HydroICE Project Developing a Solar-Powered Combustion Engine 144
cylonlover writes "OK, first things first – stop picturing a car with solar panels connected to its engine. What Missouri-based inventors Matt Bellue and Ben Cooper are working on is something a little different than that. They want to take an internal combustion engine, and run it on water and solar-heated oil instead of gasoline. That engine could then be hooked up to a generator, to provide clean electricity. While that may sound a little iffy to some, Bellue and Cooper have already built a small-scale prototype."
On the oil/steam separator... (Score:2)
Separating oil and water which have been mixed at such a fine level doesn't seem the easiest. While I know it can be done, can it be done in such a manner to maintain any of the heat energy which remains? Or does one just accept that energy as lost?
Re: (Score:1)
..could be used to preheat the water which is to be injected i suppose
Re: (Score:3)
seems stupid, though: we have good heat-exchangers that don't require mixing the two fluids. Just coiled metal pipes (add fins if needed) would do the trick.
We've been building liquid sodium/water exchangers for nuke plants for years. There is zero reason to mix the fluids and then add a separator (which is a real pain in the ass given the oil is in a closed cycle.)
Re:On the oil/steam separator... (Score:4, Interesting)
seems stupid, though: we have good heat-exchangers that don't require mixing the two fluids. Just coiled metal pipes (add fins if needed) would do the trick.
The point of mixing the fluids is that you cannot otherwise impart enough heat to flash boil the water.
Not to mention that it's really hard to do what you're suggesting inside the cylinder
There is zero reason to mix the fluids and then add a separator (which is a real pain in the ass given the oil is in a closed cycle.)
The whole point of their technique is that they create steam inside the strongest part of an engine.
As it turns out, oil and water will try to separate on their own, which makes this a less than complicated issue.
Re: (Score:2)
The point of mixing the fluids is that you cannot otherwise impart enough heat to flash boil the water.
That begs the question, can you not otherwise impart enough heat to flash boil the water? Why not a big metallic thermal load, made out of recycled popcans?
Re: (Score:2)
The point of mixing the fluids is that you cannot otherwise impart enough heat to flash boil the water.
That begs the question, can you not otherwise impart enough heat to flash boil the water? Why not a big metallic thermal load, made out of recycled popcans?
That's not begging the question.
Re: (Score:2)
That's not begging the question.
An assumption is being stated as a given... what, then, is?
Re: (Score:2)
Re: (Score:2)
I believe the trick here is that because you're injecting the "fuel" (liquid water) and injecting the heat source you are able to very precisely control the timing of the engine as well as control the steam's wave front. If you had a static heat source inside the engine there's not only the question of how you deliver heat to that, but also how you control triggering of the p
Re:On the oil/steam separator... (Score:4, Insightful)
seems stupid, though: we have good heat-exchangers that don't require mixing the two fluids. Just coiled metal pipes (add fins if needed) would do the trick.
The point of mixing the fluids is that you cannot otherwise impart enough heat to flash boil the water.
Not to mention that it's really hard to do what you're suggesting inside the cylinder
That is just not true. Look at a steam catapult, or a pressure cooker, or even a classic rail locomotive. You just need a boiler under some pressure.
There is zero reason to mix the fluids and then add a separator (which is a real pain in the ass given the oil is in a closed cycle.)
The whole point of their technique is that they create steam inside the strongest part of an engine.
As it turns out, oil and water will try to separate on their own, which makes this a less than complicated issue.
"Trying to separate" is a lot different from actually separating. Heat a pan of oil to 400 degrees in your kitchen, now dribble water drops onto the oil for a minute or two. Notice how greasy your kitchen tops are getting? Heat transfer == physical motion in liquids == oil in your steam.
How do you plan to separate the stream/oil droplet mixture? Do simple experiment: shake a pint of cooking oil and water together. How long did they take to separate back out? 1 hour to get to 95%? Now try it at high temperatures: you are talking days unless you have a serious refrigeration unit in your engine.
Re: (Score:2)
How do you plan to separate the stream/oil droplet mixture? Do simple experiment: shake a pint of cooking oil and water together. How long did they take to separate back out? 1 hour to get to 95%? Now try it at high temperatures: you are talking days unless you have a serious refrigeration unit in your engine.
