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."
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.
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.
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, is an interesting one.
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.