Theory

• The stirling engine has multiple configurations which have both advantages and disadvantages. 
  
• Below are diagrams of some of the most common configurations. 
• No matter the configuration though, they all work on the same principles.
  

Alpha Configuration http://www.ohio.edu/mechanical/stirling/engines/alpha.gif

Beta Configuration http://www.ohio.edu/mechanical/stirling/engines/beta.gif

Gamma Configuration http://www.ohio.edu/mechanical/stirling/engines/gamma.gif

Stirling Cycle The stirling cycle uses air as its working fluid. The cycle is as follows. 1-2 Constant expansion: This is where heat is taken from the heat source which causes the gas to expand in the cylinder. 2-3 Constant regeneration: This is where most of the hot gas is forced towards the cold side. (Regeneration is a process in which heat is transferred to a thermal energy storage device and then later in the cycle the heat is transferred back to the working fluid.) 3-4 Constant compression: This is where the waste heat is rejected to the cold side as all of the gas is now cooling and contracting in the cylinder. 4-1 Constant regeneration: This contracting gas then moves back to the hot side where it picks up heat from the regenerator then the cycle repeats itself.

P-V Diagram http://www.mpoweruk.com/images/stirling_pv.gif