Stirling engine generators

Thats a difficult one, but I have one company in mind that might be able to help you out. Try Stirling Technology, Inc. they are a US company but I think all the engines are manufactured in Japan now. There is also a company called Mechanical Technology Incorporated that made free piston stirling engines for NASA, although I don't know if they still make them.

Thank you

I would like to start up a firm to produce Stirling engine gensets. Do you know anyone interested in such a venture?

Charlie charles@silacon.com www.silacon.com 651-738-1965

Can't say I do, but I like the technology. A device that I have heard is beginning to catch on in Europe but is not really available in the US yet is CHP (Combined Heat and Power) using Stirling engines. I think this would have a better market than just a genset, I know I would love one they were available and I could afford it.

People

I want you to invent a new kind of engine. I think Stirling solved a problem howver is there not a better way to do a closed system heat engine? I have an idea I am about to release for consideration by you sterling stirlings. Your ideas are safe with me. We have the funds to experiment a bit so would pay you a little bit for any idea the we apply. Thank you for your time and effort. All of us have moral obligation to wax strong on this issue.

Charlie

Try a start here. This is a research JV with Sandia Laboratories 15 minutes from my home in Albuquerque.

http://www.stirlingenergy.com/images.asp?Type=gensets

I will be at Sandia soon. I better get your contact information. I am always good for a free lunch. Thank you for your help.

Charlie charles@silacon.com

the WhisperGen^TM converts over 90% of the fuel supplied into heat and electricity.

I couldn't resist commenting on this quote from the WhisperGen site. For most generators, even those running on old tech gas engines, you can say that the genset converts 100% of the fuel supplied into heat and electricity. In the case of a gas engine, about 25% might end up as electricity, and the rest goes off as heat out the exhaust, off the cooling system, etc.

The WhisperGen site is here.

Hola Ken,

Off topic a bit >>> We can do 94% with trigeneration. These Wartsila dudes were a client of mine for 3 years; developing technology and markets . . . . . have a look at a cool (pun?) installation.

http://www.wartsila.com/Wartsila/global//docs/en/power/media_publications/brochures/Airport.pdf

Most of the 6% losses (about 4-4.5%) are radiated off the block and heads due to oil temps and water temps heating up the iron itself in the engine room. The sides of these babies gets bloody hot. Nobody has tried to recover that small bit off the iron itself.

Very cool!

In winter, just put apartments for maintenance personnel above the engines, so they get free heat. In summer, I suppose the excess heat could be used for cooking the food that goes on the planes. (What was the classic meal cooked over the engine in a car?)

Maybe they can machine round pads here and there and you mount little Stirling engines.

Engine cooked meals ? I remember something wrapped in tin foil but I can't remember what. My pals and I load up the exhaust manifold with little pop top cans of Beanie-Weenies and Vienna Sausages a few miles before we arrive back to deer camp for a warm snack.

We are really off topic now . . . . . . . .

Hi Ken,

Can I be a teensie bit pedandic/argumentative...well discursive maybe?

you can say that the genset converts 100% of the fuel supplied into heat and electricity

doesn't some of the energy get used in scraping molecules off bearings, lifting fuel from the tank, drawing in air, circulating oil....(much of this will also generate some heat) ?

www.ormat.com

Me thinks brother Ken meant that all fuel is converted to electricity and heat, albeit the heat component that is not recovered is wasted (out the exhaust, radiation, molecular bumping and grinding such as your 'hydrodynamic scraping' comment, etc). Those items are in fact heat. So from a pure analytical view of a gen set, you put fuel in, and 100% of the fuel is converted to electricity and waste heat . . . . . .. but it is heat. Maybe Ken will correct me, though.

If you define everything as heat...then sure it's heat!

What about a simple example:-

Say over a day the fuel pump lifts 1 gallon of fuel 1meter this is work, which unless I'm sadly deluded is not heat!

Hi Del:

Your comment seems perfectly reasonable. However, there's a principal of energy-work equivalence you may be forgetting. You are correct that pumping fuel is work, as is pumping oil, pumping water (or air) through the cooling system, etc. There is also heating of the lube oil by mechanical shearing or the fluid, heating of air by compression (in the compression stroke) etc. But when all is said and done, all the energy for this work comes from the fuel (the energy content of which is measured in BTUs in backwoods countries like mine). BTUs convert directly to kWh, or HPh. So in a perfectly efficient engine, the mechanical HPh out is equal to the BTUs in. Looked at in this way, IC engines are marvels of inefficiency: 60% of the fuel is thrown out as waste heat.

