Steam-Powered Cars-Why Not?

Factual Questions
61

Oh, I just wanted to add a couple of things. My anecdotes experimenting with chemistry as a kid are not supposed to illustrate anything more than teenagers are dangerous and stupid and you should keep an eye on them.

OTOH, there is no doubt that hidrogen is much more difficult to handle as a consumer fuel. It would have to be compressed to very high pressure and tanks would have to be very large.

I have CNG (Compressed Natural Gas) bottles on my boat for the stove. IIRC they are filled to about 2000 PSI and donot hold that much. They have to be tested and recertified every couple of years. A major pain and expense. A car would lose a lot of trunk space to make space for hidrogen tanks.

Tuckerfan, your numbers are misleading in several ways. First, cars will not be carrying liquid hydrogen (although this makes zero difference). The fact that H as fuel carries less energy per volume just means a car will have to carry more volume of it in detriment of payload space. The amount of energy carried will be the same and the effect in an explosion the same. Except hydrogen is much more explosive than gasoline. And say what you will, gasoline in a crash is dangerous but I much prefer it to hydrogen.

There are buses and other vehicles that run on CNG (in DC among other places). This is comparable to H in handling and storage and serves as guidance.

62

In addition to crash risks, hydrogen leaks are extremely dangerous in enclosed spaces. None of the parking garages around here will allow propane or LNG vehicles to park in them, for that reason. One car with a leaky hydrogen tank could cause an entire structure to blow apart.

If hydrogen makes it into cars as a fuel, it will be in fuel cells that are designed to contain it.

But please remember - hydrogen fuel cells are useful for lowering pollution, but they are NOT an energy source. The hydrogen has to be produced in the first place, and that takes more energy than can be released. Given the electricity shortages of late, and the difficulty of bringing new power plants on line, this issue would have to be resolved before you can move to fuel cell vehicles.

You could sell me on the whole scheme if you are willing to build nuclear power plants to provide the power to generate the hydrogen. We talked about this in another thread a while ago - Canada has a proposal for building a ring of CANDU reactors for making hydrogen. Put the whole thing out in the desert somewhere by a big lake for a water source, and you can generate all the hydrogen fuel cells you need for the country. And the byproduct of the hydrogen creation is heavy water, which can be used in the reactors given you an efficient energy cycle. CANDU reactors can even burn spent fuel from other reactors. If it were in Nevada, they might even be able to economically eat some of the waste headed for Yucca Mountain, if it were separated from the low-level wastes at the original reactors before being shipped.

63

Quote sailor again
Quote sailor
I know of no small marine steam engines.
Well now you do.

Quote sailor
A marine diesel has a specific consumption in the order of 180 - 200 g/kwh. That is in line with Scanía’s 187 g/kWh for a 420-hp diesel

Gallons per kilowatt hour???
Now you’re talking about generators??? where did that come from???

Wern’t you the one that was explaining the simple efficency of ICE???

Speaking of efficency I believe I heard some where that the turbine was much more efficent than the piston engine.

Quote sailor
Of course I am talking of marine engines under (say) 350 HP, of the size that could be used in a car. I am not talking about humongous powerplants for ships or about humongous electric powerplants on land. We are discussing the small motors which could be used in cars. That same size is used in small boats and, if steam were practical, a boat has fewer requirements with respect to volume, weight, refrigeration, elasticity, etc. I know of no small marine steam engines.

Hey guy you are really jumping around.

If you’ll just go to the first site I suggested you can read about the 350 hp engine that broke the land speed record.
Is it a practical engine for todays housewife? no.None of those experimental engines are.

Go to the build your own steam engine site and see how simple the engines can be. Just try to build your own lawnmower engine from scratch.

Go back to the first site and find out a volkswagon has been running on a converted snowmobile engine for decades. They just hooked it up to a computer.
Joking when I linked to a hobbiest page??? I think you’d better take another look.

64

sailor, how are my numbers misleading? What makes hydrogen more dangerous than gasoline?

From Fuel From Water

Try that with gasoline some time.

From the same source:

Again from above:

(emphasis in the original)

It all depends upon the car design. If you shoehorn a hydrogen powerplant into an existing design, you’re correct. However, GM’s not planning on doing that.

