Star Rotor Engine

[Winston001]

A post on the global warming thread about the future hydrogen economy reminded me of the StarRotor engine http://www.starrotor.com/Engine.htm.

This engine is a simple turbine. Easy to manufacture and capable of burning bio-fuels - methane, alcohol, etc. Much more efficent than internal combustion and with far less parts. http://engineeringnews.tamu.edu/news/1325

The hydrogen economy is unlikely to happen - at least in the popular form breathlessly talked about by ill-educated journalists. To get the hydrogen in the first place you have to dissociate it from oxygen (as in H2O). That takes electricity - which has to come from somewhere. So hydrogen power generation is a zero sum game. You can never get more out than what you had to put in at the beginning.

Plus hydrogen is highly volatile. Damned hard to move around and store. Basically, it is bloody dangerous stuff. Bio-fuels on the other hand can be made from plant waste. Bacteria do the work for us - no electricity needed.

[cowpoos]

cool and excuse to throw out more rubbish!!!!!

[sAsLEX]

Similar to http://www.quasiturbine.com/

and for explanations http://auto.howstuffworks.com/quasiturbine.htm

[Pixie]

It's an oil pump!

[Winston001]

It's an oil pump!

Well...........yes. And it burns petrol/kero/methane/propane/alcohol etc. Simple eh. Can be manufactured in third world countries and they can make their own fuel. The StarRotor might not be the complete answer but there are some clever engineers in the world and eventually we'll see a simple reliable engine arise.

[Fooman]

Hmmmm, I'm a bit dubious about some of the claims. It will probably work but not at the outputs and efficiencies claimed. The most efficient simple cycle gas turbines (i.e. still the Brayton cycle) are around 41% thermal efficiency (at combustion temperatures of ~1300°C - the higher the temperature, the more work out of the cycle). With an HRSG and steam turbine added, combined cycle gas turbines are at around 60% thermal efficiency - and this is only at large (300 MW) scale with everything being optimised for continously running at a certain speed.

I cannot see this engine running at anywhere near the temperatures and speeds of an axial flow turbine which are the main contributors to power output.

And this statements is rubbish:

"What are the expected torque characteristics of the StarRotor engine?

Theoretically, at a given compression ratio, the torque curve will be absolutely flat with rotational rate. In actuality, at low rational rates, the torque will be slightly reduced because of leakage. In contrast, the torque of Otto cycle engines is strongly affected by rotational speed."

The torque of an Otto cycle is a function of combustion efficiency and stroke only. Modern engine designs (espcially using turbocharging) give fairly flat torque curves. In fact, a torque curve is a measurement of engine efficiency versus engine speed.

FM

[Fooman]

The hydrogen economy is unlikely to happen - at least in the popular form breathlessly talked about by ill-educated journalists. To get the hydrogen in the first place you have to dissociate it from oxygen (as in H2O). That takes electricity - which has to come from somewhere. So hydrogen power generation is a zero sum game. You can never get more out than what you had to put in at the beginning.

Plus hydrogen is highly volatile. Damned hard to move around and store. Basically, it is bloody dangerous stuff. Bio-fuels on the other hand can be made from plant waste. Bacteria do the work for us - no electricity needed.

Actually the major source of hydrogen is from fossil fuels (mainly natural gas). Run the natural gas at a high enough temperature across a catalyst with steam and you get synthesis gas, a mix of hydrogen, carbon monoxide, steam, methane etc. It's used to make methanol, ammonia, petrol etc. And it is the major source of industrial hydrogen.

The reason why people like hydrogen is that it combusts very efficiently, and does not release carbon dioxide.

