Stirling engines

[Jens]

Has anyone seen anything out there in the 3kw power range that can be built or purchased and that works ?
I have been thinking .... which is always dangerous for me, that I might want to experiment with a veggy oil fired stirling engine running 24/7, charging batteries, producing domestic hot water and home heating.
On the surface, this seems to make more sense than running a diesel engine to produce heat. It would seem to be a much lower maintenance setup and run quieter as well.
The concept has been incorporated by a company called WhisperGen. Their units are gas powered and lower power (800W). If anyone has any first hand experience with WhisperGen units or anything remotely related, I would like to hear more.

Jens

[bschwartz]

If you find something, why not power it from the exhaust heat from the engine.  Wouldn't that be even more efficient?

[rcavictim]

If you find something, why not power it from the exhaust heat from the engine.  Wouldn't that be even more efficient?

Capturing exhaust heat and using a Sterling engine to power an additional generator would be a nifty, if complex and expensive way of getting the most electrical power out of a petroleum fuel.  Why stop at the exhaust?  Perhaps engine coolant could be utilized as well in such a scheme.

[AdeV]

Has anyone seen anything out there in the 3kw power range that can be built or purchased and that works ?

Do a google on "5hp stirling engine", you'll find there's a couple of options: A chap in Bangladesh who made his own, and a commercial one (called the ST05 I believe), although the only price I saw anywhere was someone boggling at $45,000. Somehow, paying the equivalent of a new car seems a bit OTT for a stirling engine.

I have been thinking .... which is always dangerous for me, that I might want to experiment with a veggy oil fired stirling engine running 24/7, charging batteries, producing domestic hot water and home heating.
On the surface, this seems to make more sense than running a diesel engine to produce heat. It would seem to be a much lower maintenance setup and run quieter as well.

I'd wondered along those lines too (although I was also thinking of capturing & concentrating solar energy - still am, actually). But I think if I'm going to burn fuel, then I'll either build a steam plant (=dangerous) or use my Lister (=safer). I'm not sure it's possible to get the required efficieny out of a Stirling engine.

The concept has been incorporated by a company called WhisperGen. Their units are gas powered and lower power (800W). If anyone has any first hand experience with WhisperGen units or anything remotely related, I would like to hear more.

Unfortunately not, but those WhisperGens certainly look cool.

[mobile_bob]

i think the whispergen is only about 10% efficient at making electrical power, the rest is waste heat
that is recovered for domestic hot water or space heating, which if the recovery efficiency is high
the overall efficiency can also be quite high,,
although i doubt it is over ~90% efficient in real world installations

your listeroid generator is probably about 22-24% efficient at making electrical power, the balance is waste heat
you are working to recover.
your system is contained in an insulated box, so it would seem to me that a heat pump could remove a very high
percentage of the systems waste heats, coolant, exhaust and radiant heat from the engine, generator, belt drive
and any other heat producing bits and pieces

with a well insulated box, and a well matched heat pump system, my bet is you could match the efficiency
of the whispergen without much trouble, and for a lot less money.

i personally don't think the sterling engine will ever be a significant player on the small scale stuff, save for very
specialized installations where cost is no object and attention to detail with the engineering and matching of the unit
to the structure is very high.

i really think we can get to 80-85% with our systems, using the engine's at max efficiency, harvesting the waste coolant heat
effectively and as efficiently as we can (plate exchangers come to mind), harvesting the exhaust waste heat with similar
goals, and perhaps even a belt driven compressor system to drive a heat pump to capture most of the rest.

maybe for around 1/7th the cost of a whispergen?

thats what this forum is about anyway, isn't it? 
the diy design of a competing cogeneration system, using our engine's and what we can scrounge and produce ourselves?

i would like to think so

bob g

[cognos]

I want one of these...

http://www.infiniacorp.com/infinia-solar-system.html

A 3KW solar-concentrator-powered grid-tied linear stirling engine-powered generator. With a tracker! 25 years no-maintenance! It's even liquid cooled, so you can heat your house with the cooling fluid!

No smelly WVO, no mystery WMO, no chemically-questionable Bio diesel... I suppose that takes most of the fun out of it, really...

Caution - high-speed internet required to view the very good videos on this site.

Wonder if this qualifies for the 80¢/kwh that Ontario Hydro is paying for solar-powered micro-generation?

[rcavictim]

I want one of these...

http://www.infiniacorp.com/infinia-solar-system.html

A 3KW solar-concentrator-powered grid-tied linear stirling engine-powered generator. With a tracker! 25 years no-maintenance! It's even liquid cooled, so you can heat your house with the cooling fluid!

No smelly WVO, no mystery WMO, no chemically-questionable Bio diesel... I suppose that takes most of the fun out of it, really...

