25-03-2011, 11:38 AM
Prepared by:
Avijit Singh Rathore
Nikhil Athale
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A Stirling engine is a heat engine operating by cyclic compression and expansion of air or other gas, the working fluid, at different temperature levels such that there is a net conversion of heat energy to mechanical work.
• Robert Stirling was the Scottish inventor of the first practical example of a closed cycle air engine in 1816 i.e. Stirling Engine.
Key Components:
• Heat source
• Recuperator
• Heater
• Regenerator
• Cooler
• Heat sink
• Displacer
Principle:
• Isothermal Expansion. The expansion-space and associated heat exchanger are maintained at a constant high temperature, and the gas undergoes near-isothermal expansion absorbing heat from the hot source.
• Constant-Volume (known as isovolumetric or isochoric) heat-removal. The gas is passed through the regenerator, where it cools transferring heat to the regenerator for use in the next cycle.
• Isothermal Compression. The compression space and associated heat exchanger are maintained at a constant low temperature so the gas undergoes near-isothermal compression rejecting heat to the cold sink
• Constant-Volume (known as isovolumetric or isochoric) heat-addition. The gas passes back through the regenerator where it recovers much of the heat transferred in 2, heating up on its way to the expansion space.
Steps Of Operation:
Cooling
Compression
Heating
Expansion
Applications:
• Solar power generation
• Marine engines
• Nuclear power
• MicroCHP
• Chip cooling
Advantages:
• Stirling engines can run directly on any available heat source, not just one.
• It can provide emission less power generation.
• No valves are needed ,as there is no mass transfer.
• The risk of explosion is low as Stirling engine uses a single-phase working fluid .
• They start easily and run more efficiently in cold weather, in contrast to the IC engine which starts quickly in warm weather, but not in cold weather.
Disadvantages:
• Size and cost issues
• Power and torque issues
• Gas choice issues