Years ago, I went to a lecture delivered by Willis Hawkins on hydrogen as a fuel. He was an aeronautical engineer for Lockheed for more than fifty years (he ended up being Kelly Johnsons boss). A lot of his work was done on hydrogen power aircraft and safety thereof. He stated, that for an explosion of the same magnitude, he would much rather be in a hydrogen fueled one rather than a hydrocarbon fueled one. Apparently the nature of the hydrogen/oxidiation reaction is such that there is much less damage from it (something to do with specific volumes of the reaction product and the effective radiant heat produced). Also, if hydrocarbons leak, they tend tend to pool, whereas hydrogen escapes, disperses or reacts quickly such that a small amount of combustion takes places continously rather than a big explosion.

FM

[vtec]

With regard to your opinion on the Hydrogen economy being a farce.

You're right that you have to put energy in to make the Hydrogen. This is a simple fact of life. Bio fuels actually take a fair bit of energy to make too. It's just solar energy, and energy used in the manufacture, and transportation.

But the reason why they are in essence the same, is that they are both just methods for storing energy. The beauty with Hydrogen, is that it is clean to make, and clean to burn, and there is a shitload of energy stored in a small amount of chemical.

It's just a matter of getting enough energy to make Hydrogen. Where will we get it from? Massive solar/wind plants? Nuclear power (not my first option because it's not renewable)? More Hydro? Wave/Tidal generators? There is a huge amount of energy that falls on our rooftops every day that could be converted directly into Hydrogen chemical energy.

I believe that solar generation will become cheaper and cheaper, and eventually all roofcladding will be interlinked solarpanels. Combined with technological advances in eletrolysers (whatever the things are called that convert water and energy into Hydrogen), everyone will have their own way to make Hydrogen which they can then inject into their vehicles. With R 'n' D this is definitely the most plausible future that I can see. Still if you are thinking solar panels on roofs won't be enough, you are probably right, but there is shitloads of energy out there, and as long as the human population doesn't keep shooting up, there is plenty of energy to convert to Hydrogen. Just a matter of being smart about harnessing it.

I like the idea of having a whole lot of mirrors in a desert that follow the sun reflecting light to a tower that could have a whole lot of water in it that would boil due to the reflected light, and would drive steam turbines. Instead of putting the electricity into lines and feeding it to cities. You convert the energy produced straight into Hydrogen, to avoid losses down power lines... Hydrogen economy ... I love the idea. Now, it's just going to require the peeps with the money to make it happen.

P.S. There are tonnes of energy generation ideas out there. Now let's make a few happen.

[vtec]

Just did a bit of looking up on the net about my cool idea about reflected light energy powering steam turbines. Here's a good article:
http://www.physics.usyd.edu.au/app/r...olar/clfr.html

"To give a sense to proportion, the CLFR technology, working with standard steam turbine and generator sets, could satisfy the entire electrical usage of Australia with only 1000 km2 of such land. There exist many such suitable sites around the world."

Just shows, there's shitloads of solar energy that we know how to tap, just haven't got round to it yet. Aussie has the potential to generate huge amounts of hydrogen going by this article.

[Winston001]

I like the idea of having a whole lot of mirrors in a desert that follow the sun reflecting light to a tower that could have a whole lot of water in it that would boil due to the reflected light, and would drive steam turbines. Instead of putting the electricity into lines and feeding it to cities. You convert the energy produced straight into Hydrogen, to avoid losses down power lines... Hydrogen economy ... I love the idea. Now, it's just going to require the peeps with the money to make it happen.

P.S. There are tonnes of energy generation ideas out there. Now let's make a few happen.

Interesting stuff. An even better way is to use space mirrors which are in geosychronous orbit. Beam concentrated light down to drive the turbines.

[vtec]

Another point, conventional piston and rotary engines are able to run on Hydrogen if they are designed for it. All a combustion engine needs is a decent mix of oxygen and a fuel source, and then on cue of a spark (preferably) it explodes forcing a piston down, or a rotor around. It's just a matter of being able to control the release of fuel... With hydrogen you would probably need direct injection into the cylinder just before you intend it to explode, as it is highly volatile, and does not even need a spark if it is mixed with the correct amount of air.

[Winston001]

The world isn't running out of energy but we lack the technology to capture it at present. I'm thinking of fusion and even better - anti-matter reactors. That might be a long haul because producing antimatter is extremely energy intensive.

