stirling engine term Project Report

7/31/2019 stirling engine term Project Report

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3RD SEMESTER, MECHANICAL ENGG;

TERM PROJECT REPORT

Semester TERM Project Report On

DESIGN AND FABRICATION

OF A STIRLING ENGINE.

1.:- Syed Anis Badshah UW-09-ME-BE-001

2.:-Qazi Naseer Ahmad UW-09-ME-BE-020

3.:-Muhamad Umair UW-09-ME-BE-030

4.:-Shafique Ahmad UW-09-ME-BE-032

5.:- Syed Shahid Raza UW-09-ME-BE-034

Wah Engineering College

UNIVERSITY OF WAH

JANUARY 2011


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TERM PROJECT REPORT

Looking at the present power scenario we can get an idea of the importance ofalternate ways of getting energy. One of the simpler and cheaper one of these methods is

the Solar-Stirling method. In this method a Stirling engine is coupled onto a solar collector.

One such mechanism for energy generation was desired. The part of the project that is

presented here only deals with the Stirling engine. The engine was designed except for the

regenerator part which was built on hit and trial methods as has been done in nearly all

experimental engines since the calculations involved are too difficult. The theoretical

calculations of the engine were done along with the position analysis of the engine and the

values sorted were used to design the engine. The structural analysis and the thermal

analysis of the engine was done and based on this the design was finalized. The design is

still being fabricated but due to frequent load shedding and other issues the engine could

not be tested in time.

This project is dedicated to

our parents AND Teachers without whose

support and prayers we are nothing.


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TERM PROJECT REPORT

First of all we would like to thank Allah Almighty for giving us the chance and the

courage to carry out this project. Although the task is not complete yet but we have

achieved a lot from this project so we keep on praying to Allah for more.

Secondly, we would like to thank ourSupervisor Engr; Muazma for all the support

and guidance without which we would have never gone so far.

Thirdly we would like to thank WEC lab Staff for their technical advices.

We would like to thank Engr; Tehseen for helping us re-assemble the system.

Stirling engine is a regenerative thermal machine, which operates on a "closed

regenerative thermodynamic cycle, with cyclic compression and expansion of the working

fluid at different temperature levels. The flow is controlled by "volume changes", and there

is a net conversion of heat to work or vice versa.

In this context, closed-cycle means that the working fluid is permanently contained

within the system, whereas "open-cycle" engines such as internal combustion engine and

some steam engines, exchange working fluid with theirsurroundings as part of the cycle.

Regenerative refers to the use of an internal heat exchanger - the regenerator -

which greatly improves the engine's potential efficiency.
http://en.wikipedia.org/wiki/Thermodynamic_systemhttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Steam_enginehttp://en.wikipedia.org/wiki/Thermodynamic_systemhttp://en.wikipedia.org/wiki/Thermodynamic_cyclehttp://en.wikipedia.org/wiki/Stirling_engine#the_regeneratorhttp://en.wikipedia.org/wiki/Stirling_engine#the_regeneratorhttp://en.wikipedia.org/wiki/Thermodynamic_cyclehttp://en.wikipedia.org/wiki/Thermodynamic_systemhttp://en.wikipedia.org/wiki/Steam_enginehttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Thermodynamic_system


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TERM PROJECT REPORT

There are many possible implementations of the Stirling engine, the majority of

which fall into the category of a reciprocating piston engine.

The Stirling engine is traditionally classified as an external combustion engine,

though heat can equally well be supplied by non-combusting sources such as solar or

nuclear energy. A Stirling engine operates through the use of an external heat source and

an external heat sink having a sufficiently large temperature difference between them

In the conversion of heat into mechanical work, the Stirling engine has the potential

to achieve the highest efficiency of any real heat engine, theoretically up to the full Carnot

efficiency, though in practice this is limited by non-ideal properties of the working gas and

engine materials, such as friction, thermal conductivity, tensile strength, creep, melting

point, etc. The engines can run on any heat source of sufficient quality, including solar,

chemical and nuclear.

The major advantages of Stirling Engines are:-

1) They can run directly on any available heat source.

2) A continuous combustion process can be used to supply heat, emissions can be

greatly reduced.3) Most types of Stirling engines have the bearing and seals on the cool side of the

engine; consequently, they require less lubricant and last significantly longer

between overhauls than other reciprocating engine types.

