REPORT #39 Jan 1999

Produced by the Belize Development Trust
Below is a list of machine tools for the shop and method of construction of a Uniflow Steam Engine system. ( Information collected from the fertile mind of retired Canadian Engineer Peter Singfield living the Mayan village of Xaibe in northern Belize.)

A basic "prototype shop:

  • The lathe like I had in Montreal, was a 48 in centers, 8 inch over the table -- 16 with throat out -- full metric and NC threading -- 5/10,000 min accuracy. Automatic feeds of course but manual tail stock.

    This is your standard Taiwan copy of a 1895 Southbend -- but improved. Used to cost around $3000 new with 4 jaw and 3 jaw + couple face plates and live centers etc.

  • Plus the tooling -- high speed steel for aluminum and brass and stainless steel. Carbides, boring bars, drill chuck for head stock. Tapered drills, reams -- well you know the list.
  • Milling machine: Combination boring bar and vertical milling machine. Taiwan again -- round $2000. Again tooling.
  • Metal Band saw -- 6 inch. can be used as a small bandsaw. Around $200. But get a couple of good bimetal blades ($50 each).
  • One basic drill press.
  • Air compressor -- I like to use surplus refrigeration compressors with high pressure storage -- like 250 PSI -- then regulated to user pressure. No variation in line pressure that way.
  • electric welder -- AC/DC
  • Torches/cutting torch
  • Bench Grinder- Stone for grinding carbides.
  • Numerous hand tools.
Anyway -- you get the idea -- to be able to build just about any device --

What to build:
The solar powered boiler -- Using Butane as the working fluid there is no need to concentrate the solar energy to "amplify" the operating temperature.

Ergo -- the solar collector is just a hot water heater -- best would be aluminum roofing that we can "anodise" here. That will give better than 80% absorption efficiency. Anodised aluminum being the best "black-surface". This is the solar facing side of your solar water heater.

The "cold" side of this thermodynamic engine would be a simple copper tube immersed in this hot water bath. Here the pumped/circulating butane (liguid when coming in and vapour when coming out) would absorb the "heat" to reach vapour phase for that pressure. An incredible increase in volume.

From here is goes to a simple "uni-flow" steam engines.

From the exhaust of the Uniflow is goes to the hot side -- that is where the hot gets cooled. This can be in the shade under the solar collector or in a well.

I did measurements. Black object easily reaches 145 deg. F, in the sun here. The shade is normally less than 95 F. That gives us a delta T (change in temperature) of 50 deg. Plenty!!

Later I can show you the math -- that tells us how much H.P. we can get from what size solar collector. It works out very nice!!

Uniflo engines were invented just before turbines became common. It was the highest efficiency "piston" steam engines ever built. Got lost when turbines were introduced. Present advantage -- easy to build here in Belize!!

I plan to "cast" the cylinders from cast iron. A very cheap material here. Easy to make up a foundry for.

Uniflow designs are really well suited for compression/pumping -- they were used exactly for that purpose turn of the century -- for refrigeration, pumping water, compressed air for mines -- etc. In these style applications very high efficiency as there is no need to convert from linear to rotary motion.

In my prototype shop in Montreal I once designed and build a "linear" alternator. This is quite simple. I used a simple car altenator -- but instead of rotating the armature I simple passed it back and forth through the stationary fields -- along the axis. I had two bushings supporting it in the center so it could reciprocate 4 inches. If you do this at 3600 rpm you get 60 cycle AC current. There is a unique property in using steam (or butane vapour) in that to reverse direction no energy is expended (or very little lost) as in the uniflow design you simply compress part of the charge in the apposing cyclinder where the power of stopping is saved and given back when uncompressing into the other direction -- including the "power" of an injection of steam.

And the list goes on and on ---

If you ever get down here we'll have fun!! Wait till I tell you about my ideas to make a "Air" shotgun. Like a pellet gun but using 2000 PSI air pressure to fire a 12 gauge charge of pellets at around 900 ft per second!!

I have a whole list of "third world" projects. That is devices that third world people not only would really like to have -- but could afford to buy.

I built a prototype uniflow "contruction" compressor once that was powerd by a water/steam boiler fed by chopped up chunks of car tires. You know -- one car tire has 300,000 BTU of heat energy in it. And this thing does not "smoke". Thought it would be great for compressed air for jack hammers etc.

This can also be applied to a very large hydraulic pump -- like in running a hydraulic shovel.

