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The origins of the steam engine

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Re: The origins of the steam engine

#3

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.

It is a toy. It is not efficient in first place and how it works doesn't actually produce much torque. Or likely power either.

Water power with something like Egyptian screws might have been better solution.

Re: The origins of the steam engine

#4
post #3

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.

It is a toy. It is not efficient in first place and how it works doesn't actually produce much torque. Or likely power either. Water power with something like Egyptian screws might have been better solution.

> It is a toy

Exactly. It was basically a kettle on an axle, with two spouts, causing it to spin as the water boiled off. It had no valves so couldn't build up enough pressure to do usable work. It couldn't be reloaded with water when operating. The overall concept was constrained by the limited metal working skills of the era, which weren't up to making reliable high-pressure vessels.

The development of usable pistons for steam engines followed centuries of experience gained making cannons and associated ammunition, which slowly provided the skills to make metal tubes that fitted and could hold pressure without themselves exploding.

Re: The origins of the steam engine

#5
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

Re: The origins of the steam engine

#6

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

What you’re missing here is pressure.

Steam turbines work not because of steam alone, you can fill a room with steam insert a turbine and nothing happens. To get them to spin you need higher pressure on the input side of the turbine than the output. If you want to have steam go up a shaft that’s going to increase the pressure on output side and thus reduce the amount of energy generated by the turbine.

Re: The origins of the steam engine

#8
post #6

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

What you’re missing here is pressure. Steam turbines work not because of steam alone, you can fill a room with steam insert a turbine and nothing happens. To get them to spin you need higher pressure on the input side of the turbine than the output. If you want to have steam go up a shaft that’s going to increase the pressure on output side and thus reduce the amount of energy generated by the turbine.

Yes, it's the difference in pressure/heat that is exploited, as Sadi Carnot noted (by analogising the steam engine to a water-wheel exploiting a fall of water, treating it as a "fall of heat")

Re: The origins of the steam engine

#9
post #3

Earlier quoted context omitted.

It is a toy. It is not efficient in first place and how it works doesn't actually produce much torque. Or likely power either. Water power with something like Egyptian screws might have been better solution.

> It is a toy Exactly. It was basically a kettle on an axle, with two spouts, causing it to spin as the water boiled off. It had no valves so couldn't build up enough pressure to do usable work. It couldn't be reloaded with water when operating. The overall concept was constrained by the limited metal working skills of the era, which weren't up to making reliable high-pressure vessels. The development of usable pisto…

Though note, from the post, that there were some applications of stationary aeolipiles with their spouts directed at vanes to do some light mechanical work - things like turning roasting spits and grinding pigments. All known throughout the fourteenth through to the seventeenth centuries, if not earlier, though it's unclear how widely any of them were adopted.
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