Oil and water separation is a solved problem.
"How" depends on the volume of emulsion, the available space and power.
Maybe they'll use a centrifuge. Maybe electrostatic separation.
Maybe they'll heat the oil with a peltier and use the cool side as "a serious refrigeration unit".
I'm not an engineer and even if I was, TFA doesn't provide enough information to 100% answer your question.
But like I said, it's a solved problem.
Oil/Steam seperation (Score:2)
Maybe they'll use a centrifuge. Maybe electrostatic separation.
Maybe they'll heat the oil with a peltier and use the cool side as "a serious refrigeration unit".
All of those take energy that would sap the efficiency of the system. I'd probably go with a large condensation box that has baffles in it like a septic tank to keep disturbances down. As the liquids cool and travel through/around the baffles, they're slowed and turbulence is minimized.
You might not need a 100% efficient separation system to make it work.
Still, I don't see it being more efficient at this point than traditional steam engines and turbines.
Re: (Score:2)
Re: (Score:2)
Since they have to condense the water back out to run it through the engine once again, presumably it shouldn't be that hard. At some point you'll get it all back into a reservoir of liquid water with oil mixed in. Skim the oil off the top and feed the engine with water pumped from the bottom.
dom
"Presumably?" Have you ever cooked in a kitchen or worked with machinery that has an oil/water interface?
Re: (Score:2)
Re: (Score:2)
In my early years I did a bit of basic motorcar repairing. Nothing ambitious. ;-)
One obvious issue for all, was that whenever a watercooled motor got a leak between oil and water, the result was *mayonnaise*, a compound of oil and water which DEFINITELY won't separate "on their own" --just try it: get a mayonnaise cup, and watch it separating
At that time basically the motor was dead.
Now, I understand there may be ways to try separating. Maybe.
Re: (Score:2)
There is one, oil/steam mixtures are ferociously combustable, and would easily allow one to burn diesel or even used engine oil in an spark ignitioned internal combustion engine; but even that seems a little like a Rube Goldgerg machine to me. There are people who are working on converting the Detroit Diesel Series 71 [wikipedia.org] engines to steam operation, a two cycle diesel would seem fairly easy to convert.
Re: (Score:2)
Yes, and the Russians may get it right this time with the reactor they have under construction. I'm a bit disgusted that you are trivilising it as if it is a common thing and as if they are not major maintainance problems and pretending you know what you are writing about. The French had to rebuild such systems from scratch several times for Superphoenix and their final result is the current state of the art.
Re: (Score:2)
Re: (Score:2)
The oil is assuredly atomized to increase surface area and heat transfer, seeing as the timing of such an engine depends on precise (and rapid) water phase change. Much like a diesel engine you're relying on very precise injection timing and predictably fast burning/expansion.
A oil/water mixture composed of such tiny droplets is not trivial to separate.
Re: (Score:2)
Re: (Score:2)
Only the water turns to steam.. Explosively. It'll be floating above the oil, one would think.
Re: (Score:3)
Separating oil and water which have been mixed at such a fine level doesn't seem the easiest. While I know it can be done, can it be done in such a manner to maintain any of the heat energy which remains? Or does one just accept that energy as lost?
Wouldn't you just cool it below the vapor temperature of the oil and/or water then separate it as liquids? A lot of the will be lost, but not all. Some of the energy can be recaptured by preheating the liquid water and oil.
They're going to have to cool and return at least the water back to liquid state anyway before it can be injected again for the next cycle.
Re: (Score:2)
A lot of the will be lost, but not all.
I see what you did there...
It's not an internal combustion engine, dumbass! (Score:1)
It is in fact a steam engine, using solar-heated oil to flash water to steam right in the cylinder.
And since TFA can't be arsed to state a single reason why one might choose this over, say, a Stirling heat engine, I'm going to assume there's no good ones.
Reinventing the steam engine (Score:3)
Yes, they have reinvented the steam engine.
In this case, literally: it runs on stream. (As opposed to many more modern heat engines, which usually use other working fluids).
