"Inspired" by gas prices...

Dave--the shaft speed would be reduced to 67% for the steam engine--or 335 rpms
which means the shaft speed would not make the steam vessel faster--given all variables equal...unless i missed something, this is why diesel is better in that area

 

Thing with steam is its an external combustion process, so lots of carbon neutral fuels could be used. I was thinking of a pellet type stove burner, a blower combined with a monotube boiler.

I still like the idea of a steam powered retirement yacht. ;-)

 

whats a carbon neutral fuel, nuclear?

 

50% of the yacht would be wood storage and I don't think the co2 level or the smoke itself be acceptable.

You would need oil fired boiler and then what would be the point a steam engine is approx 8% efficient, be too heavy, and would take an hour to fire it up. You would return home black in the face couching.

Why go backwards in technology, I thought you were trying to be green

 

I am frosty, wood pellets are carbon neutral, so basically no amount of exhaust from wood is going to screw up the climate. Might give you cancer, but won't heat the planet.

I once calculated the amount of wood pellets needed for one of my retirement yacht designs to cross the Atlantic. It was something like 7 tons. But here's the thing, Wood pellets were the cheapest fuel pr/btu So although there is a weight penalty, as well as a volume penalty, its cheap, and it still could be done. So while I was considering steam I worked it all out and its doable but, building an automated system in steam is pretty difficult. It would be fun to have a steam powered boat, but I think the fuel I have developed for the truck is working pretty well. Its cheap, pretty easy to make and offers more btu's pr/g than diesel.

The real question is, can an external combustion engine approach the efficiency of an internal combustion engine. I'm pretty sure the answer is no. But you could burn a huge variety of fuels. Including dried peletized sea weed, in which case, efficiency becomes less of an issue.

 

Frosty- thats accurate only for outdated systems-- there are now thermally efficient boilers to 21% and with upgrades to 27% --diesel is 36% but costs 15 times more to run...so steam is now more viable commercially than diesel since coal is 15 times less expensive...if people adopted steam and accepted slower speeds steam would soon replace diesel--however i suspect then that coal prices would skyrocket because its in huge demand and we are back in that viscious cycle...I still prefer steam as burning wood IS more natural -and produces less co2 if im not mistaken...

see this very

interesting article...on steam efficiency in modern times!

http://www.internationalsteam.co.uk/trains/newsteam/modern50.htm

 

Boston--you will like this--try 27% efficiency!!
http://www.internationalsteam.co.uk/trains/newsteam/modern50.htm

 

If we start talking garbage then I agree.

Garbage would be a great fuel.

What about air blast furncace?? increase temps many fold just with a simple fan.

 

How do you take a carbon storage device like wood and burn it to release the co2 and call that neutral?

 

its got to do with the life span of CO2 in the atmosphere. If a plant takes CO2 from the atmosphere and you then cut that plant down and burn it, Yes it returns its CO2 to the atmosphere. With no net gain to atmospheric CO2. As long as the plant didn't store the CO2 for longer than it would take for it to lock itself into a more permanent storage medium.

its called carbon neutral when you form a cycle with the atmosphere. Fossil CO2 on the other hand is dredged up from underground and released into the atmosphere, raising atmospheric levels of CO2

 

i may be just shooting in the dark here--but wood has adifferent chemical composition--so as it burns it woudnt release the same emissions as a carbon fuel even though its carbon based...but what do i know...
is that forest fires actually help the environment by releasing the emissions from them ..but dont ask me how--just know it does...

 

Boston...thanks for clarifying that for me...

 

Thats splitting hairs
burn pine and maybe ok,
burn one of these and it may as well be coal
http://www.wired.com/wiredscience/2010/03/old-tree-gallery/all/1
So for your atlantic crossing you have your 7 ton forrest growing for a few years then convert it back to Co2 in a couple of weeks and the environment is good with that?

Large 2 stroke ship engines and powerstations with diesel turbines are close to 50% thermal efficiency

How about you burn the wood at the rate your forrest is consuming Co2 thats what I would call carbon neutral and sustainable energy ( assuming you have your exhaust particulate filters installed)

 

not splitting hairs at all, by using plants for fuel who's life cycles are less than the cycle life of CO2 IE the time it takes to to get into the ocean and end up calcium, we effectively don't add anything to the atmospheric CO2 levels. CO2 in the overall system lasts about 100,000 to 500,000 years although there is some debate surrounding this time frame, numbers as low as a few hundred years have been kicked around. The single cycle time of the CO2 in the atmosphere is somewhere between 5 and 12 years, although thats a really "squishy" number due to the discovery of plant discrimination against fossil based CO2. Interesting eh, plants apparently prefer the more natural isotope of CO2 than the fossil based stuff.

So in the end CO2 produced by organic processes is preferred by organic processes. CO2 produced from fossil fuels is discriminated against, kinda sounds evil now don't it

So there is room to argue what exactly a carbon neutral fuel is and isn't, but basically anything thats less than 100 years old is accepted as being carbon neutral. But once again there's a lot of wiggle room.

To me, and this is just personal opinion, I'd say any tree is carbon neutral. After all its not that old and it would have fallen, rotted, and released its CO2 back into the system again anyway.

Think of it like a forest fire, perfectly natural and doesn't seem to effect atmospheric CO2, but this forest fire is happening in my boiler.

Fossil fuels that spent millions of years developing only to all be burned within a few hundred years, have obviously raised the levels of atmospheric CO2 dramatically

another way to think about it
best if we only burned annuals
not as good if we only burned trees, some of which might last as long as 1000 years
worse if we burn fossil fuels, who's carbon stores have been building up for millions of years.

Cheers
B

 

oh and really interesting article there Tug

I'm slowly working through it but yah.

I'm looking at a reliable steam company 18~40 HP engine. I'd need two for the cat. as well as two boilers. Thing is there is a big penalty if the energy density of the fuel. I'd want to use pellets. So a cat platform which is sensitive to weight, might not be the best for steam.