Sam, it’s a great idea. Sadly, I don’t think that we’ll ever see anything like the set-up you describe anytime soon. The CANDU reactors and others like them are fantastic inventions which for all their merits are totally unable to get out of the shadows cast by Three Mile Island and Chernobyl. (Never mind that its been proven “pebble bed” reactors can’t melt down and go “boom”!)

65

Why not consider cost/KWH rather than specific fuel consumption? For example the wood burning marine engine.

http://www.geocities.com/Yosemite/Rapids/2068/TW.html

66

Ok, this is no longer a GQ and very much a GD.

justwannano, you and I have had similar encounters before and got nowhere so I am not going to waste my time again. You wave your hands a lot and talk of generalities. It is wishful thinking. The fact that you wish something does not mean it is actually true. We had pretty much the same exchange in the thread about solar heating and you never provided any solid evidence or supporting numbers. Just generalities and wishful thinking about what “could be”. You are doing the same here and I am posting this reply for the benefit of others as I know you will not learn anything from it even though you have so much to learn.

>> Quote sailor
>> I know of no small marine steam engines.
>> Well now you do.

When I say I know of no small marine engines, it is clear I am talking of the real world and in the 100 - 500 HP range. Toys do not count. Hobbyists do not count. Those are not in that range and in any case and fundamentally, the builders and owners have no concern about efficiency which is probably in the awful to dismal range.

>> Quote sailor
>> A marine diesel has a specific consumption in the order of 180 - 200 g/kwh.
>> That is in line with Scania’s 187 g/kWh for a 420-hp diesel
>> Quote justwannano
>> Gallons per kilowatt hour???
>> Now you’re talking about generators??? where did that come from???

This is so sad. Sad but comical. You are not even familiar with the units used to measure the efficiency of an engine. You are not familiar with the metric system and its units. It is used in industry all over the world, including the US. Let me introduce you to it. “g” stands for grams, Kw stands for Kilowatts and is a unit of power, h stands for hour and is a unit of time. Kwh is power multiplied by time and, so, is a unit of work. It is not a unit of electricity, it is a unit of work and is the standard unit of mechanical work for motors everywhere. Grams of fuel consumed per KWh of mechanical work produced is called “specific fuel consumption” and is used to measure the efficiency of a motor. The reason mass is preferred to volume is because fuel can vary in specific gravity and the energy contained in it more closely correlates with mass than with volume.

You, obviously, have no clue about the basic units and measurements of a motor’s efficiency and you just look foolish here. It would be good if you knew what you were talking about. Did you visit the Scania page I linked to? Did you see that motor is for a bus and not a generator? Did you see the specific consumption is cited in g/Kwh? Did you search for other motors and compare their specific fuel consumptions? Of course you didn’t. You don’t know what you are talking about and you do not care. You are not qualified to have any informed or expert opinion on this matter. You are just expressing your wishful thinking.

Some more pages with specs of diesels of different types (stationary, locomotive, marine, etc):
Locomotive: The power per cylinder is 40-60 kW, the specific consumption is 195 g/kWh
Stationary: 211 g/Kwh

As we have some innumerate people around here I did the conversion and .26 lb/hp equates 160 g/Kwh
Marine: 200 g/kwh (heavy oil)
Scania buses: 187 g/kWh for 420-hp

Efficiency is expressed in numbers. Numbers. Give me numbers.

>> Speaking of efficency I believe I heard some where that the
>> turbine was much more efficent than the piston engine.

a) “I heard” is not recognised a a good source here
b) It is probably true. That would be my guess too.
b) It is absolutely irrelevant. Yes a gas turbine may be more efficient that a gas ICE. So? We are talking about steam. As I said before, if you introduce steam as an intermediate step, you are inevitably introducing losses. This is basic physics. The losses introduced in the boiler are much higher than any gain achieved by using a turbine. In any case, why not use a turbine directly and skip the steam? That is what is done in the real world unless the fuel forces you to have an intermediate steam cycle. You have not addressed this (and I do not expect you to)

>> Quote sailor
>> Of course I am talking of marine engines under (say) 350 HP,
>> of the size that could be used in a car. I am not talking
>> about humongous powerplants for ships or about humongous electric
>> powerplants on land. We are discussing the small motors which could be
>> used in cars. That same size is used in small boats and, if steam
>> were practical, a boat has fewer requirements with respect to volume,
>> weight, refrigeration, elasticity, etc.
>> I know of no small marine steam engines.
>> Quote justwannano
>> Hey guy you are really jumping around.

