History UsefulNotes / SteamPowerAndOtherIndustrialUses

At the time, the word "engine" was used to mean any sort of complicated or clever device (Think the word ingenious). Siege towers, catapults, and such were Siege Engines, an early mechanical computer was a "calculation engine". (The word kind of sticks around today in [[UsefulNotes/GameEngine Game Engine]]). Along these lines, a clever device using steam was a "Steam Engine". As power generating engines got common, the word got its modern meaning.

Most ships have shifted to other sources of power, but steam systems are still used on nuclear powered ones: nuclear power, as mentioned above, produces heat, but a steam system is needed to convert that heat into useful energy. Nuclear power is used by navies and some icebreakers. On navy ships, it allows long patrols while using little space for fuel[[note]]Fission releases so much energy that several decades of fuel can be loaded into a somewhat small reactor[[/note]], on submarines, nuclear power requires no oxygen and allows the sub to stay underwater for months if needed (crew supplies are the limit here). Militaries also usually have the money and clout to be allowed to use and spend money on such systems.

Railroads were made possible by steam engines. Travel on rails is more energy efficient than on roads or the ground, so like on ships, locomotives have some extra space for a bigger engine. The basic design of steam locomotives never changed much outside some early experiments, and you can recognize the design in [[SteamNeverDies pop culture]]. Fuel and water are fed from a tender (that cart behind the engine) or from tanks on the locomotive. Both are fed to the boiler, in your standard [[TheWestern western]] or WesternAnimation/ThomasAndFriends, this is the large horizontal cylinder that takes up most of the locomotive. Fuel is burned in a firebox for heat, water is pumped separately thriugh the boiler. Exhaust from burning fuel goes up the chimney, steam goes to pistons at the bottom of the locomotive (those small horizontal cylinders on either side.). Pistons power the wheels, they push those bars you see attached to the wheels to turn them. The familiar "chug chug" sound you hear comes from steam travelling through the piston, as the train moved faster, the piston did as well, as did the sound. Locomotives vented steam out the chimney: condensers would take up a lot of space, especially air cooled ones, so bringing extra water proved simpler. Steam turbines were never commonly used on locomotives despite the size and efficiency advantages they theoretically would bring, they only run well at one speed, but locomotives need to change speeds often.

Most steam engines today and historically follow a similar cycle. Start with low pressure water. First, pressurize it using a pump. Then, feed it into a boiler. Here, the water is boiled and heated. Next, feed the steam into a power device, either a piston or turbine. Today, turbines are the device of choice, but they were invented later. In the power device, steam pushes against the piston or turbine, doing work. The energy for this work comes from the heat in the steam, as a result, the steam cools. As the steam pushes, it also expands, and the lower temperature and higher volume mean its pressure drops. Once the team is expanded as much as it can be, send it to a condenser, where it changes back into low pressure water, and the cycle repeats.

The work it takes to pump a liquid is the volume multiplied by the change in pressure, the work done by an expanding gas is roughly the change in volume multiplied by the pressure (That;s not a typo, the reason for this difference is a bit much to explain. Expanding gases change pressure as they expand, so more exact formulas exist to measure work). Liquid water takes up much less space than steam, and gases expand by quite a lot more the liquids do, so expanding steam does far more work than it takes to pump water. The fraction of heat added that is captured as useful work is called the thermal efficiency of the engine, the best steam engines can reach around 40-45% of heat energy to work. Because the boiling point of any liquid rises with temperature, the boiler temperature must be higher than the condenser temperature. A higher pressure difference between boiler and condenser is useful if possible, it allows the steam to do more work in the power device, increasing thermal efficiency.

Actual steam systems can be more complex than this: steam may be used elsewhere, preheating and precooling of certain flows is common, reheating of steam and passing it through a second turbine before condensing it is sometimes done. These work around or take advantage of the properties of the water, or are other ways to get that little extra efficiency increase from a steam system. Some steam engines in the past did not have a condenser, instead, outside water was fed to the boiler, then steam was vented after being used for power: many railroads ran this way, as did many early engines in all uses. A reversal of a steam engine is how most refrigeration and air conditioners work. A liquid is boiled at a low temperature and pressure, compressed instead of expanded, condensed at a high temperature and pressure, and the pump is usually replaced by a simpler to use valve, that lowers pressure by restricting flow. The low pressure partially evaporates some liquid, cooling it to the low temperature needed, and the cycle repeats.

The first steam engines used a different method: using steam to create a vacuum. Steam boiling at atmospheric pressure would fill a piston, then be condensed. The condensed water took up a lot less space, sucking the piston (more properly, allowing outside atmosphere to push the piston) back into place, where a valve would open to let in more steam, and the cycle would repeat. It's a much less efficient system, and takes up for more space for its power than high pressure steam systems, but was easier to build using the tools of the time.

!!The History of Steam Engines, or why it is called Steampunk

Devices and ideas using steam to do cool things have existed for a long time, but the first practical engines were created around 1700 in Western Europe, Britain in particular. These first devices were used as pumps for coal mines. They were vacuum engines as described above: boiled water filled a piston, letting it rise, then cool water was added, condensing the steam and sucking the piston back down, to start the cycle again. The piston was attached to a beam, on the opposite end of the beam was the pumping mechanism. These engines were very inefficient, but coal near a coal mine was cheap, and they were easier to take care of than work animal who otherwise would have powered the pumps.

At the time, the word "engine" was used to mean any sort of complicated or clever device (Think he word ingenious). Siege towers, catapults, and such were Siege Engines, an early mechanical computer was a "calculation engine". (The word kind of sticks around today in [[UsefulNotes/GameEngine Game Engine]]. Along these lines, a clever device using steam was a "Steam Engine". And thus the modern meaning of engine started.

