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

  1. #151

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    One way to get high efficiency in a piston steam engine is to use a compounded piston steam engine with steam reheat and heat regeneration. Three cylinders or more is preferable. There are many ways to go about this, but all have the same basic goal: expand high pressure steam through the engine while reheating the steam before it expands into the next cylinder - this boosts temperature (and therefore pressure) to increase engine output - then regenerate the excess heat back into the system. Thermodynamically the ideal state of affairs is heating the steam as it moves through the engine such that the steam temperature is never allowed to drop below max, fully expanding the steam down to condenser pressure, then sending the very high temperature but low pressure steam through an air preheater that is able to cool the steam down to saturation, sending the heated air to the furnace, then sending the low pressure saturated steam to the condenser (note that in practice it may not be possible to reheat the steam fully to the prior peak temperatures as this would generate steam at the final exhaust that contains so much superheat that it all could not be regenerated - so the goal is to reheat up to that point). This is basically what modern steam power plants do to approach 50% net thermal efficiency. There is no physical reason why a piston engine cannot be devised to see similar performance, but it would be a nightmare to actually build something like this. A two cylinder compound engine can see a net efficiency equal to a conventional small wood gas engine system with steam at 500 psig and less than 600F if it were a good engine and made good use of this strategy. So, it would have all the benefits of a small wood gas engine system with all the advantages of steam power (quiet, wider range of fuel, cleaner combustion, slow moving and long lasting, all heat available at condenser for ease and efficiency in cogeneration). Still, this option is not practical without access to the necessary hardware. For this reason biomass gasification for fueling internal combustion engines is the practical alternative for making use of biomass for cogeneration.

    NOTE: A strategy that has been used in piston steam engine systems of the past was to transfer the heat in the system to a refrigerant part way through the cycle. This boosts the average pressure in the engine. Below a certain steam pressure, the higher friction in a piston engine can lead to diminishing returns. This is why small piston steam engines generally do not expand the steam below a certain value (generally keeping steam pressure well above atmospheric while in the cylinder). Well, this corresponds to a temperature on the order of 250F or higher. What can be done (and has been done) is to use the steam condenser to heat and vaporize a refrigerant under pressure. This high pressure refrigerant can then be used to drive another piston (or two). This keeps cylinder pressures very high to minimize friction losses, and allows for extending engine operation to much lower temperatures. I am aware of this strategy applied to a large stationary piston steam engine power plant that increased overall efficiency by about 50%. Another strategy that was used on the Titanic was to put a low pressure turbine on the exhaust of their compounded piston steam engines. This also increased efficiency on the order of 50%. Unfortunately, small turbines are not generally efficient, especially at low pressure. So, a low power (small) system could use the former strategy to boost efficiency. Still, a better strategy for very small systems is to increase efficiency by making full use of the heat from the system for other applications.
    Last edited by buenijo; 06-17-2014 at 10:10 PM.



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  3. #152

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    Looks like money is getting thrown at small scale steam power:

    http://www.vdg.no/?menuid=16

    http://www.vdg.no/index.php?articleid=12

    I can't find specifics on the engine, but if an established engine manufacturer is behind this, then it's very promising.

    Addendum: This appears to be an organic rankine cycle using n-pentane as the working fluid.
    Last edited by buenijo; 02-14-2014 at 04:17 PM.

  4. #153

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    Quote Originally Posted by noxagol View Post
    I'm thinking I might try to make a steam engine now.

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  5. #154

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    Making a steam engine isn't terribly difficult. Making a useful steam engine would be difficult and expensive. Please consider a charcoal or wood gas engine system instead. You will be surprised how easy it is to make a small charcoal gasifier that can be useful. You can even make it compact enough to power a bicycle and it's efficient... can get 15-20 miles per pound of charcoal on a bike/scooter in city driving and it's possible to supplement the charcoal with biomass like wood pellets or chips to extend the range of the charcoal further.

    Last edited by buenijo; 11-24-2013 at 12:46 PM.

  6. #155

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    Quote Originally Posted by Henry Rogue View Post
    Hey, that almost looks like Kinzers PA.
    Through lives and lives shalt thou pay, O' king.

  7. #156

  8. #157

    Default Heat Battery for Steam Engine

    Sending the exhaust of a steam engine into a container of a strong hygroscopic salt solution such as sodium hydroxide or calcium chloride will cause the solution temperature to rise. The effect can be strong enough to heat the steam generator used to power the engine itself. In fact, small locomotives have been powered using this principle: http://www.aqpl43.dsl.pipex.com/MUSE.../soda/soda.htm . Note that the vessel containing the solution is not pressurized. Rather, the solution surrounds the steam generator tubing that is pressurized. The system is silent during operation and with no emissions. The vessel when heated for regeneration will release the water previous absorbed in the form of superheated steam.
    Last edited by buenijo; 06-17-2014 at 10:13 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

  9. #158

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    Quote Originally Posted by buenijo View Post
    Making a steam engine isn't terribly difficult. Making a useful steam engine would be difficult and expensive. Please consider a charcoal or wood gas engine system instead. You will be surprised how easy it is to make a small charcoal gasifier that can be useful. You can even make it compact enough to power a bicycle and it's efficient... can get 15-20 miles per pound of charcoal on a bike/scooter in city driving and it's possible to supplement the charcoal with biomass like wood pellets or chips to extend the range of the charcoal further.

