Should we consider LP and Nat. Gas CHP systems instead of diesel?

[Henry W]

I have been thinking again. Since we seem to be at a dead end on importing diesels, how about LP and Nat. Gas engines. It might be time to forget about diesel CHP because diesel is getting expensive. And, how many of us want to make our own bio diesel? Propane is half the price of diesel and in other states it is cheaper yet. I think we need to get serious and plan what the next step will be.

I ran into this before a couple years back. I always liked this engine:
http://www.marathonengine.com/downloads/diesel_progress_08-04.pdf

Anyways, I feel we need to come up with an engine first before we proceed with the next step.

Henry

[Henry W]

Here is some more info I found.

http://www.propane.net/uploadedFiles/Council/Research_and_Development/Ecopower%20Brochure_Update_042511_opt.pdf

The manufacture is also extracting heat from the engine oil.

[Thob]

I've been looking for an oil field engine myself - large flywheel(s), big, slow turning, single cylinder.  Runs on natural gas or propane (some also run on gasoline).  Something like a Fairbanks Morse 208.  I found one on Craigslist, but SWMBO wouldn't go for it.  I'm still working on that problem.

All of our natural gas now comes from domestic sources.  Thanks to fracking and horizontal drilling, it's way cheap.  In fact, I've heard that they are considering re-working the port in LA so we can export natural gas.

I also have a propane tank in the back yard, 500 gal size.  We use it for heat in the winter and water heating.  So I have a large quantity on hand most of the time, and it doesn't go bad.  I'm also considering contacting the local utility and see what it costs to get a natural gas line run to my place, it wasn't available when we built but I think it may be now.

[BioHazard]

This is what I've been trying to work on all along! With current diesel prices, I see no advantage to a diesel engine if you're running pump fuel. It seems to be rather hard to find a good CHP sized natural gas engine though, they're either super expensive or don't have a governor. The only cheap ones I've seen (sub $1000) are usually old V8s.

My worry would be the gas lines breaking in an earthquake, especially in OR, so propane backup would be nice to have. I've always wanted to have a big greenhouse that makes use of the CO2 in the exhaust from a natural gas source.

I'm still looking for the right engine.....

[Henry W]

An engine with no governor can always have an electric governor retrofitted. I been looking into this since last month.

The Marathon engine was origionaly made by Briggs and Stratton. They sold off the division. This is to bad.

[BioHazard]

Yeah, I've tried in vain to get a "marathon" engine but they simply refuse to sell them for any price.  That would be an ideal CHP system but not quite worth $30k or whatever they want for the whole system. Never seen a used one pop up.

[LowGear]

How do you spell "complicated"?

Casey

[Henry W]

Hi LowGear,

It is not to complicated, and if a member needs help figuring something out he is at the right place to ask questions.

[BioHazard]

Here's a spreadsheet I made comparing the cost per BTU of different fuels, propane is currently winning by quite a bit. You can put your own local prices in it...

[Carlb]

my listeroid is currently setup as backup only generator but using diesel as the pilot ignition and natural gas fogged into the intake i can run a 85/15% mixture of natural gas / diesel at 2000 watts which is the sweet spot for my needs when using it as a backup generator.  It the load increases the amount of diesel is increased by the governor since the natural gas flows at a fixed rate.  The amount of natural gas is regulated by a needle valve.  While this is not the ideal setup it works well for me in a backup situation.   



Carl.

[mobile_bob]

i am leaning heavily toward Carl's approach,

having had to change my plan after the move, wherein originally i was to be offgrid
i am now in an ongrid situation.

good and bad i suppose

the good side is i have nat/gas to the house, so it would seem natural to use it in a dual fuel
application of the S195 changfa.

while i haven't tried it yet, i see no reason why it wouldn't work, it works well with propane in dual fuel mode.

have also been giving some thought to converting one of my direct injected 195's to spark ignition just to see how
it would work out, my thinking is longevity should be improved. the exhaust should be much cleaner in any event.

question for Carl

do you notice a reduction in the diesel knock in dual fuel mode?

bob g

[SteveU.]

Hi All
Short answer is yes!
But with either dedicated or spark converted engines.
No offense to Carl intended. Pilot fuel igniting is certainly one way to go.

MB I think you should look at the IDI versions instead. On My IDI R180 pull out the large body injector with it's pre-chamber and there is room to bracket clamp in a spark plug.
The higher line 17.5 to 30 hp Kohler and B&S coil packs have an electronic spark advance/retard capability built in and are designed to be flywheel magnet energized and triggered.

Different ways to govern it from the one fellows Generac conversion to Lloyds linear actuator system.