The innovation seems to be that they have separated the heat absorption from the expansion of the working fluid.
If the best they can do is 15%, it will not be competitive with photovoltaic, ever. This needs tracking and mirrors, and that kind of moving parts just can't beat the production efficiencies of silicon solar cells.
Re: (Score:3)
The only reason this MIGHT compete with solar is the ability to store the thermal energy overnight. Storing heat (as molten salt or hot oil) is easier and less expensive than batteries to store electricity.
That said, this seems like an awfully inefficient way to go about it and there are already solar thermal plants of different varieties that are commercial-scale, more efficient and less Rube Goldberg-y. I can't see any sensible way to get the oil out of the cylinder without high pressure purge, and if the
Re: (Score:2)
You can store solar panel energy with molten salt or hot oil as well...
Re:Reinventing the steam engine (Score:4, Informative)
Not really. You could turn photovoltaic power into heat energy (with a resistor), and use it to heat up a molten salt, but the efficiency losses and the cost of turning this back into electrical power is absurd.
Re: (Score:1)
Or, you could go for a Solar Sterling [youtu.be]...
Re: (Score:2)
According to TFA 15% is the same efficiency as photovoltaic but the cost of the system is supposed to be 1/3 of equiv photovoltaic.
Yes, but they're wrong [Reinventing the steam...] (Score:2)
According to TFA 15% is the same efficiency as photovoltaic but the cost of the system is supposed to be 1/3 of equiv photovoltaic.
Yes, they said that, but they're wrong. No possible way it can get down to 1/3 the cost of photovoltaic panels. I frankly doubt if they can make it as low as twice times the cost of photovoltaic.
On a large enough scale, I think a Brayton engine might make it cheaper than photovoltaic, but part of that is because of the high efficiencies, and the other part the economy of scale of large turbines. I doubt a piston engine can be that cheap, not operating at these temperatures.
Maybe they're thinking about the
Photovoltaic cost is a rather fast moving target (Score:2)
You really have to take into account potential reduction in costs for any technology meant to compete with photovoltaics (not saying this doesn't have that potential).
Re: (Score:2)
The cost for X amount of steel, y amount of machining, z for mirrors, etc...
The costs for PV panels has dropped substantially. At this point I think that only large scale thermal solar will beat it's economy.
Re: (Score:2)
Hot oil won't last long (Score:2)
Re: (Score:2)
This could probably happen on the way back to the solar collector as the oil is heated back up, then you would just have to condense the steam back into water. Most of the steam would likely just exhaust on its own, but what's trapped in the oil would come out once it's reheated.
Cheers
Why bother with the oil? (Score:2)
Re: (Score:3)
Re: (Score:2)
Re: (Score:2)
Could they not just heat the 'combustion' chamber itself?
This would probably give poor timing control over the vapor explosion.
Re: (Score:1)
I don't see why it would; you'd just time the water injection (like diesel).
Re: (Score:2)
Does the oil eliminate the high pressure steam? Sounds like the steam is still there.
The high pressure steam is only inside the piston chamber. After expanding and pushing the piston, the pressure drops.
Re:Why bother with the oil? (Score:5, Informative)
It's not being burned, it's only being used as a heat carrier. Seems to me it would be more efficient to just heat the water directly, and use it in a steam turbine. What am I missing here?
The hydraulics. I can't be bothered to crack open a steam table at this time of day, but a substantial sized tank of stored 500F water is going to be ridiculously thick walled and heavy... 500F oil can be more or less unpressurized.
Reading the article I'm not sure what "oil" they're using. Cheap canola oil isn't going to like 500F however asphalt isn't going to like being piped around at room temp.
The journalist articles don't detail it, but stereotypically there is a huge insulated front end tank being heated by panels so you can run the engine at midnight. Usually its a couple orders of magnitude cheaper to redesign the system to not require operation at midnight, but thats a higher level system failure.
Re: (Score:3)
Usually its a couple orders of magnitude cheaper to redesign the system to not require operation at midnight, but thats a higher level system failure.
In the near term, for residential power production I think the best method is to use the grid for "storage". The system would need to be able to gracefully shut down and restart without human intervention, though. PV handles that very gracefully and naturally, this would have to be engineered for it.
