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co-gen system


By stop4stuff, Section Homebrewed Electricity
Posted on Thu May 12th, 2005 at 07:26:32 PM MST
water heating and stirling generator

Saw this on a BBC news report the other day...
A commercially available unit that...
Replaces a gas hot water boiler....
...and...
generates electricity using a stirling engine
they also make a unit for of grid
see; http://www.whispergen.com/
co-gen system | 9 comments (9 topical, 0 editorial)

Re: co-gen system (3.00 / 0) (#1)
by 41south (cglarsen[at]clear[dot]net[dot]nz) on Thu May 12th, 2005 at 02:20:42 PM MST
(User Info) www.41south.net.nz

Wonderful machine, built here in good old New Zealand. Very expensive for us locally to buy, but a fascinating design.
Cheers - Colin
3rd Law of Computing: Anything that can go wr___ Segmentation fault -- Core dumped


Re: co-gen system (3.00 / 0) (#2)
by bob golding (photoman290 at yahoo dot com) on Thu May 12th, 2005 at 03:25:07 PM MST
(User Info)

i looked at those a while ago and worked out that you could build one with the same power output using  high temp peltiers for about the same price. have to do a  bit of  heat exchanger design but i think it would be more reliable. just my 2 cents.

bob golding



Re: co-gen system (3.00 / 0) (#3)
by windstuffnow (elenz(at)windstuffnow(dot)com) on Thu May 12th, 2005 at 05:38:08 PM MST
(User Info) http://www.windstuffnow.com/main

  I looked at them a few years back also, I don't know what they cost now but back then it was priced where I couldn't see a payback in my lifetime, not to mention the fuel to run it.  A good wind genny and a couple solar water heaters would be more cost effective...

  They are nice machines though.. just a bit pricey for my budget.

Hav eFun
Windstuff Ed

Have Fun! Windstuff Ed
[ Parent ]



Re: co-gen system (3.00 / 0) (#4)
by stop4stuff on Fri May 13th, 2005 at 12:46:17 AM MST
(User Info) http://www.stop4stuff.com

i've done a bit more research into whisoergen...
A UK electricity/gas supplier, Powergen, is installing the units in 550 new home near Manchester. Powergen also have sole UK rights. I've not yet found any pricing tho.



Re: co-gen system (3.00 / 0) (#5)
by troy on Fri May 13th, 2005 at 02:29:20 PM MST
(User Info)

I also was fascinated by the Whisper Gen and even tracked down a place that would import one for me.  I think the starting price was a shade over $10,000, plus the import duties, shipping, all applicable federal red tape, etc.  I also discovered that they have dissappointingly small output, like 1,000 watts or so (I'm just going from memory, so someone jump in if I'm wrong there).  Better than nothing, but it would be tough to run even an efficient house on that, unless you add a battery bank, etc.  And of course, we all know a battery bank greatly adds to the price and complexity, there has to be an inverter involved.  Tack on another wheelbarrow of money.

So, I built my own biodiesel cogenerator using a Lister 6 horse diesel.  Instead of ten+ grand, I spent about $2,000 and a bit.  It will make 3,000 watts all day long if necessary and surge to 6,000 long enough to start my table saw.  Plus the Lister has proven longevity with 50-100,000 hours between major overhauls.  And mine can run on used veggie oil, or kerosene, or jet fuel (really just kerosene again), home heating oil, lard, suet, biodiesel, regular diesel, waste motor oil, etc.

Theoretically, as a Stirling, the whispergen could burn various fuels, but what you get is what you get, no choice after that.  I think they have a gas and maybe a diesel in their boat version.  Of course, theirs is quiet and sexy and compact, while mine is noisy and vibrates a lot and looks like a remnant from the last century, which it is.

Now, if you guys want to donate one so I can do a head to head comparison, I'd be happy to take it...

Dang! No offers...

Finest regards,

troy  




Re: co-gen system (3.00 / 0) (#6)
by bob golding (photoman290 at yahoo dot com) on Fri May 13th, 2005 at 04:00:59 PM MST
(User Info)

hi troy,
 i just got hold of an old  5 hp lister st1. when you run it on  kerosene or waste veggy oil did you have to do an mods ot it? will it start on kerosene or do you start it on  diesel then change over when its up to temperature?

thx
 bob golding

[ Parent ]



Re: co-gen system (3.00 / 0) (#8)
by sawyer335 (sawyer335@gmail (DOT)com) on Sat May 14th, 2005 at 08:43:51 AM MST
(User Info)

Sorry Bob,
An ST Lister is not at all the same as a CS Lister.
Regards,
Joel
Joel
[ Parent ]


Re: co-gen system (3.00 / 0) (#9)
by troy on Sat May 14th, 2005 at 11:01:06 AM MST
(User Info)

Runs fine on kero, had to use a two tank system for veggie oil, start on diesel or biodiesel, then switch to veggie oil.  Veggie oil preheated to 150F and prefiltered to 10 microns or better.  Keep in mind, this beastie lives in my basement, so it never gets cold.  If yours is outside, you may have a much different experience with alternate fuels.  Plus, as pointed out by the other post, your engine is significantly different than mine.

As a practical matter, I have wads of biodiesel at my disposal now, so I burn that exclusively and the Lister loves it. It's nice to have other options though...

Good luck and have fun!

troy

[ Parent ]



Re: co-gen system (3.00 / 0) (#7)
by Ungrounded Lightning Rod on Fri May 13th, 2005 at 08:25:04 PM MST
(User Info)

I also was fascinated by the Whisper Gen and even tracked down a place that would import one for me.  I think the starting price was a shade over $10,000, plus the import duties, shipping, all applicable federal red tape, etc.  I also discovered that they have dissappointingly small output, like 1,000 watts or so (I'm just going from memory, so someone jump in if I'm wrong there).  Better than nothing, but it would be tough to run even an efficient house on that, unless you add a battery bank, etc.  And of course, we all know a battery bank greatly adds to the price and complexity, there has to be an inverter involved.  Tack on another wheelbarrow of money.

I think the point of cogen devices like this is to pick up otherwise wasted energy and put it to use.

In this case you're going to burn the gas to fire your heater anyhow.  The gas burns a LOT hotter than the max water temperature.  Running that heat across that temperature difference increases the entropy of the universe without doing anything useful.

So instead you run the same heat through the heat engine, and end up dumping it in the hot water anyhow.  And you generate some power in the process.

$10/watt is comparable to solar panel prices - at least it was a few years back.  Maybe a bit high, but what the heck.

You'd need an inverter, of course.  But if you have net metering you wouldn't need a battery bank (unless you want backup power).  You use the grid as a big battery - "charging" it by feeding it power when the heater is running, "discharging" it when the heater is off.  If you discharge more than you charge you pay for the excess.  If you charge more than you discharge you probably get zilch for it, but you'd get zilch if you had to use a dump load anyhow (unless you used it to heat the water some more and thus cut off the flame sooner  B-)  ).  Meanwhile you don't pay for self-discharge.

(And yes putting the stirling in there DOES steal some of the energy that would have heated the water.  But you may find that the collection of the heat by the stirling is enough better than the absorbtion of the heat by the pipe up the middle of a non-stirling water heater to make up the difference.)

[ Parent ]



co-gen system | 9 comments (9 topical, 0 editorial)
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