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Thread: 1903 six HP steam engine powers modern off grid power system

  1. #211
    I just became aware of a small scale steam engine system constructed and operated during the early 1980's. It was used to heat and power a modern home in Pennsylvania. It was fueled by anthracite coal. I understand there is an ASME paper describing the details. So, if I can get the paper, then I will post it here.

    The details I acquired show the system was extremely efficient. Well, actually, since it used saturated steam at only 135 psig and atmospheric exhaust, the highest possible efficiency is very low under these parameters. However, it showed 80%+ of Rankine cycle efficiency (or theoretical maximum). I would not have thought it possible to do so well in so small an engine (actually, until I get the ASME paper, then I am going to doubt the figure). The White Cliffs expander was measured at about 70% of Rankine cycle efficiency using saturated steam at 540 psig and exhausting to a condenser at 160F (roughly 3.5 psia). There were additional losses in that engine due to the incomplete expansion (since it used high pressure steam plus a condenser under vacuum), clearance volume losses due to the bump valve configuration, thermal losses mainly from the high temperature differential in the cylinder (but also the higher steam temperatures), and the higher pressure likely contributed to steam leakage past the rings. Also important is small steam engines are very poor at extracting work from low pressure steam. So, a small engine with atmospheric exhaust can potentially show a very high percentage of theoretical maximum efficiency provided the other losses are minimized.

    The expander was a single cylinder, single-acting, uniflow piston engine converted from a small industrial internal combustion engine. The steam admission used a single poppet valve with a push rod and cam. The system operated 24/7 during the heating seasons over a period of four years. Typical operating speed was 600 rpm. Power output was about 2 hp.

    http://www.thesteamboatingforum.net/...ile.php?id=187
    http://www.thesteamboatingforum.net/...ile.php?id=186
    Last edited by buenijo; 10-03-2019 at 04:06 PM.
    “The beginning of wisdom is to call things by their proper name.” - Confucius.
    "When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it." - Frederic Bastiat
    "Being well adjusted to a sick society is not a measure of health." - Jiddu Krishnamurti



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  3. #212
    Still doing a bit of casual reading on steam engine systems. The same engineer who devised the residential scale CHP steam engine system described in the previous post also devised and operated a small steam generator using a simple principle I considered years ago. Apparently, it works very well. A problem with traditional monotube steam generators is the water feed rate must be closely matched to the furnace output. Otherwise, insufficient water flow can lead to excessive temperatures and possible tube burnout (or lube oil destruction), or excess water flow can flood the coil and carry water into the engine. The solution here is simple: just pump excess water at all times, then use a small separator vessel to accept the steam/water mixture from the tube - pressurized saturated steam is taken from the top and saturated water is drained from the bottom. The water level remains more or less constant as long as the orifice to the drain line is properly selected with respect to size. Turns out the mass flow rate of water through an orifice is on the order of 10 times greater than steam. So, very little steam can escape. As long as what little steam escapes has its heat captured and regenerated into the system (along with saturated water that drains through), then there is no loss beyond the very slight mechanical energy needed to operate the pump at the higher rate. Well, this reminded me of another idea. As long as the peak temperature of the water/steam is limited, then oil can be circulated with the steam/water without separation. This has been done before. As I recall, the early Doble steam cars did this for a while. However, they did show some problems that I suspect were caused by excessive steam temperatures. Taking the temperature down a notch while using very good synthetic oil should solve the problem (I speculate). Maintaining a steam generator of the type described here would allow for never superheating the steam - so the oil would be positively protected from excessive temperatures. Yeah, efficiency would be capped, but dry saturated steam can show good results - especially at higher pressures. NOTE: However, the steam/water separator should do well to remove most of any lube oil. Therefore, the saturated steam taken off the top could be shunted through a superheater to increase efficiency.