Or to a meat freezer made out of a semi-trailer reefer rig. Simply substitute the uniflow pump for the reefer compressor. If I remember -- it would need about one 15 inch car tire per hour for full capacity.

I also keep thinking of wave action power supplies. For those living by the sea.

And I have a couple of ideas on how to make some simple egg-beater style "vertical" windmills for where there is steady winds.

That is by casting chicken wire in ureathane high density foam inside of plastic molds.

Oh -- no one is recycling the toms of plastic thrown into the garbage here. Yet every dump here has people practically living in them to scavage anything they can. Would be easy to make cheap recyled plastic here.

Oh -- the list goes on -- if only people were more engineering oriented!! That is what happened in Taiwan you know. 50 years ago they were more backward than Belize -- a lot more -- then we started seeing all kinds showing up at McGill University in Montreal -- all taking Engineering courses.

Hey Terry -- believe me -- that is the only answer to successful intrigration of third world into modern world -- a very good supply of young, sharp, engineers.

Not more civil servants and clerks -- or even welders, mechanics, carpenters or clerks! But engineers!

July 6TH, 2001- 6 years later, someone else discovers the Belizean Butane Stirling Heat Engine in Miami ??

STERLINGSOLAR.COM Renewable Resource Power Generation Solar Powerplants featuring Rotary Valved ORC Engines & Gravity Cycled Feedpumps

Sterling-Gonzalez Rotary Valves convert refrigerant compressors into solar powered refrigerant-charged vapor engines.

Sterling has developed a thermally driven powerplant comprised of a heat collector, an evaporator, an ORC rotary valved piston engine, a condenser, and Sterling's proprietary "gravity cycled feedpump".

The Sterling-Gonzalez rotary valve converts off-the-shelf refrigerant compressors into refrigerant-charged steam engines.

Sterling seeks energy related partners or investors to help get its prototypes to market. Licensing opportunities are available. 2 U.S. patents have been issued for Sterling's unique cycle. Several patents are pending for rotary valve technology, enabling common compressors to be converted into refrigerant-charged engines.

Optional equipment includes electric generator, PTO, refrigeration & air conditioning compressors, irrigation pumps.

Sterling does not make nor use Stirling engines (spelled differently) .

What is An Organic Rankine Cycle Engine?

A Rankine cycle is a closed circuit steam cycle. An "organic" Rankine cycle uses a heated chemical instead of steam. The chemicals include refrigerants, like freon, butane, ammonia, and the new "environmentally safe" refrigerants.

Why use a refrigerant?

A refrigerant boils at a temperature below the temperature of frozen ice. Solar heat, for example, of only 150 degrees Fahrenheit from a typical rooftop solar hot water heater, will furiously boil a refrigerant. The resulting high-pressure refrigerant vapor is then piped to the organic Rankine cycle engine.

That's all that our refrigerant engine needs in order to make power. The exhaust vapor is recycled in our patented closed-circuit piping system. Sterling's thermal power plant is unique in that its recycling pump consumes heat, not power. The result is that the powerplant's engine can be 15-50% smaller.

Why is it called "organic"?

"Organic" is a term used in chemistry to describe a class of chemicals that includes Freon and most of the other common refrigerants. There is nothing natural about freon.

Refrigeration was discovered in an early experiment with ammonia. Although it is toxic to us when concentrated, it is non-ozone depleting, non-global warming, environmentally safe, and is cheap to buy. Ammonia is used in many modern refrigeration systems. It can be economically utilized in our ORC (organic Rankine cycle) heat engine. Sterling's power plant can use any refrigerant.

What fuels an ORC heat engine?

The refrigerant working fluid can be heated by almost any heat source. Solar, geothermal, waste heat, wood, propane. High temperatures aren't necessary. A garden hose reaches the required temperature.

Can the engine run at night without solar energy ?

1.)The storage of thermal energy is as easy as storing an insulated tank of solar heated water. In limited situations, Sterling's patented low temperature heat sink thermal storage system stores the heat of the sun as ice. It's many times more compact than storing heated water. The ice is used when needed to make electricity.

2.)Storage batteries are always an option.

3.)A tank of propane is an inexpensive back-up solution. The propane is used to heat the refrigerant.

4.) Sterling Solar Power Plants make electricity, which can be used to produce hydrogen by electrolysis. Fuel cell, an up and coming technology, need hydrogen to make electricity. Sterling's thermal converters will be used to produce and store hydrogen. Upon demand, fuel cells will convert the stored hydrogen into power.

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