    I like the idea of a wood fired bike.. I'd love to take the smell of a stove with me. Sadly I don't think I'd get very far without being pulled over .

  10. #159

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    I just considered an interesting configuration for the "caustic soda steam engine".

    SUMMARY: Regenerate the solution (while the engine is running) at a low rate equal to the average system power. This will allow for a much smaller quantity of solution to store energy for transients in engine power while allowing a small, simple, low power furnace.

    Heating the solution during engine operation can provide a system with the benefits of a fire tube boiler (high energy storage capacity), but without the disadvantages of a large (and expensive) pressure vessel. Rather, the pressure vessel is a monotube steam generator contained within. So, the system can be heated at a low rate, but provide a store of energy much like a fire tube boiler to take the engine to higher power levels as required. The quantity of solution required would be much smaller, and the concentration can be maintained high for higher steam temperatures and pressures. Also, the superheated steam vented can be used to preheat boiler feed water for higher efficiency. Add a recuperator that uses furnace exhaust gases to preheat combustion air for even better efficiency.

    I can't think of a practical application for this, but any system that otherwise calls for a modest fire tube boiler might be used. It makes sense only where the output of the system is likely to change frequently. A small steam boat might make use of it. As long as the average output required is very low, then the furnace required to support the system can be a low output. This would make it possible to use a small and simple updraft biomass furnace. While not necessarily practical, I think such a system could be fairly simple.
    Last edited by buenijo; 01-24-2014 at 01:04 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

  11. #160

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    Quote Originally Posted by luctor-et-emergo View Post
    I like the idea of a wood fired bike.. I'd love to take the smell of a stove with me. Sadly I don't think I'd get very far without being pulled over .
    In my opinion, the most practical way to fuel a motorcycle (i.e. "bike") with wood is to start by not trying to fuel it 100% with wood. Rather, a small wood gasifier can be used to supplement fuel to the engine. This can increase MPG on gasoline fuel many fold. Here's how: the engine in a road vehicle normally operates at a small fraction of its rated power. Therefore, a small wood gasifier can provide nearly all the fuel during this time. For example, a typical motorcycle requires only about 10 hp to maintain highway speeds on level ground. Therefore, a gasifier need not provide more fuel gas than required to maintain 10 hp. Gasoline fuel can be used during acceleration and hill climbing to boost engine power as required. A smaller gasifier requires a proportionally smaller filter and cooling system as well. Therefore, configuring a bike in this manner could be more practical as compared to the 100% wood gas conversion.
    Last edited by buenijo; 12-15-2013 at 09:19 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

  12. #161

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    Engineer775 of YouTube is staring an organic rankine cycle project using an automotive scroll a/c compressor:

    http://www.youtube.com/watch?v=roxTv1Xtaps
    “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

  13. #162

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    Quote Originally Posted by buenijo View Post
    Engineer775 of YouTube is staring an organic rankine cycle project using an automotive scroll a/c compressor:

    http://www.youtube.com/watch?v=roxTv1Xtaps
    Interesting....

  14. #163

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    Quote Originally Posted by Acala View Post
    I live in literally one of the sunniest places on earth and have a 2kw photovoltaic system up and running on my house. So I am bullish on solar energy. BUT it has some seroous drawbacks. The biggest is that it will only produce power during the hours of peak daylight. So how are you going to power your freezer, lights, ham radio, ac, furnace, whatever from late afternoon to mid-morning?

    Batteries suck for long-term off-grid purposes. They are expensive, heavy, toxic, have a limited lifespan, and cannot be easily improvised.

    I have given serious thought to the idea of storing solar energy and the options are not very good. If you have lots of land with a significant elevation gradient, and plenty of water, you can set up a system that pumps water into a reservoir on the high end of the property using solar energy during the day and then at night drain the water back down to a lower reservoir through a turbine at night. But I don't have much water.

    You could also use solar to electolyse water, store the hydrogen, then burn it in an internal combustion engine to run a generator. But there are so many steps in the process it becomes very inefficient. And hydrogen is a bitch to work with.

