CONTENTS:• INTRODUCTION
• HISTORY
• WHY STIRLING ENGINE?
• WORKING PRINCIPLE
• EFFICIENCY
• DIFFERENT CONFIGURATIONS
• MAIN COMPONENTS
• APPLICATIONS
• ADVANTAGES
• DISADVANTAGES
• CONCLUSIONS
• REFERENCES
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INTRODUCTION:
• Device that converts heat energy to mechanical power by alternately compressing
and expanding a fixed quantity of working fluid at different temperatures.
• A thermodynamic system in which the working fluid is permanently contained
within the system.
• A closed-cycle regenerative heat engine with a permanently gaseous working fluid.
• Works on Stirling cycle.
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Stirling engine
HISTORY
• Inventor = Robert Stirling (1790 - 1878).
• Sought to replace the steam turbines of his days due to frequent explosion caused by
unsustainable high pressure killing and injuring workers.
• Invented Stirling engine in 1816 which could not explode and produce more power than the
steam engine used that time.
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Robert Stirling
His 1816 patent application
WHY STIRLING ENGINE?
• Best teaching and learning device for any engineering students especially in the field of
thermodynamics.
• Unique technology.
• An innovation with hundreds of application.
• An innovation with a mission to save the earth.
• Fuel independency.
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A low temperature Stirling Engine
WORKING PRINCIPLE
• BASED ON STIRLING CYCLE.
• ONE SIDE OF THE ENGINE IS CONTINUOUSLY HEATED WHILE THE OTHER SIDE IS CONTINUOUSLY
COOLED.
• FIRST, THE AIR MOVES TO THE HOT SIDE, WHERE IT IS HEATED AND IT EXPANDS PUSHING UP ON A
PISTON.
• THEN THE AIR MOVES THROUGH THE REGENERATOR TO THE COLD SIDE, WHERE IT COOLS OFF AND
CONTRACTS PULLING DOWN ON THE PISTON.
• TEMPERATURE CHANGE INSIDE THE ENGINE PRODUCES THE PRESSURE CHANGE NEEDED TO PUSH ON
THE PISTON AND MAKE THE ENGINE RUN.
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Stirling cycle T~S and P~V diagram
CONTD…
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MAIN COMPONENTS
FIVE MAIN COMPONENTS…
• WORKING GAS
• DISPLACER & POWER PISTON
• HEAT EXCHANGER
• REGENERATOR
• EXPANSION/COMPRESSION MECHANISM
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EFFICIENCY
• Theoretically
• Stirling engine efficiency = Carnot efficiency
• Unfortunately working fluid is not ideal this causes the efficiency to be lower than Carnot efficiency.
• In fact, Stirling engine efficiency depends on
• Temperature ratio (proportionally)
• Pressure ratio (inversely proportional)
• Specific heat ratio (inversely proportional)
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Comparison between Carnot Cycle and
Stirling Cycle
DIFFERENT CONFIGURATIONSTHREE MAIN CONFIGURATIONS OF STIRLING ENGINE…
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• Alpha Type • Beta type • Gamma type
ALPHA TYPE STIRLING ENGINE
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BETA TYPE STIRLING ENGINE
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GAMMA TYPE STIRLING ENGINE
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ADVANTAGES
• Various heat sources (solar, geothermal, nuclear energy, waste heat, biological etc.) can be used.
• High efficiency close to Carnot engine efficiency.
• Environmental friendly.
• Heat is external and the burning of a fuel-air mixture can be more accurately controlled.
• Operates at relatively low pressure and thus are much safer than typical steam engines.
• Less manpower needed to operate any type of commercial stirling engine.
• The technological simplicity makes it possible to have engines with a very great reliability and requiring little maintenance.
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DISADVANTAGES
• Its cost is probably the most important problem, it is not yet competitive with other means well established.
• The ignorance of this type of engine by the general public.
• The variety of models prevents standardization and, consequently, lower prices.
• The problems of sealing are difficult to solve as soon as one wishes to have high pressures of operation.
• The choice of “ideal” gas would be hydrogen for its lightness and its capacity to absorb the calories, but its ability to diffuse through materials is a great
disadvantage.
• Heat transfers with a gas are delicate and often require bulky apparatuses.
• The fast and effective variations of power are difficult to obtain with a stirling engine.
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APPLICATIONS
• Water pump stations
• Combined heat and power(CHP) plant
• Solar power generation
• Stirling cryocoolers
• Heat pump
• Marine engines
• Nuclear power
• Aircraft engines
and many more…
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Solar Power
generation field
CHP layout
CONTD…
• WATER PUMP STATIONS-A stirling engine used for pumping water can be
configured so that the water cools the compression space. This is most effective when
pumping cold water.
• STIRLING CRYOCOOLERS-Any stirling engine will also work in reverse as a heat
pump. When a motion is applied to the shaft, a temperature difference appears between
the reservoirs.
• NUCLEAR POWER-Replacing the steam turbines of the nuclear power plant with
stirling engine might simplify the plant, yield greater efficiency, and reduce the
radioactivity by products.
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Stirling Cyrocooler
A Water Pump Station
Nuclear Reactor-schematic
CONCLUSIONS
• Compatibility with alternative and renewable energy sources has become increasingly significant as the price of conventional fuels rises.
• Currently exciting interest as the core component of micro combined heat and power (CHP) units , in which it is more efficient and safer than a
comparable steam engine.
• Need to make popular.
• Highly efficient engine.
• Engine for the future.
• Substantial reduction of CO & HC emissions.
• Environment friendly.
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REFERENCES
• http://www.stirlingbuilder.com/survey/survey-results
• http://www.smartplanet.com/blog/report/new-alliance-could-make-cable-a-catalyst-for-cleaner-power/364?tag=search-river
• http://www.dekaresearch.com/stirling.shtml
• http://web.archive.org/web/20080801212651/http://www.lanl.gov/mst/engine/
• Y.A. CENGEL & M.A. BOLES, THERMODYNAMICS-AN ENGINEERING APPROACH, 4TH ED.
• STIRLING ENGINES", G. WALKER (1980), CLARENDEN PRESS, OXFORD
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