A Stirling engine is a heat engine that operates by cyclic compression and expansion of air or other gas (the working fluid) at different temperatures, such that there is a net conversion of heat energy to mechanical work. More specifically, a closed-cycle regenerative heat engine with a permanently gaseous working fluid.

1. STIRLING ENGINE
 INTRODUCTION
 HISTORY
 WHAT IS STIRLING ENGINE
 WORKING PRINCIPLE OF STIRLING ENGINE
 DIFFERENT CONFIGURATION OF STIRLING ENGINE
 COMPARISON BETWEEN ALPHA,BETA & GAMMA STIRLING ENGINE
 FIVE MAIN COMPONENT OF STIRLING ENGINE
 EFFICIENCY
 APPLICATION OF STIRLING ENGINE
 ADVANTAGE OF STIRLING ENGINE
 DISADVANTAGE OF STIRLING ENGINE
 PROTOTYPES OF STIRLING ENGINE
 CONCLUSION
 REFERENCES

2. INTRODUCTION
 The purpose of this presentation has been to develop a
Stirling engine capable of operating on variety of heat sources, specifically
on solar heat and traditional fuel combustion. Such an engine would have
applications generating power in remote locations, using solar heat to offset
fuel consumption. This project developed a prototype engine that can be
analyzed to develop a model for use in designing a full scale engine.
 This project, proposed and funded by student sponsor
Jaan Nisar, focuses primarily on the engine itself, rather than the heat
sources or the electricity generation system. This was advised by Professor
Manoj Naik of the Mechanical Engineering Department with Professor
Sunil Kammar of the Mechanical Engineering Department acting as faculty
sponsor. Through this senior project, the poly source team has gained
experience in designing and manufacturing an engine system that combines
thermodynamic and kinetic cycles.
 The results of this project are available for future developers
of Stirling engines, including any students of SUC Poly who wish to take on
a similar project.

3. HISTORY
 The Stirling engine (or Stirling's air engine as it was
known at the time) was invented and patented by Robert
Stirling in 1816. It followed earlier attempts at making an
air engine but was probably the first put to practical use
when, in 1818, an engine built by Stirling was employed
pumping water in a quarry. The main subject of Stirling's
original patent was a heat exchanger, which he called an
"economiser" for its enhancement of fuel economy in a
variety of applications. The patent also described in detail
the employment of one form of the economiser in his
unique closed-cycle air engine design in which application
it is now generally known as a "regenerator". Subsequent
development by Robert Stirling and his brother James, an
engineer, resulted in patents for various improved
configurations of the original engine including
pressurization, which by 1843, had sufficiently increased
power output to drive all the machinery at a Dundee iron
foundry.
 Though it has been disputed, it is widely supposed that as
well as saving fuel, the inventors were motivated to create
a safer alternative to the steam engines of the
time,whose boilers frequently exploded, causing many
injuries and fatalities.
 The need for Stirling engines to run at very high
temperatures to maximize power and efficiency exposed
limitations in the materials of the day, and the few engines
that were built in those early years suffered unacceptably
frequent failures (albeit with far less disastrous
consequences than a boiler explosion) — for example, the
Dundee foundry engine was replaced by a steam engine
after three hot cylinder failures in four years.

4. WHAT IS STIRLING ENGINE
 A Stirling engine is a heat engine that operates by
cyclic compression and expansion of air or other gas
(the working fluid) at different temperatures, such that there
is a net conversion of heat energy to mechanical work. More
specifically, a closed-cycle regenerative heat engine with a
permanently gaseous working fluid. Closed-cycle, in this
context, means a thermodynamic system in which the working
fluid is permanently contained within the system,
and regenerative describes the use of a specific type of
internal heat exchanger and thermal store, known as
the regenerator. The inclusion of a regenerator differentiates
the Stirling engine from other closed cycle hot air engines.
 Originally conceived in 1816 as an industrial prime
mover to rival the steam engine, its practical use was largely
confined to low-power domestic applications for over a
century.
 The Stirling engine is noted for high efficiency
compared to steam engines, quiet operation, and its ability to
use almost any heat source. This compatibility with alternative
and renewable energy sources has become increasingly
significant as the price of conventional fuels rises, and also in
light of concerns such as peak oil and climate change. This
engine is 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.

5. WORKING PRINCIPLE OF STIRLING ENGINE

6. DIFFERENT CONFIGURATION OF STIRLING ENGINE

7. ALPHA TYPE
GAMMA TYPE
BETA TYPE SWASH PLATE DRIVE

11. COMPARISON BETWEEN ALPHA,BETA & GAMMA STIRLING ENGINE
ALPHA STIRLING
ENGINE
BETA STIRLING
ENGINE
GAMMA STIRLING
ENGINE
An alpha Stirling contains two
separate power pistons in
separate cylinders, one "hot"
piston and one "cold" piston.
A beta Stirling has a single
power piston arranged within
the same cylinder on the same
shaft as a displacer piston.
A gamma Stirling is simply a
beta Stirling in which the power
piston is mounted in a separate
cylinder alongside the displacer
piston cylinder, but is still
connected to the same flywheel.
The hot piston cylinder is
situated inside the higher
temperature heat exchanger and
the cold piston cylinder is
situated inside the low
temperature heat exchanger.
The displacer piston is a loose fit
and does not extract any power
from the expanding gas but only
serves to shuttle the working gas
from the hot heat exchanger to
the cold heat exchanger. When
the working gas is pushed to the
hot end of the cylinder it
expands and pushes the power
piston.
The gas in the two cylinders can
flow freely between them and
remains a single body.
This type of engine has a very
high power-to-volume ratio but
has technical problems due to
the usually high temperature of
the "hot" piston and the
durability of its seals.
When it is pushed to the cold
end of the cylinder it contracts
and the momentum of the
machine, usually enhanced by a
flywheel, pushes the power
piston the other way to
compress the gas.
This configuration produces a
lower compression ratio but is
mechanically simpler and often
used in multi-cylinder Stirling
engines.