    The best option I have come up with for sunny, dry climates is storing solar energy as thermal energy during the day and then extracting it at night with a heat engine. For example, you could use solar energy to heat a very large concrete block, solar oven style, during the day and then use multiple Sterling engines to run off the heat contained in the block and turn a generator during the night. This would be simple and efficient, but fixed in place, and lots of moving parts because of the multiple sterling engines. And still impacted by cloudy days.
    How about compressing air during the day?
    Twitter: B4Liberty@USAB4L
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  15. #164

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    Quote Originally Posted by Brian4Liberty View Post
    How about compressing air during the day?
    Too many losses, and the energy density of compressed air is too low.
    “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

  16. #165

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    Quote Originally Posted by buenijo View Post
    Too many losses, and the energy density of compressed air is too low.
    I like the simplicity and chemical safety (nothing toxic, hard to acquire or exceptionally flammable) of the idea. No idea how it compares to other storage options.

    Those compressed air vehicles seemed pretty cool.

    http://reviews.cnet.com/8301-31346_7...e-air-vehicle/

    http://reviews.cnet.com/8301-13746_7-10187871-48.html
    Last edited by Brian4Liberty; 01-03-2014 at 10:10 PM.
    Twitter: B4Liberty@USAB4L
    "Foreign aid is taking money from the poor people of a rich country, and giving it to the rich people of a poor country." - Ron Paul
    "Beware the Military-Industrial-Financial-Corporate-Media-Government Complex." - B4L update of General Dwight D. Eisenhower
    "Debt is the drug, Wall St. Banksters are the dealers, and politicians are the addicts." - B4L
    "Totally free immigration? I've never taken that position. I believe in national sovereignty." - Ron Paul


    The views and opinions expressed here are solely my own, and do not represent this forum or any other entities or persons.

  17. #166

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    Quote Originally Posted by buenijo View Post
    Too many losses, and the energy density of compressed air is too low.
    The post I responded to had an option of storing energy via water tanks. How does the energy compare with the same size storage tank? (Water vs compressed air).
    Twitter: B4Liberty@USAB4L
    "Foreign aid is taking money from the poor people of a rich country, and giving it to the rich people of a poor country." - Ron Paul
    "Beware the Military-Industrial-Financial-Corporate-Media-Government Complex." - B4L update of General Dwight D. Eisenhower
    "Debt is the drug, Wall St. Banksters are the dealers, and politicians are the addicts." - B4L
    "Totally free immigration? I've never taken that position. I believe in national sovereignty." - Ron Paul


    The views and opinions expressed here are solely my own, and do not represent this forum or any other entities or persons.

  18. #167

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    Quote Originally Posted by Brian4Liberty View Post
    The post I responded to had an option of storing energy via water tanks. How does the energy compare with the same size storage tank? (Water vs compressed air).
    Storing appreciable energy in a water tank requires the tank to be highly elevated and/or having a lot of water. The energy stored is proportional to both the mass of water stored and the elevation. So, doubling the elevation would reduce the amount of water required to store a given quantity of energy by half. Generally, this prospect is viable only where one has a large amount of land of varying elevation to provide the required elevation and huge mass of water. I'll give you an idea of how much water is required. One hp is 550 foot pounds per second. If you have an elevation of 100 feet, then 5.5 pounds of water must flow from this elevation per second. Over an hour, that's about 2370 gallons of water. After considering the losses involved, this would net you about one half KWh of electricity (500 watt hours, or 500 watts for one hour). This same electricity is provided by a lead acid battery weighing about 35 pounds, or a lithium iron phosphate battery weighing under 20 pounds.

    Note that the elevation is the main limitation in most cases. If I had more than a few hundred feet to play with, only then would I start to think about it seriously. Compressed air is a better prospect, but even that falls short. In my opinion, the only practical means to store appreciable energy for the production of electricity (assuming individual/residential scale) is (1) a battery, or (2) a fuel (might include biomass such as wood). Heat can be stored in a thermal mass such as water, but without high temperatures any attempt to convert the heat to electricity will be very inefficient.
    “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

  19. #168

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    Quote Originally Posted by buenijo View Post
    Storing appreciable energy in a water tank requires the tank to be highly elevated and/or having a lot of water. The energy stored is proportional to both the mass of water stored and the elevation. So, doubling the elevation would reduce the amount of water required to store a given quantity of energy by half. Generally, this prospect is viable only where one has a large amount of land of varying elevation to provide the required elevation and huge mass of water. I'll give you an idea of how much water is required. One hp is 550 foot pounds per second. If you have an elevation of 100 feet, then 5.5 pounds of water must flow from this elevation per second. Over an hour, that's about 2370 gallons of water. After considering the losses involved, this would net you about one half KWh of electricity (500 watt hours, or 500 watts for one hour). This same electricity is provided by a lead acid battery weighing about 35 pounds, or a lithium iron phosphate battery weighing under 20 pounds.

