1903 six HP steam engine powers modern off grid power system

[buenijo]

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 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

[buenijo]

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.

[buenijo]

[youngbuck]

I would like to buy one, or a build one. Doesn't appear that it's available in the US.

[Anti Federalist]

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

[sparebulb]

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?

[Anti Federalist]

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.

[osan]

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

[Anti Federalist]

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.

[Anti Federalist]

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?

[osan]

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.

[osan]

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

Was this his invention?

I suspect so.

[Anti Federalist]

Just seeing this now...nifty, thanks.

[buenijo]

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, 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.

ADDENDUM: I corresponded with Mr. Desai during May of 2020. Unfortunately, despite the incremental improvements he made to his steam engine system, they have remained a net loss for his business. Therefore, he will no longer be manufacturing steam engine systems. I suggested he make contact with Village Industrial Power (see later post #226) to see about becoming a distributor for their more modern steam engine system. I admire Mr. Desai's dedication and vision. There is potential for small scale, biomass fueled, CHP steam engine systems. Unfortunately, his systems are based on primitive designs that died for very good reasons.

[buenijo]

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.

[buenijo]

GOOD ARTICLE: https://medium.com/impact-engineered...e-dce965b13dc9

ADDITIONAL INFORMATION: https://poweringag.org/innovators/bu...ower-provision

WEB SITE: https://www.villageindustrialpower.com/

Highlights:
1. Biomass fueled including many readily available crop residues unsuitable for a biomass gasification engine system.
2. CHP
3. To be mass produced in India
4. No oil lubrication!
5. Double acting uniflow with high recompression
6. Impulse steam admission valve - no valve gear
7. Appears to be mechanically very simple ("the unit can be taken apart and put together in an hour with two wrenches")

EFFICIENCY: The system is described as generating AC electricity at a NET efficiency ("fuel to electricity") of 10% at 300C steam (572F) and atmospheric exhaust. Peak steam temperature is described in the patent as 700F. The steam pressure is described as 300-400 psig. These figures correspond to a steam cycle efficiency approximately 50% of Carnot efficiency which is just about as good as it gets at this scale. The boiler is described as "70% efficient". More important to real world operating efficiency is a uniflow of this basic design is known to show a flat efficiency profile. This is in stark contrast to gas engines. I expect the efficiency at 25% rated load to be close to the full load efficiency - and everywhere in between. Whereas, the efficiency of a gas engine generator at 25% rated load is often about half the efficiency at rated load. That noted, I consider the wide fuel capacity of the system, its mechanical simplicity, and the ease in heat recovery as the more important qualities. For example, the sophisticated Power Pallet by All Power Labs lists (1) wood chips, and (2) nut shells (walnut and Hazelnut) as the ONLY approved fuels for their unit. Of course, the wood chips must processed to the proper size and screened of fines, etc.

CONS:
1. Large pressure vessel boiler with only 70% efficiency. It appears that the system requires an operator. In my opinion, the use of a large pressure vessel boiler renders the system unsuitable for residential combined heat and power (except perhaps community scale). However, it seems a good fit for micro scale industrial CHP in "third world" settings.
2. Seems loud and with much water loss. However, this can be relatively easily resolved.
3. Much vibration. However, this also may be a function of limited development.

I am surprised this flew under my radar. Interestingly, shortly after the turn of the century, the inventor spent several years directing a team to develop a biomass gasification engine system for the same applications. However, the complications associated with that technology led him to steam power. See the article I linked. The benefits of this kind of system as discussed by the inventor are spot on.

PATENT: https://patents.google.com/patent/US9657568 Brilliant design similar in principle to previous approaches. The steam inlet valves are opened by steam recompression. There is no lift pin. The cut off is partly controlled by engine speed in a negative feedback that causes less steam to be admitted when engine speed increases, and vice versa. However, a cam limits the valve opening to control the cutoff more precisely. Note the valve is a curved spring that covers steam admission ports in the cylinder head. A very similar design was done in a steam engine I described in a previous post on this thread.

[Anti Federalist]

[tod evans]

[Badnon Wissenshaftler]

A Genuine 1870 Solar-Powered Steam Engine

Reprint of 1870 article about a solar-powered steam engine that appeared in The Technologist magazine, which proves that alternative energy is nothing new and that its benefits have long been known.

https://www.motherearthnews.com/gree...e-zmaz75ndzgoe

I don't know if this has been mentioned in this thread, as it's ridiculously long and I'm quite late to the party, but I think it's worth note.

This, combined with the wood-fired option, could've stopped "the grid", or centralized power generation, before it was ever born, at least in many areas. We'd be a better country for it.

That said, solar panels are quite inexpensive these days if you shop around. I just bought 4 kW worth for <$600.

[Anti Federalist]

Neat, I can't recall ever hearing a tractor "stack talk" like that.

[Anti Federalist]

171 hp and 5000 ft/lb of torque.

[tod evans]

[tod evans]

[buenijo]

[buenijo]

I restarted a small scale steam project that I had to terminate several years ago. I will post any material progress in the linked thread.

http://www.ronpaulforums.com/showthr...Engine-Project

[buenijo]

A Genuine 1870 Solar-Powered Steam Engine

Reprint of 1870 article about a solar-powered steam engine that appeared in The Technologist magazine, which proves that alternative energy is nothing new and that its benefits have long been known.

https://www.motherearthnews.com/gree...e-zmaz75ndzgoe

I don't know if this has been mentioned in this thread, as it's ridiculously long and I'm quite late to the party, but I think it's worth note.

