Stirlingengineforum.com

first off, i am really glad i found this forum. I plan on making my first Stirling soon after i do some due studying, but the very idea of these machines has my imagination jumping. It has been a while since i have taken physics, but i have a couple of ideas that i hope would raise some conversation here.

one is about the feasibility to use geothermal principles to power the engine. what i have in mind is, in the case of where i live, would be to bury the cold side in the ground where temperature is constant. the hot side would be on the surface. during the summer the temperature difference could be as much as 40 deg. F. Parabolic mirrors could also aid in the heating on sunny days. obvious limitations to this would be days where the ambient air temperature is the same or very similar to the temperature of the earth, and a reverse in hot and cold as the seasons change (the "hot" cylinder would be above ground in summer, but during winter the "cold" cylinder would operate as the hot cylinder. I have no clue how well this would work, i am just thinking of ways to get a temperature difference that could possibly be used to run the engine. I do not know how determine the needed temperature gaps and all the rest. i am just throwing out ideas.

The other idea is the use of nano materials to reduce weight and thereby friction inside the engines. i found a news story where the university of Michigan invented this type of nano plastic that is strong as steel. i can see pistons being formed out of this, and maybe even filled with some kind of gas to further reduce weight. beyond that, even the use of nano technology to increase efficiency of the engines. like i said i am no scientist, just a guy thinking about the possibilities. Has anyone given any thought to using high tech stuff like nano and thought about or attempted to apply it to the Stirling concept?

Link to the nano plastic story: http://www.cosmosmagazine.com/node/1637

.................You are going to loose intrest in a hurry. Thats building something you are unfamilar with out of materials few reconise. This is not to dissuade you but to encourage an effort that will result in a running engine. Tried and true design with standard materials should be your goal here. Otherwise the hours in fabricating a motor thats just going to be a door stop will just give you heart ache. Time and experiance breeds innovation............but for your first engine, go where others have been.

You can burry the cold side but the engine is not going to care. 50 deg. 2 feet down or 80 deg. above at the surface you just need enough of a temp differential to move the mechanisim and your heat input to the hot cylinder will over run any ambient temp you find for your cold side. If NASA buys some of this U 0f M plastic so I can get to the moon faster maby I'll try it in one of my models!

i will definitely start with tested materials, and i have no availability or knowledge to use the materials i listed. i was just offering those up as a theoretical. i am gonna start by building a stirling made out of cans first. i find the idea of a heat engine fascinating and if nothing else as a cool toy to have on my desk.