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Diesel

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Re: Diesel
Post by dan92677   » Fri May 30, 2014 6:19 pm

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How about using either a small Thorium liquid heat producing pile or a L.E.N.R (cold fusion) "Nanor" heat producer along with a condenser and stick with steam?
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Re: Diesel
Post by Tenshinai   » Fri May 30, 2014 6:22 pm

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Weird Harold wrote:
Aren't you making an unwarranted assumption that Charis will stick with coal and not fire their steam engines with liquid or gaseous fuels?


Go back and check the numbers someone posted on actual fuel consumption comparisons.

Ah yes, Larry posted this:
(summary only)
Notice 200 gallons of water PER MILE, 10 to 20 miles per ton of coal, 10 to 20 gallons of oil per mile,
A diesel 2.5 to 4 gallons of oil and no water per mile.


So twice as much fuel oil even at best. Which is just the way it is, steam engines does not use the energy directly, introducing an extra stage of energy loss, they simply CANNOT be anywhere near diesels in efficiency.
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Re: Diesel
Post by Weird Harold   » Fri May 30, 2014 6:25 pm

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dan92677 wrote:How about using either a small Thorium liquid heat producing pile or a L.E.N.R (cold fusion) "Nanor" heat producer along with a condenser and stick with steam?


Wouldn't that be "handwavium" (boiler) tech?

I have no idea how or whether such tech would trip the OBS into action, but I think either tech would be easier with Electricity, which means after the OBS is dealt with.
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Re: Diesel
Post by Weird Harold   » Fri May 30, 2014 6:37 pm

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Tenshinai wrote:Go back and check the numbers someone posted on actual fuel consumption comparisons.

Ah yes, Larry posted this:
(summary only)
Notice 200 gallons of water PER MILE, 10 to 20 miles per ton of coal, 10 to 20 gallons of oil per mile,
A diesel 2.5 to 4 gallons of oil and no water per mile.


So twice as much fuel oil even at best. ...


Good figures as far as they go -- I didn't go back and look at whether he was figuring ton-miles for heavy trucks or was using figures for Diesel-electric Rail. Whichever way Larry figured economy, it doesn't change the assumption above that Steam==Coal.

If the numbers are for Diesel-Electrics (and they look fairly close to Burlington Northern's TV ads) then he's talking about an "after-proscriptions" economy. In that case, he's missing cost/mile for catenary or third-rail-electric rail to the comparisons -- I don't know how they compare energy-efficiency-wise, but all electric rail has both steam and diesel beat in environmental impact.
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Re: Diesel
Post by pokermind   » Fri May 30, 2014 8:36 pm

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Hmm IIRC the efficiency (work produced/energy potential of fuel x 100) is something like 20% for a diesel engine and 10% for a steam engine. Now economics rears its ugly head if the same BTUs of diesel costs twice the same BTUs of coal then fuel cost is same for same amount of work. But the real killer for Steam was maintenance and operation costs, IIRC diesel locomotive required about 75% of the maintenance and operating cost of a steam locomotive. Personnel cost was more significant in the decision to change from steam to diesel than relative costs of fuel, or their relative efficiency.

When all else fails follow the money, that's what happens in the real world, just saying.

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Re: Diesel
Post by Weird Harold   » Fri May 30, 2014 8:58 pm

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pokermind wrote:But the real killer for Steam was maintenance and operation costs, IIRC diesel locomotive required about 75% of the maintenance and operating cost of a steam locomotive.


That will probably be true for Safehold as soon as they deal with the "real killer" in the safehold universe -- the OBS. The Diesel locomotives your numbers are based on are Diesel-Electric and the Charisians have already rejected electrics until the OBS is neutralized.

pokermind wrote:When all else fails follow the money, that's what happens in the real world, just saying.


Just as steam trucks persisted until the 1970's in England, there are reasons Charis is likely to use steam despite the economics of the situation. England "subsidized" coal-fired steam for a long time because England had lots of coal and very little oil.

Politics trumps economics and common sense every time.

Politics is the reason that American cities are generally poorly served by mass-transit despite the economic and ecological benefits. It's been a few years since I ran down the details, but Los Angeles once had one of the best metropolitan rail systems in the world -- the so called Red Cars -- and politics and General Motors bus division ripped up all the rails and trashed all the rolling stock in favor of GM Buses which never approached the level of service the Red Cars provided.
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Re: Diesel
Post by AirTech   » Sat May 31, 2014 8:07 am

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pokermind wrote:Hmm IIRC the efficiency (work produced/energy potential of fuel x 100) is something like 20% for a diesel engine and 10% for a steam engine. Now economics rears its ugly head if the same BTUs of diesel costs twice the same BTUs of coal then fuel cost is same for same amount of work. But the real killer for Steam was maintenance and operation costs, IIRC diesel locomotive required about 75% of the maintenance and operating cost of a steam locomotive. Personnel cost was more significant in the decision to change from steam to diesel than relative costs of fuel, or their relative efficiency.

When all else fails follow the money, that's what happens in the real world, just saying.

