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We use stirling engines in our diesel submarines.

deMolay wrote:Anybody here up on Stirling Engines? They were invented about 1816 by a Rev. Stirling in England. It could be a far better answer than hydrogen or some of the more hightech solutions. They work, have been around for almost 200 years and are fairly simple. They can be build by people who are trained in machine shop. I have been looking at them for about 10 years and never thought their day would come again, I think this design needs updating and modernizing. What are your thoughts? http://www.stirlingengines.org.uk/pioneers/pion2.html

Interesting. I'm looking for the simplest way to convert heat differences into energy, and a stirling engine might be the answer. It comes pretty close to Carnot efficiency in a relatively ideal situation, and it isn't that complicated.

The other option, of course, is to simply boil water and set up some sort of turbine system. One of my engineering projects managed to use a parabolic solar trough to get a steel bar up to around 120 C on a partly cloudy day in a minute, so I've already got the steam. Nice thing about turbines is that they're still in production for heavy use- not just as toys- and indeed, one can even pick up smaller turbines. Naturally, some mechanical engineer is going to tell me why I'm wrong, but they're even making relatively small "turbines" for turbochargers that might be able to be converted to putting into a pipe to turn a generator for a a KW or two of energy.

The simpler we keep things, the easier they are to fix.

Ok, just some separate elements:

1. Stirling engines have many advantages over internal combustion engines:
[from wikipedia]
* The heat is external and the burning of a fuel-air mixture can be more accurately controlled.
* A continuous combustion process can be used to supply heat, so emission of unburned fuel can be greatly reduced.
* Most types of Stirling engines have the bearing and seals on the cool side; consequently, they require less lubricant and last significantly longer between overhauls than other reciprocating engine types.
* The engine as a whole is much less complex than other reciprocating engine types. No valves are needed. Fuel and intake systems are very simple.
* They operate at relatively low pressure and won't blow up like steam engines.
* Low operating pressure allows the usage of less robust cylinders and of less weight.
* They can be built to run very quietly and without air, for use in submarines.
* They are silent, less polluting, are more reliable due to fewer parts and the absence of an ignition system, produce much less vibration and safer, less explosive fuels may be used.


ADD that they are:

-more efficient than internal combustion engines
-they're quiet
-they run on any fuel source (biodiesel, bioethanol included)
-they produce a lot of heat, which can be stored
-the cold part of the engine can be aircooled (aerodynamically as your car speeds up)
-stirlings are very simple, with only about half of the number of parts and moving elements of an internal combustion engine
-they can be used as efficient generators


2. Heat storage (thermal batteries) have a much higher energy density than electric batteries; e.g. 1 kg of magnesium-hydride has the capacity to store 0.8 kWh of medium-temperature heat reversibly and practically without loss, this is about 2880 KJ/Kg;
http://www.bsrsolar.com/core1-3.php3
compare this to the best li-ion batteries, with an energy density of around 0.11-0.16 kWh/kg or 500 KJ/kg

3. So the configuration would be as follows:
-a small stirling generator acts as a battery charger (charges li-ion batteries which are the main propulsion)
-the excess heat is stored in a magnesium-hydride battery, and released back to the stirling generator after you've used your car (at night); it silently recharges the batteries while your car is parked
-now your batteries (both electric and thermal) have enough energy to warm up the stirling next time you drive (because stirlings need a while to warm up) and the li-ion batteries have enough to drive you around (and get recharged by the warmed up stirling, as you drive)
-the stirling genset operates on any fuel, so there's no need to have a dedicated infrastructure

Okay, that's it. Someone plz do the math and tell me this makes sense!

one was made in the 70s when oil get expensive
the big car companies got together and made it
from what i know it took about 20 seconds .. to warm up before it went anywhere but was quite fuel efficient

it was dumped though when the price of oil dropped

-more efficient than internal combustion engines

That they are not. Do an analysis of the diesel cycle versus the stirling cycle and you can see why: How hot do you make the hot side and how fast can you reject waste heat with a diesel engine vs a stirling engine.

Something to do on a rainy day.

SFA Stirling Engine Project

http://www.stirlingenergy.com/whatisastirlingengine.htm

Already slated to build 800 mw/h of power in california. search google.