4) The engine mechanisms are in some ways simpler than other types of reciprocating

engine types, i.e. no valves are needed, and the fuel burner system can be relatively

simple.

5)A Stirling engine uses a single-phase working fluid which maintains an internalpressure close to the design pressure.
http://en.wikipedia.org/wiki/Reciprocating_enginehttp://en.wikipedia.org/wiki/External_combustion_enginehttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Nuclear_energyhttp://en.wikipedia.org/wiki/Heat_sinkhttp://en.wikipedia.org/wiki/Work_%28thermodynamics%29http://en.wikipedia.org/wiki/Carnot_cyclehttp://en.wikipedia.org/wiki/Frictionhttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/Tensile_strengthhttp://en.wikipedia.org/wiki/Creep_%28deformation%29http://en.wikipedia.org/wiki/Melting_pointhttp://en.wikipedia.org/wiki/Melting_pointhttp://en.wikipedia.org/wiki/Quality#In_Thermodynamicshttp://en.wikipedia.org/wiki/Quality#In_Thermodynamicshttp://en.wikipedia.org/wiki/Melting_pointhttp://en.wikipedia.org/wiki/Melting_pointhttp://en.wikipedia.org/wiki/Creep_%28deformation%29http://en.wikipedia.org/wiki/Tensile_strengthhttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/Frictionhttp://en.wikipedia.org/wiki/Carnot_cyclehttp://en.wikipedia.org/wiki/Work_%28thermodynamics%29http://en.wikipedia.org/wiki/Heat_sinkhttp://en.wikipedia.org/wiki/Nuclear_energyhttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/External_combustion_enginehttp://en.wikipedia.org/wiki/Reciprocating_engine


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6) They can be built to run very quietly and without an air supply, for air-independent

propulsion use in submarines or in space.

The Stirling engines have many advantages but some disadvantages come with the

package:-

Size and Cost Issues

a. Stirling engine designs require heat exchangers for heat input and for heat output,and these must contain the pressure of the working fluid, where the pressure is

proportional to the engine power output. In addition, the expansion-side heat

exchanger is often at very high temperature, so the materials must resist the

corrosive effects of the heat source, and have low creep (deformation). Typically

these material requirements substantially increase the cost of the engine. The

materials and assembly costs for a high temperature heat exchanger typically

accounts for 40% of the total engine cost.

b. All thermodynamic cycles require large temperature differentials for efficient

operation; however, in an external combustion engine, the heater temperature

always equals or exceeds the expansion temperature. This means that the

metallurgical requirements for the heater material are very demanding. This is similar

to a Gas turbine, but is in contrast to a Otto engine or Diesel engine, where the

expansion temperature can far exceed the metallurgical limit of the engine materials,

because the input heat-source is not conducted through the engine; so the engine

materials operate closer to the average temperature of the working gas.

c. Dissipation of waste heat is especially complicated because the coolant temperature

is kept as low as possible to maximize thermal efficiency. This increases the size of

the radiators, which can make packaging difficult. Along with materials cost, this has

been one of the factors limiting the adoption of Stirling engines as automotive prime

movers. However, for other applications high power density is not required, such as

Ship propulsion, and stationary micro-generation systems using combined heat and

power(CHP)
http://en.wikipedia.org/wiki/Air-independent_propulsionhttp://en.wikipedia.org/wiki/Air-independent_propulsionhttp://en.wikipedia.org/wiki/Submarinehttp://en.wikipedia.org/wiki/Heat_exchangerhttp://en.wikipedia.org/wiki/Creep_%28deformation%29http://en.wikipedia.org/wiki/Gas_turbinehttp://en.wikipedia.org/wiki/Otto_enginehttp://en.wikipedia.org/wiki/Diesel_enginehttp://en.wikipedia.org/wiki/Power_densityhttp://en.wikipedia.org/wiki/Ship#Propulsionhttp://en.wikipedia.org/wiki/Microgenerationhttp://en.wikipedia.org/wiki/Cogenerationhttp://en.wikipedia.org/wiki/Cogenerationhttp://en.wikipedia.org/wiki/Cogenerationhttp://en.wikipedia.org/wiki/Cogenerationhttp://en.wikipedia.org/wiki/Microgenerationhttp://en.wikipedia.org/wiki/Ship#Propulsionhttp://en.wikipedia.org/wiki/Power_densityhttp://en.wikipedia.org/wiki/Diesel_enginehttp://en.wikipedia.org/wiki/Otto_enginehttp://en.wikipedia.org/wiki/Gas_turbinehttp://en.wikipedia.org/wiki/Creep_%28deformation%29http://en.wikipedia.org/wiki/Heat_exchangerhttp://en.wikipedia.org/wiki/Submarinehttp://en.wikipedia.org/wiki/Air-independent_propulsionhttp://en.wikipedia.org/wiki/Air-independent_propulsion