    Note that the elevation is the main limitation in most cases. If I had more than a few hundred feet to play with, only then would I start to think about it seriously. Compressed air is a better prospect, but even that falls short. In my opinion, the only practical means to store appreciable energy for the production of electricity (assuming individual/residential scale) is (1) a battery, or (2) a fuel (might include biomass such as wood). Heat can be stored in a thermal mass such as water, but without high temperatures any attempt to convert the heat to electricity will be very inefficient.
    Yeah, I wouldn't try to pump water uphill as a way to store the energy for later. Plus there is the size requirements as you pointed out. And you can't compress water.

    Water and an appropriate property? All you just need is a year-round stream or waterfall.
    Twitter: B4Liberty@USAB4L
    "Foreign aid is taking money from the poor people of a rich country, and giving it to the rich people of a poor country." - Ron Paul
    "Beware the Military-Industrial-Financial-Corporate-Media-Government Complex." - B4L update of General Dwight D. Eisenhower
    "Debt is the drug, Wall St. Banksters are the dealers, and politicians are the addicts." - B4L
    "Totally free immigration? I've never taken that position. I believe in national sovereignty." - Ron Paul


    The views and opinions expressed here are solely my own, and do not represent this forum or any other entities or persons.

  20. #169

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    Quote Originally Posted by Brian4Liberty View Post
    Water and an appropriate property? All you just need is a year-round stream or waterfall.
    Or you could say property with appropriate water, .
    “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

  21. #170

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    I discuss an alternative means to distill water efficiently using heat that is cascaded in multiple stages. I am making this thread to clarify the configuration as I believe it has potential for some applications... and it's interesting.

    The simplest way to introduce the idea is to provide a straightforward example. Consider a pressure cooker. Fill the pressure cooker with water that you wish to distill. Now, place a nonpressurized vessel next to the pressure cooker, and fill this vessel with water from the same source. Place a large copper tubing coil at the bottom of this vessel. The top of this tubing coil is connected to the top of the pressure cooker. The bottom of the coil is connected to the bottom of the vessel via a needle valve. This needle valve is throttled to keep sufficient pressure in the pressure cooker (high enough for high temperature, but not so high that the relief valve lifts) - or just put a relief valve at the end of the tube.

    Now apply heat to the pressure cooker. The water in the pressure cooker will increase in temperature and steam will finally form and pressurize the vessel. The steam will fill the copper tubing. Since the steam temperature is well above 212F, then the water surrounding the copper tubing coil will boil. The steam in the copper tubing will condense to water in the process, and this water will drain from the end of the tube via the valve provided. The steam released from the nonpressurized vessel can be directed through a condenser, and this water can also be collected. Therefore, a source of heat that would have normally produced x amount of distilled water can be made to produce nearly 2x amount of distilled water through "staging".

    Consider that a system can be designed for space heating purposes that also generates distilled water at a high rate. Using 2 or 3 stages, a furnace could be used to heat the first stage, then generate steam at the final stage that can be used for heating applications. This can not only purify a local water source, but also allow for reprocessing water that is otherwise discarded as waste (recycling water through distillation). This steam can also be used for air conditioning applications using the adsorption systems I have discussed elsewhere.

    NOTE: Rain water catchment and storage for water in the remote/off grid setting is the most practical alternative I've seen for securing water in a remote setting (for most regions). Still, this distillation approach is interesting, and might be practical for a desert region to recycle water efficiently using solar thermal energy.
    Last edited by buenijo; 07-13-2014 at 04:07 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

  22. #171

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    http://www.internationalsteam.co.uk/...m/modern50.htm

    Interesting discussion on work done during the 1900's to increase the performance of steam locomotives. Most of the advances seems to have been achieved after Diesel took over the industry. Evidence suggests that the improved efficiency and lower labor costs of a modern steam locomotive, along with the much lower fuel costs of coal vs. Diesel, would make modern steam more economical. Advancements that made the most contributions include clean and efficient combustion of coal fuel using gasification, higher steam temperature and higher pressure with both compounding and heat regeneration to increase thermal efficiency, low friction with improved seals and use of roller bearings, superior insulation, streamlined steam exhaust, and advanced boiler chemistry. The average overall efficiency of steam locomotives in the U.S. was a paltry 6%. Modern locomotives actually constructed and operated have shown 14% overall efficiency. Third generation systems are projected to see 21% thermal efficiency. With steam condensing, the system is project to achieve 27% efficiency.

    I suspect that steam made little advancement over a long period quite simply because there was no competition. It was not until Diesel took over the industry that any effort was made to optimize the steam locomotive, and the funding available was very limited. All evidence suggests that modern steam can be superior to Diesel.

