single acting enclosed crankcase

A special section just for steam engines and boilers, as without these you may as well fit a sail.
lostintime
Warming the Engine
Warming the Engine
Posts: 82
Joined: Tue Nov 07, 2017 1:10 am
Boat Name: No Boat Yet

Re: single acting enclosed crankcase

Post by lostintime » Sat Nov 11, 2017 5:51 am

To Mr Lionel, I feel an arbitrary 10% rating is unjustified. I am no stranger to the Carnot cycle equations, nor entropy diagrams. At no point have I stated operating temps. The "waste" is actually a highly concentrated form of potassium and phosphorus that's value greatly exceeds the "raw form" equivalent. The "90"heat is also not done working yet however this is why I was vague, I return to the question I asked initially aside form oil contamination and carry over are there any other known problems with single acting enclosed crankcase engines?
May predictive auto spell be damned
User avatar
fredrosse
Full Steam Ahead
Full Steam Ahead
Posts: 1906
Joined: Fri Nov 20, 2009 5:34 am
Boat Name: Margaret S.
Location: Phila PA USA
Contact:

Re: single acting enclosed crankcase

Post by fredrosse » Sat Nov 11, 2017 2:59 pm

With reciprocating steam engines under a few hundred horsepower, getting efficiency past 10% efficiency is very admiral, and getting efficiency up to 20% is virtually not realistic. Steam turbines below a few hundred horsepower show actual efficiencies much lower than reciprocating engines in this size range. That is solid information.

So many people have tried and tried to develop workable steam cycles for small power production, this is an ongoing process that has occupied the minds of many professional engineers for well over 100 years. The concept of using an “external combustion engine”, able to burn any fuel, vs. a Diesel or other internal combustion cycle which requires a refined liquid or gaseous fuel is a noble endeavor on many fronts, but let us not imagine that we can out-do the practical realities of engineering and science here. From Stanley steam car technology, through the advanced designs of the Doble steam cars, not to mention the extensive work on steam car technology performed by GM, Lear, and other large businesses, (financed by US DOE in the 1970s) have not been able to achieve good efficiency with small scale steam technology.

Having said that, I am all in favor of steam boat propulsion, especially coal fired, certainly my preference, but not on the grounds of efficiency or fuel economy nor ease of operation.

With respect to knowledge of the Carnot Cycle, many of us learn about it, but I have never seen anyone attempt to use steam in a Carnot Cycle, virtually all steam cycles are based on the Rankine Cycles.
lostintime
Warming the Engine
Warming the Engine
Posts: 82
Joined: Tue Nov 07, 2017 1:10 am
Boat Name: No Boat Yet

Re: single acting enclosed crankcase

Post by lostintime » Sun Nov 12, 2017 1:47 am

I concede, had enough free time today to crunch down the numbers, 49,000 lbs a day to process, even with heating every building on my farm and my house I'd still have to dump excess heat. It quickly turned into a rube Goldberg mostrocity of bottoming cycles and working fluids.
May predictive auto spell be damned
User avatar
TahoeSteam
Full Steam Ahead
Full Steam Ahead
Posts: 813
Joined: Fri Mar 07, 2014 5:38 am
Boat Name: Wayward Belle
Location: South Lake Tahoe, CA, USA
Contact:

Re: single acting enclosed crankcase

Post by TahoeSteam » Mon Nov 13, 2017 5:34 am

Still a fun exercise and if you can afford to play around and experiment you should do it!

Plenty of steam boats have been built that will never recover even pennies on the dollar of the initial investment. It's a hobby and for fun... mpre.fun than golfing and less trouble or health problem inducing than drinking or smoking.

Have fun! You don't need to be an engineer, or even a machinist.
SL Ethel
Warming the Engine
Warming the Engine
Posts: 85
Joined: Thu Feb 24, 2011 2:50 am
Boat Name: SL Ethel

Re: single acting enclosed crankcase

Post by SL Ethel » Mon Nov 13, 2017 5:55 pm

lostintime wrote:I concede, had enough free time today to crunch down the numbers, 49,000 lbs a day to process, even with heating every building on my farm and my house I'd still have to dump excess heat. It quickly turned into a rube Goldberg mostrocity of bottoming cycles and working fluids.
If anything, having way more BTUs than you need seems like a feature, not a bug. Big, older high pressure boilers (I'm thinking 150 PSI) in good condition are often on sale for cheap, so for a stationary setup, the capital cost could be relatively reasonable. If you can heat all your buildings, and you are displacing propane heat (I'm assuming here), that could be a complete economic justification unto itself.

I have some experience in (trying to) develop power plant projects based on anaerobic digestion produced methane (on dairy farms). The economics of it always made it very hard to justify based on straight electrical production, unless the heat could be used to offset some high cost heating fuel like propane.

