Download Team P12472 : Solar Stirling Generator

Team P12472 : Solar Stirling Generator
Friday, January 20th 2012
Room 09-4425 10 AM – 12 PM
https://edge.rit.edu/content/P12472/public/Home
http://en.wikipedia.org/wiki/File:Beta_stirling_animation.gif
Team P12472
Phil Glasser – Lead Engineer, Electrical Engineer
William Tierney – Mechanical Engineer
Bryan Abbott – Mechanical Engineer
Mike Scionti– Mechanical Engineer
Dr. Alan Raisanen – Faculty Guide and Customer

Overview of the project

Confirm Engineering Specifications and Customer Needs

Review concepts

Propose a design approach and confirm its functionality

Cross-disciplinary review: generate further ideas
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Project Description
Work Breakdown Structure
Project Plan
Customer Needs
Engineering Specifications
Concept Development
Proposed Design
Risk Assessment
We wish to demonstrate a small portable Stirling cycle electrical
generator system that can be used to power small portable
USB electronics.
 Stirling generators can use any heat source to produce power
including geothermal, waste heat and in our case solar energy.
 Although mechanically more complex than photovoltaic systems,
stirling generator system efficiency can out perform
photovoltaic system efficiency.
 Our system will require the design of a solar collector component,
a stirling engine component, and an electrical generator,
power conditioner and power storage component.

