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The Stirling Engine (Merged)

Discussions of conventional and alternative energy production technologies.

Re: Application of the Stirling Engine

Unread postby pedalling_faster » Fri 18 Aug 2006, 10:22:13

i thought Lockheed had kicked in a few hundred million for one of their pilot plants.
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Re: Application of the Stirling Engine

Unread postby deMolay » Sat 19 Aug 2006, 09:34:51

Did the Manson cycle engine actually produce horsepower....Any good sites for complete online plans for Manson and Stirling engines....Thanks
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Re: sterling engine w/solar/geothermal

Unread postby TheDude » Mon 27 Nov 2006, 13:15:10

Maybe some of you get the Peak Oil.com News feed, which sent me this story: How mirrors can light up the world, about using CPS to provide for the world's power needs using a pittance of desert land:

Two German scientists, Dr Gerhard Knies and Dr Franz Trieb, calculate that covering just 0.5% of the world's hot deserts with a technology called concentrated solar power (CSP) would provide the world's entire electricity needs, with the technology also providing desalinated water to desert regions as a valuable byproduct, as well as air conditioning for nearby cities.


Sounds a lot more promising than putting PVs on every roof.

Stirling engines are cool, you can buy little desktop models that run on alcohol:

Image

From the Wikipedia Article:

Any temperature difference will power a Stirling engine and the term "external combustion engine" often applied to it is misleading. A heat source may be the result of combustion but can also be solar, geothermal, or nuclear or even biological. Likewise a "cold source" below the ambient temperature can be used as the temperature difference. (see liquid nitrogen economy). A cold source may be the result of a cryogenic fluid or iced water. Since small differential temperatures require large mass flows, parasitic losses in pumping the heating or cooling fluids rise and tend to reduce the efficiency of the cycle.

Because a heat exchanger separates the working gas from the heat source, a wide range of combustion fuels can be used, or the engine can be adapted to run on waste heat from some other process. Since the combustion products do not contact the internal moving parts of the engine, a Stirling engine can run on landfill gas containing siloxanes without the accumulation of silica that damages internal combustion engines running on this fuel. The life of lubricating oil is longer than for internal-combustion engines.

The U.S. Department of Energy in Washington, NASA Glenn Research Center in Cleveland, and Stirling Technology Co. of Kennewick, Wash., are developing a free-piston Stirling converter for a Stirling Radioisotope Generator. This device would use a plutonium source to supply heat.


This article also mentions a Liquid nitrogen economy. Hadn't heard of that one before.
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Re: sterling engine w/solar/geothermal

Unread postby JRP3 » Mon 27 Nov 2006, 19:32:58

TheDude wrote:Maybe some of you get the Peak Oil.com News feed, which sent me this story: How mirrors can light up the world, about using CPS to provide for the world's power needs using a pittance of desert land:



From that link:

Alternating current cables, which now form the main electricity grids in Europe, are not suitable for long distance transport of electricity because too much is lost on the way. Dr Trieb, of the German Air and Space Agency, says the advantage of DC cables is that the loss in transport is only about 3% per 1,000 kilometres, meaning losses between North Africa and Britain of about 10%.


I always thought it was the other way around, that AC had less transport loss and that's why it's used.
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Re: sterling engine w/solar/geothermal

Unread postby pstarr » Tue 28 Nov 2006, 02:28:39

I love these things. No danger of explosion like a steam engine. I want to build one of them. My friend has a complete metal shop with a metal lathe and biggg 3 horsepower turning machine. Any big-ass plans out there?
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Re: sterling engine w/solar/geothermal

Unread postby Frank » Tue 28 Nov 2006, 09:15:15

JRP3 wrote:I always thought it was the other way around, that AC had less transport loss and that's why it's used.


AC does have less losses - I didn't read the link but if that's what they're saying then they're screwed-up.
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Re: sterling engine w/solar/geothermal

Unread postby small_steps » Tue 28 Nov 2006, 09:55:34

Frank wrote:
JRP3 wrote:I always thought it was the other way around, that AC had less transport loss and that's why it's used.


AC does have less losses - I didn't read the link but if that's what they're saying then they're screwed-up.


DC will have less loss than AC transmission lines, but the main reason that DC is used for longer distances is that the transmission of power is no longer limited by the inductive reactance of the line. That is, you can control it easier.
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Re: sterling engine w/solar/geothermal

Unread postby JRP3 » Tue 28 Nov 2006, 21:22:48

small_steps wrote:
DC will have less loss than AC transmission lines, but the main reason that DC is used for longer distances is that the transmission of power is no longer limited by the inductive reactance of the line. That is, you can control it easier.


I don't understand this, can you explain further?
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Re: sterling engine w/solar/geothermal

Unread postby Denny » Tue 28 Nov 2006, 23:37:38

Frank wrote:
JRP3 wrote:I always thought it was the other way around, that AC had less transport loss and that's why it's used.


AC does have less losses - I didn't read the link but if that's what they're saying then they're screwed-up.


AC power can be stepped up to higher voltages easily. Higher voltages can transmit the same power wiht less current flow. It is the current flow that results in reistance line losses.

But, DC power does not have the same induction losses.

Lots of words and theories. It comes down for the bottom line that for very long distances you want very high voltages, but best the power be DC to reduce the induction losses. That means very large and expensive transforming stations as the power must be inverted to AC to boost the voltage and then rectified into DC. It is done in Quebec, which uses very high voltages from the James Bay generating stations, and Churchill Falls in Labrador to southern Quebec and the U.S. Then they convert the DC back to AC to transfer the power to neighboring grids. Expensive one time capital cost, but lower line losses for the long term.