Steam engines were improved very slowly over the 1700's, and mostly used in pumps or other niche uses. However, in the late 1700's, a man named James Watt added a couple important improvements. The first, a so called double acting piston, where a steam cycle took place on both sides of the piston. This allowed engines to take up less space and weight, a single piston could do the former work of 2 pistons. Second, he added a separate condenser, sending the steam to a separate location to be condensed instead of inside the cylinder itself. This kept the power cylinder and the steam inside hot, taking up more space and needing less from a boiler to fill the cylinder. This outside condenser improved the engine's efficiency, enough that factories began using steam engines to power their machinery. Steam entering the cylinder was now pushing against steam being sucked out into the condenser, than the chambers reversed roles.

Watt's engines were an improvement, but he also fought the next big improvement in steam engine design: using higher pressure steam. Higher pressure steam allows for greater thermal efficiencies as well as smaller engines: Higher pressures mean a smaller piston can generate the same force and the same power. These engines had been proposed in the 1700's, but started being built in the 1800's.

It is also during this time that the first steamboats and railroads were created. Early steamboats were not as fast as sailing ships, and unlike sailing ships they needed to carry fuel, too much for long ocean travel. However, they were reliable, running no matter what the wind was doing, and were used in rivers where they could stop to pick up fuel. Several experiments in land transport were tried, but freely moving vehicles turned out to be hard to build with steam. Travel on rails was a different story: horses had been used to pull carts on rails, travel on rails takes less energy than over ground. Stationary steam pullers and later steam powered locomotives could successfully fill this role, and the first railroads started service around 1800. Britain was a leader in these technologies, but they also expanded in the early united States as well.

Railroads would have an unusual economic effect in history: For most of history, water transport was far, far cheaper than land transport. Ships are still cheaper today for moving goods, not no longer have as big an advantage. As a result, land based regions became much more economically connected in the past hundred years or so. (One example may be the [[UsefulNotes/TheAmericanCivilWar U.S. Civil War]], most waterways other than the Great lakes went at least somewhat north/south, but railroads helped tie the northern states together.)

Steam engine builders may not have known about Carnot, but they would have known his work's most important implication: higher temperature and pressure differences were more efficient. However, materials and manufacturing techniques limited how much pressure steam engines could contain. Boiler explosions were a common issue, one shows up in ''Literature/AdventuresOfHuckleberryFinn'' for example. But as part of industrialization, these things improved over time (powered partly by said steam engines), and steam power did as a result. Steamboats, Railroads, and steam powered factories continued to expand. In 1837, a steamship taking advantage of the SquareCubeLaw (The drag on a ship that the engine most overcome goes as the square of the length, so required fuel does as well, while the room inside the ship increases as the cube. Build a large enough ship, and it has room for fuel to cross an ocean, build larger and it has room for useful things as well) crossed the Atlantic for the first time, followed by more ocean going steamships.

Later in the 1900's, descendants of that 1850's engine a few paragraphs ago became much more common. That was the first internal combustion engine, and these engines have replaced steam in many uses. Steam power has itself gained new uses also: most famously, the development of nuclear power. Steam today continues to improve, using new material, running at higher temperatures and pressures, being further optimized, though the cycle is still largely the same boiler/turbine/condenser/pump that it has been for about a century. The general design of modern engines comes from steam devices: Pistons are used in diesel and spark plug engines and variants, turbines are used in gas turbines including most jets.

The main competitor to steam engines are various types of internal combustion engines: Gas turbines and jets, diesel and spark plug engines and variants, chemical rockets can also be included in this group. It's not just a fancy name: In a steam engine, the heat source and the "working fluid" are separate, steam and water push the piston, turbine, etc., while an outside source provides the heat. In internal combustion engines, gaseous combustion products do the work, the same material acts both as a heat source and working fluid. Other types of "external combustion engines" exist, but aren't commonly used for various reasons.

Railroads were made possible by steam engines. Travel on rails is more energy efficient than on roads or the ground, so like on ships, locomotives have some extra space for a bigger engine. The basic design of steam locomotives never changed much outside some early experiments, and you can recognize the design in [[SteamNeverDies pop culture]]. Fuel and water are fed from a tender (that cart behind the engine). Both are fed to the boiler, in your standard [[TheWestern western]] or WesternAnimation/ThomasAndFriends, this is the large horizontal cylinder that takes up most of the locomotive. Exhaust from burning fuel goes up the chimney, steam goes to pistons in front of the engine (those small horizontal cylinders on either side, near the front). Pistons power the wheels, they push those bars you see attached to the wheels to turn them. The familiar "chug chug" sound you hear comes from steam travelling through the piston, as the train moved faster, the piston did as well, as did the sound. Locomotives vented steam out the chimney: condensers would take up a lot of space, especially air cooled ones, so bringing extra water proved simpler. Steam turbines were never commonly used on locomotives despite the size and efficiency advantages they theoretically would bring, they only run well at one speed, but locomotives need to change speeds often.

Steam engine builders may not have known about Carnot, but they would have known his work's most important implication: higher temperature and pressure differences were more efficient. However, materials and manufacturing techniques limited how much pressure steam engines could contain. Boiler explosions were a common issue, one shows up in [[Literature/AdventuresOfHuckleberryFinn]] for example. But as part of industrialization, these things improved over time (powered partly by said steam engines), and steam power did as a result. Steamboats, Railroads, and steam powered factories continued to expand. In 1837, a steamship taking advantage of the SquareCubeLaw (The drag on a ship that the engine most overcome goes as the square of the length, so required fuel does as well, while the room inside the ship increases as the cube. Build a large enough ship, and it has room for fuel to cross an ocean, build larger and it has room for useful things as well) crossed the Atlantic for the first time, followed by more ocean going steamships.

If you've lived or worked in a building with a radiator, you've experienced a common use of steam: Heat transfer. Steam is used in heating systems, chemical factories, and other places to move heat from hot places to cool ones. Steam has a couple advantages: first, water is nontoxic,easily available, well understood. Second, steam can easily transfer heat through boiling and condensing. Heat transfer through boiling and condensation is much faster than other methods, requiring less space and a lower temperature difference to move the heat. A boiling or condensing material also releases and absorbs heat without changing temperature: If you cook, you take advantage of this when boiling, steaming, or frying foods, the boiling liquid keeps the same temperature however much heat is added (compare pan cooking where things can overheat/burn easily). this temperature control makes it particularly useful in chemical plants: operations like distillation and some chemical reactions require specific temperatures for best results. Any liquid boils at a different temperature depending on what pressure it is at, so by simply changing the pressure, the temperature of heat transfer is chosen.

