yanmar clone...slow speed water cooled conversion

[veggie]

The general consensus on the forum (for CHP purposes) is approx.  1/3....1/3...1/3

Liquid cooled diesel:
1/3 lost as waste heat goes into the cooling system as potentially useable BTU's
1/3 lost as waste heat is lost in the exhaust gases (and is available for capture
1/3 becomes mechanical energy

veggie

[Dualfuel]

Ok...back from hitting the books....Veggie, I go to my happy place whenever I hear consensus. I treat that word as evil, and immediately think of Ayn Rand's Howard Roark in Fountain Head...that said, In this case, it caused me to start referencing things.....here is something taken from Heat Engines Steam, Gas, Steam Turbines And Their Auxiliaries By John R. Allen and Joseph A. Bursley, second edition, McGraw-Hill Book Co. Inc. 1914....
"The following is a statement of the distribution of heat in a gas engine taken from actual tests and expressed in per cent.
Heat used in indicated work.................25 per cent.
Heat lost in exhaust............................37 per cent.
Heat lost in jacket water.....................33 per cent.
Heat lost in radiation and conduction......5 per cent."

And so I stand corrected. One third it is....
Forcodiesel,
As far as thermal efficiency.....the theoretical number is indeed easily obtainable if one has the compression ratio, and the ratio of the volume at cut-off to the clearance volume...or Vd/Vc....but this simply gives you the total work done...and as your definition of work seems to be a moving target, I would have to wait, and see what that is before I could comment further.
I seem to be in an odd place here, in that, I have boot strapped my off-grid lifestyle from the savings produced by living off-grid. As more of these off-grid systems come on line, the more capable I am of producing more off-grid systems. The economists out there, do not like to include food or fuel, in their inflation calculations. This seems so insane from an every-mans point of view, because he is unable to do without store bought food or fuel. One result of these off-grid projects has been my insulation from fuel prices because I simply don't buy enough of it to matter. So in one sense I do agree with the economists when they say that inflation is fairly low. The point of this is that your heat recovery scheme IS justifiable and will result in an economic benefit, if its done sanely. Given the 1/3 number, I would argue that it is much less expensive to simply plumb in a gas to liquid heat exchanger to the engine exhaust and grab those BTUs immediately.
My best friend wanted a raised bed garden...so rather then buy topsoil by the bag, he built a backhoe, to excavate the soil on his property, then he built a conveyor, and a gravel screen/shaker. All out of obtainium, over a period of about six years. I had fun helping him with some of my junk, and when we made castings for the conveyor and shaker gear box. So...I do absolutely understand the joy of building these seemingly outlandish projects, and have fallen victim to them myself (I enjoy making fuel processors).
I do protest from my armchair, that a test of the available heat (and noise) should be your first consideration. The presumption being that if the return is marginal, then the resulting effort should be marginal.
DF

[veggie]

DF,

I too find it silly that the government excludes fuel prices from the inflation mix.
Especially when oil went to $147 per barrel.
One possible explanation is that the rising costs of fuels automatically work their way into the cost of other goods due to rising material and transport costs stemming from the higher oil prices. ?? ... Not sure.

When evaluating off-grid economics for heating (in regards to CHP heat capture), the numbers change considerably if the fuel costs are almost eliminated. EG: Waste vegetable oils or other waste/renewables. For those who have a steady supply of such fuels, the CHP model can make economic sense.
Then there's the "hobby factor".  If a hobby can provide energy and happiness, the economics, while still important are a bit less of a factor.  

Example:

A typical 6HP Listeroid running at 80% load (or 4.8hp)
4HP =

Rule of thumb... 4.8HP makes 2.4kw electrical energy from the generator.

2.4 kw generator power connected to a resistance heater:      :  8,195 btu/hr heat
Cooling system rejects 2,544btu/HP X 4.8HP                        : 12,200 btu/hr heat
Exhaust system rejects 12,200 btu/hr X 60% effy heat exch. :   7,320 btu/hr
===============
Total Available Heat:  27,715 btu/hr (from a modest 6HP engine)

These numbers will vary base upon the efficiency of each of the heat capture methods but the general idea is demonstrated.

One also has to factor-in the wear and service of the mechanical components.
If the fuel is near-free of costs, the CHP model seems to be a viable contender for off grid energy.
IMHO, the big draw of the CHP model is that multiple types of energy are produced. So if less heat is required, the electrical energy can be diverted to battery banks, lighting, or other electrical needs.

cheers,
veggie

[Dualfuel]

Dear Veggie,
Wow! We were just having this discussion a few hours ago....or something like it. If one removes food and fuel from the consumer price index, or any other metric, that shows the cost of core goods, then a lot of "noise" is removed from the data. Economists are always looking for a good, or service that is immune from price fluctuations. Or something that is the same through out time...like we cannot really look at the cost of babbit bearings for a steam engine, but maybe a service, like a hair cut. So if one can take out the noisy data points, then a more accurate picture of the value of US currency can be found throughout time. These semantics are all for the purpose of finding out what the inflation rate is...it has absolutely nothing to do with actual people or the pain they feel when their money doesn't work. Inflation, is only the difference in the value of the currency.

One interesting aspect of the biodiesel I make here, is that it simply doesn't work in a Beckett oil gun. Yet, it works fine in an engine...so if I was to consider a CHP project it would be because I couldn't get any more of those pot oil burners from the 1930s. Those heaters actually will burn biodiesel without any life support. Like Steve's place, this is a rather unique situation though....even with grid power...things have to be "hammer simple" to coin a friend's phrase. The trade with the heaters are that they require constant removal of the coke that builds up, which is simply too much for most folks.
All a moot point this year, as I just returned from the oil shed, where I had to shovel down to the door, to retrieve a cubie of glycerine. We got 110 inches of snow so far, and if you don't have your heating scheme already lined up....well its just  not happening.
I do support all forms of alternative energy...I think the more one experiments with it, the better understanding one has, even with a few failures (I am remembering my SVO days, and that stupid water injection idea....), and that promotes the ultimate fit for an individual's needs. I don't believe one size fits all...that only happens when you are sittiing on a few billion gallons of oil.
Back in the day, I would have told Focodiesel to simply go get a watercooled engine...engines were everywhere, most for free, before 2008. Now, hmmmm, a guy has to make do with whats out there. Schlimm Pickens!
DF

[focodiesel]

Well guys in an appeal to limited time, and just the fact that there was a changfa s1100an genset locally on craigslist, I will not be trying to convert a yanmar clone to water cooled, at least not in the near future. I still do like these little yanclones and see myself repowering all kinds of lawn tractors and other portable power units with them though. Great little engines for what they are, a light, air cooled, affordable engine.

Anyways I started a new post to get your opinions, and to document the build of my chp system utilizing my new water cooled changfa. Please go to the "Members Projects" section and check out "s1100an changfa, chp, variable speed/output build thread" or just click here: http://www.microcogen.info/index.php?topic=3264.0

Thanks,
-Focodiesel