How so? Show me a successful steam engine in the 100 -500 HP range which can compare favorably with an ICE. that is all I am asking. Toys, etc are fun but show me one which will compare in efficiency.

>> If you’ll just go to the first site I suggested you can read about
>> the 350 hp engine that broke the land speed record.

I did not find fuel consumption figures in that page. Maybe you can supply me some? the only thing that pages says is that a steam powered car moved faster than any steam powered car before it. So? What does that prove? It does not prove it did it more efficiently than if it had an ICE. It does not prove anything except that it was competing with its own class in speed.

Furthermore, can you tell me what is the specific consumption of that engine? Because, I will remind you, the OP is Steam-Powered Cars-Why Not? and my answer is they are inherently less efficient. You are saying they could be more efficient but you fail to support that in any way. You fail to explain how you can introduce one more energy conversion in the machine, thereby introducing losses, and yet still come out ahead. If you believe that is possible you might want to send these guys some money:
http://www.electricity4free.com/
http://www.freelectricity.com/
http://www.ucsofa.com/Free%20Electricity.htm
http://teslaelectric.com/

>> Is it a practical engine for todays housewife? no.
>> None of those experimental engines are.

Thank you for making my point even if you had to needlessly introduce a housewife into the picture.

Building a steam engine in terms of technology is so simple they were doing it efficiently 150 years ago. Any company who found promise in them could easily do it. For goodness sake, they are looking into fuel cells and stuff which is 100 times more complicated, why would they choose to ignore something so simple if it looked promising?

In summary, justwannano, you have failed to adress the following points convincingly:

a) How can you introduce the new energy conversion with the steam boiler and not introduce losses?
b) Show me a steam engine which has a specific fuel consumption under 200 g/Kwh
c) Explain why such a machine has not been built
d) Explain why world wide industry, scientists, engineers are not pursuing this aggresively if it looks so promising.
e) And please, justwannano, tell me why you feel qualified to judge engine efficiency when you lack the basic understanding of how and in what units the efficiency of engines is measured.

Please answer those questions concisely and precisely.

I think I have made my point.

67

No, I would quite happily drive a hydrogen powered car, and not worry about the safety. But gasoline as a “hazard” has sorta been “grandfathered” into society, and thus lawsuits do not focus on the fact that the “manufacturer showed recklessness by including an explosive (the gasoline) in the car”. Whereas hydrogen is new and scary, and when the average cowlike jury member thinks of hydrogen, they think of “Hindenburg”, “Bikini Atoll”, and possibly “Joey Ramone”, although I would have no idea why on the last one…

That’s all I’m saying, Tuckerfan. That hydrogen is going to suffer from that perception problem. One which could yield multi-billion dollar lawsuits for the “Crimes against humanity” committed by any auto manufacturer who uses it in a vehicle.

Since my expertise is combustion engineering, let me make a few comments:

  1. Compare them on a mass basis, not a volumetric basis. You cannot compare a liquid and a gas on equal volumetric terms. Unless you were thinking only of the energy available in a fuel-air explosion, in which case you are correct.

  2. Autoignition temperature depends on mixture richness.

  3. Adiabatic flame temperature is meaningless with respect to safety. It is more a measure of the maximum efficiency that you are going to get in a perfect combustion process. It by no means means that the flame temperature is going to be that level.

  4. Hydrogen does have two big problems: First - if it leaks, how do you know? Unlike a gasoline leak in your car, which you can smell a very small amount of, hydrogen is odorless. Sure, you can add ethyl mercaptan or something, but most all plans I see for hydrogen cars do not include that.