Most steam engines today and historically follow a similar cycle. Start with low pressure water. First, pressurize it using a pump. Than, feed it into a boiler. Here, the water is boiled and heated. Next, feed the steam into a power device, either a piston or turbine. Today, turbines are the device of choice, but they were invented later. In the power device, steam pushes against the piston or turbine, doing work. The energy for this work comes from the heat in the steam, as a result, the steam cools. As the steam pushes, it also expands, and the lower temperature and higher volume mean its pressure drops. Once the team is expanded as much as it can be, send it to a condenser, where it changes back into low pressure water, and the cycle repeats.

Actual steam systems can be more complex then this: steam may be used elsewhere, preheating and precooling of certain flows is common, reheating of steam and passing it through a second turbine before condensing it is sometimes done. These work around or take advantage of the properties of the water, or are other ways to get that little extra efficiency increase from a steam system. Some steam engines in the past did not have a condenser, instead, outside water was fed to the boiler, than steam was vented after being used for power: many railroads ran this way, as did many early engines in all uses. A reversal of a steam engine is how most refrigeration and air conditioners work. A liquid is boiled at a low temperature and pressure, compressed instead of expanded, condensed at a high temperature and pressure, and the pump is usually replaced by a simpler to use valve, that lowers pressure by restricting flow. The low pressure partially evaporates some liquid, cooling it to the low temperature needed, and the cycle repeats.

The first steam engines used a different method: using steam to create a vacuum. Steam boiling at atmospheric pressure would fill a piston, than be condensed. The condensed water took up a lot less space, sucking the piston (more properly, allowing outside atmosphere to push the piston) back into place, where a valve would open to let in more steam, and the cycle would repeat. It's a much less efficient system, and takes up for more space for its power than high pressure steam systems, but was easier to build using the tools of the time.

Devices and ideas using steam to do cool things have existed for a long time, but the first practical engines were created around 1700 in Western Europe, Britain in particular. These first devices were used as pumps for coal mines. They were vacuum engines as described above: boiled water filled a piston, letting it rise, than cool water was added, condensing the steam and sucking the piston back down, to start the cycle again. The piston was attached to a beam, on the opposite end of the beam was the pumping mechanism. These engines were very inefficient, but coal near a coal mine was cheap, and they were easier to take care of than work animal who otherwise would have powered the pumps.

Railroads would have an unusual economic effect in history: For most of history, water transport was far,far cheaper than land transport. Ships are still cheaper today for moving goods, not no longer have as big an advantage. As a result, land based regions became much more economically connected in the past hundred years or so. (One example may be the [[UsefulNotes/TheAmericanCivilWar U.S. Civil War]], most waterways other than the Great lakes went at least somewhat north/south, but railroads helped tie the northern states together.)

And now we get to the era of {{Steampunk}}. In the late 1800'sand 1900's, if you lived in the right place, you would buy products from steam powered factories, and use steam powered ships and railroads to travel. Britain's advantages in these technologies helped it control the largest empire in the world, and British culture became highly influential as a result. (Certainly in the {{Steampunk}}genre itself.)

Becoming more common during this time were so called compound steam engines: Instead of passing steam through one piston and than a condenser, steam was routed through several pistons in a row. This was to deal with an efficiency limitation: Cylinder walls in any engine will tend towards the average temperature in their cycle. As temperature differences in steam engines became higher, this mean that hot steam entering a cylinder would lose a lot of heat to medium temperature walls, cooling the steam, causing a lower pressure, causing it to do less work. Later in the cycle, this heat would go back into the steam, which would take the heat to the condenser. More heat loss and less work means lower efficiency. Compound engines reduced this problem: Steam would first be sent to one piston where it expanded, than the some what cooler, lower pressure steam sent to another piston, possibly another, etc., doing work,cooling, and lowering pressure in each step. Each piston experienced a lower temperature range, and therefor less heat was lost. However, more pistons had to be balanced with energy losses from flowing through more valves and pipes, plus the cost of a more complex engine. Most common were three stages in so called triple expansion engines.

The main competitor to steam engines are various types of internal combustion engines: Gas turbines and jets, diesel and spark plug engines and variants, chemical rockets can also be included in this group. Its not just a fancy name: In a steam engine, the heat source and the "working fluid" are separate, steam and water push the piston, turbine,etc., while an outside source provides the heat. In internal combustion engines, gaseous combustion products do the work, the same material acts both as a heat source and working fluid. Other types of "external combustion engines" exist, bu aren't commonly used for various reasons.

Steam power was historically used for factories, to power machinery, but most modern ones use outside electricity instead. However, chemical plants do use steam power systems sometimes. Chemical reactions being what they are,they can release a lot of heat, and it often makes sense to use this heat to power a steam system, producing power to sell to the electrical grid or to help power the plant.

Think of a non navy ship name,ans "SS Something" probably comes to mind. For their size, ships require little energy to move, and as a result can have space for relatively large engines. They also run constantly for days or weeks at a time, usually running at a mostly constant speed, and at port take a long time to load and unload (allowing the engines to be started and stopped), so are also a good fit for steam engines. Fuel storage on those long trips is another issue, even requiring little energy, long trips can require a lot of space to be used for fuel, so the generally high thermal efficiency of large steam engines is useful.

Also using steam power are some liquefied natural gas ships. Such gas is caried in insulated containers, but no insulation is perfect, and burning off the so called "boil off gas" produced as heat leaks in by burning it in a steam boiler has proven common. However, newer modified diesel engines that burn off this gas have been produced, so LNG carriers will likely switch to these if natural gas continues to be used for long enough.