Re: (Score:2)
Re: (Score:1)
I worried for a moment... (Score:2)
For the record before anyone does start talking about vehicle water injection, i
Re: (Score:2)
I thought I had seen some proposals for water injection where the water was only injected during full-power operation, where it would help keep the combustion chamber cool, and boiling the water would put more combustion energy into mechanical work instead of just heat. I agree that using it full-time would have its drawbacks.
Re: (Score:2)
It's somewhat commonly used with diesels, you inject it only when exhaust gas temperatures are high. its function is to reduce temperatures but it also gives you a power boost under maximum load conditions because the water changes state -- which is why it's so effective at removing heat. you can build a poor man's system with a pump and nozzles from AEM for about three hundred bucks, and a set-point controller like the Auber Instruments 1812, 1813 etc for about five bucks. They sell the controllers as 1/8
Ancient tech (Score:2)
Re: (Score:2)
Re: (Score:1)
For the record before anyone does start talking about vehicle water injection, it adds no power per se...
In the early days, it was used in jet engines to increase thrust due to the increased expansion value and mass of the discharged exhaust.
Re: (Score:1)
There is a FAQ here: (Score:5, Informative)
The last comment at the bottom of the article is a post by one of the project team, linking to a FAQ written in response to the comments.
http://hydroice.wordpress.com/ [wordpress.com]
Came here to say "No Combustion" (Score:2)
Ooh! Ooh! I have an improvement suggestion! (Score:2)
Re: (Score:3)
Re: (Score:1)
Could use any form of heat; combustion isn't bad (Score:3)
Most people think of "solar" or "wind" as renewable, but in fact, burning straw pellets could also work very well as a heat source and be carbon neutral (renewable). The nice thing about an engine like this is that any form of heat could drive it. Separating combustion from from the pressures in the engine also will eliminate NOx and other pollutants. So even if the solar part doesn't work out (or at night), this idea still has potential for carbon-neutral energy from just about any heat source that can heat up the oil.
Re: (Score:2)
It's mainly high compression ignition that results in NOx. That's why separating the combustion from the piston would really help, if we could do the energy conversion efficiently.
Cute idea, but... (Score:5, Interesting)
...I see a few issues, some fixable, some less so.
First, while removing the boiler from the whole "steam plant" equation really does help the safety side of things, you have to be VERY VERY SURE that your separator removes ALL the water from your exhaust. Why? Because if you have even a tiny bit of water in your oil tank, and your heat it to 700F, it's going to boil and expand... and suddenly your low-pressure oil reservoir systems just turned into a really weak boiler full of oil that's hot enough to burst into flames. Instead of venting superheated invisible steam that can strip flesh from bones in seconds, you're going to be spurting oil around at temperatures that cause spontaneous combustion when meeting atmospheric oxygen. Not sure if that's really a step up.
Second, while oil and water don't mix, they do tend to form a really annoying to work with mayonnaise-like suspension of oil globules in water when mixed together really well. This takes a long time - or a lot of energy - to completely split apart.
Third, in addition to the previous problems with separating mayonnaise, heat dissipation will be an issue. Internal combustion engines carry a LOT of their waste heat away with exhaust, but in a closed-loop system like the one they're proposing here you need to remove the 85% of the energy you don't convert into work. Steamboats traditionally do this with a condenser that sits in the water, but if you're not near a large body of water, well... let's just say your condensing apparatus is going to be a huge, complicated, and difficult to work with because even if you don't have a high-pressure steam BOILER you're still going to have a high-pressure steam CONDENSER.
You could, of course, run the oil at a cooler temperature... but that drastically cuts back on your efficiency, because your power depends on having a lot of pressure inside the cylinder, and that pressure comes from the steam, and the pressure of the steam depends on the temperature... well, you get the idea. Basic thermodynamics.
So anyway. It's a cute idea, but unless they've got some really amazing tricks to solve the glaring technical fiddly parts I don't think it's going to get very far. I hope I'm wrong... but I don't think I am.
