This story was created for the Google Expeditions project by Vida Systems, now available on Google Arts & Culture
Their power allowed large–scale industrial processes to take place en masse, and in turn led into the large spike of production and technological advancements at the end of the last millennium.
They have gotten more compact and powerful over time, and their progress has been nothing short of astounding.
An Early Attempt: Hero’s Engine
The earliest recorded steam engine was the Aeolipile, made in 1st century AD by Greek inventor and engineer Hero of Alexandria. Hero probably did not expect his invention to inspire a leap in technological advancement a millennium later.
It is a very rudimentary design with no known practical purpose but to be a “temple wonder” or decoration. It consists of a ball rotated by steam jets, powered by boiling water beneath.
Named after the Greek God of wind, Aeolus, the Aeolipile was a relatively simple invention. It consists of a rotating ball, with the rotation made possible by steam jets powered by boiling water underneath the ball.
Hero of Alexandria (10 AD–70 AD)
A famous engineer in his time and beyond, Hero was also the inventor of the Aeolipile. His other inventions include the vending machine and the windwheel — 1 of the first tools for harnessing wind on land.
Entering the Modern Age: Savery and Newcomen
More than a millennium since the Aeolipile, numerous inventors experimented with the idea of using steam as a power source.
Milestones were reached by Thomas Savery and Thomas Newcomen who, in a few decades apart, utilized steam power for practical use and added further applications for it.
Savery Engine (1698)
British inventor Thomas Savery, patented his rudimentary steam machine in 1698. It had no pistons or moving parts as Savery intended the engine to be used to raise water out of wells using the partial vacuum created by introducing steam and rapidly cooling it.
Newcomen Engine (1712)
The Newcomen Engine in 1712 was the first steam engine to utilize steam power for mechanical work. Steam pushed a piston up and was cooled by water, creating a vacuum that let the piston down by gravity. It was also used to pump water.
The Industrial Revolution: Watt and Trevithick
The industrial revolution was born out of high production demands, and with that came innovations that made processes more efficient and powerful.
A signature development in steam engines during the industrial revolution came from Scotland’s James Watt, whose improvements to the Newcomen engine made it use less steam and produce more power.
Richard Trevithick improved on the engines further by introducing high pressurized steam, and industrial processes gained a leap of progress in just a matter of decades.
Watt Steam Engine (1765)
James Watt drastically improved the Newcomen engine. His design separates the cylinder where the steam is inserted and where it is cooled down, in a separate condenser. The steam cylinder loses much less heat and it takes less coal to heat because of it.
Trevithick utilized high–pressure steam for his steam engine, which could move the pistons instead of relying on a partial vacuum for the downstroke. With this design, he created the “Puffing Devil” — a locomotive that was able to carry 6 people in 1801!
Evolution of Watt Steam Engine
Watt later allowed steam to work on both sides of the cylinder, allowing for both push and pull. For rotational work, Watt also created the “parallel motion” linkage which allows the piston to move up and down while transferring movement to an arcing beam.
Powering the World: Applications of Steam Engines
Eventually, steam engines became commonplace as power sources, and the 1800s relied greatly on steam power for commercial uses like transportation. Today, steam power in transportation is no longer common but it is used for generating electricity. Steam–powered turbines are still found in nuclear power plants today
Steam engines were used in road vehicles ever since Trevithick's Puffing Devil with engineers continually improving the design and increasing the speed. In Great Britain, legislations prevented the spread of these vehicles — limiting speeds to 4 mph because of safety fears.
Train locomotives enjoyed great improvements and widespread use in the 19th century. Intense rivalry happened between engineers, leading to much innovation. The first steam railway company, Stockton and Darlington Railway, was formed in Northeast England in 1829.
Steam turbines used for generating electricity had a simple design — rotating the turbine as a mechanical force powered by high–pressure steam. In 1884, Sir Charles Parsons created the first modern turbine, connected to a dynamo that generated electricity.
His design was adopted in major power stations worldwide.
Growth of Power
Over the years, steam engines grew more and more powerful. A good measurement for their power was developed by James Watt, the inventor of the Watt steam engine and the watt power notation.
Watt used “horsepower” to compare steam engines to the power generated by draft horses with 1 horsepower (hp) equal to 745.7 watts.
Savery Engine (1698)
The simple and basic steam engine that was developed by Thomas Savery consisted of a non-mechanical water pump that worked with steam and a vacuum. This early engine design managed to generate only 1 hp of power.
Newcomen Engine (1712)
Thomas Newcomen’s practical improvements on Savery’s model incorporated a piston. and instead of steam pressure it used the natural force of gravity. The Newcomen steam engine was able to produce 5 hp of mechanical work as power.
Watt Engine (1781)
James Watt’s improvement on Newcomen’s steam engine was revolutionary, with the design making its way into trains, boats, and automobiles. He added a separate condenser into his model and the engine was then capable of creating 10 hp.
Corliss Engine (1849)
After decades of innovation, American George Corliss made strides with the powerful Corliss engine, which featured valves that admitted steam to and exhausted it from the cylinder. An engine installed to power the Ford factory had produced hp!
Steam Power Today
While steam power is not as prevalent as it was in the industrial revolution era, it is still very relevant today. It is now mainly used for 1 thing: electricity generation. By 1996, 90% of US power plants used steam turbines to function.
Today, steam turbines are still dominant systems in electricity generation worldwide. We see their utilization from the conventional coal power plants to the cleaner, less polluting nuclear and geothermal power plants.
Coal is burned to create steam, and the steam jets are then used to rotate turbines that generate electricity - a la the Parsons turbine. Burning coal, however, releases carbon dioxide pollution that is very undesirable.
With geothermal plants, the power source is the natural steam or hot water deep within the earth. The steam or the hot water transformed into steam is used to rotate turbines. Due to the lack of combustion, this process is less pollutive.
Nuclear fission reactors are used to generate heat that then creates steam that is used to rotate turbines. This method is controversial because while it is a clean and efficient source, it uses dangerous radioactive isotopes.