But if you actually want the heat, then you can look at efficiency differently. (It's a bit like a campfire: as a heating mechanism alone, it is horribly inefficient. But as a source of light, relaxation, hot dog cooker, and radiant heat, you could call it highly efficient, right?) So the WhisperGen claim, in that context, is less impressive: without a lot of thought you can imagine many ways to capture the vast majority of "waste" heat. After all, if you can burn stuff in your furnace and get 95% of the heat content pumped into your house, then you should be able to burn stuff in an engine and do the same, without getting too exotic. None of this is to deride the WhisperGen people -- I think their products are pretty neat. But it's not the Stirling engine that produces that efficiency -- it's the fact that the "waste" heat is not considered "waste".

Further rambling: If you are fairly familiar with electric motors and drives, you can measure motor efficiency just by "laying on of hands." Feel the drive, feel the motor, and say: "that's about 90% efficient." You'll impress people. All the "waste" goes off as heat.

So no, you are not sadly deluded. I prefer to think of it as happily deluded. The parasitic load of driving the fuel pump causes the engine to work harder, creating more heat (on which the engine runs). So the work of running the fuel pump is heat, per work-energy equivalence.

Cheers Ken

My error in the previous post was the word 'waste'. As you rightly say

'But when all is said and done, all the energy for this work comes from the fuel .'

yes! I didn't think the fairies worked the oil pump! (lol)

100% of the energy in come out somewhere!....if only we could get an extra 0.5% we'd be laughing!

Clicking my name will produce a profile showing a background that should make one immediately delete all emails I write. I am an uneducated bone head, but, somehow I have managed to eeeek along a comfy living for 30+ years in the diesel power generation business (blue collar and white collar); and 16 of that as a private consultant designing large 8-10 MW (mega watt) units (8 MW = about 10,000 HP each) with some projects requiring 30 x 6 MW units. I added up how much crude oil is pumped through Crude Oil Fueled Engine Driven Pipeline Pumps (my niche) designed on my kitchen table, and it is 7.3% of the world's crude oil daily supply. Some machines do over one million barrels per day. 48" flange pumps with 1 m diameter impellers, some of them up to 7 stages. The frightens my wife as she knows I am a total bone head.

I left private life since I was tired of living in 'stan' countries (sorry StirlingStan) for 11.5 months/year, and needing a 5 point Formula One safety harness on my toilet (too much info?).

But, I am quite comfy with this subject. You are exactly right when you say a fuel pump is doing work, and that work is not directly going into electricity. Those 'loads' are termed "parasitic losses", a term my wife has borrowed for an over all description of me (her mother wanted her to marry a dentist, not a diesel mechanic). But, that work is actually producing heat, and the fuel itself cools it. Any heat (energy) that does not go directly into work is wasted. Tat is why diesel engines are only about 35-40% efficient. This is is termed the "heat balance". Fuel in (in calorific values) vs. work out (in calorific values) = heat balance.

For fun, let me tell you some other parasitic losses in a diesel engine. The fuel transfer pump (the Del pump) is minor. The fuel injection pumps are MAJOR. There we squeeze fuel into 30,000 psig (2068 barg) and the cam shaft does this work as well as lifting the valves. The cam shaft in a big engine can be 10" diameter and a cam gear can have a face width of 26 inches (66 cm). Compare this to your car's cam gear with a width of 0.75 inch. There is some serious power going into just turning that cam gear. The gears themselves 'pump' the oil that is splashed around to lubricate them. More losses. I designed a gear train that channeled oil away from the teeth a bit better and picked up 0.15 % and a reduction in heat as well.

Then there is the water pump, after cooler water pump, elastomeric coupling (we loose 0.4% in vibratory torque just in the rubber coupling to the generator to dampen the high torsional vibrations coming down the twisting crankshaft. The fluid film bearings (sleeve bearings for the mains and rods) suck energy, as you point out, by the high velocity oil sticking to the shaft as it rotates colliding with the low velocity oil film around the shell diameter. And the loads squeezing the oil here and there (pumping) suck energy. Piston ring friction is HUGE losses. HUGE! Bla bla bla bla.

Ken's idea to design a home unit which produces electricity (the generator is 95% efficient versus the "work" that goes in measured in watts versus the work available at the terminals in watts), and recovers the heat is a good idea. How best to recover the heat at home owner levels? You can get about 60% efficient by using the hot water to run through you home in winter. In summer, you must convert that heat to another form of usable power, such as refrigeration (a bit complicated, but, look at my first post for a project that does that).

