On Wed, Nov 24, 2010 at 10:20:23AM -0800, Kirk Wallace wrote: > I have been giving this some thought. If the grid is available, the only > way off-grid power makes since is if it's almost free. One of my > thoughts is to run my generator head with a steam engine which could > burn, wood, waste oil, propane, whatever. If necessary, enough batteries > would be needed to fill the gap when the mains get interrupted. There > would be enough batteries to to keep the power up until the > hydro-generator kicks in. The hydro source would be a tank on a tower, > or a tank at the top of my hill with the turbine at the bottom. The tank > would be pumped up when I have excess power. Hopefully there would be > enough hydro to allow enough time to get the steam engine up to speed. > Or maybe have the hydro turbine do double duty as a water and steam > turbine. Anyway, this is some of what I think about when I do my morning > thinking.
With 2 sq km of forest on the farm, my original reason for buying the lathe and mill was to build a steam engine, or convert an old horizontal IC engine with fat flywheels. (There's one in a corner of the shed.) It's only progressed as far as calculations of power output vs RPM, average steam pressure, cylinder dimensions, etc. The other calcs are for the boiler. Due to stiff regulations, having one made isn't cheap. So ... flash steam (monotube boiler) is very tempting. (They need a constant load, because there's no hot water to provide a steam reserve. I figure that batteries could substitute.) We don't have much clean water out there. (18,000 L total, for domestic use.) That mandates a condenser. Dam water could be used on the outside of that. All that's lacking is the round tuit. Gasification is an alternative, but cleaning the tar and crap from the gas generator output necessitates filters, which need regular cleaning. That's a grubby and non-trivial job, from the writings of those who've done it. Ideal would be a stirling engine with integral alternator: http://www.stirling.dk/ # Nifty, but still in one-off production, # after about 5 years. Smallest is 9 kw. # Larger units use woodchips. It's a while since I went through: http://www.stirlingengines.org.uk/manufact/post.html Maybe someone's within cooee of thinking hard about going commercial RSN. Erik PS: If my simple script for calculating steam engine power vs various % cut-off, etc., would amuse, then just yodel off-list. It looks like this in use: Input: Pressure(PSI) Stroke(cm) Bore(cm) RPM 200 10 8 400 <- User input ------------------ Cutoff HP kW ------------------ 25% 3.7 2.8 33% 4.2 3.1 37.5% 4.6 3.4 50% 5.2 3.9 62.5% 5.7 4.2 67% 5.8 4.3 75% 6.0 4.5 87.5% 6.1 4.6 100% 6.2 4.6 ------------------ There's also two pages of maths & musings for engine & boiler to hand, from last time I nudged closer toward something workable. PPS: Water and steam turbines look very different, unfortunately. A single Pelton wheel could do for the former, but alternating stator and rotor wheels of increasing diameter are needed in the latter, to utilise the expanding steam. (AIUI, anyway. ;-) PPPS: Hope there's some ideas in that lot. ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