Caution - high-speed internet required to view the very good videos on this site.

Wonder if this qualifies for the 80¢/kwh that Ontario Hydro is paying for solar-powered micro-generation?

That's a sweet package!  I'd love to have one here but I'll bet it is pretty expensive.  I don't see why this would not qualify for the Ontario feed in tarrif you mentioned.

[cognos]

I don't think it passes the "Made in Canada" content requirement. But it should.

I figure in my area, on a clear, cloudless day, without tracking, I get about 5 hours of sun. So that would be 3KWH x 5 = 15KWH x 80¢ = $12.00/day payback...

I use about 30 KWH/day at a consolidated price of roughly 10¢/kwh, and that's about $3.00 a day...

So even under conditions that are about 50% of ideal (so I get $6.00 return), even if it only operates 50% of the time (I'm down to $3.00), I break even. So I should probably order 2.

And I haven't even piped the coolant into my radiant floor heating system yet.

I'm only out the cost of the units themselves, and the installation of the dual-metering setup. Wonder how many 10s of thousands of dollars they want for one of these things?      

Maybe if we get together and pool an order, we can get a deal...   I tend to budget on the basis of a 2-year payback, I might not make it on this one...


Seriously though, a linear stirling/generator setup seems like a pretty good system. No need to convert linear motion of the piston to rotational motion for a conventional generator. Could even use permanent magnets on the linear armature. I like the small footprint, and the 24% efficiency - and I'll bet that's calculated without using the waste heat for anything useful.

[rcavictim]

I don't think it passes the "Made in Canada" content requirement. But it should.

I figure in my area, on a clear, cloudless day, without tracking, I get about 5 hours of sun. So that would be 3KWH x 5 = 15KWH x 80¢ = $12.00/day payback...

I use about 30 KWH/day at a consolidated price of roughly 10¢/kwh, and that's about $3.00 a day...

So even under conditions that are about 50% of ideal (so I get $6.00 return), even if it only operates 50% of the time (I'm down to $3.00), I break even. So I should probably order 2.

And I haven't even piped the coolant into my radiant floor heating system yet.

I'm only out the cost of the units themselves, and the installation of the dual-metering setup. Wonder how many 10s of thousands of dollars they want for one of these things?      

Maybe if we get together and pool an order, we can get a deal...   I tend to budget on the basis of a 2-year payback, I might not make it on this one...


Seriously though, a linear stirling/generator setup seems like a pretty good system. No need to convert linear motion of the piston to rotational motion for a conventional generator. Could even use permanent magnets on the linear armature. I like the small footprint, and the 24% efficiency - and I'll bet that's calculated without using the waste heat for anything useful.

Ah, but do YOU pass the must live in Ontario requirement?  I wish folks would be more sharing with their QTH here.  Helps to know where the person lives who you are speaking with.     I'd better check and make sure I have my location listed in my profile.

I agree that a linear sterling motor makes sense in this form of application.  These can be balanced and tuned to resonate mechanically at 60 Hz.  One end of the piston is a neodemium magnet or a coil being modulated in and out of the other.  Such a system is not out of the DIY realm.  It is far easier to accomplish than a multi cylinder rotary design.  I wonder if there can be made a sterling head for a 6/1 Lister CS?     Can you just imagine the challenge of hanging a Lister CS out in the focal point of a large reflective earth station dish antenna?  OK, I'm kidding about the Lister but not the satellite dish.

Where I live (Shelburne, Ontario) I think the yearly wind resource may beat the clear sunny day resource.  This has turned out to be about the worst place I've ever lived to do optical astronomy.  Too much cloud cover too often.  As such for my first serious off-grid renewable power system I have gone with a wind turbine plan.  That said I expect I may get a solar hot water system going someday.

[cognos]

I'm SO Ontario, that if you cut me, I bleed tobacco juice. Then Oil, but that's for family reasons.

I live in the heart of tobacco coutry - what's left of it...

[lowspeedlife]

My understanding (if correct) is if you drive a stirling engine by a mechanical means, a motor, that it will produce heat on one end & cold on the other. This seems like an exellent system to produce heat for domestic water (no contamination from coolant or exhaust). & cold for air conditioning. Of course driving it from a Lister/oid.

  Scott R.

[AdeV]

My understanding (if correct) is if you drive a stirling engine by a mechanical means, a motor, that it will produce heat on one end & cold on the other. This seems like an exellent system to produce heat for domestic water (no contamination from coolant or exhaust). & cold for air conditioning. Of course driving it from a Lister/oid.

That is my understanding as well, and is I believe called a heat pump.

One thing I'm wondering; can you swap the hot & cold ends of the engine just by reversing direction? If so, you've got winter heating and - by simply changing gear/swapping a belt/whatever - summer cooling. All from the same engine