Re: (Score:2)
in a closed-loop system like the one they're proposing here you need to remove the 85% of the energy you don't convert into work
Why? It seems to me that in a system like this one the ideal temperature for the injected water would be just below the boiling point. Retaining heat in the water would reduce the amount of energy you need to inject in the form of hot oil for the same power stroke. The ratio and amount of oil and water to be injected will be highly dependent upon the temperatures of both, but with a computerized control system that doesn't seem like it would be a problem.
Q:Water / Oil seperation A:Distilation (Score:1)
I should think the water won't last long in the oil as its being heated to 700 degrees, the watter should boill off and be recoverable with a condensor. This is assuming that you would want a closed circuit for the water.
If the plant isn't efficient as per "energy out" / "energy in" it could still be efficient as per "total energy out lifetime" / "total cost in dollars lifetime".
Re: (Score:3)
I should think the water won't last long in the oil as its being heated to 700 degrees, the watter should boill off and be recoverable with a condensor.
Only if the water is still steam when it exits the expansion chamber -- which should be easy enough to achieve by balancing the amount of oil and water injected, taking the temperatures of both into consideration.
Re: (Score:2)
When I first read this, I thought it was heating the engine block and then injecting water that flashes to stream, driving the power stroke. (So basically a two cycle engine - when the piston is at the top of the cylinder, water is injected, it flashes to steam, that drives the piston down, and when the piston comes back up on the second stroke, an exhaust valve allows the steam to escape. The exhaust valve closes at the top of the stroke, and the process is repeated.
That would "consume" water, but would
Re: (Score:2)
Right, I'm sure they never thought of these things you came up with in less than half an hour.
Re: (Score:2)
Technical problems aside, there is no way the powers that be in the US will let any technology like this come to production. Our congress critters are heavily invested in OIL. They will only invest in clean energy that will certainly fail. They may invest research money into this, but only to find a way to make it fail. It has happened time and time again.
Except that natural gas is rapidly becoming a dominant player in the US, so you're completely full of shit.
Re: (Score:2)
And natural gas is "clean" or "renewable" in which way? (Not to mention how it is retrieved ...)
IndieGogo Fundraising Campaign (Score:2)
In case anyone thinks this is interesting enough to throw money at it, I got this link from the FAQ page: http://www.indiegogo.com/hydroice [indiegogo.com].
I thought it was interesting enough to throw it a few bucks. Could be snake oil, but it could also be really cool.
No combustion involved (Score:2, Interesting)
This is not a combustion engine, at all. It's an "insert water with hot oil, use generated steam to drive engine, separate back oil and water to reuse" engine.
The potential efficiency is interesting, and the reduction of generated hydrocarbons compared to a normal motor of the awkwardness of creating and handling lead-acid batteries or other awkward electrical energy storage is also interesting. The difficulty of doing reliable water and oil separation for long periods, at low cost and with low power cost,
Re: (Score:2)
The difficulty of doing reliable water and oil separation for long periods, at low cost and with low power cost
Perhaps not so difficult if the water is still steam when it exits the expansion chamber. Then you'd be separating liquid oil from gaseous water (which would then have to be condensed). So the energy cost would essentially just be a bit more waste heat than is absolutely necessary. If you could separate them effectively while liquid you could try to tune the water/oil ratio so that the water flashes to steam but then cools back to just below the boiling point as it expands.
Re: (Score:2)
If the oil is still liquid why will it be flowing out with the steam? Unless the engine has the valves at the bottom...
Re: (Score:2)
Re: (Score:2)
No one claimed it is an combustion engine.
They want to take an internal combustion engine, and run it on water and solar-heated oil instead of gasoline.
Should I translate that for you?
Take a standard Diesel Engine. Instead of letting it "breath" air, let it breath heated oil.
Instead of injecting diesel/gasoline at the appropriated piston position inject water.
Instead of a gasoline explosion moving the piston you get an explosiv expansion of (water) steam.
Exhaust the steam, reuse the hot oil.
Works exactly l
Re: (Score:2)
I quoted the article heading, and as you claim samzenpus claimed exactly that in the article heading. you obviously neither read my quote nor the article heading, or you did not understand it. I repeat: no he did not claim that.
