Stirling Heat Engine:
From my research on the Stirling heat engine I learned right away what it was, “a little bit like a steam engine that uses no steam! Instead, it heats, cools, and recycles the same air or gas over and over again to produce useful power that can drive a machine.” Chris Woodford explains in his article on explainthatstuff.com I also learned that all though there is so much rave about it now, the Stirling heat engine has been around since 1816!
Many people refer to this as a closed-cycle, regenerative heat engines. Some describe the Sterling engines are simple, while others think they are complex. There are different designs of the Sterling heat engine, but lets focus on the beta.
How it works:
The Stirling heat engine converts heat energy into mechanical energy by repeating its cycle. First there is cooling and compression. This is when most of the gas on the cooler end of the cylinder. Then there is the transfer and regeneration this is where the displacer piston moves to the right and the cooled gas moves around it to the hotter part of the cylinder on the left. After that is the heating and expansion most of the gas is now on the left in the hot end. It is then heated by fire or another source of heat so that the pressure can grow, absorbing energy. With the gas expanding it now pushes the work piston to the right. During the heating and expansion the engine modifies heat energy into mechanical energy. Finally there is the transfer and cooling part of the cycle, the displacer piston moves to the left and hot gas moves around it to the cooler part of the cylinder. After this part the cycle restarts.
The Peltier Device:
Tech Target defines the Peltier device, also known as thermoelectric cooling, as “a temperature difference created by applying a voltage between two electrodes connected to a sample of semiconductor material”. It is beneficial to transfer heat from one medium to another on a small scale.
How it works:
This device has two side, a cool side and a heated side. The difference in temperatures is about 70 degrees. It uses a lot of electricity. It pumps the heat from one side to the other. In addition to pumping heat, it also produce heat. When this happens the system cools it self where it needs too.
References:
- http://www.explainthatstuff.com/how-stirling-engines-work.html
- http://searchnetworking.techtarget.com/definition/Peltier-effect
- http://www.activecool.com/technotes/thermoelectric.html