Railroads were made possible by steam engines. Travel on rails is more energy efficient than on roads or the ground, so like on ships, locomotives have some extra space for a bigger engine. The basic design of steam locomotives never changed much outside some early experiments,and you can recognize the design in [[SteamNeverDies pop culture]]. Fuel and water are fed from a tender (that cart behind the engine). Both are fed to the boiler, in your standard [[TheWestern western]] or WesternAnimation/ThomasAndFriends, this is the large horizontal cylinder that takes up most of the locomotive. Exhaust from burning fuel goes up the chimney, steam goes to pistons in front of the engine (those small horizontal cylinders on either side, near the front). Pistons power the wheels, they push those bars you see attached to the wheels to turn them. The familiar "chug chug" sound you hear comes from steam travelling through the piston, as the train moved faster, the piston did as well, as did the sound. Locomotives vented steam out the chimney: condensers would take up a lot of space, especially air cooled ones,so bringing extra water proved simpler. Steam turbines were never commonly used on locomotives despite the size and efficiency advantages they theoretically would bring, they only run well at one speed, but locomotives need to change speeds often.

And heat recovery in chemical plants brings this useful notes to non-steam steam engines. "But its called a '''steam''' engine! how can it not use steam?!" you maybe thinking. Actually none of how these engines work requires steam, any liquid that changes to a gas when heated and back to a liquid when cooled can in theory do the job. (It doesn't even need to boil and condense: a liquid that chemically decomposed into gases when heated, than reformed from those gases when cooled, would also work, though no such liquid has been proposed.) Water is by far the most common: it is easily available, non-toxic, boils/condenses at convenient temperatures and pressures, is well understood, among other reasons. However, there are a couple non steam based systems worth mentioning here.

First is the organic Rankine cycle[[note]]Rankine cycle is the name for an ideal steam engine cycle, as it might be analyzed using thermodynamics. As an analogy, "Otto cycle" is the idea spark plug engine cycle, "Diesel cycle" for ideal diesel engines, among other such cycles[[/note]], used for low temperature waste heat (maybe around 100-200 Celsius/200-400 Fahrenheit) or so. At such low temperatures, the pressure difference between water in a boiler and condenser would be very low, making for difficult steam engine design. However, many organic chemical have low boiling points, and can be used effectively in steam cycles at these temperatures. lowtemperature differences mean low thermal efficiencies, and the fraction of heat recovered compared to whatever process generated it is very low, but in a big industrial operation, even this small fraction of heat is worth building a system to capture.

Ideally as much heat as possible will be extracted from whatever its source is, and that heat will be transferred to a boiling material that closely matches it in temperature. The boiling working fluid and source of heat would flow in opposite directions, the working fluid smoothly heating to closely match the heat source material near it in temperature. However, a single chemical does not do this when boiling. Instead, it heats up smoothly, than stays at the same temperature while absorbing heat and turning into a gas, than the gas goes back to smoothly increasing in temperature. However, multiple chemical mixed together behave differently when boiling. when the liquid mixture first starts boiling, the more easily boiled chemical turns to gas more easily, becoming concentrated in the gas while leaving the liquid slightly more concentrated in the higher boiling liquid. This leftover liquid requires a slightly higher temperature to boil, so heats up slightly. the lower boiling chemical continues to evaporate more easily, leaving a liquid more concentrated in low boiling chemical, and the process continues. The result is that the mixture increases in temperature while boiling, creating a temperature change closer to the ideal smooth increase than a single chemical could.

Railroads were made possible by steam engines. Travel on rails is more energy efficient than on roads or the ground, so like on ships, locomotives have some extra space for a bigger engine. The basic design of steam locomotives never changed much outside some early experiments,and you can recognize the design in [[SteamNeverDies pop culture]]. Fuel and water are fed from a tender (that cart behind the engine). Both are fed to the boiler, in your standard [[TheWestern western]] or WesternAnimation/ThomasTheTankEngine, this is the large horizontal cylinder that takes up most of the locomotive. Exhaust from burning fuel goes up the chimney, steam goes to pistons in front of the engine (those small horizontal cylinders on either side, near the front). Pistons power the wheels, they push those bars you see attached to the wheels to turn them. The familiar "chug chug" sound you hear comes from steam travelling through the piston, as the train moved faster, the piston did as well, as did the sound. Locomotives vented steam out the chimney: condensers would take up a lot of space, especially air cooled ones,so bringing extra water proved simpler. Steam turbines were never commonly used on locomotives despite the size and efficiency advantages they theoretically would bring, they only run well at one speed, but locomotives need to change speeds often.

Steam: Take some water, heat it up until it boils. Yet this everyday substance [[ExcessiveSteamSyndrome fills factories]], will [[SteamNeverDies power trains until the end of time]], powers the SS something or other, and has an [[{{Steampunk}} entire gene]] named after it. Oh, and in real life, is one of civilization's most important inventions, powered the industrial revolution, and led to the development of many modern technologies.

The work it takes to pump a liquid is the volume multiplied by the change in pressure, the work done byan expanding gas is roughly the change in volume multiplied by the pressure (That;s not a typo, the reason for this difference is a bit much to explain. Expanding gases change pressure as they expand, so more exact formulas exist to measure work). Liquid water takes up much less space than steam, and gases expand by quite a lot more the liquids do, so expanding steam does far more work than it takes to pump water. The fraction of heat added that is captured as ueful work is called the thermal efficiency of the engine, the best steam engines can reach around 40-45% of heat energy to work. Because the boiling point of any liquid rises with temperature, the boiler temperature must be higher than the condenser temperature. A higher pressure difference between boiler and condenser is useful if possible, it allows the steam to do more work in the power device, increasing thermal efficiency.

In physics/thermodynamics, a steam engine is a type of heat engine: a system that converts a temperature difference into work by absorbing heat at a high temperature, converting some of it to useful work, and releasing the rest at a low temperature. In a steam engine, the boiler acts as the high temperature source, and the condenser as alow temperature source. Thermodynamics is well tested, some results show that heat loss is necessary even if the engine works perfectly, that a temperature difference is required, and makes clear a number of results earlier in this section. Today, thermodynamic results are used to help optimize steam systems.