• The Beta Type Stirling Engine consists of one
cylinder containing a displacer piston and a power
piston , coupled to a flywheel.
• The working fluid on the far side of the cylinder is heated
by some external heat source and the opposite side is
cooled by a heat sink or some method of heat rejection.
• As the working fluid on the hot side expands, it pushes
the power piston towards the cold end of the cylinder.
• On the cold end the gas contracts , pulling the power
piston back towards the hot side.
• The displacer piston acts as a shuttle, moving hot gas
towards the cold side and vice versa.
• The power piston and displacer piston rods are linked to
the flywheel 90 degrees out of phase , producing
output power.
Solar Powered Stirling
Generator
Stirling Engine
(Bryan, Mike,
Will)
Generator (Phil)
Parabolic Mirror
(Will, Bryan,
Mike)
Mounting
structure
Cylinder (Will)
Motor
Power Piston
(Will)
Power
conditioning
Mirror
attachment place
Displacer Piston
(Bryan)
Battery Charge
Circuit
Engine and
generator
attachment place
Heat Sink (Mike)
USB output
Base
Rods and
Linkages (Mike)
Seals (Bryan)
Many Small
Mirrors
Store electrical
power
Output electrical
power to USB
Condition electrical
power
Power Small
Electronics
Generate electrical
power
Convert solar
energy to thermal
energy
Convert thermal
energy to
mechanical energy
Corrosion resistant
Protect System
Weather proofing
Collect solar energy
Convert solar energy
to thermal energy
Focus sunlight on an
object
Mount Stirling engine
Place the hot side of a
Stirling engine in the
focal point of the
sunlight
Mount solar collector
Create a
temperature
difference
Convert thermal
energy to
mechanical energy
Seal fluid in a
chamber
Convert linear
motion to
rotational motion
Convert rotational
motion to
electricity
Heat the working
fluid in a Stirling
engine
Cool the working
fluid in a Stirling
engine
Week
5-8
• Design Engine parameters and 3D
Cad modeling
• Design Mirror and mount
• Electrical design
Week
8-11
• Refine and tweak designs
• In depth analysis and seek the aid of
professors to look over design
• Final simulations, artwork, and
design parameters
Task
Identify team leader
Decide on team norms and behaviors
Identify customer needs
Identify knowns and unknowns
Understand full scope of project
Assess risks and mitigation
High level system design schematic
Update project plan
Work Breakdown Structure chart
Design review powerpoint
Design handout
Detailed design
System Design Review
Peer review for group members
Engine Configuration
Research different configurations of stirling engines
Engine Type Selection Matrix
Determine how much torque engine can output
Determine operating speed of engine
Research types of seals to be used in engine
Select seal to be used in engine
Design engine
Material Selection
Research and select material used for engine block
Research and select material for piston
Research and select material for displacer
Finalize material selection
Heat sink design
Research materials used for heat sinks
Model different materials and fin shapes/spacing
Size and determine how heat sink will be implimented
Mirror design
Research methods of constructing parabolic mirrors
Size mirror to needed power input
Design mirror mount and structure
Generator selection
Research types of motors for power generation
Select motor based upon engine and specs
Autostart mechanism design
Research methods of automatically starting a stirling engine
Determine how much torque is needed to start engine
Design autostart circuit
Battery selection/power control
Appropriately size battery to meet customer needs
Design electronics to control power
Design mounting structures
Owner
Will
Will
Will
Will
All
Will
Will
Phil
Phil
Mike
Phil
Phil
Phil
Phil
Bryan
Bryan
Mike
Will
Will
Bryan
Bryan
Will
Will
Will
Will
Will
Bryan
Bryan
Bryan
Bryan
Will
Will
Will
Will
Phil
Phil
Phil
Phil
Phil
Phil
Phil
Phil
Phil
Phil
Will
Week 1
M T W R F
S
Week 2
S M T W R F
S
Week 3
S M T W R F
S
Week 4
S M T W R F
S
Week 5
S M T W R F
S
Week 6
S M T W R F
S
S M
Week 3
Week 4
Week 5
Week
Week16
Week
Week27
Week
Week38
Week
Week49
Week
Week510
Week
Week611
Task
S S M T W R F S S M T W R F S S M T W R Owner
F S S MM TT WW RR FF SS SS MM TT WW RR FF SS SS MM TT WW RR FF SS SS MM TT WW RR FF SS SS MM TT WW RR FF SS SS MM TT WW RR FF SS SS M
Identify team leader
Will
Decide on team norms and behaviors
Will
Identify customer needs
Will
Identify knowns and unknowns
Will
Understand full scope of project
All
Assess risks and mitigation
Will
High level system design schematic
Will
Update project plan
Phil
Work Breakdown Structure chart
Phil
Design review powerpoint
Mike
Design handout
Phil
Detailed design
Phil
System Design Review
Phil
Peer review for group members
Phil
Engine Configuration
Bryan
Research different configurations of stirling engines
Bryan
Engine Type Selection Matrix
Mike
Determine how much torque engine can output
Will
Determine operating speed of engine
Will
Research types of seals to be used in engine
Bryan
Select seal to be used in engine
Bryan
Design engine
Material Selection
Will
Research and select material used for engine block
Will
Research and select material for piston
Will
Research and select material for displacer
Will
Finalize material selection
Will
Heat sink design
Bryan
Research materials used for heat sinks
Bryan
Model different materials and fin shapes/spacing
Bryan
Size and determine how heat sink will be implimented
Bryan
Mirror design
Will
Research methods of constructing parabolic mirrors
Will
Size mirror to needed power input
Will
Design mirror mount and structure
Will
Generator selection
Phil
Research types of motors for power generation
Phil
Select motor based upon engine and specs
Phil
Autostart mechanism design
Phil
Research methods of automatically starting a stirling engine
Phil
Determine how much torque is needed to start engine
Phil
Design autostart circuit
Phil
Battery selection/power control
Phil
Appropriately size battery to meet customer needs
Phil
Design electronics to control power
Phil
Design mounting structures
Will

USB Charger: Stirling generator must output power through a
USB port.
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Stirling Engine: Generator component must be powered by a
heat engine utilizing the stirling cycle.
Solar Power: Stirling engine must obtain its heat energy from the
sun.
Self Start: Stirling engine must start autonomously.
Low Maintenance: Stirling generator system must operate for
one year, maintenance free.
Inexpensive: Project may not exceed the project budget.
Light Weight: Stirling generator assembly must be relatively
portable and need exceed the weight requirement.
Safe: Stirling generator must not cause any damage to people or
surroundings when operated.

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Power: Stirling generator must output at least 10 Watts of power
when operating.
Voltage: Generator component must provide a nominal voltage of
5 Volts when operating.
Budget: Stirling generator assembly must be within the budget of
$500.
Weight: Stirling generator assembly must be within the weight
requirement of 20 pounds.
Mean Time Between Failures: Stirling generator system must
operate for one year before requiring maintenance.
Weatherproof: Stirling generator must be able to withstand all
weather conditions.




