Diesel

Castenea wrote:...The distinct emissions of ICEs would be NOX, which is not produced by boilers untill you are useing pressures and temperatures high enough for supercricality,...

Your nitpick is noted, but the statement quoted above is at the heart of my point.

Steam will operate at temperatures and pressures low enough to allow complete combustion and minimal NOx emissions. Diesels can't function without high temperature and high pressures in the combustion chamber; not with anything like modern efficiencies

SWM wrote:

MWadwell wrote:
Just to address the point I have highlighted above, Pressure is potential energy.

Bleed compressed air out of a cylinder into a turbine, and you have kinetic energy (the turning turbine).

Remember - energy cannot be destroyed (only converted), and so pressure must be potential energy, as otherwise the kinetic energy from the turbine has come out of no-where.....

EDIT - check out the wikipedia article on Enthalpy - http://en.wikipedia.org/wiki/Enthalpy for more information about this form of thermodynamic potential energy.

No, Pressure is force across a surface. Pressure is not potential energy. It doesn't even have the same fundamental units. Heat is potential energy. There is a reason that it is called "thermodynamic potential energy".

Mmmm - I'm going to have to go back and have a stern talk to the professors that ran the thermodynamics and fluid mechanics courses that I did at university, as (when talking about initial and final states of fluids and gases) enthalpy (which includes pressure) was a factor. (BTW, I still have my textbooks if you want references.)

Also, regarding SI units - you are wrong. Work is measured in Joules (as it is the amount of energy that has been exchanged with an object), and to find the work done on a gas, work is the integral between the initial and final volumes of the pressure - http://en.wikipedia.org/wiki/Mechanical_work#Work_by_a_gas


It may have been 20 years ago, but I still remember what a mechanical engineering degree is....

n7axw wrote:

Weird Harold wrote:(SNIP)

It isn't about the amount of pollution, it is about the kind of pollution. ICEs operate at higher pressure than the boiler for a steam engine does; that produces more of certain types of pollution and some pollutants boilers don't produce -- unburned fuel, for example.

(SNIP)

I won't comment in detail here, but everything that burns polutes. Housmyn is conerned about the health risk to his workers, coal causing black lung. Whether you are talking coal, diesel, wood, gasoline; it all does unfortunate things to us when we inhale it to say nothing about pouring all that carbon into the air.

What we can hope for is that thanks to Owl and Merlin, Safehold will have a leg up on the solutions to all of this and won't wait centuries to figure it out.

Don

G'Day Don,

No-one is concerned about the health effects of pollution.

Weird Harold is concerned that ICE's produce specific byproducts that can be detected (and targetted) from orbit.

Without knowing more about the OBS (i.e. can it detect ICE specific emmissions), this arguement is deadlocked.....

After reading the argument about refining oil to fuel diesel engines, it struck me that in MT&T when they discovered nitrocellulose that the were talking about refining the oil to get petroleum jelly for smokeless powder. Then in LaMA it was stated that smokeless powder was on the way so that they could push the bullet for the M96 up to 2600 fps. Refining of petroleum is already taking place off screen.

MWadwell wrote:

SWM wrote:No, Pressure is force across a surface. Pressure is not potential energy. It doesn't even have the same fundamental units. Heat is potential energy. There is a reason that it is called "thermodynamic potential energy".

Mmmm - I'm going to have to go back and have a stern talk to the professors that ran the thermodynamics and fluid mechanics courses that I did at university, as (when talking about initial and final states of fluids and gases) enthalpy (which includes pressure) was a factor. (BTW, I still have my textbooks if you want references.)

Also, regarding SI units - you are wrong. Work is measured in Joules (as it is the amount of energy that has been exchanged with an object), and to find the work done on a gas, work is the integral between the initial and final volumes of the pressure - http://en.wikipedia.org/wiki/Mechanical_work#Work_by_a_gas


It may have been 20 years ago, but I still remember what a mechanical engineering degree is....

You are correct, Work is measured in Joules, or kg m^2 / s^2. But Pressure is measured in Pascals, or kg/m s^2. Not the same units! You would have to multiply Pressure by a Volume (or an equivalent set of factors) in order to get units of Work or Energy. You yourself say that work is the integral of pressure over intial and final volume. Integral means a product between Pressure and Volume. Pressure is not equal to Work or Energy, as you said in previous posts.

Your professor was correct that pressure is a factor in enthalpy, but it is not equal to enthalpy. Enthalpy is the Internal Energy plus the product of Pressure times Volume. Pressure is not potential energy; it is merely one of several factors in calculating the potential energy.

