To get a simple and low cost Stirling engine that would be manufactured and used in any district of the world, a unique atmospheric Stirling engine named NAS-1 is under study at NIHON University.
NAS-1 was originally planned to be used for the solar field, so the cylinder head was designed to have a glass head at its top with the concentrated solar beam penetrating the glass.
NAS-1 uses a rubber diaphragm for the power piston, and it has proved to be very reliable and successful. It has James Watt's approximate linear motion link mechanisms (Watt link) for the main crank shaft, instead of the usual crossed head to eliminate liquid oil lubrication.
This kind of engine has been thought to furnish very simple, low cost and efficient power for future clean energy fields.
This engine design is simple, low in cost, and doses not involve problems of high pressure, and does not produce any pollutants whatsoever such as carbonic acid gas, NOx and others' pollution.
We succeeded in low temperature operations of the new design atmospheric Stirling engine NAS-1 and 2 engine has shown very well indicated output power in our testing.
By the experiments heated with electric heater, NAS-1 and 2 engine have shown very well indicated efficiency about 10 % at even a very low temperature difference of 200 °C.