Also, if you are awash in BTU's, you might be able to bring your electrical production costs down by using a second hand turbine generator. Should be lower operating costs and hassle, and you don't need to care too much that it won't be highly efficient at relatively low pressure.

And if you still have leftovers after maxing out your grid input and heating everything, have you still solved at least part of the problem, even if you don't process all of your waste through the system?

It sounds like a fantastic project to me.

Cheers,
Scott
User avatar
cyberbadger
Full Steam Ahead
Full Steam Ahead
Posts: 1123
Joined: Thu Nov 07, 2013 9:16 pm
Boat Name: SL Nyitra
Location: Northeast Ohio, USA

Re: single acting enclosed crankcase

Post by cyberbadger » Tue Nov 14, 2017 3:14 am

I was just thinking of cogeneration....

One back burner plan certainly for me is to have some aux unit onboard that will be able to charge ~12V batteries at at least ~10A DC which is 120Watts continuous.

I have 2 5Ahr 11.7Lipo batteries to run the nav lights and dry fill electric pump. They weight are so light so I have just been swapping them and charging one at the house.

All I need is the stuart 4a+pma alternator and I could have a nice dock side demonstration and DC source.

-CB
lostintime
Warming the Engine
Warming the Engine
Posts: 82
Joined: Tue Nov 07, 2017 1:10 am
Boat Name: No Boat Yet

Re: single acting enclosed crankcase

Post by lostintime » Tue Nov 14, 2017 3:32 am

TahoeSteam wrote:Still a fun exercise and if you can afford to play around and experiment you should do it!
I in intend to, albeit on the upper right side of the mollier diagram. While I can't overcome the energy loss associated with climbing back up the saturation curve, thing start looking a lot more efficient with vapor recomp. and lots of superheat. Constant pressure/different volume (brayton cycle). But alas to use this high temp dry steam I think Im stuck with turbine, or a poppet valved single acting with copious amounts of oil circulation. Even then I dont know.
May predictive auto spell be damned
User avatar
DetroiTug
Full Steam Ahead
Full Steam Ahead
Posts: 1863
Joined: Fri Nov 27, 2009 5:56 pm
Boat Name: Iron Chief
Location: Northwest Detroit

Re: single acting enclosed crankcase

Post by DetroiTug » Tue Nov 14, 2017 4:13 pm

I have an engine driven "generator" on the tug that puts out around 10 amps at 12 volt, and ~ 400 shaft RPM.

I don't remember all of the particulars on it, but it's basically:

Nema 34 72 volt DC brushed servo, 7 amps continuous, 38 amps peak.

Belted about 15:1

The electronics are simple, just one side of a bridge rectifier used as an inline diode to prevent the battery from spinning the "generator" at low RPM.

A simple switch to connect/disconnect to the battery. Sellers around the web have small cheap solid state voltage regulators for wind generator use that would work, but I'd rather just disconnect it if I don't need it.

Then some period correct gauges :)

Any brushed DC motor will output voltage and current when spun. When connected to a 12 VDC battery, once RPM sufficient for the voltage is achieved, anything above that is current going to the battery.

-Ron
Attachments
IMG_3000 (Medium).JPG
IMG_3000 (Medium).JPG (76.83 KiB) Viewed 6917 times
User avatar
fredrosse
Full Steam Ahead
Full Steam Ahead
Posts: 1906
Joined: Fri Nov 20, 2009 5:34 am
Boat Name: Margaret S.
Location: Phila PA USA
Contact:

Re: single acting enclosed crankcase

Post by fredrosse » Wed Nov 15, 2017 3:41 am

"Any brushed DC motor will output voltage and current when spun."

Actually many DC motors will not self-excite, and thus will not generate DC power. I like
the PM types,they always have field magnetism.
User avatar
cyberbadger
Full Steam Ahead
Full Steam Ahead
Posts: 1123
Joined: Thu Nov 07, 2013 9:16 pm
Boat Name: SL Nyitra
Location: Northeast Ohio, USA

Re: single acting enclosed crankcase

Post by cyberbadger » Wed Nov 15, 2017 7:30 am

There are cheap ways to do it, but this one option ...

They are Permanent Magnet Alternators that are based on American Delco alternator cores.

They designed the windings for low speed high torque applications like small wind - or reciprocating steam!

You can actually buy just the magnets and wire it your self, or they have the windings.

Best part - no stinking battery required. But if you just wire it directly to a 12V lead acid it will charge it.

Diodes are built in as a module.

http://www.windbluepower.com/category_s/1.htm

Worse part is keep screws away because the neodymnium magnets will attract them and short the windings and cause a nice light show until you figure it out.

-CB

P.S. Ron - love the gauge!
Post Reply