    NOTE: See the description of the new fire box design for modern coal fired locomotive. A minor modification was necessary to achieve clean combustion. Anyone who has made even a brief study of solid fuel gasification could have done this. I am somewhat bewildered that this was not done far sooner (?). The only explanation I can arrive at is that people tend to get stuck in a way of doing things (if it ain't broke, then don't fix it), and a corporate mentality might have contributed. Most people including mechanics and engineers rarely challenge the status quo. The only changes that were made were to (1) make a deep coal bed, (2) provide steam with the intake air, (3) provide most of the air for combustion via a secondary path (not through the coal bed). Before, 90% of the air was forced through the coal bed. Gasification took place, but most of the air did not react with the charcoal. It combusted any combustible gases later on in the fire box, but forcing air at such a high rate entrained particles and led to dirty exhaust. Also, some conditions would lead to insufficient air for full combustion, and this would cause smoky exhaust. Not providing the excess air through the coal bed might have led to clinker formation on the grate where high temperatures cause ash to melt. Excess air would have taken the temperature down to prevent this clinker formation (but caused the other problems). Adding steam to the primary air helps to moderate the temperatures, and the steam reacts with the hot carbon to make more CO and H2 fuel gas. The final result is that air moves through the fuel bed at 1/3 the rate as before, and there is always excess air provided for full combustion... so particulates are not entrained with the air and there is no smoke... the system also gets higher efficiency. Actually, the combination of gasifying the coal and doubling the thermal efficiency means the actual rate at which primary air was forced through the coal bed was on the order of 6 times less than before. This is why a modern coal fired steam locomotive would be a great deal cleaner then the old systems.

    I have done testing with a simple updraft biomass gasifier furnace. It is EASY to control these units with respect to firing rate. Containing the fuel in a well insulated base allows for controlling the rate of combustible gas formation by simply controlling the rate at which primary air (the air moving through the fuel bed) is admitted. For full combustion, simply add sufficient secondary air to eliminate smoke on exhaust. I mean, it really is simple, and my experience with this has me shaking my head about how much smoke and soot was thrown out of old steam locomotives unnecessarily. The low thermal efficiency of the engines were also a problem, and perhaps forcing air at such a high rate was done just to get the desired power (soot be damned).

    Hmmm... I wonder what it takes for an individual to buy coal in bulk? I have no qualms at all about running an off grid home on a coal fired steam engine. I think I should build such a system optimized for coal fuel and christen it the "Al Gore", .
    Last edited by buenijo; 07-14-2014 at 07:21 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

  23. #172

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    A recent quote at a coal mine in Kansas showed $65 per ton of bituminous coal for local pick up! At that price an efficient steam engine that made full use of the waste heat could power a modest off grid home for about $1 in fuel costs per day. Such a system could use coal or wood, and any dry biomass that can feed by gravity down the hopper to the hearth. The configuration I am considering is an updraft gasifier furnace with a grate and ash pit. Primary air is forced, and secondary air is by draft. Any fuel that gets into the insulated hearth region just above the grate will be pyrolysed, and any carbon remaining on the grate will be consumed by the air entering the system below the grate. Ash falls through the grate.
    “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

  24. #173

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    Good discussion of modern steam locomotives.

    http://www.csrail.org/index.php/rese...steam-advances

    Again, it's fascinating to me how the performance of steam locomotives can be improved so dramatically using seemingly simple technologies. The changes to traditional steam locomotives that have been demonstrated include a full doubling of overall efficiency, efficient and near smoke free combustion of coal, a doubling of power/weight, and a fantastic reduction of boiler maintenance costs. The boiler water treatment increases boiler life to equal the operating life of the locomotive.

    The site also mentions the use of torrefied biomass to generate "biocoal". This is an interesting prospect. The heat released in the process of making the product can be put to use in stationary applications. The charcoal that remains has a lower ash, sulfur, and heavy metal composition than coal.

    Good link on the topic: http://www.trainweb.org/tusp/porta.html
    Last edited by buenijo; 08-22-2014 at 12:12 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

  25. #174

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    http://www.catskillarchive.com/rrextra/chapt25.Html

    Excellent discussion of the physics of steam engines, and without a lot of technical jargon.

    NOTE: I like the way this discussion describes how steam at higher pressure allows for higher efficiency steam engines. Consider a cylinder that admits 100 psi steam with 50% cutoff for 2 fold expansion. The average cylinder pressure is roughly 85 psi. Now consider the admission of 200 psi steam with 25% cutoff for 4 fold expansion. The average cylinder pressure is roughly 120 psi. While we used half the volume of steam in the second case, we must note that steam at 200 psi has twice the mass and energy as steam at 100 psi. Therefore, the amount of steam energy used in both cases is roughly equal. However, we got nearly 50% more work in the second case, which implies that efficiency increases by nearly 50%. Now, there are other dynamics at play that make this a simplistic conclusion - but, it certainly increases efficiency significantly. The same effect can be had in principle by using lower pressure steam with higher expansion ratios. However, the mean effective pressure starts to drop quickly, and this allows friction to represent an increasing proportion of the work load (hence, efficiency increases are limited there). Note also that the temperature difference of the steam as it expands in the cylinder can also be used as a proxy for the efficiency. Steam temperature falls at it expands, and this drop in temperature is proportional to the work done by the steam on the piston and crank. Of course, there are many other variables to consider, but this correlation is important to note (correlation between increased expansion ratio and larger temperature difference - and increased efficiency - ever heard of the Carnot efficiency of a heat engine?). See post #179 for a continued discussion on the efficiency of piston steam engine systems.
    Last edited by buenijo; 02-17-2014 at 05:53 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

