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The origins of the steam engine

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21–30 of 46 posts

Re: The origins of the steam engine

#21

oh wow. That makes me wonder... could we make a steam engine using the power of the sun that heats up water to boil into a fan that generates electricity, that then catches the water and flows down running a hydro generator so you get energy on the way up and on the way down. I wonder what kind of efficiency that would have compared to modern day solar? probably laughable

We could, but it would certainly be less efficient than other approaches. I haven’t seen it brought up recently but there’s a simple quote that makes it easy to evaluate any sort of energy related discussion based on the laws of thermodynamics:

“You can’t win, you can’t break even, and you can’t quit the game.” - C.P. Snow [1] (No idea if that’s the correct attribution, I heard it from a professor 20 years ago)

My personal shorthand for this is to focus on the efficiencies of energy transformation and transport. Converting or moving energy means we lose some fraction of the total energy. All we can do is minimize that fraction.

The main point being that with that mental framework, I can easily assume that your posited approach won’t be more efficient than a solar panel or some other process with fewer transformation steps because each step magnifies energy loss inefficiencies.

Basically, the entirety of the energy debate is two things: How can we harvest energy cheaply and move it with minimal waste.

This is the basis for the whole room temp superconductor story that captured a bunch of our nerd imaginations, what happens if you get super close to zero energy loss while moving electrons?

Also, one more thing to keep in mind is constraints. Your proposed solution may be way more efficient by some metric if we change the constraints. For instance, my brain mostly goes to transportation which is transport and storage with immediate demand requirements. However, if our requirements were different along the lines of “lets store as much energy as possible over months, to slowly release it over months”, inefficiencies of scale change things. Then maybe slowly moving water uphill during summer while releasing slowly during winter is a valid thing to consider [2].

[1] https://gohighbrow.com/laws-of-thermodynamics/

[2] https://medium.com/drax/how-to-turn-a-mountain-into-a-giant-...

Re: The origins of the steam engine

#23

oh wow. That makes me wonder... could we make a steam engine using the power of the sun that heats up water to boil into a fan that generates electricity, that then catches the water and flows down running a hydro generator so you get energy on the way up and on the way down. I wonder what kind of efficiency that would have compared to modern day solar? probably laughable

Thermal solar energy is a thing. The important part is concentrating the energy with mirrors to reach high temperatures and pressures. They use solar turbines because those are more efficient than steam engines. My understanding is that the efficiency is close to solar panels. Solar thermal isn't used because solar panels are much cheaper and simpler. In world without cheap solar panels, solar thermal would be prefer…

This is an awesome point related to the post I just made as a sibling comment. Solar energy is cheap! The sun blasts us with whatever crazy number real energy folks know by heart. The issue is after we collect it, how do we move it?

If you’ve read Project Hail Mary, the sci-fi part isn’t collecting energy, its the lossless transport.

Hopefully that’s not a spoiler.

Re: The origins of the steam engine

#24

The Greeks made a sort of "toy" that spins when a fire boiled water. It's almost a shame that no one took it a step further. Imagine ancient Greece and Rome entering a steam age in the 1st or 2nd century.

That's Hero's aeolipile, mentioned near the end of the article. Most scholars tend to agree that Rome [1] was nowhere near an Industrial Revolution. One take on it is here: https://acoup.blog/2022/08/26/collections-why-no-roman-indus... , but the general tl;dr is that a) even if you backported a fully working Watt steam engine to Classical Antiquity and they could manufacture it, there's nothing that they could use i…

You are correct as far as anyone alive today can know. I would just add that there was quite a bit of cultural aversion to non-agricultural enterprises among the senatorial class. Merchants and tradesmen were looked down upon. This was made worse as many skilled laborers in the city of Rome were actually slaves.

Re: The origins of the steam engine

#25

oh wow. That makes me wonder... could we make a steam engine using the power of the sun that heats up water to boil into a fan that generates electricity, that then catches the water and flows down running a hydro generator so you get energy on the way up and on the way down. I wonder what kind of efficiency that would have compared to modern day solar? probably laughable

Thermal solar energy is a thing. The important part is concentrating the energy with mirrors to reach high temperatures and pressures. They use solar turbines because those are more efficient than steam engines. My understanding is that the efficiency is close to solar panels. Solar thermal isn't used because solar panels are much cheaper and simpler. In world without cheap solar panels, solar thermal would be prefer…

A major issue with solar thermal is clouds and dust. PV works fine with indirect light from a dusty panel, but to concentrate sunlight you need a clear sky and clean surfaces. Next you need 2 axis solar tracking to get high grade heat or a complex trough system with a separate working fluid and complex plumbing/heat loss. Next you lose energy trying to concentrate sunlight and from the heat engine itself.

In the end it seems like it should be cheap but nobody got it anywhere lose to PV pricing.

Re: The origins of the steam engine

#27
post #12

Interestingly, the steam engines of the Titanic made use of the vacuum generated by condensing steam to extract additional energy from steam that's below atmospheric pressure. https://www.titanicology.com/Titanica/TitanicsPrimeMover.htm

As were most if not all the other steamships of that era; compound steam engines were already over a century old by then.

https://en.wikipedia.org/wiki/Compound_steam_engine

Re: The origins of the steam engine

#29

The Greeks made a sort of "toy" that spins when a fire boiled water. It's almost a shame that no one took it a step further. Imagine ancient Greece and Rome entering a steam age in the 1st or 2nd century.

Here on HN I read about the theory, that one of the main reasons that the time of the steam engines came, was the rise of the cannon. Over generations, every king wanted to have the best cannons as that translated into power - and once you can build a cannon, you can build something that can contain high pressures and give that pressure a direction. In other words, to take that toy further, they would have also had t…

Hmm, I don't think Savery's engine would have required that - it's just a copper vessel, and the pipes were often even made of wood. I've often seen the cannon theory applied to piston-using engines, but that was the next stage with Papin and Newcomen and beyond (hopefully our chapter II)

Re: The origins of the steam engine

#30
post #12

Interestingly, the steam engines of the Titanic made use of the vacuum generated by condensing steam to extract additional energy from steam that's below atmospheric pressure. https://www.titanicology.com/Titanica/TitanicsPrimeMover.htm

As were most if not all the other steamships of that era; compound steam engines were already over a century old by then. https://en.wikipedia.org/wiki/Compound_steam_engine

Comments like these are the reason that I still read hacker news.

I can come to a thread, and almost always there will be somebody replying with extra information on the topic at hand.

Thank you.

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