Cannot find a 5 kw Stirling engine.

Hello all

I am looking arround to locate and buy a new or used Stirling engine that is able to give mechanical input onto a generator rated @ 5kw. Or for any stirling engine of about that output capability or greater.

I am looking for a modern high efficiency compact design.
However i seem to be unable to locate a single one. What strikes me even further is that allthough its a very simple and dated design they seem to come at a great cost if found.

I ve heard that a 30 kw one may cost up to 30 k. . .

Please give me your insights and any possible sources

Thankfully
GTG

To turn a 5kW, you will need a rating of at least 7 hp. I don't know of anywhere that sells such large units. The Stirling design is somewhat of a novelty engine as far as I am aware.

Also, you will have to produce enough heat to drive the engine... with the power losses, expect to need as much as 10kW of heat to compensate.

Exactly what are you trying to accomplish, if you don't mind telling? There is probably a more efficient method (as far as cost goes anyway).

TheRedneck

reply to post by TheRedneck


Well what i want to do is no secret

Th input power i am using is the sun.
As such input energy is not a matter.

In fact i am quite fond of telling what i want to accomplish if this is to aid the environment

All i want is to build my own solar generator which gives free energy when you exclude initial instalation cost

reply to post by GEORGETHEGREEK
Well, to get that much heat energy, you will have to have a collector area of about 15-20 square meters first of all... and then you have to concentrate that heat into a small area for the Stirling engine to use.

Might I suggest a water-based collector system. Heat the water as it runs through the collector. Of course, that will add to the inefficiency, since you will need a pump.

Assuming there is some reason you don;t want to go with direct-conversion solar cells, have you considered Peltier junctions (thermocouples)? That link goes to a surplus company (one I use a lot, so I don't mind advertising for them) who has some for sale. They are billed as using power to produce heat and cool, but they also work in reverse. You'd have to calculate how many you would need to produce the wattage you are requiring, and they can be expensive, but they are much easier to lay hands on than a large Stirling engine. And you would get better efficiency as well.

You could also examine the possibility of using a geothermal sink on one side of the junction and a solar heat collector on the other side to increase the temperature difference and therefore the output.

I'm sure some of the other minds on here can give you ideas as well.

TheRedneck

reply to post by GEORGETHEGREEK


Heh, it is my project to build 16^2m parabola with simple heliostat mechanism (2 small water pumps directed by cheap Linux based router). I was thinking about stirling engine but there is lot of problems with it. Instead I decided to put old car cooler at focus connected to large water tank. Maybe I'll use steam engine later.

Another post belonging on another site completely
What has this to do with ATS???
MAYBE YOU SHOULD TRY E-BAY

reply to post by enca78


lol man

try to broaden up
don t be norrow minded

PEACE

reply to post by TheRedneck


Thank you

Although i got no solution as to where to find an efficient and siseable Stirling engine
you have given me material to work on

I am not familiar with peltier junctions but i ll sure get into it right away

Thankfull regards
George

reply to post by zeddissad


I guess you are linking the radiator with a steam engine then
Not a bad way to go even when considering the reduced efficiency.
Mind commenting on the few problems associated with the problems you spot associated with Stirling engines?
I would hate my self in case i missed one or two of the problems

Thanks
George

reply to post by GEORGETHEGREEK

I'll toss another bone out here, since I highly doubt I will ever attempt to actually build one. It's an idea I did some calcs on a while back.

It is basically a large insulated box with a clear multilayered top (for insulation). Along the bottom is a mirrored parabolic reflector focused on a black steel pipe running the length of the box. The ends are mirrored as well. The bottom of the box under the parabolic reflector is concrete, to act as a heat reservoir.

Water is pumped through the box to absorb the heat produced, and then used to turn an engine, be it a traditional steam design, a Stirling, or a direct heat-to-energy conversion such as the Peltier junctions.

The reason I did not decide to continue was the inability to provide dependable energy based on the sporadic nature of direct sunlight. A large enough collector showed to be more than capable of delivering enough energy to power a household under direct sunlight.

Return water could be shunted through pipes encased in the concrete, to pre-heat it.

I should also point out that should the heat energy be tapped for direct household heating, it would reduce the amount of electrical energy required by the household drastically, substantially reducing the size of the generating unit.

Just more food for thought.

TheRedneck

reply to post by TheRedneck


Not a bad idea.

However you would need temperature controled valves for the preheating return pipes. You would only be wanting those to flow during a cold start.
After a certain point they would act as an inhibitant effectively cooling your main pipe.

However if i got the picture right its a sound design

Where i am located in Crete, Greece, direct sunlight is the norm most of the year.
I don t exactly know how i am going about this all but still this is the stuff of the future



[edit on 7/1/2010 by GEORGETHEGREEK]

reply to post by GEORGETHEGREEK

I was actually using the cooling effect to maintain pressure to some extent. By cooling the pipes inside the box, the heat energy was conserved. But the same design could work with pressure regulators as well.

Do me one favor? If you build one, post a picture? It would be nice to see that idea in action.

TheRedneck