See Hydro-Quebec - Distance is the mother of invention
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Re: sterling engine w/solar/geothermal

Unread postby JRP3 » Wed 29 Nov 2006, 09:37:55

Thanks for the explanation.
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fresnel + sterling + ....heliostat?

Unread postby canuckinczech » Fri 02 May 2008, 03:03:26

I am new on PO...bit nervous.
I have thoroughly enjoyed everyones comments...and applaud the amount of effort you all have made to share all your valuable knowledge with others. This site has become truely a beakon for so many who seek answers to some very difficult problems we are now facing...'nuff said.
I have been researching getting off the grid for some time now, and after all I have read (thanx to PO)...it seems like solar is to be the only fesiable answer at this stage in the game.
The fresnel lens hooked up a sterling motor...seems like a combination designed by god himself...however, why did he make the sun such a chimera. I have been playing around with a home made heliostat design...which am in the process of building, when I found this site;

http://scientificsonline.com/product.as ... der_E_true

Which seems ok however...doesnt seem to follow the seasons. My question is,

"What am I missing about this combination to get all the power one could need?"
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Re: fresnel+sterling+....heliostat?

Unread postby Gerben » Fri 02 May 2008, 08:04:35

One solar panel won't give you a lot of power. And only at daytime.
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Re: fresnel + sterling + ....heliostat?

Unread postby WisJim » Fri 02 May 2008, 11:22:58

The solution to using solar generated electricity to power your home is to reduce your usage to match the amount that you generate.

As far as tracking mounts for PVs is concerned, Wattsun and Zomeworks are two of the companies that have been around quite a few years. My Zomeworks unit is over 20 years old and works fine. They do increase the energy output of your panels, but I feel that the additional cost is as much or more than just buying more panels to increase your energy output. Tracking mounts for large PV panels aren't cheap. Making a heliostat (a device that would move mirrors so that the reflection of the sun is always pointed at the same place, which could be your PV panels), would be another possibility. Redrock is a good source of info, ideas, and components for home-built systems.

A problem with concentrating collectors, fresnel lenses, etc., is that PV panels generally get less efficient as the temperature rises.
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Re: fresnel + sterling + ....heliostat?

Unread postby canuckinczech » Fri 02 May 2008, 11:39:29

The idea I'm after is avoid using the solar panels and just using the focusing power of the Fresnel lens directly on Stirling(...sorry mis-spelled that earlier) engine. As seen here;
http://youtube.com/watch?v=fUrB7KRvxUk
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Re: fresnel + sterling + ....heliostat?

Unread postby mos6507 » Fri 02 May 2008, 14:15:48

canuckinczech wrote:The idea I'm after is avoid using the solar panels and just using the focusing power of the Fresnel lens directly on Stirling(...sorry mis-spelled that earlier) engine. As seen here;
http://youtube.com/watch?v=fUrB7KRvxUk


How much space is there between you and your neighbors? I think any mechanical generator is going to run into noise issues with neighbors. PV solar will meet the least resistance in the suburbs.
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Re: fresnel + sterling + ....heliostat?

Unread postby davep » Fri 02 May 2008, 14:48:40

canuckinczech wrote:The idea I'm after is avoid using the solar panels and just using the focusing power of the Fresnel lens directly on Stirling(...sorry mis-spelled that earlier) engine. As seen here;
http://youtube.com/watch?v=fUrB7KRvxUk


As Wisjim said, try the redrock site. I bought some solar tracking units off him very cheaply. You can use them for two axis tracking, which is what you need for your setup.

Where do you intend getting a stirling engine from? Are you designing it yourself?
What we think, we become.
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Re: fresnel + sterling + ....heliostat?

Unread postby oowolf » Fri 02 May 2008, 15:18:14

Is this what you have in mind?
http://www.news.com/8301-11128_3-9868931-54.html

I don't know if these demonstration units are still manufactured, but they often turn up on ebay:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0218340412
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Stirlingsolar

Unread postby Vegas » Sat 14 Jun 2008, 10:49:54

http://www.stirlingenergy.com/default.asp

Heat-based solar collector. Mirrors and engines seem easier to scale up than silicon based stuff, though I could be wrong.

Desperation is the mother of all invention.
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Re: Stirlingsolar

Unread postby mos6507 » Sat 14 Jun 2008, 13:29:04

Vegas wrote:http://www.stirlingenergy.com/default.asp

Heat-based solar collector. Mirrors and engines seem easier to scale up than silicon based stuff, though I could be wrong.

Desperation is the mother of all invention.


The one thing I don't like about stirling engines is the mechanical components. Aside from solar trackers, there is nothing more reliable than photovoltaics because they are completely solid state (except for organic solar cells which have an electrolyte in them).

Rollout of solar beyond a certain scale will be a maintenance nightmare. Imagine hundreds of thousands of these solar collectors spread out over many square miles. There will always be a certain percentage of them breaking down and a long trip required to get to and repair them. You really need something you can set up and largely forget about.
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Re: Stirlingsolar

Unread postby Vegas » Tue 17 Jun 2008, 10:50:34

mos6507 wrote:
The one thing I don't like about stirling engines is the mechanical components. Aside from solar trackers, there is nothing more reliable than photovoltaics because they are completely solid state (except for organic solar cells which have an electrolyte in them).

Rollout of solar beyond a certain scale will be a maintenance nightmare. Imagine hundreds of thousands of these solar collectors spread out over many square miles. There will always be a certain percentage of them breaking down and a long trip required to get to and repair them. You really need something you can set up and largely forget about.


Everything you say is true. I think they are running sterling engines at a greater EFF% than photovoltaics. As for reliability, we ain't talking combustion engines, no carbon deposits, no viscosity breakdown.
But, they do run at godawful temps.
Scaling up any kind of energy 'solution' is going to be a pain in the ass....
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