Why not me? PNW Rural. Diesel at $4.59 a US gallon IS still BTU cheaper than delivered propane. And the Canadian derived natural gas lines are a hard rinver mountanous 15 miles away.
IF I lived in a natural gas service area though it would be a no brainer as primary fuel with an LP tank as back up.

Regards
Steve Unruh

[BruceM]

I agree with Henry's premise. There is a lot bigger range of applications for LP/Nat Gas CHP because of the cleaner exhaust, and potentially quieter engines. Having a storage stable fuel that is piped in or trucked in is also a big plus. Someday, fuel cells might do the job, or a non-rotary linear generator feeding a battery/inverter, but today's biggest CHP market would be LP/Nat Gas with rotary engine and AC generator.

I appreciate Propane a lot more at my off grid home as I become more disabled. Transporting and transferring diesel is a pain, literally.

I'd like to convert my Listeroid after I get past some current projects.  Alas, for me, conventional spark is a no-go, so until Mark Cherry is successful in getting a market for his SmartPlugs, I'd be stuck with a diesel/propane mix as Carl uses (bravo Carl)...which is twice as many fuels and fuel systems as I'd like to have, as Steve suggests.

[Carlb]

Yes there is  reduction in diesel knock when i am running on a mix of natural gas and diesel  but i would not call it extreme.  The real benefit of using diesel as the pilot fuel is that if you turn off the natural gas the engine will run completely on diesel with no changes.  The only thing i noticed is that when i run on diesel only i need to make a slight adjustment (1/2 turn more) to the governor to keep the freq at 62hz no load.  Since my gen head has a freq meter in it setting the governor is quite simple.

[artificer]

This thread is interesting because I've been thinking about how to use the power unit I'm building.  Since its air cooled, I was considering using a Geo Metro radiator to capture some of the waste heat from the engine.  I intend to enclose the engine for noise control anyway, so ducting the air through the radiator is simple.  If the engines fan in the recoil start/flywheel doesn't provide enough air for adequate cooling, I was going to use a lovejoy coupler on the end of the shaft and drive a home built blower rotor.  Size it for adequate air flow, but not so much that it uses excessive fuel to drive it.

The point of this is that the engine I'm using is a 6hp cheap Honda clone for less than $200.  I STILL don't have the listeroid running, and I'm afraid of all the problems it will have when get it running.  Its a 12-2, so broken cam shafts, bad idler... Instead of getting the listeroid going first,  I've decided to go the way Google did with their computer servers:  plan that they'll fail, get backups in place, and buy commodity parts.  They don't get server grade computers at higher cost, they just have a maintenance/backup system that lets servers fail without effecting the system as a whole.  My commodities engine is a Honda clone.

My power unit should cost about $1000 for 1.6kw of pure sine wave power.  Someone mentioned $30k for the marathon unit, which will have 2.5-5kw of power.  I can buy a lot of clone engines, or even real Honda engines for the difference.  Even going to a water cooled ATV/motorcycle/lawnmower engine will be less expensive, and make heat recovery easier.  I have to check out the xls file on fuels to see how gas compares to propane for the off grid farm.  If I install the system at home, with natural gas, and sell back to the electric company, I wonder if they'll notice that the 100w solar panel is putting out 1000w of power, even at night?

What makes the Marathon engine so special?  I've heard of Honda engines running for 10,000+ hours.  If you doubled the size you need, and run it half speed, could you get similar life out of the Honda?  Running it on propane or natural gas will help last a long time, and increase the maintenance interval.  I'm just wondering if there's any breakthroughs in technology, or is it just how the set them up?

One question I have about using diesel engines is:  why?  Yes they get better fuel efficiency, but we're talking about CHP, aren't we?  We WANT waste heat.  Diesel was always cheaper than gas, until I bought my VW Jetta TDI.  Now its priced like premium around here.  It makes it hard to justify the extra $6k purchase price.  It used to be that diesels needed a lot less maintenance, as long as you used good fuel.  Now, with electronic ignition and fuel injection, you don't even tune up a car for 100,000 miles.  Don't get me started on the 2006 TDI engines need for a new camshaft after 150,000-250,000 miles.  Diesels last longer, but do the numbers add up?  $200 for a gas engine or $550 for the diesel engine for my power unit.  Add the fact that I can run propane/cheap NG in the gas engine, and the answer isn't as clear as it once was.

I've become less of a fan for really cool engines that do exactly what you want, but are uncommon/unavailable.  I'll settle for a common as dirt engine that does most of what you want with a few modifications.  I'm looking at the 3cly geo metro engines fairly closely.  I wonder how slow it can run with 300#s of flywheel attached?

Michael