®
L o w D e l t a T S t i r l i n g E n g i n e
SE-8576A
2
rod to the displacer could be a string and the engine would
still work.
Usage
Place the Low Delta T Stirling Engine on the palm of your
ward hand with the label toward you. After the engine has
warmed up for a couple of minutes, gently spin the flywheel
in a clockwise direction to get it started.
NOTE: Hand temperatures vary widely. Not everyone has
warm enough hands to make this engine run. If your hands
are cool, find someone with warm hands to try this.
You can also run the engine in the opposite direction by plac-
ing the bottom plate on a cold object, letting it cool down,
and then gently spinning the flywheel in the counterclock-
wise direction.
Maintenance
•
Dust is the number one enemy of this engine. Cover it
when it is not in use.
•
It is a good idea to store it in a plastic case.
•
Never oil the engine.
•
Do not store the engine where it will be exposed to
bright sunlight or the colors will fade.
•
Handle with care. The Low Delta T Stirling Engine is a
delicately balanced precision engine and it is very frag-
ile.
Troubleshooting
Generally there are three reasons why Stirling engines fail to
run: too much friction, air leaks, or inadequate thermal trans-
fer. The most likely reason for the Low Delta T Stirling
Engine to fail to run is inadequate thermal transfer.
If the engine will not run, try the following:
Put 2.5 cm (1 inch) of water in the bottom of a coffee mug.
Heat the water until the water is boiling vigorously. Care-
fully remove the mug from the heat source, and place the
engine on top of the mug. Wait for 15 seconds, and then gen-
tly spin the flywheel. Try spinning the flywheel in both
directions if it fails to start in a minute or so.
If the engine will not run when you try this test, it needs to be
returned for maintenance.
A Brief History of the Stirling Engine
The Reverend Robert Stirling, a minister of the Church of
Scotland, was troubled by some of the dangerous engines
that were used at the beginning of the industrial revolution.
Steam engines would often explode with tragic effects to
anyone unfortunate enough to be standing nearby. So in 1816
he invented and patented “A New Type of Air Engine with
Economizer”.
Robert Stirling realized that the engines he built would be
more efficient if some of the heat that was used to warm the
air for one cycle was saved and used again in the next cycle.
He called the device that saved the heat an “economizer”.
Today, this is usually called a “regenerator”, and is probably
Robert Stirling’s most important invention.
“Hot air engines”, as they were initially called, couldn’t
explode and often produced more power than the steam
engines of their day. The problem was that the only readily
available metal in the early 1800s was cast iron, which oxi-
dizes rapidly when left in a very hot flame.
Despite this difficulty, Stirling engines were widely used as
water pumping engines at the turn of the century. They
required little service, never exploded, were fairly quiet, and
the water provided a good cooling source for the cool side of
the engine. Thousands of these engines were sold
The Low Delta T Stirling Engine
.In 1983, Ivo Kolin, a professor at the University of Zagreb
(in what was then Yugoslavia) demonstrated the first Stirling
engine that would run on small temperature differences.
After he published his work, Dr. James Senft, a mathematics
professor at the University of Wisconsin - River Falls
(United States), built the first engines similar to the PASCO
Low Delta T Stirling Engine.
The Carnot Energy Cycle
In the mid 1800s, a Frenchman named Sadi Carnot figured
out the maximum limits of efficiency. His formula is an
accepted standard for determining the maximum possible
HEATING
EXPANSION
COOLING
CONTRACTION
REVOLUTION
COLD AIR
HOT AIR
Foam displacer
Graphite
power
piston
Operation of a displacer type Stirling Engine