Decision Matrices:
Engine Configuration – Alpha, Beta, Gamma, Free Piston,
Rotary, Ringborn
Linkage – Standard 90 degree offset, Rhombic Drive
Motor – Brushless DC, Stepper, Handwound Flywheel
Battery – Nickel-Metal Hydride, Rechargeable Alkaline,
Lithium Ion, Lead-Acid
We are continuing with the Beta Type Stirling Engine
http://en.wikipedia.org/wiki/Stirling_engine
http://www.ohio.edu/people/urieli/stirling/engines/gamma.html
http://www.bekkoame.ne.jp/~khirata/english/fpse.htm
http://www.bekkoame.ne.jp/~khirata/english/mk_rot.htm
http://www.moriya-press.com/illustrations/ringbom_patent.html
We are continuing with the 90 Degree Offset Crankshaft
http://en.wikipedia.org/wiki/Stirling_engine
We are continuing with the AC Stepper Motor
http://www.edn.com/article/510206-Hardware_controlled_brushless_dc_motors_ease_the_burden_on_CPUs.php
http://en.wikipedia.org/wiki/Stepper_motor
http://www.waterfuelcell.org/phpBB2/viewtopic.php?t=800
We are continuing with the Nickel-Metal Hydride Battery
http://www.batteryfacts.co.uk/BatteryTypes/index.html
http://www.kollewin.com/blog/lead-acid-batteries/
http://www.daviddarling.info/encyclopedia/A/AE_alkaline_battery.html
Parabolic Mirror
and Mount
Beta Type
Stirling Engine
Crank Shaft and
Gearing
Stepper Motor
Power
Conditioning
Battery Charge
Circuit
USB Output 5V
10W
Soft start
Mechanism
Temp sensor
with comparator
Stepper Driver
Chip
Arduino with
temp sensor
Power FETs