Devices and ideas using steam to do cool things have existed for a long time, but the first practical engines were created around 1700 in Western Europe, Britain in particular. These first devices were used as pumps, in coal mines in particular. This was a time when numerous scientific discoveries were being made, especially in early chemicstry and physics, and these inspired several ideas leading to early steam engines. The earliest engines were vacuum types described above, using condensing steam to either directly suck water upwards, or to pull a piston used to power a separate pump.

Steam engines were improved very slowly over the 1700's, and mostly used in pumps or other niche uses. However, in the late 1700's, a man named James Watt added a couple important improvements: Instead of being condensed directly to generate a vacuum, steam was sent to a separate condenser. He also created a so called double acting piston, where a steam cycle took place on both sides of a piston instead of just one. The first change greatly improved fuel efficiency, the second decreased the needed size of engines, and his engines were the first widely successful engines, used to power newly developing factories as well as pumping water.

Watt's engines were an improvement, but he also fought the next big improvement in steam engine design: using higher pressure steam. if you've read above, higher pressure steam can be more energy efficient, and the engines can also be smaller, requiring smaller cylinders to produce the same overall forces. These engines had been proposed in the 1700's, but were first put into practice in the late 1700's and early 1800's.

It is also during this time that the first steamboats and railroads were created. Early steamboats were not as fast as sailing ships, and the amount of fuel needed meant they were only used in rivers, but they could move even when wind wasn't that great. Several experiments in land transport were tried, but freely moving vehicles turned out to be hard to build with steam. Travel on rails was a different story: horses had been used to pull trains, but steam powered locomotives could be successfully built to fill this role, and the first railroads started service around 1800. Britain was a leader in these technologies, but they also expanded in the early united States as well.

In 1924, in an attempt to better understand steam engines and how to improve them, a French engineer named Carnot wrote a book about how they could be better understood. His original goal was to help France better compete in building these engines, but instead his ideas were ignored for some time, later discovered, used by other scientists and engineers, went in several adventures to become the field of thermodynamics, and later reunited with its parents as the field of thermodynamics is now used to better build all sorts of engines, among its many, many other uses. While Carnot was working with an incorrect understanding of how heat works, he still managed some useful discoveries: a general model of heat engines, how much work can actually be produced from temperature differences, among other things.

Steam engine builders may not have known about Carnot, but they would have generally known his work's most important implication: higher temperature differences were more efficient. Steam engine designers were pursuing higher temperatures and pressures to improve their engines, but were limited by available materials and manufacturing techniques. Boiler explosions were a common issue, one shows up in [[Literature/AdventuresOfHuckleberryFinn]] for example. But as part of industrialization, these things improved over time (powered partly by said steam engines), and steam power did as a result. In 1837, a ship crossed the Atlantic for the first time using steam power, allowing more ocean going ships to be built. Railroads continued to expand, as did steam powered factories.

In the 1850's and 60's, some engineers designed and created new types of engines, that instead of steam used combustion products to do work. Come back later to [[ChekhovsGun see why this is important]]

You may now see why {{Steampunk}} has that name. In the late 1800's and early 1900's that it is based on, steam power was the go to, most important source of power. Steam powered railroads and steamships moved people around the world, steam powered factories were changing society. Britain was a center of this technology, and was conquering/had conquered its huge empire based partly on that advantage. This time period also started some culture tropes, including the steam locomotive as a [[SteamNeverDies symbol of railroads]].

Becoming more common during this time were so called compound steam engines: Instead of passing steam through one piston and than a condenser, steam was routed through several pistons in a row. This was to deal with an efficiency limitation: Cylinder walls in any engine will tend towards the average temperature in their cycle. As temperature differences in steam engines became higher, this mean that hot steam entering a cylinder would lose a lot of heat to medium temperature walls, cooling the steam and causing it to do less work. Later in the cycle, this heat would go back into the steam, where it would be released through the condenser. This reduced the efficiency of the engines. Compound engines reduced this problem: each piston experienced a lower temperature range, and therefor lost less heat, making up for the cost of a more complex engine, and the efficiency loss from flowing through move valves and pipes. Most common were three stages in so called triple expansion engines.

The final major advance in steam power came in the early 1900's, when steam turbines were first used. Turbines were a lot smaller for the same amount of power, and also generally more thermally efficient. Turbines were first used on warships, later spreading to passenger ships as well. using a combination of piston engines and turbine was an [[BlatantLies obscure White Star Line shipe ending in -ic that few have heard of]], as well as its [[BaitAndSwitch sister ship]], [[UsefulNotes/RMSTitanic The Titanic]]. (And a third sister ship). At the time, turbines were still new, somewhat noisy and caused vibrations, the ship's designers decided to use a smaller turbine to get some of its advantages combined with well tested piston engines to keep noise down. Another important change was increasing use of oil for fuel: Almost all steam power to this point had burned coal, but oil was easier to pump (so no gangs of stokers with shovels needed), and often produced less smoke. Oil or coal powered turbine ships fought most naval battles in World Wars 1 and 2.

As the 1900's continued, Steam power was replaced in some areas, as that engine from the 1850's was improved, and new variations developed. One of these, a diesel engine, replaced steam in many railroads and ships. Fuel efficiency was often not the main reason, as you might expect, but instead labor savings, flexibility, and some other advantages described in the next section. Steam continued to be used in electric power production, and gained a new use in nuclear power. Since the turbine was developed, most steam power works approximately the same, but newer materials and designs allow it to take advantage of higher temperatures.

!!When is it used? When will it be used? And a teaser: Non-steam steam engines

That engine from the 1850's was an early internal combustion engine. It;s not just a fancy name: engines like this use the products of burning as the so called working fluid: the liquid/gas that actually does the work inside the engine. Steam power is a type of external combustion engine: the heat source is something different (burning coal, burning wood, nuclear reactions, etc.) than the working fluid (steam + water). Other extrenal combustion engines exist, but are not nearly as common. Other power sources (photovoltaics, windmills, hydroelectric turbines etc.) do not use heat or burning at all. This difference, as no one could predict, has advantages and disadvantages.