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Power and Torque Issues:

a. Stirling engines, especially those that run on small temperature differentials, are

quite large for the amount of power that they produce (i.e. they have low specific

power). This is primarily due to the low heat transfer coefficient of gaseous

convection which limits the heat flux that can be attained in an internal heat

exchanger to about 4 - 20 W/(m*K). This makes it very challenging for the engine

designer to transfer heat into and out of the working gas. Increasing the

temperature differential and/or pressure allows Stirling engines to produce morepower, assuming the heat exchangers are designed for the increased heat load,

and can deliver the convected heat flux necessary.

b. A Stirling engine cannot start instantly; it literally needs to "warm up".

c. Power output of a Stirling tends to be constant and to adjust it can sometimes

require careful design and additional mechanisms.

Gas Choice Issues:

a. Hydrogen's low viscosity, high thermal conductivity and specific heat make it the

most efficient working gas, in terms of thermodynamics and fluid dynamics, to use in

a Stirling engine. However, given the high diffusion rate associated with this low

molecular weight gas, hydrogen will leak through solid metal, thus it is very difficult to

maintain pressure inside the engine for any length of time without replacement of the

gas. Typically, auxiliary systems need to be added to maintain the proper quantity of

working fluid. These systems can be a gas storage bottle or a gas generator.

Hydrogen can be generated either by electrolysis of water, or by the reaction ofacid

on metal. Hydrogen can also cause the embrittlement of metals. Hydrogen is also a

very flammable gas, while helium is inert.

b. Most technically advanced Stirling engines use helium as the working gas, because

it functions close to the efficiency and power density of hydrogen with fewer of the

material containment issues. Helium is relatively expensive, and must be supplied by
http://en.wikipedia.org/wiki/Specific_powerhttp://en.wikipedia.org/wiki/Specific_powerhttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Viscosityhttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/Specific_heathttp://en.wikipedia.org/wiki/Thermodynamicshttp://en.wikipedia.org/wiki/Fluid_dynamicshttp://en.wikipedia.org/wiki/Molecular_weighthttp://en.wikipedia.org/wiki/Electrolysishttp://en.wikipedia.org/wiki/Acidhttp://en.wikipedia.org/wiki/Hydrogen_embrittlementhttp://en.wikipedia.org/wiki/Inert_gashttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Inert_gashttp://en.wikipedia.org/wiki/Hydrogen_embrittlementhttp://en.wikipedia.org/wiki/Acidhttp://en.wikipedia.org/wiki/Electrolysishttp://en.wikipedia.org/wiki/Molecular_weighthttp://en.wikipedia.org/wiki/Fluid_dynamicshttp://en.wikipedia.org/wiki/Thermodynamicshttp://en.wikipedia.org/wiki/Specific_heathttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/Viscosityhttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Specific_powerhttp://en.wikipedia.org/wiki/Specific_power


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bottled gas. One test showed hydrogen to be 5% absolutely (24% relatively) more

efficient than helium in the GPU-3 Stirling engine.

c. Some engines use air or nitrogen as the working fluid. These gases are less

thermodynamically efficient but they minimize the problems of gas containment and

supply. The use of Compressed air in contact with flammable materials or

substances such as lubricating oil, introduces an explosion hazard, because

compressed air contains a high partial pressure ofoxygen. However, oxygen can be

removed from air through an oxidation reaction, or bottled nitrogen can be used.

Stirling engines have the following major applications:-

Combined heat and power (CHP) applications

CHP is an economical source of mechanical or electrical power, which uses a heatsource in conjunction with a secondary heating application, usually a pre-existing energy

use, such as an industrial process. Usually the primary heat source will enter the Stirling

engine heater.

Solar power generation

Placed at the focus of a parabolic mirror a Stirling engine can convert solar energy to

electricity with an efficiency better than non-concentrated photovoltaic cells, and

comparable to Concentrated Photo-voltaics.

