Adaptive Maze

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Adaptive Maze

• Finding a project through a changing maze of
  complications

Project Team Krista Miller Sohaib Hasan John
Helme
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Excess Thermal Energy From Solar Panels

• Problem
• Solar panels installed in the Alternative
  Energy Laboratory can be damaged if heated to
  temperatures above 180 F.

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Considered Solutions

• Energy Dumping System
• Dissipate excess heat by routing the solar panel
  output through underground coils.
• Energy Conversion System
• Dissipate excess heat by converting it to other
  forms of energy
• Mechanical Energy Stirling Engine
• Electrical Energy Seebeck device
• Energy Blocking System
• Cover solar panels to reduce energy input.

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Energy Dumping System

• Install valves and pipes to allow the output of
  the solar panels to run through underground pipes

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Energy Dumping System

• Advantages
• System is always on.
• Few components.
• Convection currents maybe used to allow the
  system to work without motors, sensors or
  switches.

• Disadvantages
• Excess energy is lost
• To simple to earn an acceptable grade.
• Excavation and plumbing maybe to expensive.

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Energy Conversion Systems

• How much excess energy is available?
• Q cm(T1-T2) Q Heat energy
• c specific heat
• cwater 4.186j/gC
• For one kg of water T1 90F 32.2C
• Q3669kJ T2 180F90C

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Energy Conversion Systems

• How much power is being added to the system?

Panel Characteristics Panel Characteristics
Quantity 10
Area 2.96m2
Efficiency Up to 70
Solar insolation for Vermont 400W/m2
Powernew Quantity Area Efficiency Solar
insolation 8288W
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Energy Conversion Stirling Engine

• The stirling engine uses a temperature
  differential cause gases to expand and compress.
  This expansion and compression is used to drive
  one or more cylinders.

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Stirling Engine

• Advantages
• High efficiency engine
• Direct conversion from thermal energy to
  mechanical energy
• Mechanical energy could be applied to cooling the
  facility

• Disadvantages
• Very complicated and experimental
• May require higher temperatures to work without
  using special gases
• May not dissipate enough energy to keep the
  panels cool

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Energy Conversion Seebeck Device
A voltage is created when there is a temperature
difference between two different metals or
semiconductors.
V (SB-SA) (T2-T1) V Voltage generated S
Thermoelectric Power Coefficient for materials A
and B T Temperature at junctions 1 and 2
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Seebeck Device
Seebeck Power Generation Module Seebeck Power Generation Module
Output T1 150C, T2 50C 5.8 W
Price (each) 43.95
Approximate cost to generate 50W with a temperature difference of 50 880.00
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Seebeck Device

• Advantage
• Thermal energy is converted to electrical energy
• Electrical energy can be applied to other
  applications in the facility

• Disadvantage
• Expensive
• Will not dissipate enough energy to keep solar
  panels cool

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Energy Blocking System
Solar Panel
Panel Screen

• Solar panels will be covered before the critical
  temperature of 180F is reached. Covers will
  stop the panels from continuing to heat.

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Energy Blocking System

• Advantages
• Definitive control of solar panel heating process
• Uses electro-mechanical devices and systems.

• Disadvantages
• Potential energy is not acquired

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Solution Summary
Solution Resolves Problem Economically Feasible Conserves Energy Uses Electro-mechanical systems
Dump heat into ground Yes No No No
Sterling Engine No limited heat dissipation Unknown Yes Yes
Seebeck Device No limited heat dissipation No Yes Yes
Energy Blocking Yes Yes No Yes
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Solution Statement

• Blinds or screens will be automatically
  positioned to cover a solar panel before the
  panel temperature reaches a critical level.
• Each panel will have an complete and
  independent blind system.
• The blind system for multiple panels can be
  controlled by a single override control.

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Heat Blocking System Overview
Water Temperature Sensor
Panel Position Sensors
Manual Override
Controller
Battery
Motor to raise/lower panel
Panel Assembly
Active Solar Panel
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Mechanical System Diagrams
Below is a photo of how the gears will rotate and
move the shade up and down, to cover or uncover
the panels.
Above is a picture of how the solar panel cover
will be mounted on the existing panels.
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State Diagram
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States of Panel Covers
Cover Panel Too much Sun, Cover starts to
slide over Panel due to Temperature exceeding
limits.
Wait Panel finished being covered and is
shielded from sun.

• Start Sun levels OK, not Overheating.

Remove Cover Temperature has been lowered,
remove cover.
Wait Temperature has decreased, cover fully
removed.
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Solar Panel Covers

• Metal Shading
• Advantages
• Holes in it will allow wind to escape
• Commercially Available
• Attaches very well onto other things
• Disadvantages
• Depending on metal, may rust
• Will get hot

• Plastic Fabric
• Advantages
• Weatherproof
• Commercially Available
• Disadvantages
• Wind will get caught without holes to escape
  through
• Will have to have a fastening system
• Depending on material, can get hot

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Temperature Sensing

• Integrated Circuit
• Advantages
• Most Linear
• High Output
• High Accuracy
• Inexpensive
• Disadvantages
• Power Required
• Slow
• Self Heating
• Not meant to be used outdoors

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Temperature Sensing

• Thermistor
• Advantages
• High Output
• Fast
• Two Wire Ohm Measurement
• Disadvantages
• Non Linear
• Limited Temperature Range
• Fragile
• Current Source Required
• Self Heating

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Temperature Sensing

• RTD
• Advantages
• Stable
• Accurate
• Disadvantages
• Expensive
• Current Source Required
• Small ?R
• Self Heating

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Temperature Sensing

• Thermocouples
• Advantages
• Self Powered
• Simple
• Rugged
• Inexpensive
• Wide Temperature Range
• Disadvantages
• Non-Linear
• Low Voltage
• Sensitivity

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Switches
Upper Limit Switch
Lower Limit Switch
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Brushless DC Motors

• Advantages
• Increased Reliability Efficiency
• Longer Life
• Elimination of Sparks from Commutator
• Reduced Friction
• Faster Rate of Voltage Current
• Precision Voltage Current Applied to Field Coils

• Disadvantages
• Requires Complex Drive Circuitry
• Requires additional Sensors
• Higher Cost
• Some designs require manual labor
• (Hand wound Stator Coils)

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Microcontroller

• Freescale HCS08
• 10bit analog to digital converter
• Ease of use
• Inexpensive
• Available Code

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Personnel Assignments
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Expected Costs
  Cost Each Quantity Cost Per Panel
Motor 40.00 1 40.00
Panel Covering 50.00 1 50.00
Gears 2.50 4 10.00
Chain 1.50 20 30.00
Gear Box 25.00 1 25.00
Cover Sensors 1.50 4 6.00
Temperature Sensors 1.25 2 2.50
Battery 50.00 1 50.00
Active Solar Panel 100.00 1 100.00
      313.50
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Questions?