The Moving Cylinder Stirling Engine

by Hubert Stierhof

Page first established: 18th of March 2001
 Last update:  19th of January 2006
Steady something new !

Welcome to my web page of Low Temperature Differential Stirling engine designs.

For several years I have been developing Stirling engines looking for a design, that is applicable for the needs of Third World countries, to serve as solar water pumps or small scale power stations (< 50 Watts).

Such a design has to be

• cheap in production and made of local materials
• simple in design
• easy to handle and support
• robust and durable

These requirements were satisfied when I discovered the Moving Cylinder technology (see description).
This exotic concept of moving the cylinder, letting the displacer move freely, and having the piston fixed
has the extraordinary advantages of simplicity and higher efficiency over classical Stirling engines.

The basic design:

• has only two moving parts
• works as a linear engine
• works as a rotary engine

The MC design has a higher efficiency because of its discontinuous movement of its displacer.

Stirling engines usually have a 90 degrees phase angle between the power piston and the displacer.
This leads to almost 180 degrees of 'misbehavior'.
After the displacer has reached its dead center the power piston is expanding for a further 90 degrees,
while the displacer is lowering the average temperature by moving up again
and vice versa for another 90 degrees angle when compressing.
The Yoke-drive and the rhombic drive are a solution to that 'misbehavior', but they are expensive and are mechanically inefficent.

In a MC Stirling this angle can be brought to a minimum with the help of magnets and/or springs.
(see my performance paper, held on at the 10th ISEC in Osnabrueck, September 2001)

The MC Stirling is best for Low Temperature Differential Stirling engines like the solar pumps I develop, as well as other applications

like the MC Cooler , using the MC Stirling technology for refrigeration.

MC Solar  The simplist sunpowered engine I know .
It's made of wood, (polycarbon) glass, aluminum, polyurethane(or cork), rubber and some bolts and some metal.
A design made to solve some pumping problems in Third World countries.
Have a look at the construction plans and the instructions to build a linear engine to drive a water pump

...or build a small functional model of a modified MC_Solar with springs.

The Gloy engine -  
a NEW or forgotten basic design for LTD and MTD Stirling engines

The next three engines are NO Stirling engines and have only low performance, but they show
a simple way to pump water, for example for watering flowers is:
The Solarpumpcan ---- the most simple heat pump engine  

and

the CROSS-CAN-ENGINE  -- a most simple rotary heat engine  
Here just the first drawing..    

and

SOLRAD - higher torque than the CROSS-CAN-ENGINE , but as simple as it    

Coming Soon here:

• Ericsson LTD engine  -  an alternative to Stirling designs
• some more pictures