Stirling Cycle Engine- a primer

[darcane]

Originally Posted by aerohead

There has been some mention of the Stirling engine and here is what I have so you all don't think it's some new savior technology:

The Stirling Cycle is,as is the Erricson Cycle,given a theoretical enthalpy efficiency,as the Carnot Cycle,80%.
In 1955,GM Research Labs were investigating the engine.
In 1973,with the Arab Oil Embargo and 'energy-crisis,' interest was renewed.
GM,Ford,Philips Research Laboratories,Holland,and NASA were all doing R&D with it.
When crude prices fell,so did interest for some.Ford quit it after umpteen millions of dollars spent on it.
GM had achieved BSFCs of 0.418-0.358 pounds/Bhp-hr ( 39% enthalpy efficiency ).

Does that 80% theoretical efficiency account for inefficiencies of combustion or is that just for converting the heat energy into motion?

Much of the inefficiency of a gasoline engine comes from the need to get rid of waste heat (through exhaust and coolant). If you are using combustion of a fuel to power the Stirling engine, you will have to consider that also. I suspect that's why GM's testing was only around 39% efficient.

As project to learn how to use the tools in the machine shop, I built a Stirling engine in college many years ago. I still have it somewhere...

[aerohead]

Originally Posted by darcane

Does that 80% theoretical efficiency account for inefficiencies of combustion or is that just for converting the heat energy into motion?

Much of the inefficiency of a gasoline engine comes from the need to get rid of waste heat (through exhaust and coolant). If you are using combustion of a fuel to power the Stirling engine, you will have to consider that also. I suspect that's why GM's testing was only around 39% efficient.

As project to learn how to use the tools in the machine shop, I built a Stirling engine in college many years ago. I still have it somewhere...

darcane,they're saying that 80 % of the chemical energy contained in the fuel could be delivered to the flywheel as useful mechanical power.
If you had the materials technology to pull it off,which appears to be the sticking point.