As an advantage, steam power, properly designed, can use almost any source of heat. Sine any other energy can be converted to heat, this means steam power could in their capture almost any source of energy if designed right. Other engines are more fussy: Internal combustion piston engines need fuel with the right ignition characteristics, and that can be pumped and mixed with air easily, and certainly have a hard or impossible time using non-burning sources of heat. Photovoltaics, hydroelectric turbines, etc. are custom designed for one source of power. Gas turbines are a little more flexible fuel wise, but still need pumping and mixing with air.

As a disadvantage, steam power tend to take up a lot more space, and not be as fast responding. Steam requires a heat source, boilers to transfer heat to water, pistons and/or turbines/some non-invented power device, and a condenser, all of which add weight and space. Internal combustion engines, by using combustion products to do work, remove the need for boilers and condensers, no heat needs to be transferred into the engine. These boilers and condensers are often the most heavy parts of an engine, so the weight saving is very, very high. A big boiler full of water also takes a long time to heat up, meaning seam engines start slower, and stopping them is a longer process as well, while most internal combustion engines can be started simply by spinning them up and adding fuel. Steam turbines also often run best at one particular speed, and are not as responsive as piston engines.

In thermal efficiency terms, steam can compete with the most efficient other engines if given enough space. If forced to get smaller, steam drops off quite a bit.

Overall, as a result, steam is best used when weight is not a problem and/or an exotic power source must be used, and the power source does not need to be fast responding.

Electric power generation is a great fit, and is where most steam power use used today. Electric plants are fixed in place, so no vehicle must worry about carrying an engine around. It is also used more or less throughout a day, so plants can be run continuously with little starting and stopping. Power generation can, as a result, take advantage of energy sources that transportation cannot. Examples of such energy sources include nuclear energy, geothermal power, and coal. Coal, the original source of heat for steam engines, is hard to inject/push into newer internal combustion engines, and converting it chemically to a liquid or gas loses a lot of energy. Nuclear fission produces a lot of heat, but no gases or other direct reaction products that can do work. Fission for power usually uses two cycles: water than passes through the reactor itself is used to boil a second cycle of water than actually runs the generator. This helps prevent radiation leaks, the water in contact with the reactor never leaves containment, and adding more cycles makes leaks less likely. Geothermal heat shows up as hot rocks or magma, either requiring added water, or producing natural water, as a working fluid. The newest use of steam as exploiter of unusual heat source is in so called combined cycles. In these, a gas turbine is first used to get power from (usually) natural gas. Gas turbine exhaust is hot, right in the temperature range that steam is good to exploit, so steam engines can be used to capture this waste heat. Burning the gas in a pure steam engine theoretically possible, but such a system would have a hard time handling the high temperatures a gas turbine can produce, needed to match its efficiency. Such combined cycles are the most thermally efficient heat engines used today.

Steam using power plants are typically "base load" plants: the long startup time means they run constantly, producing power throughout the day. "Peak load" plants and/or energy handle periods of high or low demand: these include lone gas turbines, some diesel or spark plug engines specifically designed to produce power, hydroelectric plants where water flow can be carefully controlled, some of which can also pump water back if needed, and most recently, cheaper batteries and other energy storage that can store power during low demand and release it during high demand. These devices are usually more expensive than base load systems, so are not run fully time. Renewable energy fills a similar role: cheap "fuel" cost, but produces power when it is not necessarily wanted.

Ever seen those gigantic steaming towers in pictures of nuclear plants? Those are cooling towers, used to produce cooler water for condensers. These towers evaporate a small amount of water, absorbing heat and cooling the rest, generating colder water and creating a higher temperature difference between boilers and condensers, increasing efficiency. The use of water for condensation does point to a problem with steam plants: that can be water hungry, and the heat released can increase temperatures of rivers or lakes, causing environmental issues. It is possible to use air in a condenser, but this requires bigger equipment.

Steam was commonly used on ships, in particular on passenger ships when those were the main way to move across oceans, hence the "SS something" as a stereotypical ship name. SS originally stood for "steam screw", a steam powered propeller ship in other words as contrasted to paddle wheels or sailing ships, but as all engine powered ships used propellers over time, the meaning shifted. It is still today used in nuclear powered ships, and in some LNG transport ships: the LNG ships constantly boil off gas (the containers for the gas are insulated, but no insulation is perfect), and steam engines are a good way to burn/use this boiled off material. However, more recent ships are switching to modified diesel engines for this role, using diesel fuel to ignite a natural gas/air mixture. Steam goes well with ships: shipping uses relatively small amounts of energy for what it carries, meaning ships have plenty of room for large engines, and ships sped days to weeks travelling, than spend long times at port exchanging passengers and goods, so the time it takes to start and stop and engine isn't as big a problem.

Railroads started with steam engines, and locomotives never really switched to steam turbines: turbines are best at one particular speed, but steam locomotives have to run at a wide range of speed and power, so pistons had to be used instead. In the traditional steam locomotive shape, the big cylinder taking up most of the engine is a boiler: coal(usually) shoveled from the cab is burned, gases travel thruough the boiler to create steam, and are released through the smokestack up front. The steam produced than pushes pistons located in small cylinders on the sides of the engine. Pistons would push on rods connected to wheels seen on the side. Engines mostly would not use condensers, instead venting the steam and carrying water for the trip, saving weight. The "che che" sound of such an engine comes from steam moving through the pistons.

