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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