Anyway, using the commonly stated estimate that it would take 4000sq miles of solar utilized land to meet current demand (yes i understand exponential theory, currents the key word) based on 20% efficient photovoltaics... we're down to around 2667 square miles with 30% efficient collectors. and this technology is immature.

2667 square miles ~50 square miles.

50 square miles spread out across the US really isnt much at all.

anyway, just wondered if you all had seen this.

most photovoltaics are 15% efficient, this represents a doubling of efficency. thats huge.

beefstuinit wrote:2667 square miles ~50 square miles.

???

Doly wrote:

beefstuinit wrote:2667 square miles ~50 square miles.

???

50 sq. miles per state.

It was kinda implied

I would not call steriling engines immature technology. Sterilings are just little known and mostly unfunded. They have been used on boats to desalinate water for years using the thermal diferential between the air and water. Solor powered sterilings will need to replace PV as the cornerstone of solor expansion due to the recent silicon shortages.

Stirling Engines

I was just talking to the site mud engineer about portable generators because, as some of you know, our biggest city auckland had a power cut recently, and much of the central south island is without power due to a snow storm. He suggested I look up Stirling engines so I did. Here is the excellent Wikipedia article about these, but please note that at the bottom is a list of manufacturers including one from NZ - WhisperGen.

http://en.wikipedia.org/wiki/Stirling_engine

There is a company called Stirling Energy Systems that is building 2 giant solar thermal power plants using Stirling engines in Southern California, each of them is larger than the entire solar projects in US combined together. Any one heard any progress on their projects? Their web site is www.stirlingenergy.com.

Here's a practical working Stirling engine that you can actually buy and put to use. It sits on a wood stove, runs from the heat of the stove, and turns a fan to circulate air. Other similar heat operated fans use a device that uses the heat to produce electricity to turn a motor to turn the fan, and that style is damaged by too high of temperatures. The Stirling motor fan can apparently take extremely high temps with no damage.
http://www.thermalengines.com/

$200 for a nice little Stirling engine powered fan.

The problem with any of the proposed large scale solar or wind electrical generation projects is getting the power to where it is to be used. There aren't adequate transmission lines in many parts of the country, and the people in between don't want to give up their property, no matter how small of an amount it is, to put up new transmission lines to deliver power to people in metropolitan areas who refuse to have the means of generation within their site.

This is a current problem in Wisconsin, where they are going to build new lines across the state, to deliver electricity to the South Eastern part of Wisconsin, with lines and towers built through farms and wetlands, to carry power produced by hydroelectric facilities on flooded Indian (or is it Native American?) lands. But they don't want wind generators in Lake Michigan because they might see them.

Fortunately, wind and solar power can be locally produced, eliminating the need for long transmission lines...

I had a chance to talk to the founder of this company last year, and got a chance to look into some technical details of design. From what I know (I used to be a physicist and now a electric engineer), this is the closest thing we have to silver bullet to mitigatge the upcoming energy crisis (not only peak oil). But I haven't heard anything about them for about a year. I won't be suprised that this company breaks out; but I won't be suprised that this company may fail either. Looks like all they need is couple of hundreds of million dollars to build the power plant since they got the contracts already. I don't understand why it is so difficult to raise that tiny piece of fund; that is much less than a typical Las Vegas or New Year condo building.

Ludi wrote:Fortunately, wind and solar power can be locally produced, eliminating the need for long transmission lines...

No, this is exactly the problem. Most sites that are excellent for wind power are not near population centers and thus not local to the people that want the power. PVs are a different story, as good power production is possible in most parts of the world.

neo wrote:I had a chance to talk to the founder of this company last year, and got a chance to look into some technical details of design. From what I know (I used to be a physicist and now a electric engineer), this is the closest thing we have to silver bullet to mitigatge the upcoming energy crisis (not only peak oil). But I haven't heard anything about them for about a year. I won't be suprised that this company breaks out; but I won't be suprised that this company may fail either. Looks like all they need is couple of hundreds of million dollars to build the power plant since they got the contracts already. I don't understand why it is so difficult to raise that tiny piece of fund; that is much less than a typical Las Vegas or New Year condo building.

when you see Dubya in there getting his photo op I think it bad news for the company, after all he is part of the problem and not part of the solution, nothing but oil for that guy.

check out "who killed the electric car" docu playing in theaters now