4 ms·
Not even close. Second law of thermodynamics puts a limit on heat engine. Gravity storage is not subject to such limit. But it is a great idea to burn any fuel
by pishpash 6y ago
Not even close. Second law of thermodynamics puts a limit on heat engine. Gravity storage is not subject to such limit.
But it is a great idea to burn any fuel whose oxidized product is not a gas. The only reason why burning hydrocarbons is problematic is because carbon dioxide is a gas, otherwise it could be captured and recycled like this.
- stkdump 6y agoSeems about right. Pumped storage is at about 70% efficiency round-trip, this is 40%. Also, not producing greenhouse gases sounds like a good idea.
- knolax 6y agoWell I think in this case the iron is feeding a furnace so it's not going through a heat engine, it's just giving off heat.
- socialdemocrat 6y agoYes and anyway you could use combined heath and power systems to get higher efficiency.
- ncmncm 6y agoRight, conversion of iron to rust yielding heat is 100% efficient, less only the work needed to move the rust out of the way. If you wanted to convert that heat back to electricity, there would be losses, but nowhere near as much as some people are saying. 1800 degrees minus ambient is a very big delta T. You are not bound to a closed cycle, so Carnot does not apply. So it is likely 80+% would be achievable, maybe over 65% round trip.
- Ensorceled 6y agoGravity storage IS subject to the same law, why do you believe it isn’t? Burning hydrocarbons is problematic for a host of reasons besides CO2 release: fracking, oil spills, release of other pollutants, political issues with the supplier countries, pipelines, ...
- thereisnospork 6y agoGravity storage is not a heat engine, ergo Carnot's rule does not apply.
- deleted 6y ago[deleted]
- Ensorceled 6y agoBut the second law of thermodynamics still does. Gravity wells are still a mechanical system, just not a heat engine.
- ClumsyPilot 6y agoLaws of thermodynamics apply to the entire universe, ergo i dont think anyone is claiming to break laws of physics
- thereisnospork 6y ago>Not even close. Second law of thermodynamics puts a limit on heat engine. Gravity storage is not subject to such limit. Emphasis mine. Don't be a pedant.
- Ensorceled 6y agoWell, my important point was that hydrocarbons are fucking terrible but keep focusing on the first part.
- ergwwrt 6y ago2nd law of t only applies to mass. Gravity works via gravitons which are massless so the 2nd does not apply..