On both ships and railroads, diesel engines were the main replacement for steam. Like steam, diesel engines can be made very fuel efficient, and are also relatively heavy for the power they produce (though having a greater range of power to weight than steam does). However, they can run well at a greater range of speed and power, and are much faster to start up, trading stricter fuel requirements for these advantages. On ships, the fuel requirements weren't a big problem: properly designed diesel engines can run on fuel oil, which many ships were already using. On trains, diesels faster starting, lack of need for water to be carried also, and better efficiency than pistons proved big advantages. The original reasons to switch were less about fuel savings the labor costs: starting up an engine, cleaning boilers, etc. takes a lot of time, meaning a lot of people need to be paid to do those jobs. The most common abbreviation for modern generic commercial ships is MS or MV, for motorship or motor vessel, used for diesel powered, sometimes gas turbine powered ships. not otherwise abbreviated. In the future, civilian battery, fuel cell, or nuclear powered ships(even is steam was used to do the work, the nuclear part is considered more important), or other futuristic propulsion methods, if they become common, would have their own abbreviations.

Steam power was never commonly used for cars, trucks, or air travel. In these roles, engines weight and space saving is very important, requiring engines that produce a lot of power for their weight. Long startup times for steam power were also a problem with cars, where being able to hop in and go somewhere is very important. Steam was tried in cars and trucks, but rapidly outcompeted by spark plug engines, later diesels as well, and battery power for specific roles. Airplanes started out using piston engines and later gas turbines. Airships were originally steam powered, but were replaced with diesel engines for similar reasons as ships and trains. Weight saving in space travel is even more important, so power sources tend to use less efficient but lighter methods than steam systems. A theoretical rocket kind of mimics a steam system: using a nuclear reactor as a heat source to boil and heat a pressurized liquid, than is expanded through a nozzle. this somewhat mimics the "pump -> boiler -> power device" in earthbound engines, but the technology if produced owes more to rockets.

Factories have mostly shifted to using outside electricity instead of driving their own machines, but chemical plants today still may maintain their own power generating machinery. Chemical reactions being what they are and sometimes releasing lots of heat, it is sometimes worth it to capture this heat and produce electricity, saving some outside costs or selling excess energy.

And this brings us to future uses of steam power, as well as no steam steam engines. "Non steam steam engines,?" you are thinking, don't worry, the next paragraph will explain. Renewables largely don't need steam or any similar system, photovoltaics, wind turbines, wave capture all directly capture energy without changing it to heat first, so these would likely not use steam systems. If fusion is ever developed ("20-30 years away, always has been and always will be" as the joke goes) it would likely use a steam system to capture the heat produced and turn it into work. Steam systems would continue to play their roles in waste heat recovery, fission power, and such, though use of fossil fuels almost certainly will decrease (to avoid global warming, and because other power sources are getting cheaper.)

And waste heat recovery brings us to non steam based engines. "But its called a '''steam''' engine, how can you use anything else" you may be thinking. Actually, these systems do not require steam in particular, all they need is something that changes from liquid to gas under the right conditions (this doesn't need to be boiling and condensations: a liquid could chemically decompose at high temperature, with the resulting gases reacting to reform it at low temperatures. In practice, no such system has been widely used). Organic chemicals, ammonia, mercury, nitrogen, and many others could in theory be used if conditions are right. Water is most common because, as said at the beginning, it is nontoxic/safe in general, widely available, and well understood, but a couple of variations are proposed/in use.

The first of these, used for waste heat recovery, is the so called "organic rankine cycle". This uses organic chemicals to exploit relatively low temperature waste heat, in the same cycle as normal steam power. While water's freezing and boiling points can be changed by raising and lowering temperatures, creating low pressure system needed for the temperatures under consideration would make preventing leaks into the system hard, and would require pipes and containers to resist outside air pressure, too expensive for the heat being recovered. Instead, organic chemicals with lower boiling temperatures are used. These systems don't produce much power, but in large plants, enough waste heat is produced that the cost of designing and building such a system is worth it.

The second of these is a so called Kalina cycle, which uses a mix of two or more chemicals in place of pure steam (the original proposal used water and ammonia). The reason to use such a cycle requires some explanation: One result from thermodynamics is that heat transfer between similar temperatures wastes less energy. In systems where exhaust or some other fluid heats the steam (fuel fired boilers with exhaust, exhaust streams with waste heat, nuclear reactor coolant with two circulations), this fluid must cool as it leaves the boilers, it cools as it flows past the boiling liquid and smoothly decreases in temperature as it flows. This means that, to absorb heat as efficiently as possible, the boiling liquid should smoothly increase in temperature to match as closely to the heat source as possible. If a single component mixture is used in the engine, this smooth increase doesn't happen: the boiling liquid stays at the same temperature as it boils.

However, a mixture of two or more chemical acts differently; it boils over a range of temperatures. The easier to boil chemical evaporates more easily, leaving a mixture more concentrated in the harder to boil mixture. This takes a higher temperature to boil, further concentrating it, and the process repeats until the entire mixture boils. As a result, a mix of two chemicals increases more smoothly in temperature as it boils, improving efficiency somewhat in appropriate situations. Similarly, a condenser where cooling water or air is limited gets advantages from a mixed system. It is also possible that a more complex design could get efficiency by separating streams of different chemical mixtures. Kalina cycles currently are not used much, but could conceivably get more common if conditions are right.

Steam: Take some water, heat it up until it boils=. Yet this everyday substance [[ExcessiveSteamSyndrome fills factories]], will [[SteamNeverDies power trains until the end of time]], powers the SS something or other, and has an [[{{Steampunk}} entire gene]] named after it. Oh, and in real life, is one of civilization's most important inventions, powered the industrial revolution, and led to the development of many modern technologies.

Steam: Take some water, heat it up a lot until it boils, simple to make. Yet this everyday substance [[ExcessiveSteamSyndrome fills factories]], will [[SteamNeverDies power trains until the end of time]], powers the SS something or other, and has an [[{{Steampunk}} entire gene]] named after it. Oh, and in real life, is one of civilization's most important inventions, powered the industrial revolution, and led to the development of many modern technologies.

Steam: Take some water, heat it up a lot until it boils, and you have it. Yet this everyday substance [[ExcessiveSteamSyndrome fills factories]], will [[SteamNeverDies power trains until the end of time]], powers the SS something or other, and has an [[{{Steampunk}} entire gene]] named after it. Oh, and in real life, is one of civilization's most important inventions, powered the industrial revolution, and led to the development of many modern technologies.