  5. Second big problem - and this is the key issue here with respect to safety - hydrogen has an enormous flammability limit in air at standard temperature and pressure. It’s limits are:



Fuel           Lower Limit, vol%     Upper Limit, vol%

Acetylene            2.5                         80
Gasoline             1.4                         7.8
Hydrogen             4                           74.2
Methane              5                           15
Methanol             5.88                        49.94
Natural Gas          4                           14
Propane              2.05                        11.38

So if you compare the ranges of mixtures in atmospheric air at which hydrogen and gasoline will burn, you can see the danger of a hydrogen leak. Gasoline has a very narrow range at which it will burn, relative to hydrogen - in fact, the only common fuel with a wider range than hydrogen is acetylene.

There are some other factors to consider as well - I think this page can lend itself to some good reading. Note that they do find several measures where gasoline would be more dangerous as well - they end up saying the two are about equal in risk.

68

If you are not careful, you are going to force me to affect a sigh.

Gallons per kWh is a measure of specific power production - this can be measured with the same units, regardless of whether it is electrical, mechanical, or thermal power you are talking about. Power is power, from a measurement standpoint, and sailor is using the correct units.

Depending on the circumstances, yes, a steam turbine can be more efficient than a steam piston system, and a gasoline-powered turbine would be more efficient than a gasoline-piston IC engine. But you have the trade-offs of ease of manufacture and flexibility of operation versus lower cost manufacture and greater flexibility of operation. It would depend on the situation which one would choose.

Been there, done that. People in my Mech Eng practical shop class built a crude 2-cycle lawnmower engine. It’s actually much easier than building a condensing steam engine. Now, a non-condensing steam engine would be easier to build than a lawnmower engine, slightly, but then again, for practical automotive use, one would never use a non-condensing steam engine.

The Virage cars they use at the Malibu Grand Prix family fun centers use a snowmobile engine too, and they work really well. But I am unclear how this enters into the conversation…?

69

One big problem with antifreeze in the boiler circuit, BTW, is that it also acts as an anti-boil. In a steam engine, you need to keep a careful watch on the actual vaporization temperature when you are designing the components and operating them, and a system where the anti-boil characteristics were variable (as the effectiveness of the antifreeze degrades over time), or there is variability in the proportions, is not good. It works on a crude level just fine, but for a high-efficiency engine, it would be another alligator to wrestle with.

The specific heat capacity of the anti-boil solution is also a bit lower than water, so you have to increase the physical size of your system - the sizing of the condenser, the pipes, and the heating systems.

70

sailor “The losses introduced in the boiler are much higher than any gain achieved by using a turbine.”

I notice that you yave mentioned the losses and inefficiency of boilers several times. Do you have any information that boilers are inefficient?

71

This thread has taken off in all directions at once and many interesting points have been raised but I think it is better if we can keep it focused on the OP "Steam-Powered Cars-Why Not? and open other threads for topics like alternative fuels etc.

Steam is just a transmission system, it does not produce energy. The energy to make the steam can come from many different sources. Traditional and alternative sources of energy are a very interesting topic in themselves but I am afraid that topic is highjacking this thread. If we think we want to discuss alternative fuels then I would suggest a new thread and I will be very glad to participate in that one too.

As I said before, a steam intermediate transmission may be necessary in certain circumstances, like when burning solid fuel, but it is unnecessary when the energy in the combustion gases can be transformed into mechanical energy directly either in an ICE or a turbine. Adding the unnecessary steam stage lowers efficiency due to losses introduced, weight added, etc.

heavysteamer, welcome to the board.
>> I notice that you yave mentioned the losses and inefficiency of boilers several times. Do you have any information that boilers are inefficient?

Um, no transmission is 100% efficient. That is basic physics. Of 100% energy produced in the combustion only a part will go to the steam and of that part, only a fraction will be transformed into mecanichal energy. Every transformation incurs losses. That’s just basic laws of physics. Transform energy, transport energy and you incur losses.

Around 1821, Swedish inventor John Ericsson, at the young age of 19, came to the realisation that the steam cycle was an unnecessary intermediate stage and if he could dispose of it efficiency would rise so he started to work developing a “hot gas” engine which did not use steam. His work and that of Stirling laid the foundations for the “steamless” internal combustion engine.

