Stirling Cycles

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Stirling EngineFacts and Technology

Marc Alessandria

Ernesto Bosque

Jobe Dyson

Kirby Little


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Overview

History

Advantages

Applications

The Stirling Cycle


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History

Robert Stirling; 1816

Introduced to engineering by his

father

Did not study science in schoolthough

Studied math and Law and

decided to become a preacher

Appointed a minister of theChurch of Scotland in 1816


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History

Here he decided to invent a new

engine

His parish worked the steam

engines

Were very inefficient and often

blew up

Wanted to make his parish lives

more comfortable and safe


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History In 1816 applied for a patent for his

Economiser

It is the most important part of his

engine

The Economiser is responsible forincreasing the efficiency of the

engine

Sadly his engine was never utilized

It always took a back seat to

traditional engines


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History

1850; J. Ericsson

Sold nearly 2,000 engines in N. America

1940s; Phillips Co

Batteries became the preferred source of power


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Advantages

External Heat Source

Environmentally

friendly

Less Wear and Tear Minimal emissions

One cycle medium

Simple design

2 Cylinder

No valves

Minimal maintenance


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Advantage: Efficiency

Highest thermal

efficiency

Difference in temp

Full regeneration,100% effeciency

Combustion engines

lower efficiency


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Disadvantages

Low Power to weight

ratio

Impractical for motion

Internal combustion Practical for motion

Production costs

No large scaleconstruction


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USAGES OF THE STIRLING

ENGINE

Stirling Engine are used in our everyday lives.

Stirling Engine are used in refrigerators.

Liquefied gases founded in welding supply

company are made in Stirling Engine.

The satellite weather channel uses a tiny Stirling

cryo-cooler to cool the image sensor to near

abolute zero.


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Disadvantages to using Stirling

Engines in Vehicles In the past 25 years, Stirling Cycling Research

Group has directed it interest towards theautomotive field.

They are a couple of key characteristics whyStirling Engines are impractical for manyapplications, including most cars and trucks.

Since the heat source is external, it will take a

longer time for the engine to respond to thechanges in the amount of heat that is applied tothe cylinder.


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Cont

In other words, the

engine needs to warm

up to obtain and

produce the usefulpower.

The engine can not

change its power

output quickly.


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Stirling Engines in Aviation

The main reasons these engines are needed in

Aviation is because their motor is silent. Smooth

torque and lack of vibrations.

Aviation is the last major user of leaded fuel,Stirling Engines produce less pollution.

Altitude performance is the strong reason why

these engines are needed. If a plane could hold

a constant power, it could cruise twice as fast at

40,000 ft as it can at sea level.


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Cont

As a safety

precaution, the plane

can also fly above the

weather instead ofthrough it.


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The Stirling CycleProcess breakdown

For stirling enginewithout regenerationFor stirling engine with regeneration


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The Stirling CycleMaterials used in the shop.

k = Thermal Conductivity = Coefficient of Thermal Expansion

= Heat Conduction EquationQ -k A (dT)t dx

Stainless Stealk = 15.9 (W / m*K) = 16E-6 (C-1)

Brassk = 120 (W / m*K)

= 20.0E-6 (C-1

)

Displacer

Cylinder

DisplacerPiston


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Materials used utopia.

The Stirling Cycle

Diamond Displacer Cylinder

k = 3150 (W / m-K) and Displacer Piston = 0.11 - 1.23E-6 (C-1)Cp= 520 (J / kg-K)

Coating of portion ofk = 10 (W / m-K) Diamond Cylinder directly

above flame.

Q -k A (dT)t dx

=


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Materials used utopia.

The Stirling Cycle

= 1 -T

C

TH

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Stirling Cycles

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