  26. #175

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    http://reneweconomy.com.au/2013/retu...or-solar-34662
    http://www.terrajoulecorp.com/unexpe.../how-it-works/
    http://www.terrajoulecorp.com/unexpe...hat-it-is-not/

    I've been aware of this for a while. I like the idea. In my opinion, it's not suitable for micro scale CHP, but I think it has promise for medium scale installations - and this seems to be the target market.

    The way I understand this system based on what I read, and extrapolating from my knowledge of steam power, is that a two cylinder compounded engine is used. These systems provide steam at high pressure to a small cylinder where the steam expands, then exhausts the lower pressure steam to a larger cylinder for additional expansion before finally exhausting to the condenser. The system here uses Skinner unaflow engines that were manufactured as late as the 1940's. These engines had a reputation for high efficiency, and extreme reliability. During the day when the solar concentrators are generating high pressure steam, then the steam is sent to the high pressure cylinder. The larger low pressure cylinder is not used when additional energy storage is desired. Rather, the steam is exhausted to a large insulated steel pressure vessel filled with water. The steam exhaust raises the temperature and pressure of the water. When sufficient energy storage is achieved, or whenever higher power is desired, then the low pressure cylinder may be used in addition to the high pressure cylinder. When solar is not available (such as at night), then high pressure steam is not available, and the system draws low pressure steam from the pressure vessel by flashing water to steam to drive the low pressure cylinder. Turns out that there is negligible loss of efficiency by going this route. That is, while the engine is most efficient when full expansion is achieved with both cylinders, the energy otherwise used to drive the low pressure cylinder is stored in the pressure vessel for later use. The system achieves 24 hour power generation from solar without batteries, and the storage system is the most cost effective I've yet seen.

    The discussions on the web site about the benefits of piston steam engines in lower power ranges are spot on. Turbines are great for high power and constant output. Below a certain power, the piston steam engine is more efficient, and the efficiency of piston steam engines vary little as the power varies. So, anything below about a megawatt favors the piston steam engine.

    http://www.greentechmedia.com/articl...Energy-Storage (See the comments by the CEO of the company in the COMMENTS section of the page)

    Turns out that the steam pressures and temperatures achieved with this system, along with using irrigation water pumped by the system to cool the condenser, will allow for good efficiency. The CEO claims 30% cycle efficiency with 70% concentrator efficiency, and this would allow for 20% overall conversion of solar energy to work. More important, the efficiency of the system is not important - it's all about COST. In my opinion, this is where this system shines. I think it's brilliant.
    Last edited by buenijo; 04-05-2014 at 11:42 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

  27. #176

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    Quote Originally Posted by buenijo View Post
    The discussions on the web site about the benefits of piston steam engines in lower power ranges are spot on. Turbines are great for high power and constant output. Below a certain power, the piston steam engine is more efficient, and the efficiency of piston steam engines vary little as the power varies. So, anything below about a megawatt favors the piston steam engine.
    This is largely because turbines are efficient in only a comparatively very narrow range of operating speeds. At lower speeds the slip losses are large and lots of usable energy goes out the pipe. The Tesla turbine is perhaps the worst in this respect having miserable startup characteristics and is well served by a vein-type starter turbine to get it going. Because piston engines are perfectly sealed for all practical purposes, the minimal effective energy charge to produce power is far smaller than for turbines, which leak tons of energy until they come up to snuff. Because of the good seal at all operating speeds, piston engines run with similar efficiencies over a very broad operating range. Turn them on and off often... no big deal when compared with turbines, all else equal. In this they are far more flexible, the price being mechanical complexity and the attendant reliability reductions.
    Through lives and lives shalt thou pay, O' king.