Stirling cryocoolers: Any Stirling engine will also work in reverse as a heat pump: i.e.

when a motion is applied to the shaft, a temperature difference appears between the

reservoirs. One of their modern uses is in refrigeration and cryogenics.
http://en.wikipedia.org/wiki/Airhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Compressed_airhttp://en.wikipedia.org/wiki/Partial_pressurehttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Photovoltaic_cellshttp://en.wikipedia.org/wiki/Concentrated_Photo_Voltaicshttp://en.wikipedia.org/wiki/Heat_pumphttp://en.wikipedia.org/wiki/Refrigerationhttp://en.wikipedia.org/wiki/Cryogenicshttp://en.wikipedia.org/wiki/Cryogenicshttp://en.wikipedia.org/wiki/Refrigerationhttp://en.wikipedia.org/wiki/Heat_pumphttp://en.wikipedia.org/wiki/Concentrated_Photo_Voltaicshttp://en.wikipedia.org/wiki/Photovoltaic_cellshttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Partial_pressurehttp://en.wikipedia.org/wiki/Compressed_airhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Air


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Heat pump:A Stirling heat pump is very similar to a Stirling cryocooler, the main

difference being that it usually operates at room-temperature and its principal application to

date is to pump heat

Marine engines:Kockums, the Swedish shipbuilder, had built at least 8 commercially

successful Stirling powered submarines during the 1980s. As of 2005 they have started to

carry compressed oxygen with them (see Gotland class submarine).

Nuclear power: There is a potential for nuclear-powered Stirling engines in electric

power generation plants. Replacing the steam turbines of nuclear power plants with Stirlingengines might simplify the plant, yield greater efficiency, and reduce the radioactive by-

products.

Automotive engines: While it is often claimed that the Stirling engine has too low a

power/weight ratio and too long a starting time for automotive applications there have been

at least two exclusively Stirling powered automobiles developed by NASA besides earlier

projects by Ford and American Motor Companies.

Aircraft engines: Stirling engines hold theoretical promise as aircraft engines. They are

quieter, less polluting, gain efficiency with altitude, are more reliable due to fewer parts and

the absence of an ignition system, produce much less vibration (airframes last longer) and

safer, less explosive fuels may be used.Geothermal energy: Some believe that the ability of the Stirling engine to convert

geothermal energy to electricity and then to hydrogen may well hold the key to replacement

of fossil fuels in a future hydrogen economy.

Low temperature difference engines:A low temperature difference Stirling engine

will run on any low temperature differential, for example the difference between the palm of

a hand and room-temperature or room temperature and an ice cube. Usually they are

designed in a gamma configuration, for simplicity, and without a regenerator.
http://en.wikipedia.org/wiki/Heat_pumphttp://en.wikipedia.org/wiki/Kockumshttp://en.wikipedia.org/wiki/Gotland_class_submarinehttp://en.wikipedia.org/wiki/Geothermal_energyhttp://en.wikipedia.org/wiki/Geothermal_energyhttp://en.wikipedia.org/wiki/Gotland_class_submarinehttp://en.wikipedia.org/wiki/Kockumshttp://en.wikipedia.org/wiki/Heat_pump


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Stirling's air engine was invented by Reverend Dr Robert Stirling and patented by him in

1816. When the name became simplified to Stirling engine is not known, but may be as

recently as the mid twentieth century when the Philips company began to experiment with

working fluids other than air - the instruction book for their MP1002CA still refers to it as an

'air engine'. The main subject of that original patent was a heat exchanger which Stirling

called the "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 an air

engine, in which application it is now commonly known as a regenerator.

An engine built by Stirling was put to work pumping water in a quarry in 1818. 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

1845 had sufficiently increased the power output for it to successfully drive all the

machinery at a Dundee iron foundry.

As well as conserving fuel, the inventors sought to create a safer alternative to the steam

engines of the time whose boilers frequently exploded with dire consequences, often

including loss of life. However, the need for the Stirling engine to run at a very high

temperature to maximise power and efficiency exposed limitations in the materials of the

day and the few engines which were built in those early years had rather short and

troublesome lives. In particular, 'hot end' failures occurred more frequently than could be

tolerated, albeit with far less disastrous results than a steam boiler explosion.