72

Hey, I didn’t bring up alternate fuels and hydrogen - I’ve responded to issues brought up by others. I’m not going to let things sit if I feel there is a clarification needed, additional helpful information I can add, or something I can positively contribute.

Let’s look at what the highest boiler efficiency that one can expect is: based on my experience with huge-assed industrial boilers (which, like transformers, is a place where larger is often more efficient), I can tell you that with light oil-firing, one can expect boiler efficiencies of between 92-94% on a higher heating value basis, at the absolute best. This means that of the fuel input to the boiler on a higher heating value basis, about 92-94% of the energy of the fuel goes into the steam. However - this includes the following assumptions:

  1. Very low excess oxygen in the combustion gases.
  2. Use of a regenerative air heater, to pre-heat the combustion air to about 150 F.
    2a) Air heater leakage of around 5%.
  3. Very low to non-existant losses due to CO and HC.
  4. A huge residence time for combustion to complete.
  5. Clean heat transfer surfaces without excessive slag or fouling.
  6. Combustion gases leave the system at more than 212 F.

So, if we want to look at maximum possible efficiency, in a practical setting, you are looking at about 94% boiler efficiency. I sincerely doubt that any small-scale application is going to top that, and I would expect a more realistic number to be 90%. But let’s say 94%.

Now, what the hell do we do with the steam? Most likely, it goes to a turbine/condenser system, since that is a more efficient way of converting it to power than via a piston. Well, looking again to huge-scale turbine/condenser systems, we can see that the steam power industry has produced the most efficient examples of these.

You can expect, at full load operation, a superior turbine to convert the heat in the steam to energy at a heat rate of about 7000 Btu/kWh. NOTE that this assumes the following:

  1. Minimal superheater spray.
  2. Use of a reheat cycle, with minimal spray. Note that if your system does not use reheat, you have just lost about 20% of your efficiency from the 7000 Btu/kWh figure above.
  3. Use of an economizer. Note that without an economizer, you are losing another 10-15% of your efficiency from the 7000 Btu/kWh figure above.
  4. Condenser backpressure of about 2 in Hg. Note that this means you must have a superior condenser system, with a lot of cooling going on - I mean, to get down to 2 in Hg, you typically are looking at cool river water at 55 F as the heat transfer media. If you are talking about a car, using atmospheric air as the cooling medium for the condenser, what could your best possible condenser backpressure be? 4 in Hg? 5? At even 4 in Hg, you have lost about 250 Btu/kWh efficiency relative to the 2 in Hg case. I would guess that a motor vehicle would be hard pressed to have a backpressure under 6 in Hg, which means you might have to take 500 Btu/kWh off of the efficiency figure of 7000 Btu/kWh. Which would make it 7500 Btu/kWh. (yes, that is correct - higher numbers are worse).

Let’s assume you are using an economizer, condenser, and reheat system, and have a Net Turbine Heat Rate of 7500 Btu/kWh (I’m going to give the benefit of the doubt to the steam power advocates, and assume that the boiler feed pump is turbine driven, and not electric driven (which would makes things less efficient)). Then, on a fuel input basis, the gross power generation can be expressed in terms of:

GPHR = (Net Turbine Heat Rate/Boiler efficiency)

GPHR = 7500/0.94 = 7978 Btu/kWh

This is a gross thermal efficiency of 100*(3413/7978) = 42.8%

42.8% under the best case reasonable for a turbine/condenser system firing gasoline. NOW…note that this is Gross Plant Heat Rate (GPHR) - we have not deducted for the power of the alternator, water pumps (outside of the boiler feed pump, which I gave a freebie for), power steering, A/C, etc. Let’s assume a low figure for these - say 5% total losses (very low, if you ask me, but OK). Now, let’s calculate the NPHR (Net Plant Heat Rate):

NPHR = (Net Turbine Heat Rate/((Boiler efficiency)*(1-Aux/Gross))

NPHR = 7500/(0.94*.95) = 8398 Btu/kWh

This is net thermal efficiency of 100*(3413/8398) = 40.6%

So, 40.6% Net under the best case situation I can think of IRL operation, and giving a couple of freebies on power (BFP, for example).