Re: (Score:2)
Does not matter, the article is completely clear that it does not have anything to do with combustion.
Re: (Score:2)
Ah well, forgott to mention: what is the difference of a "heading" of the article on /. and the summary?
For me it is the same. Perhaps learn to read as I suggested a few posts back already.
Wrong internal combustion error to use (Score:2)
A quick review of the Wankel engine also shows that this technology might be better applied there. The engine destroying accidental misfires known to some Wankel designes would not occur, and the problems handling the spark plug or with lubrication also would not apply.
Questions (Score:2)
Interesting if it works.
- How hot is this engine going to get (safety)?
- Insulation? (as he says)
- Capture of waste heat? Something like this [transpacenergy.com]?
- How is solar energy transferred to oil? With parabolic trough [wikipedia.org]?
- Energy loss due to vibration of one piston?
- Breakdown of oil?
- Any limit to length of pipe running through collector?
Been done already and better (Score:2)
The Solar Energy Generating Systems power plants in the Mojave Desert have been using parabolic mirrors to generate electricity via solar heat for nearly 30 years now, using oil as the heat transfer fluid.
"The sunlight bounces off the mirrors and is directed to a central tube filled with synthetic oil, which heats to over 400 ÂC (750 ÂF). The reflected light focused at the central tube is 71 to 80 times more intense than the ordinary sunlight. The synthetic oil transfers its heat to water, which
Re: (Score:2)
The heat collector system used in the SEGS plant isn't high-pressure. The oil used in the collector pipes never boils so it is only at a few atmospheres pressure, just enough to keep it circulating. The 400 deg C oil passes through a heat exchanger in central locations at each collector "farm" to produce steam that drives a turbine and generates electricity. This vastly simplifies the piping structure and keeps costs down while maintaining decent efficiency in terms of heat capture versus the amount of elec
Stored Heat Engines Aren't Going in Your Car! (Score:2)
This format of a heat engine isn't "going" anywhere as it would work only on a stationary position where the sun loading could be high with steerable mirrors. You could use molten oil, water or any material you chose to act as a heat source for a heat expansion engine.
For mobile uses, it all comes down to kilocalories stored per kilogram. This solution "won't go anywhere" mobile.
who cares about the efficiency? (Score:2)
What is interesting/important is it's potential as (pointed out lots of times in the comments) a steam engine that avoids big boilers and has the same kick as an ICE since it uses the same mechanical layout. Any other heat-driven engines that can do the same? same kick, same overhead?
reading comments seem
2-stroke diesel engine? (Score:1)
It is NOT and ICE. (Score:2)
Re: (Score:1)
From the indiegogo [indiegogo.com] campaign (yes, the summary neglects to mention this is a bloody crowdfunded uni project):
Efficiency: Both steam turbines and Stirling engines are known to be quite efficient, typically falling around the 40% efficiency range. We won’t know exactly where our HydroICE technology will fall until testing is complete, but we’ll be able to reach at least 15% efficiency with projections falling closer to 30%.
Manufacturing and cost: Both steam turbines and stirling engines are extremely precise machines and as a result, we see that reflected in the high price that it costs to manufacture and purchase one. This makes them economically feasible only for large industrial scale applications.
Yep, Stirling engines are too precise to be economically feasible, but similarly precise gasoline engines are so cheap that even with extra modifications they'll be feasible... right.
Re:Why not use a Stirling engine? (Score:4, Interesting)
stirling engines are extremely precise machines
What, their fuel injectors? Old fashioned mechanical carburators?
Yeah I know the guy is trying to get at the wider temp fluctuations in cylinder and piston temp, unless you go uniflow which has whole nother kettle of fish, but its not really much of a problem.
See if you try to crank up the efficiency and power of a trad ICE, eventually you get all manner of predetonation (ping) and trouble keeping crankshaft loads low enough while not letting the valves float and it gets all technical very fast. With a stirling you just crank up the heat until you melt or deform the piston/cylinder. Its more easily understood so its easier to empathize so its "seems" harder, but actually ICE are way more difficult its just we can't talk in uneducated company about the actual challenges. Any moron can understand "it melted" so any moron thinks stirlings are more difficult because they can't even talk about ICE engine optimization.