Though it ultimately failed as a competitor to the steam engine in the field of industrial scale

prime movers, during the latter nineteenth and early twentieth centuries smaller engines of

the Stirling/hot air type (the boundary between the two is often blurred as in many the

regenerator is of dubious efficiency or omitted altogether) were produced in large numbers,

finding applications wherever a reliable source of low to medium power was required, most

commonly perhaps for raising water. These generally operated at lower temperatures so as
http://en.wikipedia.org/wiki/Robert_Stirlinghttp://en.wikipedia.org/wiki/1816http://en.wikipedia.org/wiki/Philipshttp://en.wikipedia.org/wiki/Regeneratorhttp://en.wikipedia.org/wiki/1818http://en.wikipedia.org/wiki/1845http://en.wikipedia.org/wiki/Steam_enginehttp://en.wikipedia.org/wiki/Steam_enginehttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Steam_enginehttp://en.wikipedia.org/wiki/Steam_enginehttp://en.wikipedia.org/wiki/1845http://en.wikipedia.org/wiki/1818http://en.wikipedia.org/wiki/Regeneratorhttp://en.wikipedia.org/wiki/Philipshttp://en.wikipedia.org/wiki/1816http://en.wikipedia.org/wiki/Robert_Stirling


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not to tax available materials and thus tended to be rather inefficient, their major selling

point being that in contrast to a steam engine, they could be operated safely by anybody

capable of managing the fire in a domestic range. As the century wore on, this role was

eventually usurped by the electric motorand small internal combustion engines and by the

late 1930s the Stirling engine was a largely forgotten scientific curiosity represented only by

toys and a few small ventilating fans.

At this time Philips, the large Dutch electrical and electronic manufacturer, began research

into the engine. Seeking to expand the market for its radio sets into areas where mains

electricity power was unknown and the supply of short-lived batteries uncertain, Philips

management decided that what was needed was a low-powered portable generator andtasked a group of engineers at the company research lab (the Nat. Lab) in Eindhoven to

investigate the practicalities. Reviewing various prime movers old and new, each was

rejected for one reason or another until the Stirling engine was considered. Inherently quiet

and capable of running from any heat source (common lamp oil cheap and available

everywhere was favoured), it seemed to offer real possibilities. Encouraged by their first

experimental engine, which produced 16 watts of shaft power from a bore and stroke of

30x25mm, a development program was set in motion.

Remarkably, this work continued throughout World War II and by the late 1940s they had

an engine the Type 10 which was sufficiently developed to be handed over to Philips

subsidiary Johan de Witt in Dordrecht to be productionised and incorporated into a

generator set as originally planned. The set progressed through three prototypes (102A, B,

and C), with the production version, rated at 200 watts electrical output from a bore and

stroke of 55x27mm, being designated MP1002CA (affectionately known as the 'Bungalow

set'). Production of an initial batch began in 1951, but it became clear that they could not be

made at a price that the market would support, in addition to which the advent of transistor

radios with their much lower power requirements meant that the market for the set was fast

disappearing. Though the MP1002CA may have been a dead end, it represents the start of

the modern age of Stirling engine development.

Philips went on to develop the Stirling engine for a wide variety of applications including

vehicles, but only ever achieved any commercial success with the 'reversed Stirling engine'cryocooler. They did however take out a large number of patents and amass a wealth of
http://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Philipshttp://en.wikipedia.org/wiki/Netherlandshttp://en.wikipedia.org/wiki/Eindhovenhttp://en.wikipedia.org/wiki/Prime_moverhttp://en.wikipedia.org/wiki/1940shttp://en.wikipedia.org/wiki/1951http://en.wikipedia.org/wiki/Stirling_engine#Stirling_cryocoolershttp://en.wikipedia.org/wiki/Stirling_engine#Stirling_cryocoolershttp://en.wikipedia.org/wiki/1951http://en.wikipedia.org/wiki/1940shttp://en.wikipedia.org/wiki/Prime_moverhttp://en.wikipedia.org/wiki/Eindhovenhttp://en.wikipedia.org/wiki/Netherlandshttp://en.wikipedia.org/wiki/Philipshttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Electric_motor


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information relating to Stirling engine technology, which was later licensed to other

companies.

