by Doug Coulter » Mon Aug 02, 2010 9:43 am
Oh, man, we're going to have to swap some things around this, or me get busy on the scanner. I have a few really old "engineer" books from the period that get into considerable detail on things like this -- it was all there was at the time (but the schemes for self-feeding carbons into lamp arcs were a close second in coolness). In some ways I'd say those guys were at least as smart as we, considering what they managed with crummy materials. I also have some machine-shop books from pre and post WW I that show how to get sub mil accuracy out of machines that we'd put in a museum and not consider refurbishing for actual use. And I use some of the tricks for getting better results out of some of the modern Chinese machines I own today.
The sound of those hit and miss engines is just so neat....they are a big attraction at the flea market in Hillsville (this is two-three blocks wide by a few miles long, and you cannot see it all in a day).
Turbines can do better than pistons -- these days they are pushing the high 40% range from calculated BTU in coal to output electricity -- but might be past our speed to make at that level (many stages with interstage reheats, first stage supercritical). However, a 2 stage design with the first stage pelton-wheel like, and the second (and any further stages) your basic turbo fan is fairly decent, and by controlling how many nozzles are open can handle a wide range of inputs -- I'd been looking at that too. As in, could one design a turbine with blades cast from melted down beer cans? Yes, these would wear out all too quick, but -- considering where they'd be going, maybe not a problem if the basic design makes it easy to keep up. A lot of people in some places have plenty of time, but not a lot of good toolage, and I've seen quite a lot of ingenuity from there, from cars made almost all out of scrap metal to even transformers made of cut up sheet metal for the cores (from back when beer cans were iron). If you can make them a design where the only parts that wear out can be made by them -- that's gold for all concerned.
No question IC engines are better -- but this is because they use a better fuel too, can't burn logs or coal in one. My purpose built backup generator for the solar system is sweet on that level. It uses a 6.5 hp high compression Honda engine driving the generator from a WWII Spitfire. After many thousands of hours, the generator brushes still look new -- I couldn't believe it when I tore it down "just in case" -- we must have really wanted to win that war. But also, the IC engines fail easier....and need two special fluids to work, not junk you just find laying around.
In my case, BTU's are nearly free anyway -- we have a large woodlot and a few tons of "thermal security" in the form of coal out back. Not to mention plenty of sun much of the time. But can't use any of those in an IC engine, hence the interest in something else. Particularly, things that work in sun-free February. Electricity from an IC engine is a buck a kwh when you consider wear along with oil and fuel.
What I was looking at was for power generation, simple and cheap, for myself and for parts of the world that need this kind of thing -- cheaper than my solar stuff, and possible for an idiot to run and repair. Safety in the event of a little over-firing would be a pretty big deal, which is why I mentioned that, along with self starting (for solar dynamic heat input). Can't count on a microprocessor control for 3rd world kinds of apps. This actually makes the turbine look best, if relief valves control the extra input nozzles to keep boiler pressure in range no matter what. The whole unit could be sealed in that case -- no shaft seals that have to hold off steam pressure if the generator is inside the casing for example, direct coupled. No need for speed control (other than safety) if the generator is going to charge batteries -- it will be DC anyway (or alternator plus diodes).
Have you seen the old B&W books called "Steam, it's generation and use"? Boy are those thorough -- I have a couple I got in used bookstores from before McDermott bought them out. They have more info on water in all possible states than you'd think existed. I note that just this AM, McDermott spun off B&W again -- and their stock tanked 48% on open. B&W fell on hard times around asbestos issues and almost failed, McD saved them....but didn't know what they had -- B&W are THE guys in USA who do nuclear for example, having bought nearly all the competition earlier on.
The B&W guys are really good at what they do -- should a fusor get near to gain, they are who I'd be on the phone with right away.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.