So, the question is:

  1. What is the real, expected net turbine heat rate of unit? And what would the real condenser backpressure be in road operation?
  2. What would the real, expected boiler efficiency be?
73

Thank you for the welcome, sailor. I don’t know how much I’ll post here, the board makes me log in every time I try to post. Probably operator error on my part.

The basic reason many small steam are less efficient than internal combustion plants is not the number of conversions gone through, but because of the maximum temperature limitation on the working fluid.

Stirling engines are external engines, not internal combustion engines. The working fluid is a gas.

Regarding the efficiency of the gasoline automobile. There is a vast difference in a gas car between the advertized horsepower and the measurable horsepower to the road. A Stanley steam car of 20 horsepower will put 20 or more horsepower directly to the road.

74

Anthracite, I was not refering to you specifically. I know many side issues have come up and several of us have addressed them, including myself. I wast just trying to keep this thread focused and, if we feel the need to discuss alternative fuels, then I would suggest we open another thread so this one can remain focused.

Your last post is extremly interesting. Of course, we know often things do not scale down well. Weight and space are hardly a concern in an industrial powerplant whereas in a vehicle they are primary concerns. Also, power plants can use solid fuels which would not be practical in a vehicle.

heavysteamer, maybe I didnot express it well. The point I was trying to make is that both Stirling and Ericsson had the same concept: Take a steam engine, if you can take out the steam cycle, you will increase efficiency. At any rate, it is a historical footnote I got from “A History of the Machine” by Sigvard Strandh.

Please answer these questions
Do you believe a small (<500 HP ~ 370 Kw) steam engine can be more efficient than an internal combustion engine? Yes or no.
If so, can you show me such a steam engine which would have a specific fuel consumption under 200 g/kwh? Please provide some verifiable information.
If you believe it is possible but do not know any cases where it has been built, why do you think such a steam engine has not been built? What would the cause be?

Thank you

75
76

Quote sailor to anthracite

“Please answer these questions
Do you believe a small (<500 HP ~ 370 Kw) steam engine can be more efficient than an internal combustion engine? Yes or no”

Hey guy there you go.Thats the way. I’m so proud of you. You’re finally beginning to think in a real world manner.

Emphasis on “can”

77

Was sailor addressing me, or heavysteamer? :confused:

78

If it may please the court:

I have provided ample documentation proving small (< 500HP)internal combustion engines achieve specific fuel consumptions under 200 g/Kwh. Stationary, marine, automotive and airplane ICEs achieve this efficiency.

The other part claims steam engines could be designed and built which would yield better efficiency but said other part has failed to produce any evidence (other than his own opinion) that this is indeed possible. No figures, no cites, nothing.

The other part further claims that it is possible to build it but the reason it has not been built is the entire automotive industry, domestic and foreign, the entire marine engine industry, domestic and foreign, the entire stationary engine industry, domestic and foreign, have a vested interest in not developing this type of engine, and this in spite of the fact that these same industries spend billions in R&D of many other types of engines. The court will appreciate the lack of proof or support for any of the assertions of the other part.

I therefore move the court to dismiss the other part’s claims with prejudice. May it please the court.

I rest my case.

79

The questions were directed to justwannano and heavysteamer (quite obviously I would think, since they are the ones defending the point of view I address) and not to Anthracite.

In any case, I have made my point here and feel I have nothing further to contribute unless and until the other side provides some tangible proof and support rather than the general “the only reason it can’t be done is because Detroit opposes it”.

If and when any solid evidence is presented in this thread showing a steam engine (<500 HP) with a specific fuel consumption below 200 g/kwh is possible, then I will address it. In the meanwhile I have said all I had to say.

80

Sigh

The neat thing about steam is that you are not limited to the fossil fuels that we are running out of at such an alarming rate.
Sailor cannot see that the steam is the propellant.
The fuel used can only be gasoline or a similar fossil fuel.
His closed mindedness is something that I have gotten used to in argueing with him.(see his solar comment above.)

If there is a gpkwh for kingsford charcoal briquetts would someone please inform sailor?
How about pelleted wood chips?

You rest now sailor. Someone has work to do.