It was also employed in reverse as a heat pump to produce early refrigeration

Think Nordic, an electric car company in Norway, is working with inventor Dean Kamen on

plans to install Stirling engines in the Think City, an otherwise all-electric vehicle that will be

commercially available at the end of 2007, at least in Europe.

Since 1988, Kockums shipyards have equipped submarines with Stirling engines. They are

currently used on submarines of the Gotland and Sdermanland classes. These engines

are run on diesel and liquid oxygen and are fitted under

Engineers classify Stirling engines into three distinct types. The Alpha type engine relies on

interconnecting the power pistons of multiple cylinders to move the working gas, with the

cylinders held at different temperatures. The Beta and Gamma type Stirling engines use a

displacer piston to move the working gas back and forth between hot and cold heat

exchangers in the same cylinder.

An alpha Stirling contains two separate power pistons in separate cylinders, one "hot"piston and one "cold" piston. 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. 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.

ACTION OF AN ALPHA TYPE STIRLING ENGINE
http://en.wikipedia.org/wiki/Heat_pumphttp://en.wikipedia.org/wiki/Refrigerationhttp://en.wikipedia.org/wiki/Think_Nordichttp://en.wikipedia.org/wiki/Dean_Kamenhttp://en.wikipedia.org/wiki/Kockumshttp://en.wikipedia.org/wiki/Gotland_class_submarinehttp://en.wikipedia.org/wiki/S%C3%B6dermanland_class_submarinehttp://en.wikipedia.org/wiki/Heat_exchangerhttp://en.wikipedia.org/wiki/Heat_exchangerhttp://en.wikipedia.org/wiki/S%C3%B6dermanland_class_submarinehttp://en.wikipedia.org/wiki/Gotland_class_submarinehttp://en.wikipedia.org/wiki/Kockumshttp://en.wikipedia.org/wiki/Dean_Kamenhttp://en.wikipedia.org/wiki/Think_Nordichttp://en.wikipedia.org/wiki/Refrigerationhttp://en.wikipedia.org/wiki/Heat_pump


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The following diagrams do not show a regenerator, which would be placed in the pipe

connecting the two cylinders. The crankshaft has also been omitted.

1. Most of the working gas is in contact with the hot cylinder walls ,

it has been heated and expansion has pushed the hot piston to the

top of the cylinder. Expansion continues in the cold cylinder piston,

which is 90o

behind the hot piston in its cycle, extracting still more

work from the hot gas.

2. The gas is now at its maximum volume. The hot cylinder piston

begins to move most of the gas into the cold cylinder , where it

cools and the pressure drops.

3. Almost all the gas is now in the cold cylinder and cooling

continues. The cold piston, powered by flywheel momentum or

other piston pairs on the same shaft, compresses the remaining

part of the gas.

4. The gas reaches its minimum volume and the hot cylinder

piston will now allow it to expand in the hot cylinder where it

will be heated once more and drive the hot piston in its power

stroke.

A beta Stirling has a single power piston arranged within the same cylinder on the same

shaft as a displacer piston. 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
http://en.wikipedia.org/wiki/Displacerhttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_8.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_4.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_16.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_12.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_8.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_4.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_16.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_12.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_8.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_4.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_16.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_12.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_8.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_4.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_16.pnghttp://en.wikipedia.org/wiki/Image:Alpha_Stirling_frame_12.pnghttp://en.wikipedia.org/wiki/Displacer


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the cylinder it expands and pushes the power piston. 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. Unlike the alpha

type, the beta type avoids the technical problems of hot moving seals.

ACTION OF A BETA TYPE STIRLING ENGINE

A beta Stirling has two pistons within the same cylinder both connected to the same

crankshaft. One of these is the tightly fitted power piston and the other a loosely fitted

displacement piston.

1. Power piston (dark grey) has

compressed the gas, the displacer

piston (light grey) has moved so

that most of the gas is adjacent to

the hot heat exchanger.

2. The heated gas increases its

pressure and pushes the power

piston along the cylinder. This is

the power stroke.

3. The displacer piston now

moves to shunt the gas to the

cold end of the cylinder.

4. The cooled gas is now

compressed by the flywheel

momentum. This takes less

energy since when it cooled its

pressure also dropped.

