiki/Combined_cycle_power_plant
- greesil 4y agoI think the parent is referring to harvesting some of the waste heat
- lilililililili 4y ago[dead]
- Sohcahtoa82 4y agoThe added weight and complexity would probably negate any benefit gained.