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HydroICE Project Developing a Solar-Powered Combustion Engine
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."
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/
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.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
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.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
...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.
Never underestimate the stupidity inherent in all human beings.
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.
[Fuck Beta]
o0t!
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.
[Fuck Beta]
o0t!
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.
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.
http://www.geoffreylandis.com