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 gas in the two cylinders can flow freely between them but remains a single
http://en.wikipedia.org/wiki/Flywheelhttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_8.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_4.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_16.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_12.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_8.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_4.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_16.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_12.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_8.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_4.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_16.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_12.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_8.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_4.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_16.pnghttp://en.wikipedia.org/wiki/Image:Beta_Stirling_frame_12.pnghttp://en.wikipedia.org/wiki/Flywheel


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body. This configuration produces a lower compression ratio but is mechanically simpler

and often used in multi-cylinder Stirling engines.

Changes to the configuration of mechanical Stirling engines continue to interest engineers

and inventors. Notably, some are in pursuit of the rotary Stirling engine; the goal here is to

convert power from the Stirling cycle directly into torque, a similar goal to that which led to

the design of the rotary combustion engine. No practical engine has yet been built but a

number of concepts, models and patents have been produced.

There is also a field of "free piston" Stirling cycles engines, including those with liquid

pistons and those with diaphragms as pistons.

A recent development of Stirling engines are the thermoacoustic stirling engine, which looks

like the beta Stirling engines but without the displacer.

Virtually, any temperature difference will power a Stirling engine. The heat source may be

derived from fuel combustion, hence the term "external combustion engine", although the

heat source may also be solar, geothermal, nuclear or even biological. Likewise a "cold

source" below the ambient temperature can be used as the temperature difference. A cold

source may be the result of a cryogenic fluid or iced water. In the case where a small

temperature differential is used to generate a significant amount of power, large mass flows

of heating and cooling fluids must be pumped through the external heat exchangers, thus

causing parasitic losses that tend to reduce the efficiency of the cycle.

Because a heat exchanger separates the working gas from the heat source, a wide range

of heat sources can be used, including any fuel or waste heat from some other process.

Since the combustion products do not contact the internal moving parts of the engine, a

Stirling engine can run on landfill gas containing siloxanes without the accumulation ofsilica
http://en.wikipedia.org/wiki/Compression_ratiohttp://en.wikipedia.org/wiki/Rotary_combustion_enginehttp://en.wikipedia.org/wiki/Thermoacoustic_stirling_enginehttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Geothermal_energyhttp://en.wikipedia.org/wiki/Nuclear_powerhttp://en.wikipedia.org/wiki/Biologyhttp://en.wikipedia.org/wiki/Cryogenhttp://en.wikipedia.org/wiki/Landfill_gashttp://en.wikipedia.org/wiki/Siloxanehttp://en.wikipedia.org/wiki/Silicahttp://en.wikipedia.org/wiki/Silicahttp://en.wikipedia.org/wiki/Siloxanehttp://en.wikipedia.org/wiki/Landfill_gashttp://en.wikipedia.org/wiki/Cryogenhttp://en.wikipedia.org/wiki/Biologyhttp://en.wikipedia.org/wiki/Nuclear_powerhttp://en.wikipedia.org/wiki/Geothermal_energyhttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Thermoacoustic_stirling_enginehttp://en.wikipedia.org/wiki/Rotary_combustion_enginehttp://en.wikipedia.org/wiki/Compression_ratio


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that damages internal combustion engines running on this fuel. The life of lubricating oil is

longer than for internal-combustion engines.

.;The Stirling cycle is similar, in some respects, to the Carnot cycle. It is illustrated in

figure.
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The cycle is composed, therefore, of four heat-transfer process.

Process 1-2: isothermal compression; heat transfer from the working f luid at Tminthe external

dump.

Process 2-3: constant volume; heat transfer to the working fluid from the regenerative matrix.

Process 3-4: isothermal expansion; heat transfer to the working fluid at Tmax from an external

source

Process 4-1: constant volume; heat transfer from the working fluid to the regenerative


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We need one more value beside the inputs in order to solve the ideal cycle of the Stirling

engine.


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ENGINE DESIGN:

Our engine design was based around previously designed Stirling engines. Various alpha

type Stirling engine designs along with low speed fossil fuel reciprocating engines were

used to get a rough sketch for our design requirements. Based on these studies and our

design requirements, the following features were to be incorporated in out engine:

A two cylinder design in which one cylinder known as initiating sleeve would

involve the heat addition process and the other known as displacer sleeve,

involveheat rejection process.

The two cylinders are to be at 90o to each other.

Basic reciprocating engine components to give the desired displacement: crankshaft,

connecting rod.

Design of the displacer element keeping in mind the sealing requirements and thepressures inside the cylinders.

Design of the head section and the connection between the two cylinders

stirling engine term Project Report

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