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Locomotive boilers are not a particularly good example here of efficiency, good coal dust fired commercial power generation boilers run at about 40% efficiency (60% on power recovery installations (gas turbine generator exhaust with afterburner to steam boiler/turbine)). Diesel power generation is a definite loser on the efficiency stakes. (Turbochargers help but losses from exhaust gas heat and pressure are still significant).
There were some attempts at building water tube boilers (and steam turbines)for locomotives but by that time the diesel engines developed for submarines had become too cheap and the oil price too low to be overcome.
Efficiency can be judged by the temperature of the exhaust against the combustion temperature of the fuel and diesels have a much higher exhaust temperature than an efficient boiler. Other tweaks include running a Kalina cycle in the boiler to drop the steam exhaust closer to ambient by running a mixture of water and ammonia (which obviously requires a closed circuit condenser), higher steam pressures (2000psi super-critical with air and water preheaters, superheater and inter-stage reheaters to extract the maximum heat from the flue gas) and the use of a turbine power plant (although a 4 stage piston engine comes close). (Kalina cycle systems also are faster to bring on line due to the higher pressures of the ammonia).
A good coal fired power station puts out significantly less carbon dioxide than an equivalent power diesel (and no-one builds gigawatt class diesels).
The killer, for steam power, was the delay in getting up steam (the fireman had to get in two hours before the start of the day to raise steam on a fire tube boiler (and clean it out at the end of the day- hence the extra 20% on labor costs compared to a diesel on the same route). Flash boiler designs can shorten this to a value comparable to warm up times on a diesel.
A bigger issue is fuel availability, with no fossil fuel oil production infrastructure in existence, I doubt anyone could organize the thousand tons of fuel oil needed for an ocean crossing, and any number of coal mines would have that level of inventory on hand.
The killer, for steam power, was the delay in getting up steam (the fireman had to get in two hours before the start of the day to raise steam on a fire tube boiler (and clean it out at the end of the day- hence the extra 20% on labor costs compared to a diesel on the same route).
(BTW my Great Grandfather was an engine driver during the transition first from steam to electricity on metropolitan lines and then to diesel (which displaced electricity on some lines due to lower fixed infrastructure costs. Coal dust firing was also tried and worked a little too well (excessive fire box heat and pressure) but this was overcomeable as was the bunker explosion risk (fixed by nitrogen blanketing the coal bunker) but oil firing was easier).
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Re: Diesel
Post by Tenshinai   » Sat May 31, 2014 10:35 am

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pokermind wrote:Hmm IIRC the efficiency (work produced/energy potential of fuel x 100) is something like 20% for a diesel engine and 10% for a steam engine.


With basic engines that´s close enough yeah.
About twice that for evolved/complex engines of both types.

Where steam shines(and why it´s still used today) is when you put it in a fixed largescale system that includes a secondary system for exploiting waste heat, as well as using very very extended running cycles, at that point you can achieve something like 40-50% for steam engines.

That´s not realistic at all for Safehold though, and those kind of installations need to be MASSIVELY big to get the benefits without too much of the problems with maintenance.

pokermind wrote:Now economics rears its ugly head if the same BTUs of diesel costs twice the same BTUs of coal then fuel cost is same for same amount of work. But the real killer for Steam was maintenance and operation costs, IIRC diesel locomotive required about 75% of the maintenance and operating cost of a steam locomotive. Personnel cost was more significant in the decision to change from steam to diesel than relative costs of fuel, or their relative efficiency.

When all else fails follow the money, that's what happens in the real world, just saying.

Poker


Nah, it´s much worse than that. Maintenance/operating costs for diesel aren´t even half that of steam once you count everything involved. Just the upkeep for the water reservoirs needed is a BIG chunk of money.
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Re: Diesel
Post by Tenshinai   » Sat May 31, 2014 10:55 am

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AirTech wrote:The killer, for steam power, was the delay in getting up steam (the fireman had to get in two hours before the start of the day to raise steam on a fire tube boiler (and clean it out at the end of the day- hence the extra 20% on labor costs compared to a diesel on the same route).


2 hours? Heh, that´s not nearly enough. When my brother was involved in a steam engine railroad in the 80s and 90s, whenever they were going to run the trains, they had to start firing up the boilers the night before.

If you go from ambient temperature to operational temperature in 2 hours repeatedly, you´re going to wear out the boiler FAST. And all the tubing connections are going to require drastically more maintenance.

Or you have to build everything with much larger margins. Which means 20-100% heavier machinery.

AirTech wrote:Flash boiler designs can shorten this to a value comparable to warm up times on a diesel.


And the lifespan those can have with Safehold tech is? Not long enough to be worth the cost of production. Except in torpedoes maybe, where they´re single-use.

You really do not want flash boilers with 19th century tech.

AirTech wrote:(BTW my Great Grandfather was an engine driver during the transition first from steam to electricity on metropolitan lines and then to diesel


Eh... My mothers uncle was an engine driver who started with steam, my grandfathers, one was a train engine mechanic, the other a hmm, frankly i havent a faintest what to call him in English, lets just say his primary task was dealing with trains, especially engines, and like i mentioned, my brother was a steam engine enthusiast, my father has been involved with a lot of trains, including steam...

Uh yeah, a bit train crazy, up until about 10 years ago, my family has had a minimum of 3-4 people(or much more at some times) working with trains ever since the great expansion of railroads here started in the 1870s.
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Re: Diesel
Post by Dutch46   » Sat May 31, 2014 6:45 pm

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pokermind wrote:Hmm IIRC the efficiency (work produced/energy potential of fuel x 100) is something like 20% for a diesel engine and 10% for a steam engine. Now economics rears its ugly head if the same BTUs of diesel costs twice the same BTUs of coal then fuel cost is same for same amount of work. But the real killer for Steam was maintenance and operation costs, IIRC diesel locomotive required about 75% of the maintenance and operating cost of a steam locomotive. Personnel cost was more significant in the decision to change from steam to diesel than relative costs of fuel, or their relative efficiency.

When all else fails follow the money, that's what happens in the real world, just saying.

As a curiosity item, I would be interested in where those numbers came from and how they were derived. I think a diesel has a higher comparative efficiency than you cite but, I am working mostly from memory and long years of experience and my built in data storage device seems to be developing more and more bad sectors as I age.

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