Why aren’t we driving engines partly by steam in our quest for renewable energy sources? We already generate heat, right? It could be used as a component in a car; in fact steam already passes through it now. In other environments its scalding water could be kept away in a space where steam & pressure is contained. Or use solar instead of an engine.
And even with predicted upcoming water shortages, if these mini engines (for electricity perhaps?) were designed strictly as boosters in all these systems and not essential to their operation… I think this might make sense. Engines already produce heat that can be used and even amplified. Million upon millions of small steam boosters could cumulatively enhance our power consumption.
New technologies to capture lost heat from car engines, including the use of such heat to generate power through steam convesion, are being explored. Cite. As for why we aren’t doing this already, the addition of a whole new system to a car to capture and convert lost heat entails costs, and so far it has not been cost-effective to bother. With rising fuel prices seeming here to stay for a long time, manufacturers are taking a closer look at the technology.
How would you use steam in addition to the gasoline engine? You’d have to put in a separate steam turbine/piston engine in addition to the existing combustion one. This is what’s done in hybrids with an electric motor, but those are much smaller, lighter, and (nowadays) very easy to construct and install. Not so with a steam engine. Even a relatively small steam turbine will need some connection to the transmission, or it’s own transmission. And the small amount of steam that is/could be generated probably wouldn’t add up to much more power.
ETA: It seems to me that the best way to “capture” excess heat from a car would be just to directly convert it into electricity with a peltier device. just install them along the radiator and exhaust of a hybrid car and have them charge up the battery when the combustion engine is working.
Using waste heat to create steam for power is, in theory, a great idea. Power companies generate extra power from combustion turbines by using the exhaust gas to fuel a boiler for a steam turbine. The design is referred to as a combined-cycle plant.
Its benefit is that it is more efficient than a turbine only (simple cycle).
Its drawback is that it only makes sense if you plan to run it for extended periods (days instead of hours) and it cost more to build a plant with a steam system.
Those same issues would apply to cars. It would cost more to build the engine. And for short trips you wouldn’t get much out of the steam system.
You would also have to overcome some thermal issues. Parking the steam assisted car in subzero weather for a length of time means you either have to dump your water source or risk having it freeze in the steam lines.
You would also have to overcome the problem of relieving excess pressure once you stop the car and insuring that the car’s water supply contains no contaminants to mess up the steam system. Tap water has too many minerals and a closed system would have that freeze problem mentioned above.
he drawbacks aren’t necessarily deal killers but they do pose some significant engineering obstacles.
Currently, petroleum and hybrids. I’m talking here about using heat waste that all ready exists, such as in a car’s engine. With an eye towards their reducing petroleum using systems partly powered or boosted by steam to do so.
This includes stationary systems in houses and buildings. And using solar for direct heating of water for steam. People already heat their water everywhere using solar. It we have an incentive for generating hotter water through solar systems, we’d do it if there’s money in it. And maybe better solar systems too. All steam heating produces another way to generate mechanical movement. Such as producing electricity by spinning a wire spool on a spindle in a separate compartment, activating a pump, or so on. I don’t think it likely that we’ll go to full scale engines but rather smaller ones that boost performance or run a specialized task.
BTW, it’s a step back to steam powered toys that ancients in the middle east – perhaps Babylonian IIRC – once played with. They missed realizing steam’s mechanical ability on large scales. Being in a fully agrarian society it would probably have taken a truly brilliant person make the connection to big steam power. I believe it took something like 2000 years before the modern steam engine came about.
One use I have seen for a truck is to use the waste heat from the engine to generate steam. This steam would then be used to drive a turbine to run the refrigeration unit in the trailer. At the moment these are usually powered by an auxiliary diesel engine.
First of all, most commercial power is generated via a steam-based thermodynamic cycle. typically the Rankine cycle or some variation therefrom. There are other thermodynamic cycles and other media that can be used instead of water steam, but water is cheap, only very moderately corrosive (in pure form), and operates very predictably at a pressure-temperature range which is suitable for use with common metals and alloys. Of course, steam generation plants tend to be big, because the efficiency of steam cycles increases (up to a limit) with size. Also, because of the fixed nature of the installation and the bulk amount of heat-energy within it, even small losses are worth recovering via a regeneration or cogeneration cycle. (The BMW steam turbine cited previously is an example of a regeneration cycle, albeit one based on an Otto cycle process of the main engine.) A very small steam-driven generator has a lot more inefficiencies in terms of energy lost to heat and a lot less margin for recovering the small amount of lost heat; thus reciprocating piston and gas turbine generators are more effective for portable applications.
The problem with using waste heat from other processes to generate steam is that you have to have a sufficient temperature–>100°C at standard atmospheric pressure–to generate it; otherwise, you just have hot liquid water, which tends to just sit there and doesn’t expand very much at all. Steam is an effective power conversion media because of its expansion properties, which cause it to move at the high speeds that can efficiently drive a turbine. All hot water is good for is washing clothes or washing dishes. If you can’t concentrate the lost heat sufficient to create steam, you might as well just let it disappear into the environment. (To be fair, there are heat pump generation systems which can use a few thermodynamic tricks to magnify the heat in a liquid water system up to a useful temperature or otherwise provide cogenerative recovery, but the complexity is rarely worth the effort except in limited applications.)
