8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 1/15

Welcome toNASA Power Systems:

Research in New Energy

TechnologyNetwork of Educator Astronaut Teachers

(NEAT)

Education Outreach

Glenn Research Center Region

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 2/15

NASA Glenn ResearchCenter

Research Areas•Power Systems Research

•Solar Voltaics

•Nuclear Power•Wind Energy

•Electric Propulsion

•Fuel Cells•Stirling Engine

•Battery Technology

•Microgravity Research•Drop Towers

•Exercise Countermeasures

•Return to Flight Impact Risk Research

•Vacuum Research

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 3/15

“Any sufficiently advanced

technology isindistinguishable from

magic.”Arthur C. Clarke

Science = Exploration,

Mystery, and Magic

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 4/15

1816

by Rev. Robert Stirling

of Scotland

Stirling Engines

Sir William Robert Grove &his “Gas Voltaic Cell”

1839

Fuel Cells

Ion Propulsion

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 5/15

Stirling History

• Stirling engine invented in 1816 by Rev. Robert Stirling of Scotland

• Kinematic engine with crankshaft and flywheel

• Competed with early steam engines as higher efficiency alternative

• Efficiency was high because Robert Stirling’s original patent included

the economizer, known today as a regenerator.• Operated at 1 atmosphere of air mean cycle pressure

• As popular as steam engines until the development of boiler code, highpressure boilers

Reverend Robert Stirling

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 6/15

Charles’s LawV1 V2

T1= T2

How Does a Stirling Engine Work

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 7/15

Stirling Operation

The Key

Economizer = Regenerator =Displacer

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 8/15

Stirling Operation

Th

Tc

Displacer Displacer at Cold End

Working Fluid in Hot Space

CreatesHigh Pressure

Displacer at Cold End

Working Fluid in Hot Space

CreatesHigh Pressure

Th

Tc

Displacer at Hot End

Working Fluid in Cold Space

Creates Low Pressure

Displacer at Hot End

Working Fluid in Cold SpaceCreates Low Pressure

Th

Tc

Th

Tc

Power OutputFrom the Engine

Power Output

From the Engine

Low Power Into

the Displacer Drive

Low Power Into

the Displacer Drive

Gamma Configurationof Stirling Engine

Gamma Configuration

of Stirling Engine

Add a Displacer to Shuttle the

Working Fluid between the Hot& Cold Spaces

Add a Displacer to Shuttle the

Working Fluid between the Hot

& Cold Spaces

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 9/15

Rhombic Drive Stirling

• Rhombic driveprovides linearmotion

• Sliding seals areused and the internalpressure is raised

• Use gas other thanair, such as helium orhydrogen

• Greatly increases thepower and efficiency

• Including the

regenerator (aka, theeconomizer)

Birth of the Free Piston

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 10/15

Birth of the Free-PistonStirling

Free-Piston Stirling

Power Convertor

Free-Piston Stirling

Power Convertor

Rhombic Drive Stirling

Engine

Rhombic Drive Stirling

Engine

Th

Tc

Heat In

Heat In

Electric

Power Out

Electric

Power Out

Th

Tc

With the appropriate areas andpressure, the displacer drive rod

can become unloaded, i.e. self 

driving operation

With the appropriate areas andpressure, the displacer drive rod

can become unloaded, i.e. self 

driving operation

With the addition of a load,

such as a linear alternator,

the Stirling engine becomes a

Stirling power convertor

With the addition of a load,

such as a linear alternator,

the Stirling engine becomes a

Stirling power convertor

With proper masses, spring rates, areas,

and damping coefficients (dynamictuning), the convertor will resonate as a

Free-Piston Stirling Convertor

With proper masses, spring rates, areas,

and damping coefficients (dynamic

tuning), the convertor will resonate as aFree-Piston Stirling Convertor

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 11/15

How Can We Use Stirling in Space?• Could be solar heated if used in earth orbit

• Nuclear power system, either surface poweror flight

• Radioisotope heat source for deep space

• To remove waste heat from electrical systemsand habitats.

Nuclear Lunar Station Nuclear Flight System

Solar Dynamic System

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 12/15

Why Would We Use Stirling in

Space?

• Reduce the use of plutonium

• Stirling is 4 times more efficient thanother options

• Specific power (W per kg) is higher

than other options• The best option for deep space

probes that cannot use solar power

in deep space.

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 13/15

The Current Technology

NASA/MTI 25-kWe Space Power

Demonstrator EngineCFIC/CPG 5-kWe solar terrestrialconvertor

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 14/15

For Teachers only:

Lesson Connections:

• Gas Laws

• Kinetic theory

• Simple Machines

Can you think of others?

8/4/2019 Stirling Power

http://slidepdf.com/reader/full/stirling-power 15/15

INAAPTApril 21, 2007NASA Power SystemsNew Space TechnologyUsing Stirling EnginesPresenter:Doug PorterRising Sun High School210 South Henrietta StreetRising Sun, IN 47040(812) 438-2652

e-mail: dporter@risingsun.k12.in.usNASA Network of Educator Astronaut TeachersNASA Ames Airspace EducatorNASA Spaceward Bound Mojave Expedition 2007

Links:

Stirling Engines Website

http://www.stirlingengine.com/Stirling Engine Forumhttp://www.stirlingengine.com/bboard/q-and-a.tcl?topic_id=5&topic=Stirling%20engines%20for%20education

Test tube Rhombic Stirling Engine Site

http://www.geocities.com/~rrice2/my_engines/ttr/ttr.htmlTest Tube Stirling Engine Labhttp://www.mech.canterbury.ac.nz/documents/testube.pdf