  28. #177

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    Quote Originally Posted by osan View Post
    This is largely because turbines are efficient in only a comparatively very narrow range of operating speeds. At lower speeds the slip losses are large and lots of usable energy goes out the pipe. The Tesla turbine is perhaps the worst in this respect having miserable startup characteristics and is well served by a vein-type starter turbine to get it going. Because piston engines are perfectly sealed for all practical purposes, the minimal effective energy charge to produce power is far smaller than for turbines, which leak tons of energy until they come up to snuff. Because of the good seal at all operating speeds, piston engines run with similar efficiencies over a very broad operating range. Turn them on and off often... no big deal when compared with turbines, all else equal. In this they are far more flexible, the price being mechanical complexity and the attendant reliability reductions.
    Yes, very good description of the problem. The quality of steam engines you described shows itself as a flat torque profile at all speeds. The qualities of the turbine are great for very large scale systems that run one or more large turbines to provide a base load for the grid. This is good for centralized power. The qualities of the piston steam engine are ideal for micro to medium scale distributed energy systems.
    Last edited by buenijo; 02-05-2014 at 09:25 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

  29. #178

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    EXCELLENT reference on piston steam engines: "Steam Engine Principles and Practice"

    https://archive.org/stream/steamengi...ge/n0/mode/1up
    “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

  30. #179

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    The book I referenced in the previous post has very good discussions about how to optimize efficiency in piston steam engines. While I didn't learn much from the book, the information available took me a while to gather piecemeal from other sources. So, this is a very good single reference source for those who wish to learn the subject of piston steam engines - probably the single best source I've yet seen.

    Consider the simple counterflow, double-acting, piston steam engine with slide valve that uses saturated or very slightly superheated steam at modest pressures. These kind of engines include the engine shown in the original post of this thread, the Mike Brown engine, and the engines made by Tiny Tech India that were discussed earlier in this thread. A major loss in these kinds of engines is condensation of steam in the cylinder. The steam exhausted from the cylinder moves through the same passageways through which the high pressure steam is admitted during the power stroke. What happens is this low temperature steam cools the metal. So, the hot incoming steam reheats it, and during the process a lot of the incoming steam is condensed. Well, this means more steam is consumed to achieve the same pressure effect - more steam means more heat for the same effect, and therefore lower efficiency. Furthermore, some of the condensation in the cylinder will flash to steam when the valve opens up the cylinder to the lower exhaust pressure, and this can give the cylinder head a particularly thorough cooling. This tends to aggravate the problem of incoming steam condensing. For this reason, putting a condenser on these simple engines with high vacuum does not increase efficiency all that much since the very low vacuum will flash the condensate effectively and cool the cylinder head. It's a catch 22 - one can try to boost the low efficiency by decreasing the back pressure on the engine with a condenser vacuum, but the condensate in the cylinder flashes to cool the cylinder head. More incoming steam condenses, and this increases steam consumption (and therefore dampens any gain in efficiency due to vacuum). It might boost efficiency, but it's generally not worth the additional hardware for these simple engines. For this reason the simple engines were used when steam heating was desired since low thermal efficiency doesn't matter much here. A small engine of this type typically sees a thermal efficiency of around 6% not including boiler losses. So, even a good small scale steam engine system using this engine would see an overall efficiency of 4-5% at best. This isn't so bad if the primary purpose is something like space heating a home, but don't expect to generate much electricity or shaft power. Larger engines of the same design are often better since the ratio of cylinder volume to surface area lessens condensation, and lessens cylinder blow by/friction losses/and thermal losses from the cylinder. Simple counterflow engines with a different valve mechanism can improve efficiency. One example is the Corliss engine. By using separate exhaust and inlet valves the cooling effect does not cause so much condensation of the incoming steam, and efficiency improves. If one desires higher efficiency, then consider a compounded engine and/or a uniflow.

    The compounded engine increases efficiency by increasing expansion - or should I say by allowing a given quantity of steam admitted into the engine to achieve high expansion. Good simple engines can boost efficiency with expansion (done by shortening the valve cutoff), but a small simple counterflow engine can't tolerate much expansion. Even the larger engines like locomotive engines didn't allow for more than about 4 fold expansion in a single cylinder. Saturated steam shows some condensation as expansion takes place, and the combination of expansion and thermal losses from the cylinder (especially cylinder head cooling) increases condensation and negates a lot of the gains. Superheating the steam helps a great deal. However, this is not good for slide valves that tend to warp with high superheat and see their lubrication compromised. All these put a cap on the expansion (and hence efficiency) possible in a simple counterflow engine. If expansion is done in two or more cylinders (as in the compounded engine), then the pressure seen in the first cylinder on exhaust is not nearly so low as in the single cylinder version. So, the steam exhausted from the first cylinder isn't at such a low temperature. The cylinder head and passageways in the first cylinder don't get cooled so much, and condensation that may flash to steam on the lower pressure is carried over to the second cylinder to do work. The lower differential pressure across the pistons and valves also lessens leakage, and the forces are distributed over the crank shaft evenly in many designs for lower peak forces on the bearings which raises mechanical efficiency. In short, the compounded engine is a lot more efficient. These dynamics make it possible to expand steam over a much wider range and see higher efficiency. The book I referenced has a lot of data on the efficiency of these engines, and the compounded engine often shows twice the efficiency of the simple engine when using the same steam source. These engines benefit a great deal from a condenser vacuum, yet the simple engines do not gain much in efficiency with condenser vacuum as discussed previously. Throw in steam reheat and regeneration, and the efficiency of a compounded engine can be remarkable. One multi compounded engine mentioned in the book showed a thermal efficiency of 27% using steam at only 600F - it did this by reheating the steam exhausted from each cylinder before entering the next, and then finally regenerating the added heat back into the system after the superheated steam was finally exhausted from the last cylinder. Without this complicated reheat and regeneration scheme, a large compounded engine using saturated steam under 200 psi and with condenser vacuum can show an efficiency of 20% (not including thermal losses from the boiler). This is pretty amazing.