This, combined with the wood-fired option, could've stopped "the grid", or centralized power generation, before it was ever born, at least in many areas. We'd be a better country for it.

That said, solar panels are quite inexpensive these days if you shop around. I just bought 4 kW worth for <$600.

Solar heat engines cannot compete with PV panels at micro scale and small scale. However, they are viable at medium scale and large scale (with diseconomies of scale beyond a certain point). The best approach I've yet seen is being pursued by Terrajoule.

https://www.terrajoule.energy/product

Perhaps the most interesting aspect to this technology is the ability to scale RAPIDLY by repurposing existing manufacturing infrastructure. A side benefit of these systems is the ability to use fuels if/when solar insolation wanes as during inclement weather.

https://www.terrajoule.energy/cost-breakthroughs

https://www.terrajoule.energy/capital-efficiency

Without low cost energy storage systems, there can be no solar powered future. That noted, the superior alternative for meeting the lion's share of global industrial energy demands is modern nuclear power fission reactors.

ADDENDUM: Actually, in some settings a residential scale solar thermal system with low cost thermal storage could be cost-competitive with solar PV and batteries. This is argued by Robert Mierisch, the engineer who invented and holds the patent on which the Terrajoule technology is based. He believes mass production will allow for constructing these systems for about $10,000 AUD (he's from Australia), and would be suitable for most regions in Australia - and other regions with high solar insolation. Personally, I believe off grid solar energy is good for meeting residential energy demands in many regions. However, I think trying to meet industrial energy demands with solar energy is an absurd notion - especially when modern nuclear power fission reactors provide a far superior alternative. Incidentally, the thermal storage system for the proposed residential scale solar thermal system is crushed rock and/or sand. The engine is a single cylinder piston steam engine used to maintain charge on a small battery with AC power provided with inverter. All direct heating applications will be derived from the steam engine exhaust heat. The main advantage of this configuration is extraordinarily low cost solar energy storage with significant useful heat available. One of the major problems with solar energy is the sheer mass of batteries and panels required. Whereas, the hardware required for these small solar thermal systems are primarily steel, rock/sand, and water.

From Robert Mierisch: "Currently working on a Rural Residential Energy System that will provide electricity, hot water, winter heating, summer cooling and electric car charging, at night. The system uses Solar Collector Assemblies (SCAs) that track the sun and collect heat. Thermal Energy Storage Systems (TESs) hold enough heat to provide up to 20 kilowatt hours of electrical output and 80 kilowatt hours of heating at temperatures up to 50C. Dry cooling ensures that any water consumption is trivial."

[buenijo]

Modern wood chip fired steam tractor to be manufactured in New Zealand.



https://mackwell.co.nz/mackwell-a35-engin

https://mackwell.co.nz/wp-content/up...compressed.pdf

SOME SPECIFICATIONS:

2 cylinder, double-acting steam engine rated at 35 hp continuous (64 hp intermittent maximum), 400 rpm, 1300 ft-lbs torque, piston valves
Bore/Stroke: 4.25"/6.5"
Steam Conditions: 300 psig, 750F
Range: 191 miles (90 miles when towing full load of 7.6 tons at 25 mph)
Fuel bunker capacity: 275 pounds wood chips
Feed water capacity: 132 gallons
Hours operation at 50% rated load: 4 hours
Transmission: 2 speeds (LOW up to 12.5 mph , HIGH up to 25 mph)

The large cylinder that makes up the bulk of the body is NOT a pressure vessel. Rather, it is an insulated casing that contains and directs furnace combustion gases across a water tube boiler. The draft booster on the front of the vehicle (the tall stack) is steam powered like traditional steam locomotives. So, this is not a condensing engine. The draft booster is an important part of the control system. When engine output is increased by the operator, then the increased steam flow through the engine also increases steam flow through the draft booster to increase furnace output. This makes more steam to compensate for the increased engine demand.

The tractor is also capable of powering a pto generator at 26 KWe while providing heat at a rate of 180 KW. Price is listed at $65,000 NZD which equates to approximately $38,250 USD. The "GST" tax in NZ is 15%.

ADDENDUM: I can't find many specifics. I did learn there is a steam powered pump in the steam generator circuit just before the superheater along with a steam/condensate separator. The pump takes the hot pressurized condensate back to the inlet of the steam generator where it mixes with incoming feed water. The pump keeps the condensate flowing at a high rate through the tube to strip steam bubbles off the tubing walls. This enhances heat transfer significantly.

The furnace has a large well insulated combustion chamber designed to burn all the fuel before the combustion gases reach the boiler tubes. This is very important, and traditional steam locomotives were poorly designed in this regard - and it was a major contributor to their high fuel consumption. There is NO smoke or soot thrown out with this design (at least not after warmed up from a cold start). I know it's possible because the furnace I designed for my small steam engine project was based on the same principles: https://www.flickr.com/photos/184818...-wkkCBj-ocUDM6 (high temperature on the order of 2000F and no smoke or odor)