> It is true that the technology poses some difficult problems, but one cannot help but be curious how efficient a steam car might be with the benefit of modern materials and computers.
It's easy to shrug off questions like this, placing them in the category of "if it were feasible, someone would obviously be doing it already", but it's still interesting. Having read a pretty extensively about how steam locomotives work, and some additional reading about steam power in general, it's interesting to read this article and catch small windows in to the overall progress of steam during the era. For example, reading the remarks about closing the steam circuit reminds me of the progress made in condensate and heat recovery developed in steam power at the time. Really remarkable to see that in something as small as a car.
As an academic exercise, I think it'd be really cool to develop a "steam powered auto challenge". Of course, no one is going to get behind it because steam is not a green technology, but sometimes we can learn important lessons from the past. Working on a completely unrelated technology and studying its progress can teach us lessons about the development of current technologies.
Because the combustion products must transfer their heat to water before the energy can be used, I think there is an inherent limitation on the efficiency of a steam engine as compared to internal combustion.
I was interested in steam cars for a while, I have a manual to a Stanley Steamer and a short book published by Lindsay on them.
However it was reading the history of steam that is in the opening chapters of Lyle Cummin's "Internal Fire" and his description of the limitations of steam and sterling engines, that I came to think there was a fundamental reason behind it.
The Doble and Stanley era cars seem to have gotten about 10 mpg.
On the other hand, they do have a possible advantage in being able to consume a variety of non-standard fuels. There may be a niche market for that, which given the relative size of the car markets in 1925 vs 2015, is quiet huge and could support a sizeable company.
This is far less of an issue than you might assume. Modern steam engines can have around 48% efficacy and combined cycle power plants can hit ~60% where IC engines rarely top 35% with cars generally averaging less than 25%.
A much larger issue is trying to scale this down. Power plants are optimized for efficiency and cost not weight, where IC engines can be very light relative to their power output.
From what the article claims, rediscovering their principles would produce a car with much better noise characteristics than turbines and modern ICEs. I wonder what modern metallurgy could do for the design? The part count is extremely low. With remote control from a smartphone, the big disadvantage -- boiler start time -- would be entirely solved. As it was, they had gotten it down to something comparable to starting diesel cars on a cold day.
Boiler startup was essentially solved by Doble 80 years ago. The steam generator (Sort of a JIT for steam) could produce useable pressure in less than a minute.
Like I said: Comparable to an old diesel. That kind of delay still got massive hate from my ex-girlfriend. However, if you give people a remote to have it done by the time they get down to the car, they'd feel it was nifty technology and it would make them feel powerful.
Condenser size/effectiveness/whatever ends up being the limiting factor. The Jay Leno video someone linked has him stating that the car gets 200 miles out of the water in warmer weather (which isn't a huge problem, water is cheap, but radiators are pretty well advanced technology at this point so there isn't much reason to expect big improvements).
I would like to see a gas/steam hybrid engine that uses waste heat from the engine to make steam to power an additional couple of pistons. That might get you better gas mileage than a gas/electric hybrid.
The best setup for that is not additional cylinders, but to run a 6-stroke cycle - injecting a drop of water at the end of the exhaust stroke, which will expand and generate some extra power.
Though not terribly efficient, we could certainly use thermoelectric generators like Peltier junctions to pull energy out of the waste heat in car exhaust. On the plus side they are cheap and have no moving parts (and they're not even radioactive).
I wonder if steam would be "green" today. I've got an electric steamer that I use as an alternative to ironing clothes. It probably takes a lot of electricity to turn water into steam but who knows.
Why is that true? Just because of the loss of generating electricity from heat sources only to turn it back into heat?
Because isn't an electric heating coil essentially a big short-circuit? I would've thought it would be extremely efficient at changing electricity directly into heat.
Resistive heating is terribly inefficient as a heating method in most cases. Much more effective(in most cases) is stuff like heat pumps. Remember, you aren't grading it on "amount of electricity turned into heat", but on "amount of heat added per unit of energy". You can technically push that above 100%. A good heat pump can do something like 3.5 CoP, i.e. you put in 1 kWh of electricity, it heats the "hot side" by 3.5 kWh of heat.
Your answer is correct, but remember that if we are heating steam, it is at a much higher temperature differential than a typical heat pump. Good luck getting a COP of 3.5 from room temperature up to steam engine temperature. Steam engines operate at well above 100C. Actually, good luck even finding a heat pump that will operate at those kind of temperatures.
There is a huge gap in what is commercially available in high temperature heat pumps for e.g. boiling water. The best example that I am aware of is the EcoCute for water heating. Heat pumps are much more efficient for heating water for domestic use than resistive heating. However, the only ones on the market are fairly expensive. I'd be very interested if someone on HN knew of a better option.
I've tried building my own high temperature heat pump to go up to around 300C. It isn't easy, because most refrigerator technology is not designed to operate above 100C, so if you use off-the-shelf parts the seals will go or various temperature limit switches will actuate. Then if you try marrying engine parts to AC parts, you have to make your own high-pressure adapters. Overall, its a great way to burn a lot of dollars and hours in the garage.
I've considered just buying a Stirling engine and running it backwards, but I've not yet found one which is designed to be able to run effectively as a heat pump. Any Stirling aficionados here? I'd love some advice on using a Stirling as a heat pump.
Resistive heating is 100% efficient, yes, but the electricity required to power the element is rarely above 40% efficient for most combustion powered sources (combustion turbines, combined cycle, etc.).
It is a fantastic automobile and a great video from Jay Leno, whom we all owe a debt of gratitude for preserving our technological legacy, similarly to Bill Harrah from a generation earlier.
Imagine what a Doble could be with a few processors handling all the complexity....
Yeah I really wanted a Doble for a few years. I eventually realized that it would take either a decade or two of hunting, or a few hundred grand to make it happen and gave up.
It's really cool how they can arbitrarily turn the prop on and off like an electric aircraft, even reversing its direction. Might this be one of the earliest examples of thrust reversal for breaking? Also, could this be a more efficient arrangement than IC engine+prop governor?
Was I the only one who saw this as a sorta commentary on how we might be looking at combustion engines in 100 years? It will probably seem ridiculous that we were burning smelly fuel.
Steam is primarily an engine driven by gas pressure (as are most combustion engines). I see the compressed air car as an evolution of the Steam car. https://en.wikipedia.org/wiki/Compressed_air_car
Steam is cool, yes, I love the history behind antiques and the insight into their periods of history, but electric is SOOOO much better. Steam does not give instantaneous torque, nor the ability to precisely control individual wheels / motors. I just can't see steam making a comeback.
It's easy to shrug off questions like this, placing them in the category of "if it were feasible, someone would obviously be doing it already", but it's still interesting. Having read a pretty extensively about how steam locomotives work, and some additional reading about steam power in general, it's interesting to read this article and catch small windows in to the overall progress of steam during the era. For example, reading the remarks about closing the steam circuit reminds me of the progress made in condensate and heat recovery developed in steam power at the time. Really remarkable to see that in something as small as a car.
As an academic exercise, I think it'd be really cool to develop a "steam powered auto challenge". Of course, no one is going to get behind it because steam is not a green technology, but sometimes we can learn important lessons from the past. Working on a completely unrelated technology and studying its progress can teach us lessons about the development of current technologies.