updated on 05/23/07 |
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created May 200 |
version 1.0
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There are nearly two centuries (1816), a Scottish minister named Robert Stirling, filed the patent for his hot-air engine.
Dethroned by the steam engine and internal combustion engines, it did not successful, despite a good performance and the ability to use any type of fuel.
But the most amazing
features is to operate from power sources deemed unusable: for example, thermal
springs, although that bringing tens of thousands of calories per hour from
the depths of the earth, are absolutely incapable of cook a boiled egg or
a bowl of rice ...
Well, the Stirling engine can, without problem, extract the energy contained
in a little hot water, as shown in this little DIY.
The first model, placed on a cup of boiling water (careful, it burns!) and
cooled by an ice cube, can run for about 35 minutes. Its speed varies from
170 rpm, shortly after its inception, up to 25 rpm at the end of operation.
The difference in temperature between the hot face and cold surface is then
about 22 ° C.
The mechanical power developed is very low, just enough to offset the loss
by friction. Measurements performed by different methods, estimate to 1
mW of excess power provided by this device. Assuming that we convert this
mechanical energy into electrical energy with an efficiency close to 1,
and that can be stored without the loss for 1 month, we could power a light
bulb low consumption of 20W for 2 minutes. .. Or mount a mass of 1 kgf
to 240 m high (if my calculations are correct ... :-)
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General
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Details |
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Materials (mainly recovery)
- The upper and lower plates are from an aluminum Ø 94, which I mention
the brand, and which can not keep the lid and the bottom part
- The sides are transparent from a soda bottles 1.5 l which we have taken a slice
of 24 mm high
- The ice cube tray (not essential) piece of tube or aluminum box
- The mover (piston inside the cylinder) piece of ceiling tile of expanded polystyrene
(roughly 10 mm thick)
- The cylinder: packaging film 24 x 36 (translucent)
- The piston engine: a piece of vinyl disposable glove
- The portico shaped plastic 10 x 10 x 1
- The rods, axes, crankshaft: piano wire Ø 0.8
- The landing, slide and slide adjustment: brass tube 2.5 int
- Miscellaneous: screws, washers, glass beads roughly Ø ext. 2.3 - int
roughly. 0.9 / / cyanoacrylate adhesives & heat silicone sealant
- And for the flywheel: an absolutely original AOL CD "50 hours of free
trials", otherwise it does not work! ... Just kidding, any CD can agree:
choose a color well, much nicer ... :-)
| Plans and skinned |
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- to build this engine, you can inspire the method described in his page or in the latter - this little DIY poses no particular problem, and size data have nothing critical for practical reasons, length of guides and bearings, it is not advisable to reduce the size of this model, conversely, you can increase the diameter of the cylinder, which will benefit all - it is particularly well advised to treat leakage that this model works with small temperature differences, and to properly lubricate the bearings and guides with an oil fluid enough (possibly based Teflon); oil has Indeed three functions: reduce friction, seal and prevent corrosion of parts may be subject to condensation |
if desired, can be purchased online at American Stirling Company, engines or complete kit for a price ranging from $ 109 to $ 379 from Japan, there is also the kit Otona no kagaku that resembles the simplified Stirling engine 1.0 and found since 2006 on ebay for about $ 53.00 including postage |
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Good
DIY ...
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