However there is an international project underway, based in France, to develop a fusion reactor. Could take 30 years but they'll get there. http://en.wikipedia.org/wiki/ITER

[vtec]

Interesting stuff. An even better way is to use space mirrors which are in geosychronous orbit. Beam concentrated light down to drive the turbines.

Yeah, if set up correctly, you could probably use them as a devastating weapon too, if you could get big enough reflectors in space... Just concentrate heaps of sun energy on a small area... and you cause a lot of damage to said small area. I learnt this lesson at high school physics. My 6th form science teacher had a reasonably small concave mirror which he used to set a live tree trunk on fire. Just like using a magnifying glass pretty much, only reflecting instead of refracting.

But I don't think you need anything in space to get enough solar energy. There's plenty of it already landing on earth... did you check out that link I put in a couple of posts ago. You only need 1000km2 (that's only 32km by 32km of reflectors and collectors) of desert land to generate enough energy to power the whole of australia. We'll be rich... no need for oil anymore.

P.S. Thanks... I didn't know there was anything going on with fusion. I'll check it out.

[Mr. Peanut]

My father designed an engine like that, but died before the prototype was completed.

I still have the plans, the tricky bit was the tip seals on the rotor. He never wrote down how to do that.

The way it was designed, before one combustion cycle had finished, another started in the same chamber. Monster torque at low revs.

[Fooman]

I like the idea of having a whole lot of mirrors in a desert that follow the sun reflecting light to a tower that could have a whole lot of water in it that would boil due to the reflected light, and would drive steam turbines.

It's a good idea, only about 40 years too late. There's been operating plants (as proof of concept) in both California and France since the 1960's. You don't even need a steam turbine. Stirling motors will do. See:

http://en.wikipedia.org/wiki/Solar_thermal_energy
http://www.imp.cnrs.fr/foursol/index_en.shtml

to start off with. There is all sorts of other ways of getting power from the sun - wind is driven by the sun's energy. Photovoltic cells are inefficient and have insufficient power density. Bio-fuel is stored (by plants) solar energy. As most people use about 50-70% of their power on heating (water and space), it is most efficient to use direct solar heating. You can generate energy by utilising the temperature difference between the top of the ocean (heated by the sun) and the water ~100m down.

There are two problems with all this sirt of stuff. The first is that solar power is cyclic - you need some way of storing it so you can use it while the sun is not there. Hydrogen is an obvious choice. Using solar/wind energy to pump water up to a reservoir to run back down through a dam is another. Growing straw to feed into coal fired plant is another (they do this in Denmark - 5% of the fuel going into a powerplant like Huntly is straw bales - but it potentially accelerates the corrosion of the boiler tubes).

The technology exists to do this. The major obstacle is that the technology is too expensive compared to burning coal. I went to a conference earlier this year on materials issues surrounding advanced energy systems. Because it was international, a lot of it was on fossil-fuel generation. Some stuff on geothermal/alternative (e.g. hydrogen) and gasification (turning coal into methane/hydrogen and storing the carbon dioxide). There is no real incentive to try cleaner sources of power - the most advanced coal fired powerstation in the US was built in the early 60's. It has great efficiency, it is just too expensive to build it again - high temperatures and pressures require more exotic materials which dramatically increase the capital cost.

And when power generators make their years profit on the highest demand days, and run at a loss on the median spot prices, as in NSW, there is no economic incentive to build new, cleaner plant, as you have removed your profit margin by increasing supply and reducing the high spot prices. That is the problem with running the power supply as an unregulated, free market business.

The adaptation of renewable, or clean technology (and I include new generation "pebble bed" nuclear reactors - much more suitable for NZ than the large, complex PWR-type reactors) relies on their being demand for such power. Such demand is increasing, but hand in hand with that must come the realisation that to adapt new power technologies is the fact that it will cost more.

I think this qualifies as a rant...

FM