If you keep water liquid, it will cool any engine. Notice you car temperature ! Well above the boiling point, yet, how does it stay cool? Because we add chemicals and pressure to keep the water from reaching the vapor pressure and flashing to steam. With a small diesel engine, you can purchase a heat exchanger to cool it (water to water shell and tube system) and then run that water (already near boiling from the engine) through a exhaust gas boiler to super heat it. We keep it pressurised (maybe as high as 100 psig) to keep it liquid. Each one psig = 3*F boiling point increase. So we can have water at 400*F baby! . . . or higher. Then we pipe that high pressure, super hot 'engine' water to a mini-steam turbine and flash it to steam (go back to atmospheric pressure) across the steam turbine blades and make another power generator. We run that now hot water (not super hot) through our house to re-condense it back to liquid water, and finally to a real condenser named a "water maker" and send it back to the engine at perhaps, 150*F where the process starts all over.

The ONLY way you will overheat an engine is to let the water not stay as a liquid. If the system is too small, you keep building heat until you flash the water to steam and then you toast it!

Ken . . . Del . . . are you in tears after reading such profound and informative writing? Do you want the phone number of my mother-in-law to explain to her that my wife is all wrong about the dentist thing?

A very lucid piece of writing, just shows that not all ejinears are illigerant!

I just wish I hadn't quibbled about the 100% claim and I wouldn't have had to plough through that lot!

Joking aside, I had read your profile...excellent...I've seen plenty of graduates who don't know which end of the soldering iron to pick up!

Cheers

Del

PS Illigerant... illiterate & ignorant...

I'm ambiphibious myself (I can write with either hand ...under water!)

Maybe Ken will correct me, though.

If I could, I would... but it sounds right on target to me.

Last night, I wrote a lengthy reply to Del the Cat, but I evidently screwed up the posting, because it is not here today. Sad, because it's profundity would have moved all grown men to tears, causing them to re-evaluate their lives and to re-measure their worth. If I recall correctly, the post revealed a secret that if implemented, would end virtually every one of our environmental woes, virtually overnight!

Actually, it said something pretty close to what you said in your post, but in more words, and with a little more rambling.

Although I am involved in a consuming project right now, I'd like to build a demonstration house in which a typical genset is used to supply electricity and heat. If one were not adverse to killing off the people in the house, exhaust could be run right into the living space, and the genset would be centrally located in the house, so all it's "waste" heat would warm the house. (Of course, there is the obvious problem that the genset would stop running when the O2 was consumed.) Even here in northern Georgia, it is cool enough that my largest energy needs for 6 mo of the year (by far) are for heating the house and water. I'd think that a reasonably well-engineered system could yield 95% overall efficiency -- because all the little "leaks" that a normal system has would nevertheless go to heating the house. Much of the heat from the big leak, exhaust, could be recovered by an efficient heat exchanger.

I think that modern home furnaces are 95% (or higher?) efficient, with the exhaust going up the chimney being very low temp. (In fact, I think, [or dreamed??] that the exhaust for some of these can be routed through PVC pipe.) So if this genset is thought of first as a furnace, and secondarily as a generator, then an IC engine is a thing of beauty, instead of the wart-covered, flabby, inefficient toad we often think of. Electricity arrives at our homes with about 38% efficiency. We could create it on site at very high efficiency (provided we can use the heat).

Ah, maybe I see the confusion?

...I'm thinking more in terms of say a car engine where the oil and water pumps are mechanical...and consume a significant amount of power.

If, in your gen set, these functions (if they exist) are driven with the electricty you have generated then I s'pose you could say virtually all the fuel is converted into electricity and waste heat. But I don't see that you can ever get 100% as there is always some mechanical work done accelerating/deceleration components which is neither electricity or heat.

They say : Convert 90% of the fuel supplied into heat and electricity.

Make sense to me. Let say generator efficiency is 30%, and 60% heat.

May not be suitable for warm country but can be very useful for country around the north pole

I wasn't challenging the truth of what they say, and I think they make a good unit, as do Honda and some others. I was only commenting on the wording: Every genset converts essentially all the fuel into either heat or electricity. (Even the sound the engine makes is converted into heat in the motion of air molecules.) The difference with any combined heat and power system, is that the heat that would otherwise go off as waste heat is instead collected as usable heat.

These systems are pretty simple but can pay very large dividends in overall efficiency, provided, of course, that you have a use for the heat.