    An interesting dynamic on heat transfer is counterintuitive to many. Consider the following: compare two steam generator tubes (one steel and one copper) that have the same dimensions. Now, with all else equal, which one will generate steam at the higher rate when heated by the same furnace? The answer is the rate will not differ by much. The higher thermal conductivity of copper is not a significant factor here because it's the low rate of heat transfer from the flue gases to the outer tubing wall that is the bottleneck. It turns out the temperature of the inside tube wall is on the order of only 10F higher than the steam/water flowing within. The outside tube wall temperature for the copper might be just 2-3 degrees F hotter than the inner wall temperature. The outside tube wall temperature for the steel will be higher than the copper, but only on the order of 20-30 degrees F (based on the thermal conductivity of copper being roughly 10 times higher than carbon steel). So, this lower outer tube temperature for copper makes negligible difference to heat transfer rates when the furnace temperature is 1500F. Now, if one were using a liquid heat transfer fluid to generate steam, or using much lower temperatures, then copper might make sense - but not when using a furnace directly. Anyway, considering this, then it seems reasonable to circulate oil with the water/steam provided the steam generator tubing is always flooded with some water thereby making superheating impossible. If the pressure is set at say 300 psig, then the temperature of the oil could never rise above the saturation temperature for water at this pressure (which is 421F). Many synthetic lube oils can handle this temperature. Yeah, the efficiency of the system would be limited, but I've shown that it's possible to achieve 10-12% overall thermal efficiency at this steam temperature - with a good design. If the heat from the system is the main energy requirement, then efficiency doesn't matter so much. However, again, optimizing efficiency is important because good design can increase the efficiency many fold over poor design - and while being simpler mechanically! For example, the steam engine system that started this thread is quite literally 2-3% efficient in converting the chemical energy in wood to shaft work. A safer, simpler, and much more compact system can increase efficiency four fold - and it can be practical in the sense that it need be fueled only once or twice daily while it runs unattended to provide heat and electricity. The most recently described steam system proves it's possible to do this - after all, it was constructed and operated over a period of four years to heat and power a modern home.
    Last edited by buenijo; 06-16-2019 at 11:08 AM.
    “The beginning of wisdom is to call things by their proper name.” - Confucius.
    "When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it." - Frederic Bastiat
    "Being well adjusted to a sick society is not a measure of health." - Jiddu Krishnamurti

  4. #213
    “The beginning of wisdom is to call things by their proper name.” - Confucius.
    "When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it." - Frederic Bastiat
    "Being well adjusted to a sick society is not a measure of health." - Jiddu Krishnamurti

  5. #214
    Quote Originally Posted by buenijo View Post
    I would like to buy one, or a build one. Doesn't appear that it's available in the US.

  6. #215
    Just found a lead on a 7 HP vertical single, like the one in the OP, in working condition for a decent price.

  7. #216
    Quote Originally Posted by Anti Federalist View Post
    Just found a lead on a 7 HP vertical single, like the one in the OP, in working condition for a decent price.
    This thread is too long to review, so are you talking about a Lister engine?

    And if is, is it Limey or Injun built?

    Edit:

    Oh, hell.

    I just reviewed the OP.

    Nevermind.

    Steam, huh?



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  9. #217
    Quote Originally Posted by sparebulb View Post
    This thread is too long to review, so are you talking about a Lister engine?

    And if is, is it Limey or Injun built?

    Edit:

    Oh, hell.

    I just reviewed the OP.

    Nevermind.

    Steam, huh?
    The Limey Listers are going for a small fortune these days, since they have been banned for import by EPA fatwa

    Yup, steam...or the old "make and break engines", those have potential as well.

  10. #218
    Dan Gelbart is a rather interesting fellow. Here is something he threw together in his free time:

    Through lives and lives shalt thou pay, O' king.

    Freedom will be stolen from you in a heartbeat if you do not behave as a wild and ravening beast pursuant to its protection.

    "Government" is naught but a mental construct, a script to which people meekly accept and play out their assigned roles by those with no authority to dictate such.

    Pray for reset.


  11. #219
    Quote Originally Posted by Anti Federalist View Post
    The Limey Listers are going for a small fortune these days, since they have been banned for import by EPA fatwa

    Yup, steam...or the old "make and break engines", those have potential as well.
    You can get the Injun ones, but they require some post purchase fiddling, since to get around the EPA fatwas, they have to be imported as "air compressors" and then the fule system added after the fact.

