The Stirling Engine
The Stirling engine was invented almost 200 years ago by a Scotsman named
Robert Stirling. It was designed as an alternative to steam engines which had
the dangerous habit of exploding when the internal pressure became too high.
Stirling engines are much safer because they rely on changes in temperature to
create movement.
The Stirling engine has a sealed chamber containing either air or some other gas
like hydrogen or helium. The gas is repeatedly heated and cooled which causes a
piston to rise and fall. As gas is heated it expands, and the expanding motion
of the gas is what caused the piston to rise. As the gas cools off, it contracts
and the piston falls to its resting position.
The Stirling engine is a simple device which requires no valves and gives off no
exhaust fumes. The gas chambers are contained within the pistons cylinders. Some
engines are designed with multiple pistons which circulate the gas from cylinder
to cylinder, each at a different temperature.
There are three main types of Stirling engines. The alpha Stirling has two
separate power pistons -- 1 hot and one cold. Gas is transferred between them
through a heat exchanger. The second type of Stirling engine is the beta
Stirling. This engine has a single power piston coupled with a displacer piston.
The displacer piston is used to exchange the gas from the hot and to the cold
end.
The third type of Stirling engine is the gamma Stirling. Gas flows freely
between the power piston in the displacer piston which are part of the same
unit. This simple design can be used in multi-cylinder engines.
There are many advantages to Stirling engines. Unlike internal combustion
engines, the heat source of Stirling engines is external and can be easily
controlled. There is a large reduction in the amount of fuel emissions, so
Stirling engines are much cleaner to operate. They are also lightweight engines
because they operate under much lower pressure than other types of engines.
On the negative side, Stirling engines have to be quite large to produce
adequate power. It is also hard to change the power level of the engine -- they
usually run at a consistent power output.
But that negative is no problem when you use one in your home to produce
electricity and heating.
A company that produces stirling heating and electricity devices is
Whispergen,a New Zealand company that
really makes Sterling Engines that can be installed as easily as a central
heating device. It will produce enough heat and electrical power to keep the
average household going.
Articles of interest:
Home
Heating and the Stirling Engine.
The Stirling
Engine as Your Private Power Plant
Whispergen
Stirling Engine
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