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

[deeiche]

got a link to these engine sales?

bob g

Daihatsu EF-series (660 cc) info.
Japanese company listing used Daihatsu EF, DAIHATHU EF Used Petrol Engine

Generic JDM sales are advertised across the county, someone would have to contact several to see if they would bring in Kei car engines.  I venture to guess they already do because there is a fair number of JDM Kei trucks brought into the US for off road use.

[Henry W]

That Daihatsu engine is probably a very nicely built engine but, looking at the torque and hp specs I would think the Kohler, Briggs or Kawasaki liquid cooled V-twin engines would be better suited for our purpose. The EF-CK engine has roughly 30 hp @ 4900 rpm and a peak torque curve of 37 ftlbs. @ 3200 rpm.

The Briggs Vangaurd 2/LC engine has a recommended maximum 27 BHP @ 3600 and 13 BHP @ 2000 rpm and has a peak torque of 40 ftlbs at 2000 rpm. I think this is where we should be.

I feel the Daihatsu engine would not be very efficent at low rpm's.

The EF-VD model would be tempting to get for an ATV project.

Henry

[BioHazard]

Probably splitting hairs here, but a 2 cylinder is probably slightly more efficient than a 3 cylinder, while at the same time slightly less stable and balanced.

[Henry W]

The 90 deg. V-twins are much smoother than the 2 cylinder odd firing inlines. The Kawasaki and Vangaurd V-twins I have are pretty smooth at all speeds.

Henry

[Tom Reed]

Another thought for a chp system is to use a water cooled generator. If a typical generator is at best 85% efficient, there's a potential 15% return of waste heat there.

[mobile_bob]

typical generator "head" might be 85%, but the prime mover is rarely over about 33% in sizes we are apt to use
so 85% of 33% equals about 28% overall efficiency, leaving about 72% as differing forms of waste heat to recover.

of that we might 75% on a good day, recovering waste coolant heat, waste exhaust heat, and maybe heat from the oil cooler.
so maybe 72% as waste heat times 75% equals about 54% of the fuel burned recovered as waste heat.

28% plus the 54% recovered heat equals about 82% overall efficiency, in other words if we use the heat we can put to use about 82%
of the available btu's in the fuel.  not bad but we can do a bit better i think.

eeking out a bit here and there really add up in overall efficiency of a cogen unit, using a higher efficiency genhead will return us probably
another 5% point bump in overall efficiency.  using the most efficient heat exchangers (which is easier with nat/gas or propane in my opinion)
running at higher delta T, i think it is within the realm of possibility to reach 90% overall efficiency.

put all the equipment inside an insulated enclosure, and use it as a heat pump heat source, going over 90% becomes very attainable in my opinion.

trick is, finding a use for the recovered heat, without which efficiency is no better than a standard genset.

bob g

[BioHazard]

trick is, finding a use for the recovered heat, without which efficiency is no better than a standard genset.

You got it. If I could use the heat all year long I'd have had a cogenerator set up years ago. Unfortunately we don't need a lot of heat here. We really need to come up with a small absorbtion chiller of some sort that can use the waste heat!

Somewhere I think I read the Honda CHP system is supposed to be 91% overall efficiency...

[Tom Reed]

Our chp is a nice combination with our off-grid solar system. In the winter when the sun does not shine the Listeroid is running, we need the heat too. Also the radiant floor in the concrete slab is good at using low grade intermittent heat.

[BioHazard]

Looks like somebody is one step ahead of us with the Kawasaki and Dihatsu engines!
http://polarpowerinc.com/products/generators/2-3,5kwGas.htm
http://polarpowerinc.com/products/generators/4-14kw_daihatsu.htm
http://polarpowerinc.com/products/generators/cogenset.htm

Typically most applications will use a generator to produce electrical power to run an electric compressor as part of a typical air conditioner / heat pump, this is not efficient. Fuel is wasted in converting mechanical power into electrical power (generator) and back again into mechanical power (motor) as required to drive the refrigeration compressor.

The Micro-cogenerator's efficiency and cost savings is based on reducing fuel consumption by using the engine to direct drive both the alternator (generator) and the air-conditioning compressor at the same time. The air-conditioning compressor uses an electric clutch to disenguage it from the engine when cooling/heating is not required. Fuel consumption is reduced by more than 50% over typical applications by eliminating the unnecessary conversion processes.

[Henry W]

I have some 48 volt PMG alternators that will mount on any of the V-twins. If I only can find a good 48 volt 5000 watt or more pure sine wave inverter setup. Cheap.

http://www.microcogen.info/index.php?topic=2679.0

[Henry W]

http://polarpowerinc.com/products/alternator/3500&6250alternator.htm

They talk about 12 pole pmg alternators. I checked the spare rotors I have and as far as I can tell the Eagle Pitchers are 12 pole.

It looks like alternators I have are set up for three phase. But looking at with wiring on the Eagle Pitcher's, I think they might be able to be setup for other configurations.

What i need to do is fire up the LRG-425 and check voltage and hertz.

Henry  

 

[Henry W]

I fired up the LRG-425 and have some numbers.

Volt meter hooked to Phase 1 and 2 with no rectifier and no load:

About 52 Volts @ 2170 rpm.

Henry

[SteveU.]

Hi All
Well 7 days without Internet service due to a Mt Saint Helens created lightning storm cell event. We get these local "events" here every 2-3 years.
Small Engines:
NOTHING beats a properly balanced V-Twin for smooth running and quietness in the single and two cylinder ranges. DOES need one of the larger industrial dual end entry mufflers though to opposing cancel out the exhaust events. Two cylinder opposed are large motion smoother but over all busy noisier with all of the combustion and energy transfer events wing flapping large area unsupported out in the air space.
And yes I have many different single cylinders in my life. And now even some big single Listeroid experience. You pay a price for that single cylinder lowest piston/ring/bearing drag in shake rattle roll and hopping.
Inline's - I have two different Yammar diesels in my life. Shaky low speed running - just OK at RPM under a load. And neither will run at all if one cylinder drops out. Even have some hours of loaded experience with Suzuki/Chevy Sprint, Metro, Kubota DG972 three cylinders. Gasoline and gaseous fuels make them quieter yes - but again not all that smooth compared to the V-twins under a load.
Four cylinder inline is the most reasonable least cylinder type in an inline. Six cylinder inline Much, Much better yet.

So . . . Idealism versus a use it today usable practicality as I see it.
Give me a good V-twin anytime for this kind of system.

All my own opinions.
Steve Unruh

[Henry W]

Once you are around a good 90 Deg. V-twin to experiance how they run you will understand why Steve and I like them. The 25 Hp Kawasaki I have on my Z-turn has been fantastic. Lots of low end torque and very smooth through the whole operating range. The Kawasaki engine has been through so much the past six years. It mostly runs in HOT and SANDY enviroment. All I ever done to it was replace starter bushings twice, adjust the valves once out of  five valve lash maintenance checks. Oil and filter changes every 50 hours. And spark plugs changed twice. If these engines run in a clean enviroment with LP or NAT gas I feel these engines will last many hours.
I guess it would be good to think about using V-twins for Cogen projects.

Henry

[BioHazard]

Oil and filter changes every 50 hours. And spark plugs changed twice.

Thats something we'll have to work on...the Marathon engine claims 4,000 hours between oil/spark plug changes and I think the Honda CHP claims 6,000. How many hours do you think you put on the plugs? I'm thinking I'd hookup some kind of external oil tank with a couple gallons of lube in it.