    The uniflow engine improves efficiency by exhausting the steam through ports in the cylinder wall. This lessens the cooling of the cylinder head, and therefore lessens the condensation or cooling of incoming steam. For this reason, the uniflow does well on a condenser vacuum. Using a vacuum also helps to exhaust the steam, and indirectly allows for higher expansion of the steam. For best results, the uniflow requires a condenser at high vacuum. However, they can be run exhausted to atmosphere, and the gain in efficiency by moving to a vacuum condenser increases by only about 20% (all else equal). Also, uniflow engines generally use poppet valves that can tolerate higher steam temperatures. The combination of higher steam temperatures and higher expansion allow for the uniflow to see significantly higher efficiencies than simple engines. One engine noted in the book showed a thermal efficiency of about 30% with steam at 461 psi and 1000F. The White Cliffs uniflow engine using bash valves showed 23% with steam at 600 psi and 800F (boiler losses not included), and exhausting to a condenser at 160F. Ideally the uniflow engine shows very high compression of the residual steam. In fact, the ideal system would recompress the steam up to the boiler pressure. The intake valve would then open and let in steam from the boiler for a short time, then the valve would abruptly shut and allow the steam to see high expansion. The exhaust ports would then be uncovered by the piston, and the cycle would continue again with recompression. It's interesting to me how this relatively simple system can show impressive efficiency. Good compounded engines were generally more efficient than a uniflow using the same steam source, but a single cylinder uniflow is simpler. There are highly efficient engines that use a combination of compounding and uniflow exhaust (see Skinner Universal Uniflow engines). These have shown nearly 30% efficiency with steam at about 600F and exhausting to a high vacuum (figure does not include boiler losses).

    Since my primary interest in steam power is biomass-fueled micro scale combined heat and power, I have considered that the most practical way to make use of steam power would be a single acting uniflow tuned for an overall thermal efficiency on the order of 10-15%. I think the bump/bash valve is the simplest way to do this. Much higher efficiency than this would be difficult and likely require excessive temps or excessive expansion ratios. Since heat is the most desirable product in many settings, then there is little need for very high efficiency in that case. However, I believe 10-15% can be had with a simple system. In my opinion, the main design consideration should not be high thermal efficiency, but the emphasis should be on simplicity, reliability, making good use of the heat from the steam exhaust, a modest speed and constant low output, and the ability for the system to be fully serviced by the end user. For example, every wear component should be easily accessed and replaced with readily available and inexpensive components, and the base system should be extremely rugged.

    http://kimmelsteam.com/docs/Cylinder...pp203-4red.pdf
    Last edited by buenijo; 07-25-2015 at 07:13 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

  31. #180

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    Speaking of long term energy storage, I cannot help but wonder whatever happened with IBM's nano capacitor technology. IIRC, using folded carbon nanotubes as a dielectric, the surface area of the conductors is absolutely enormous, thereby greatly increasing the charge density such that they can be used as batteries. I remember the press releases were all going on about how this was going to revolutionize battery technology... electric cars that can go 500 or more miles on a charge and recharge in seconds, cell phones needing no charging for weeks on end, and so on.

    Since than I have heard nothing about it, which is a damned shame. Way back in the pre-civil war days when I was an engineering student at UC Davis, I'd wondered about capacitors as batteries. As it turned out, charge densities were too low, but this new tech is supposed to be well on the way to solving that problem.

    What happened to it? Take a look at this:



    And this:



    The best part of all this: you can do it at home. No $#@!. All you need is a graphite source, a few chemicals, and a CD drive.

    This could be a real improvement to steam generators. Imagine having a bank of these batteries that would store many coulombs of charge, perhaps enough to run your household for, say, a month. You fire up your steam rig, perhaps here a turbine would be the way to go for efficiency's sake, and in a few hours your storage is topped off and you can shut it down for the next 30 days.

    I am wondering why we're not hearing more about this and someone, somewhere, in the process of designing practical graphene batteries for manufacture.
    Through lives and lives shalt thou pay, O' king.

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