  12. #220
    Quote Originally Posted by osan View Post
    Dan Gelbart is a rather interesting fellow. Here is something he threw together in his free time:

    Electronic timing on single stage steam engine...fascinating.

    Was this his invention?

  13. #221
    Quote Originally Posted by Anti Federalist View Post
    The Limey Listers are going for a small fortune these days, since they have been banned for import by EPA fatwa

    Yup, steam...or the old "make and break engines", those have potential as well.
    You can get single- and double-lung hit-or-miss engines that are made right here in the USA. Arrow Engines is a primary source. We were to be the sole representatives for sales and service for the states of WV and PA. Gary, my "partner" was one of those perpetually struggling losers who, as it turned out, was more afraid of success than he was covetous of it. Just as I was getting the relationship established with Arrow, that $#@! tells me that things were happening "too fast" and he pulled out, retired, and moved to Florida. $#@!. What pissed me off most was that he asked ME to run the business for him. All that jerkoff had to do was sit back and count money, and it likely would have been substantial amounts. I SO dislike stupid, timid, do-nothing people who shy away from success because it asks of them just a smidge of committed effort.

    My indigestion aside, Arrow makes engines that can run for years, virtually non-stop, and are extremely fuel-efficient.

    You're welcome.
    Through lives and lives shalt thou pay, O' king.

    Freedom will be stolen from you in a heartbeat if you do not behave as a wild and ravening beast pursuant to its protection.

    "Government" is naught but a mental construct, a script to which people meekly accept and play out their assigned roles by those with no authority to dictate such.

    Pray for reset.


  14. #222
    Quote Originally Posted by Anti Federalist View Post
    Electronic timing on single stage steam engine...fascinating.

    Was this his invention?
    I suspect so.
    Through lives and lives shalt thou pay, O' king.

    Freedom will be stolen from you in a heartbeat if you do not behave as a wild and ravening beast pursuant to its protection.

    "Government" is naught but a mental construct, a script to which people meekly accept and play out their assigned roles by those with no authority to dictate such.

    Pray for reset.


  15. #223
    Just seeing this now...nifty, thanks.

  16. #224

    TINY TECH INDIA UPDATE

    The following is a video of one of Tiny Tech India's steam engines. It describes a very clever mechanical "Buckeye" speed governor system. It is difficult to understand the description. The basic idea is the combination of spring tension and the force on the flyweights act to rotate the eccentric to adjust the steam valve cutoff as rpm changes. This is more efficient than using a governor to position a steam throttle valve. Very clever indeed. See description of operation here: https://www.loc.gov/resource/rbpe.13803100/?st=text





    Video showing complete assembly of one of their engines. Interesting to see the eccentric includes ball bearings. I am not sure why they installed the compression rings on the crosshead piston(?) - to lessen crankcase oil from escaping perhaps? It seems desirable to remove these to lessen friction. I can't help but wonder if the compression rings were placed as a matter of habit.



    I now believe a good CHP steam engine system could be had using one of their compounded engines. It could show reasonably high efficiency (on the order of 10% conversion of fuel lower heating value to AC electricity), and the ability to drive a generator head directly using one of their governors is a big plus. The improvements Mr. Desai has made to his engines over the years include: (1) installing steam cylinder onto small stationary diesel engine crankcases using the lower trunk piston as a crosshead guide for the steam piston, (2) using gun metal steam cylinder liner, (3) replacing slide valves with piston valves, (4) providing the Buckeye speed governor. The manual cylinder lubrication pump is undesirable and should be replaced with a displacement lubricator or mechanically driven oil pressure pump.
    Last edited by buenijo; 03-31-2020 at 07:40 PM.
    “The beginning of wisdom is to call things by their proper name.” - Confucius.
    "When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it." - Frederic Bastiat
    "Being well adjusted to a sick society is not a measure of health." - Jiddu Krishnamurti



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  18. #225
    A simple and crude, but fairly high output wood fired monotube steam generator. While not efficient, it shows that a surprisingly simple system can generate steam at a high rate. This unit produced steam at a rate of 3 kg per minute. For reference, Mr. Desai's 6 hp compound steam engine consumes 1 kg of steam per minute at full power.

    Last edited by buenijo; 03-30-2020 at 08:24 AM.

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