5 Volt Output, 2 Amps, 10 Watts

Assuming ~60% efficiency of the generator, 18W motor
needed

Rectify ac stepper voltage to DC by
mixing all the phases through diodes

Linear regulator or buck/boost to desired V
for charge circuit and USB output

Drive motor to overcome generator torque
Materials List
COMPONET
Cylinder
Displacer Piston
Power Piston
Enclosure
Stepper Motor
Battery
Electronics
Parabolic Mirror
Stand
DIMENSIONS
2.55" dia x 8.5"
2.0" dia x 4.6"
2.3" dia x 1"
8" x 3" x 3"
2.2" x 2.2" x 2.2"
2" x 2" x 1"
18" dia
MATERIAL
COST
304 Stainless
Aluminum
304 Stainless
Low Carbon Steel
Lithium Ion
PCB and IC's
Aluminum
Plastic/Wood
Total:
VENDOR
$87.44 McMaster Carr
$21.81 McMaster Carr
$0.00 McMaster Carr
$42.77 McMaster Carr
$50.00 Allied Electronics
$30.00 All-Battery
$80.00 PCB123 and Digikey
$49.95 Edmund Scientifics
$30.00
$391.97
1
Parts arrive late
2
Team runs out of time
3
System weighs too much
4
Mounting structure fails
5
Parts break during installation
6
7
8
9
10
11
12
13
14
Cause
Schedule is delayed
Unreliable vendor, or part is
ordered too late
2
2
Project doesn't get finished
Poor project planning
1
Poor material selection/design 1
Customer needs not met
Mirror breaks and/or
generator system breaks
Need to order/make new
parts to complete
System no longer meets
requirements
Goes over budget, doesn't
finish on time, significantly
increases work load
Poor mounting design
Designed electronics do not
function
Engine does not produce enough
power
Importance
Effect
Careless assembly or poor
assembly procedure
Requirements change
Customer changed his
throughout the project
needs/we change design
Scope of project changes or
A total redesign is needed after
severe miscalculations were
detailed design review
made in detailed design
Something breaks and has to be
Project goes over budget
Can't afford to pay for all parts
re-made/purchased
Battery failure
Severity
Risk Item
Likelihood
ID
Action to Minimize Risk
Owner
4
Constant communication with vendor, good
understanding of lead times
Phil
3
3
Follow and update the project schedule
Phil
2
2
2
3
6
2
3
6
1
2
2
1
3
3
Carefully complete detailed design with factors of
safety
Will
2
2
4
Carefully machine parts, get parts donated
Bryan
Strongly consider weight in engine design and part
selection
Good mounting design. Account for weight and
weather
Plan out how the product will be assembled with
ease
Stay in close contact with customer throughout
design process
Use a fuse and appropriately size battery or add
external power source. Add feature to only allow
charging while engine is running.
Prototype designs and run in depth simulations.
Have a design review with EE professors.
Electronically regulate the voltage and design with
a large factor of safety.
Bryan
Will
Will
Phil
Can't regulate current or start
generator
Battery shorts or is run dry
2
3
6
Generator runs but the USB
does not provide power
Faulty circuit design
1
3
3
2
2
4
2
1
2
Purchase extra sensors and be sure to have good
contact between engine and sensor.
Phil
2
3
6
Prototype designs and run in depth simulations.
Do a power study.
Phil
1
3
3
Test seals without system inside.
Bryan
Engine is not spinning fast
enough
Sensors don't make contact with
Thermo sensor fail to accurately Engine will not auto-start at an
the cylinder, or faulty
measure temperature difference
appropriate time
equipment
Thermocouple fails, motor fails,
Autostart mechanism fails
Engine will not auto-start
batteries die, poor circuitry or
control logic, etc.
System is exposed to the
Poor sealing or mounting of
Weatherproofing fails
environment
enclosure.
Customer needs not met
Phil
Phil
Phil
15
16
17
18
19
20
21
Teammates do not do assigned
work
23
Teammates do not meet
deadlines
25
26
27
Importance
Cause
Melting point of selected
material is too low or the
focused energy was too great
Constructed mirror doesn't have Can't efficiently heat the hot Poor contruction and inprecise
a concentrated focal point
side of stirling engine
parabolic shape
Temperature difference does not
Not imputing enough energy or
reach minimum value to operate
System will not operate
the heat sink is not working well
engine
enough.
Engine will not operate, either
Tolerance buildup or poor
Piston/chamber don't integrate
jam or leak.
machining or communication.
Seal can ware due to usage,
Efficency of engine drops
Seal does not function
corrosion, or possibly not size.
significantly.
Deformation of seal.
Mistakes, not checking
Improper sizing or selection of
Teammates do work incorrectly
eachother work, not
components.
understanding theory.
Progress is not made, work is
Lack of communication among
Falling out amoung team
repeated, components don't
team
members.
integrate.
Engine material on hot side
melts down
22
24
Effect
Severity
Risk Item
Likelihood
ID
Action to Minimize Risk
Owner
1
3
3
Carefully model the temperature that can be
reached with our mirror and properly select metal
Will
1
2
2
Purchase premade mirror
Mike
2
3
6
Appropriately select mirror and design heat sink.
Mike
1
3
3
Measure twice, cut once.
Bryan
2
3
6
Minimize friction and maximize heat expelled
through heat sink
Mike
2
2
4
Check eachothers work, run simulations and have
design reviews.
Phil
2
3
6
Weekly meetings, check email frequently.
Phil
Work doesn't get done, trust is Not know how to do the task, a
2
lost, and confilcts arise.
major event arised, or was lazy.
2
4
If you need help, get help. Let the group now asap
if you think there will be trouble completeing the
task.
Phil
1
3
3
Actively manage eachothers time.
Phil
2
2
4
Have a discussion with a moderator. Hang out as
group and not do work.
Phil
1
3
3
Try to contact him or go to Mark Smith.
Phil
1
3
3
N/A
Mike
3
2
6
Be forward about time commitment issues
Will
System fails
Timeline keeps getting
Laziness, high external work
pushed back and project is
load.
getting delayed.
Team does not work
Teammates do not follow team
efficiently and a hostile work
Ego's and stubborness.
norms
environment is created.
Team won't know if customer
He get's too busy to dedicate
Inability to contact guide/mentor needs changed or if our design
any time to us.
is reasonable.
Resources lost, work load is
Freak accident/disregard for the
Reduction of team size
increased. Project scope may
team.
be changed.
Reallotting of teammate time
Meeting times must change
Job status changes
commitment