12. FIVE MAIN COMPONENTS OF STIRLING ENGINE
 Working Gas:
The Stirling cycle is a closed cycle and the various
thermodynamic processes are carried out on a working gas that is
trapped within the system.
 Heat-Exchanger:
Two heat exchangers are used to transfer heat across
the system boundary. A heat absorbing heat-exchanger transfers the
heat from outside the system into the working gas, and a heat
rejecting heat-exchenger transfers heat from the working gas to
outside the system.
 Displacer Mechanism:
This moves(or displaces)the working gas between the
hot and cold ends of the machine (via generator).

13.  Regenerator:
This acts both as a thermal barrier between the hot and
cold ends of the machine, and also as a “thermal store”for the cycle.
Physically a regenerator usually consists of a mesh
materia(Household pot scrubbers have even been used in some
engines), and heat is transferred as the working gas is forced
through the regenerator mesh. When the working gas is displaced
from the hot end of the machine(via regenerator) to the cold end of
the machine, heat is “deposited”in the regenerator, and the
temperature of the working gas is slowered. When the reverse
displacement occurs, heat is “withdrawn”from the regenerator
again. And the temperature of the working gas is raised.
 Expansion/Compression Meahanism:
This expands and/or compresses the working gas.In
an engine this mechanism produces a net work output.

14. EFFICIENCY

15. APPLICATION OF STIRLING ENGINE
1. STIRLING ENGINES FOR PUMPING WATER USING
SOLAR ENERGY AS A SOURCE OF POWER
 Limited availability of petroleum product and electricity in
rural areas and high demandable human need for water
make demand for searching another alternative for pumping
water.
 One optional and potential engine solving this problem is
the solar stirling engine.
 In this system, the solar heat collector provides heat for the
solar,stirling engine whic h in turn provide AC power. The
electrical power can be transferred toa battery charger, then
to DC control unit which can either go into a battery or into
an inverter. Efficiencies for this type of small scale system
can range from 18% - 23%.
 Cost of the equipment is low comparetively.
 Aviation is last major user of leaded fuel, stirling engine
produce less pollution.
 Altitude performance is the stronger reason why these
engines are needed. If a plane could hold a constant power,
it could cruise twice as fast at 40000ft as it can at sea level.
 The main reasons these engines are needed in aviation is
because their motor is silent, smooth torque and lack of
vibration.

16. ADVANTAGES OF STIRLING ENGINE
 Silence of operation : There is no expansion in the atmosphere like in
the case of an internal combustion engine, combustion is continuous
outside of the cylinders. In addition, its design is such as the engine is easy
to balance and generates few vibrations.
 The high efficiency : It is function of the temperatures of the hot and
cold sources. As it is possible to make it work in cogeneration (mechanical
and caloric powers), the overall efficiency can be very high.
 The multitude of possible “hot sources” : Combustion of various
gases, wood, sawdust, waste, solar or geothermic energy...
 The ecological aptitude to respond to the environmental requirements
on air pollution. It is easier to achieve a complete combustion in this type of
engine.
 Reliability and easy maintenance: The technological simplicity makes
it possible to have engines with a very great reliability and requiring little
maintenance.
 An important lifetime because of its “rusticity”.
 The very diverse uses because of its autonomy and adaptability to the
needs and the different kinds of hot sources (from mW to MW).

17. DISADVANTAGES OF STIRLING ENGINE
 The price : its cost is probably the most important problem, it is not yet
competitive with other means well established. A generalization of its
employment should solve this problem inherent in any novelty.
 The ignorance of this type of engine by the general public. Only a few
fans know it exists. It is therefore necessary to promote it.
 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 lack of flexibility : the fast and effective variations of power are
difficult to obtain with a Stirling engine. This one is more qualified to run
with a constant nominal output. This point is a great handicap for an
utilisation in car industry.

18. PROTOTYPES OF STIRLING ENGINE

36. CONCLUSION
 GENERAL:
 The stirling engine is noted for its high efficiency compared to steam
engines, quiet operations, and the ease with it can use almost any heat
source.
 This engine is 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.
 Substantial reduction of Co &HC emissions
 Easy to install
 Payback within a year or less depends upon driving
 No maintenance required and life long
 Can be used on any engines as an auxiliary unit for emission reduction
 Not much popular
 Patented secret construction technology

37. REFERENCES
G. Walker (1980),
W.R. Martini (1983),
T. Finkelstein; A.J. Organ (2001),
Sleeve notes from A.J. Organ (2007),
F. Starr (2001),
C.M. Hargreaves (1991),
Graham Walker (1971).