Steam: Take some water, heat it up a lot until it boils, and you have it. Yet this everyday substance [[ExcessiveSteamSyndrome fills factories]], will [[SteamNeverDies power trains until the end of time]], powers the SS something or other, and has an [[{{Steampunk}} entire gene]] named after it. Oh, and in real life, powered the industrial revolution, many famous ships (such as the {{UsefulNotes/RMSTitanic}}), lots of trains, and is still commonly used today.

Most of this useful notes is about steam engines, but as those steam filled factories in movies suggest, it has other industrial uses, so this article will start with:

If you've lived or worked in a building with a radiator, you've experienced possibly the most common use of steam: Heat transfer. Steam is used in heating systems, chemical factories, and other places to move heat from hot places to cool ones. In theory, many types of liquids or gases can and are used for this, but steam is commonly used for a couple reasons. Water is cheap, plentiful, non-toxic, and well understood, so if it makes sense to use it, water will probably be used. The second reason: Water is a pretty good heat carrier. In liquid form, it has a good heat capacity per weight, allowing smaller amounts of water to transfer the heat needed over the temperatures of interest. More importantly for steam, Water boils and condenses at appropriate temperatures for a lot of uses. Boiling and condensing themselves absorb/release a lot of heat, in water's case, around 6 times the heat it takes to get water from freezing to boiling. This first allows huge amounts of heat to be carried by boiling water, moving it to where the heat is needed, and condensing it, but it also allows good temperature control. You have likely done this yourself when boiling or frying food: a boiling liquid or condensing gas stays at the same temperature until it is completely converted. Pick the correct pressure (Higher pressures mean higher boiling points), and you control the temperature that steam condenses or water boils in your process.

As a result, steam is common in chemical plants: control of temperature is important in chemical reactions and separations (like distillation), and a lot of things are heated and cooled. Radiators in a home is another use: general building heat systems, although others are more common nowadays.

Sometimes, high pressure steam can be used similar to pneumatic systems, to directly operate or power devices. The stereotypical train whistle is an example: steam is available in these locomotives, so it makes sense to draw some for a whistle.

Steam is useful in material treatments/cleaning. You've probably heard of steam cleaning carpets, but it can also be used to harden concrete, sterilize objects (see autoclaves), or to add some other desirable properties to some other materials. In these cases, steam does a few things: it is hot, but temperature can be controlled easily, is easily available, and adds humidity if this is a concern (concrete is a good example: concrete needs water as part of its during reaction, so dry heat may dry out the concrete and compromise it, so steam is used in some cases to speed up the reaction without drying the material.)

In most steam and flames factories, the steam is being used for..well, it's there to [[RuleOfCool look cool]], so [[MST3KMantra don't think too much further]]. However, if you need to make it a real thing, it is likely a leak from some kind of heating system or steam controlled machinery. or cold air leaking and creating condensation, which doesn't really fit this article.

Of course, most of you aren't reading for how radiators work, you are interested in engines. So now we go to:

All steam engines are based on a couple properties of materials: gases take up more space than liquids, and gases expand more than liquids over the same temperature and pressure changes. Provide a heat source to boil water, a cold source to condense it, and the expansion and contraction of the steam and liquid water can generate work.

Most steam engines today and historically follow a similar cycle. Start with water at low pressure. Pump it to raise its pressure. Than, pass the water through a boiler. The resulting steam goes through a power device: today, turbines are the go to choice, in the past pistons have been used. In the power device, the steam expands from a higher pressure to a lower pressure, pushing against the power device, and doing work. This extracts energy from the steam, lowering its temperature as well. A higher pressure difference, and a higher temperature difference, allows more work to be extracted from the steam. Finally, take the low pressure steam and send it through a condenser. At a lower pressure, a liquid's boiling point is lower, so the condenser operates at a lower temperature than the boiler. The resulting water is sent back to the pumps, and the cycle repeats. Expanding steam in the power device does much more work than it takes to power the pump, and the extra work is used for whatever is desired: making electricity, powering a propeller, powering machines, etc.

Actual steam systems are often more complex then this: steam may be drawn off for other uses, preheated or cooled, multiple boilers or condensers, sometimes reheated after passing through a turbine and run through a second. Some systems may not have a condenser: Fresh water will be drawn from and outside source while steam is vented (steam locomotives historically would often do this, as well as some early ships.). This saves space/weight/cost/etc. of a condenser if a good source of water is available. Reverse the cycle, boiling a liquid at low pressure, compressing it, than condensing it at high pressure, and you have the most common refrigeration/freezing cycle today (although the reversed pump is replaced with a partly closed valve to lower the pressure.) the condensing, low pressure liquid absorbs heat at a low temperature, condensing high pressure gas releases heat at a higher temperature, thus moving heat from cool areas to warmer areas.

The first steam engines used a different method: using steam to create a vacuum. Steam boiling at atmospheric pressure would fill a piston, than be condensed. The condensed water took up a lot less space, sucking the piston (more properly, allowing outside atmosphere to push the piston)back into place, where the cycle repeated. This type of cycle is less efficient in almost all cases than a modern type of engine, but possibly could be useful in a few special cases. It still uses heat to generate steam, and uses the expansion and contraction of liquid and gas to do work.

In physics/thermodynamics, a steam engine is a type of heat engine: using a temperature difference to do useful work by taking heat from a higher temperature, doing something to it that converts some heat into useful work, than putting the rest of the heat into a colder temperature. In Steam engines, whatever their heat source is generates the high temperature side, while outside air or water is usually the low temperature side. A temperature difference is necessary to do work, and the higher the temperature difference, the greater fraction of input heat can theoretically be extracted as work. In steam engines, this means that the boiler (where heat is added) must operate at a higher temperature than the condenser (where heat is lots), and backs up that a higher temperature difference between the two leads to a more efficient engine. A condenser is necessary, some heat must always be expelled. (In engines without condensers, steam venting into the environment and outside water being taken in fills this role.) Steam engines themselves were the original inspiration for thermodynamics, read the next section for more.