I believe we are in total agreement about the definitions of Pressure, Work, Energy, and Enthalpy. The only thing I have been disagreeing with were these statements you made: "pressure = energy = velocity = heat" and "Pressure is potential energy". I don't think you meant that literally, since you clearly do understand thermodynamics. But it is important to be clear in statements like this, and I wanted everyone else to understand that Pressure is not actually (by itself) equivalent to Energy. It is only a factor in determining the Energy of a system.

pokermind wrote:OOPS the British Government did not like steam lorries see http://en.wikipedia.org/wiki/Steam_truck

Just goes to show how politicians and bureaucrats should NEVER, ever, be trusted anywhere near anything involving technology or engineering.

Just look at the way that legislators have ruined the automotive industry over the last half-century with their ridiculous demands.

While a lot of these arguments have been down in the weeds as to which (if any) system is more efficient, we need to remember that the systems also need to be usable in the real world.

You will perhaps notice that in the real world, trucks, trains, tanks, ships and small to medium sized stationary generators use Diesel engines. The benefits of Diesel for these sorts of applications far outweigh the various costs associated with Diesel, so much so that it is prohibitively expensive to even consider displacing Diesel with other sorts of technology, including steam, fuel cell or even exotic hybrid engines like turbo compound diesel engines (the Napier Nomad was a very extreme form of turbo compound diesel engine which was designed to power aircraft, and Napier also developed a version of their Deltic engine to work as a gas generator for a turbine with the projected output being 6000 HP, so there were real engines with real applications out there).

As far as Safehold goes, so long as there is a prohibition on the use of electricity, then steam will probably have an edge in both sunk infrastructure (coal mines, engineers trained to use steam engines etc) and for specific applications like ship propulsion and stationary power on the factory floor. Once electrical energy is allowed, then medium sized steam will no longer be economical; like on Earth the stationary steam engine providing a few Kw on the factory floor will become a monster steam power plant providing electricity to millions of electrical motors. Diesel engines have specific niches which they will migrate to on Safehold as well, unless, as some hope for, the entire IC period can be bypassed with some handwavium.

I don't think that is likely for two reasons; hydrocarbon energy is easily available, energy dense and easy to handle at STP, relatively non toxic (think about that next time you are at a self serve gas station), and machinery using hydrocarbon energy is not only easy to make, but provides the industrial and scientific infrastructure to move to the next level (as per Merlin's plan). Having people who know precision machining, thermodynamics, chemical engineering and all the other associated sciences and technologies needed to create the IC industry provides a strong foundation to build nuclear and other technologies for the future.

iranuke wrote:After reading the argument about refining oil to fuel diesel engines, it struck me that in MT&T when they discovered nitrocellulose that the were talking about refining the oil to get petroleum jelly for smokeless powder. Then in LaMA it was stated that smokeless powder was on the way so that they could push the bullet for the M96 up to 2600 fps. Refining of petroleum is already taking place off screen.

Diesels also work on alcohol and vegetable oils - in fact the first diesels were specifically designed for this. So alternative fuels for diesels are possible - including coal & water slurries at the extreme end. The only question is getting them into the engine. A reference to them as "Diesels" would however really raise eyebrows for anyone with a read on technical history on Safehold.

As for emissions - a catalytic converter will fix the NOx if the sulfur level is low enough as will adding ammonia or urea to the fuel system. Mechanical injection systems predate electronics (but electronics are cheaper for the same functionality and easier to tweak during development).
Diesel aircraft engines were used in most Junkers aircraft leading up to the Second World War. (Look up Junkers Jumo 205, the direct ancestor to the Napier Deltic and Blohm & Voss Ha 139 Airliner (it also powered the early Junkers Ju86's)).
If you really want to mess with the CoGA you could toss them a set of sectional drawings for a Deltic and watch them try to build it (the crankshaft gearing is decidedly non-intuitive).

AirTech wrote:

iranuke wrote:After reading the argument about refining oil to fuel diesel engines, it struck me that in MT&T when they discovered nitrocellulose that the were talking about refining the oil to get petroleum jelly for smokeless powder. Then in LaMA it was stated that smokeless powder was on the way so that they could push the bullet for the M96 up to 2600 fps. Refining of petroleum is already taking place off screen.

Diesels also work on alcohol and vegetable oils - in fact the first diesels were specifically designed for this. So alternative fuels for diesels are possible - including coal & water slurries at the extreme end. The only question is getting them into the engine. A reference to them as "Diesels" would however really raise eyebrows for anyone with a read on technical history on Safehold.

Biggest issue with the conversion from solid fuel engines to liquid fueled to internal combustion, is the increasing narrowness of fuel specs. Early steam engines could and often were fed anything that burned (we have literature references to wood, coal, and even blocks of lard). As internal combustion engines have gotten more efficient they require much more consistent fuel (try to get warranty repairs after running 87 octane through an engine designed for 93 octane). This may not wreck the engine, as an example, during any extreme cold snap you will read stories of buses and trucks that will not start due to out of spec fuel, as the diesel has become too viscous for the injectors.