Re: (Score:3)
I don't understand... can you make a car analogy?
Re: (Score:1, Informative)
stirling engines are extremely precise machines
What, their fuel injectors? Old fashioned mechanical carburators?
A Stirling engine [wikipedia.org] is *not* what you find inside any typical car. A Stirling engine is an external combustion engine (the heat source is provided from outside the engine) rather than the internal combustion engines (Otto cycle [wikipedia.org] for gasoline cars and Diesel cycle [wikipedia.org] for diesel vehicles) typically used. A Stirling engine has neither fuel injectors nor carburators - as an external combustion engine, it doesn't need to get fuel into the cylinders.
Re: (Score:2)
Yep, Stirling engines are too precise to be economically feasible,
I don't know about that. Stirling engines seem to be popular projects for people getting started with home machine shops. Their cost is a matter of production volume.
but similarly precise gasoline engines are so cheap
Right. Because they are high volume production items. But one must figure one's economics based upon the assumption that one will go into large scale production. Not scrounging a bunch of parts adapted from some other use. If this technology is to become viable, piston engines will be designed and built specifically for this purpose (or for Sti
Re: (Score:2)
"But one must figure one's economics based upon the assumption that one will go into large scale production."
That creates a chicken and egg scenerio. Unless you have some massive VC capital backing you then you need to be able to produce units at reasonable prices in small volumes at first. Or else your technology will be overpriced, nobody will buy it, and you will never survive large enough to reach 'large scale production'.
There are dozens of companies that make this mistake every day. If you don't have
Re: (Score:2)
Modern day robotics make precision a non-issue. And with Stirling engines you can use more ceramics in the hot section since it's not exposed to explosive forces or crazy high RPMs like a gas turbine. Plus we can use them for refrigerator compressors without any specialized refrigerant. What they don't presently have is rapid throttle response, much like a regular steam engine, and to get a lot of power, they need to be very large, which is not an issue for stationary applications.
Re: (Score:2)
What they don't presently have is rapid throttle response, much like a regular steam engine
Which, frankly, would hardly matter in a hybrid car with electric traction and battery + supercap storage, would it?
Re: (Score:2)
much like a regular steam engine, and to get a lot of power, they need to be very large, which is not an issue for stationary applications.
Re: (Score:2)
Re: (Score:3, Informative)
I just read TFA, and what is described is in no way a combustion engine. Nothing is combusted.
They seem to carefully avoid mentioning it, but most oils when preheated to 700 degrees F (holy cow) and atomized in air will burn pretty well. Probably the water addition is to prevent the cylinder walls from melting, or more likely prevent them from looking like a well seasoned cast iron pan (which would have serious issues WRT cylinder rings)
diesel's autoignition point (not flash point, you're already mechanically atomizing the vapor) is only like 400 degrees F.
diesel has a somewhat lower autoignition p
Re: (Score:2)
I just read TFA, and what is described is in no way a combustion engine. Nothing is combusted.
They seem to carefully avoid mentioning it, but most oils when preheated to 700 degrees F (holy cow) and atomized in air will burn pretty well.
Since they plan to recover and reuse all of the oil, they must be assuming a type of oil that won't burn at the temperatures used. The GP is right: according to the article there's no combustion in the process. The design is an unusual sort of steam engine.
Of course, this raises the question of why it's better than a more traditional solar-powered steam engine. It clearly avoids the need to deal with high-pressure steam anywhere except in the "combustion" chamber, and if it can work well in slightly m
Re:Not Combustion (Score:4, Informative)
They seem to carefully avoid mentioning it, but most oils when preheated to 700 degrees F (holy cow) and atomized in air will burn pretty well. Probably the water addition is to prevent the cylinder walls from melting, or more likely prevent them from looking like a well seasoned cast iron pan (which would have serious issues WRT cylinder rings)
I don't think you read the article carefully enough.
1. hot oil + water = instant steam
2. steam pushes the piston down
3. the oil + steam get recycled
4. GO TO 1
The only input is solar energy to heat the oil.
The rest of the system works on a closed loop.
Re: (Score:2)
It does not use the oil up.