Now, if you have an externally-heated process and a cycle with a partial vacuum system, you can create steam at much lower temperatures, albeit also with much lower power density. Something like a Sterling cycle writ large could, in theory, be very efficient even at temperature that are only modestly above the ambient heat rejection temperature. In practice, however, these systems are rarely practical given the current state of the art because of mechanical losses from friction and drag, and thermal conductive choke points that limit how much heat you can force into the recovery system. If you make a system that is really thermodynamically efficient, but it is too heavy or too bulky to fit within the form of a vehicle then it may offer great savings but be completely impractical to build and use.
So, we use steam all the time, albeit where it is most practical and efficient, i.e. large fixed installations. Everything you ever wanted to know about steam power, by the way, can be found in the classic Babcock and Wilcox Steam: Its Generation and Use, the traditional reference for all things technical about steam and steam-based thermodynamic cycles.
The problem with using steam in pre-Industrial societies is that they had no way to contain steam at high pressure. Without being able to contain or direct it in a vessel, you are limited by ambient pressure and natural transmissability to air for the amount of work you can have it do; essentially, you can use it to make a pig bladder fly or steam food, but making it drive a mechanical cycle requires reciprocating or rotating mechanisms with high tolerances not possible with hand-built agrarian tools.
There’s a bit of a chicken and egg problem to every new technology that’s not being talked about.
Not only do you have to create, test, and implement these new engines, you have to have the national infrastructure to deal with them. That means having the repair facilities, the trained staff, and the parts available somewhere conveniently near every place that your vehicles are likely to go.
It’s one thing to roll out a few copies of a Tesla or a hydrogen car and limit them to southern California and only sell them to movie stars and internet billionaires for the publicity. It’s another to have truckers rely on being able to care for them on every highway in the country or have every suburbanite be able to throw the kids in the back of the car and take off on a vacation.
Doing that takes as many years and as many billions to set up as developing the technology in the first place. And it’s much harder to get hundreds of individuals to buy into the new technology than it is to fund one factory to build it.
I have yet to see a discussion about new technologies here that addresses this issue. It’s absolutely critical but since it’s not the sexy part, nobody cares. Yet I guarantee you that it’s the people who solve the infrastructure issues who will win out in the end, not the people with sexiest technology.
Sure. I just think that being the 21st century, probably we could look once again at things that weren’t viable just a few years ago.
I think part of what I’m talking here is also about being able to design multi-source systems. If they can be produced it at a reasonable prices. They may not necessarily be disposable. But perhaps even useful for multiple things in some instances rather than a single task.
I think the notion of small steam is more than just that. It’s describing a mindset for to throwing everything we can, even in small increments, towards energy efficiency. Do we have to use just water for steam? Is something better available? I think if we have all kind of things like steam or whatever looked at very closely again, we might find just the right scale where different things work.
Thanks for the information and resources to my question.
True, it was the only the bronze age I believe. Still, again I wonder about the effects of continuous long term scaling up even over centuries. How long might it have taken, again with a determined effort?
You can use other fluid media for thermodynamic refrigeration cycles–for instance, automotive air conditioners generally use 1,1,1,2-Tetrafluoroethane (also known as R-134a) and other refrigeration cycles use R-410A and other halomethanes, ammonia, or liquid propane, and some extant and proposed nuclear power plants use helium under very high pressure. However, for bulk use in thermodynamic power cycles, water is both nearly ideal in properties, and also inexpensive and non-toxic.
Incremental improvements in thermodynamic efficiency are desirable, but the additional complexity or the cost and energy required for manufacture make make them impractical, and as Exapno Mapcase notes, there are additional costs in adopting a new technology from the standpoint of infrastructure and maintenance.
Until technology developed to the point of making welded or seamless pressure vessels, close tolerance moving seals, and threated fittings and fasteners, the possibility of using high pressure steam to convert thermal energy into mechanical work was nonexistent. Today, we take it for granted that you can get in a car, start the ignition, and be transported at speeds vastly exceeding those achievable by any working animal, propelled by a high precision rotating, meshing, flexing drivetrain that is essentially powered by contained explosions, but all of the technology necessary to accomplish this was developed starting little more than 250 years ago.
We do use steam for power, for most of it I think, in fixed generators including coal-fired and nuclear (as noted earlier).
And also in one of the main solar power systems, which focuses sunlight onto a boiler to run a turbine. This is renewable. So is wood-fired steam, and burning of things like sugar cane waste and garbage.
Another note. According to some history books, steam automobiles were easier to make and ran better than gasoline powered ones, which is why they died out. It seems that smoke and noise and tinkering suited early car owners much better than quiet performance did. They were young men, often eager to impress. This might start a flame war, but I think Harley-Davidson brand motorcycles are successful for exactly this reason today.
Once gasoline engines caught on, they kept evolving to meet changing customer demand, which is why today I couldn’t hear the Jeep running and tried to start it twice. Christ on crutches, the thing has thousands of explosions per minute in it, less than two yards from my ears, and I was really trying to hear it! Where was I? Oh, yes - so, if we had started with squirrel power, and we had spent many many billions of dollars over the last hundred years building billions of squirrel powered cars and trying to make them sell better, they’d probably be pretty good now too. They might not even need pretty women spread out over them to get us to buy them, who knows?
