taf(thermal accoustic refregeraton)
TRANSCRIPT
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Trevor Bourgeois
Mike Horne Peter Smith
Erin MacNeil
SupervisorDr. Murat Koksal
Team Members
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Design Description
Thermoacoustic Refrigerator
Unpressurized System Air as Gas Medium
Loudspeaker as Acoustic Driver
Variable design (stacks)
Advantages of Thermoacoustic Refrigeration
No Environmentally-Harmful Refrigerants
Mechanically Simple
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Main Prototype Components
Speaker
Gas
Tube
Stack
Heat Exchangers
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Speaker
Considerations Power Capacity
Frequency Response
Choice 10 inch
Operates At LowFrequencies (100 Hz)
400 W Maximum Power
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Gas Medium
Considerations Physical Properties
Sealing
Cost
Choice Air
Atmospheric Pressure
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Tube
Considerations Length
Diameter
Sound Reflection
Low Acoustic Losses
Sound Transmission
Choice 1.5 PVC Tube
Flat End
f
cl
2
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Considerations Gap Size
Material properties
Material thickness
Location
Length
Does not impede wave
Choice Paper
Aluminum Screen
Stack
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Heat Exchangers
Considerations Material
Type
Choice Aluminum
Water Circulated
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Solid Porous Material
Give And Takes Heat From Gas
Heat Transfer
DT Across
Stack
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Gap Size
Solid Thickness
Position
Length
Ability Of Sound To Pass Through
Physical Properties
Design Considerations
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Foil
Paper
Foam
Lexan
Screen
Stack Designs
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Foil
Aluminum Foil
Crimped
Rolled Up AroundCentre Post
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Foil
Value UnitsOuter Diameter 47.86 mm
Length 63.63 mm
Gap Size 1.07 mm
Foil Thickness 0.1 mm
Center Post Diameter 2.42 mm
Thermal Conductivity 180 W/m*K
Density 2790 K /m3
ALUMINUM FOIL STACK
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Paper
Couragrated Paper
Rolled Up
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Paper
Value UnitsOuter Diameter 49.8 mm
Length 55.4 mm
Gap Size 1.44 mm
Paper Thickness 0.12 mmThermal Conductivity 0.18 W/m*K
Density 930 K /m3
PAPER STACK
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Foam
Open Cell Foam
Cut To ApproximateShape
Tape To Hold TwoPieces Together
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Foam
Value UnitsOuter Diameter 51.14 mm
Length 54.04 mm
Gap Size 0.5 mm
PLASTIC FOAM STACK
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Lexan
Strips Thin Lexan
Monofilament FishingLine Used As Spacers
Rolled Up Around APencil
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Lexan
Value UnitsOuter Diameter (no tape) 45.18 mm
Outer Diameter (with tape) 48.71 mm
Length 51.9 mm
Gap Size 0.4 mmLexan Thickness 0.2032 mm
Center Post Diameter 7.03 mm
Thermal Conductivity 0.18 W/m*K
Density 1119 Kg/m^3
LEXAN STACK
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Screen
Aluminum Screen
Punch To Cut Circles
Many Layers
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Screen
Value UnitsOuter Diameter 50.56 mm
Length 51 mm
Gap Size 1.69 mm
Wire Diameter 0.24 mmThermal Conductivity 180 W/m*K
Density 2790 Kg/m^3
ALUMINUM SCREEN STACK
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Experimental Setup
P
ressureTransducers
Thermocouples
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Stack Ranking
Pairwise Ranking Method
Important Attributes Determined Ranked According to Importance For Each Stack
Attribute Compatibility Cost LTCS Manu. P / E DT
Compatibility ----------- 0 0 0 0 2
Cost 2 ----------- 2 1 1 2
LTCS 2 0 ----------- 0 0 2
Manu. 2 1 2 ----------- 1 2
P / E 2 1 2 1 ----------- 2
DT 0 0 0 0 0 -----------
Sum 8 2 6 2 2 10
Weight 0.267 0.067 0.2 0.067 0.067 0.333
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Stack Ranking
Aggregate Scoring System
10 = Highly Effective 0 = Not Effective
Attribute Al Screen Paper Foam Lexan Al Foil Weight
Compatibility 6 5 7 5 4 0.267
Cost 6 8 8 8 8 0.067
LTCS 9 8 2 6 3 0.2
Manu. 7 9 10 1 4 0.067
P / E 5 5 4 3 4 0.067
DT 9 9 4 5 6 0.333
Score 7.605 7.406 5.075 5.004 4.738 1
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Stack Temperature Results
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Heat Exchanger
Cold Side
To use the cold temperatureproduced and cool a cold space
Hot Side
Experiments: heat conduction fromhot side to cold side
If we cool the hot side, we will beable to obtain a colder cold side
Hot Side Heat Exchanger
Wooden Cartridge
Cold Side Heat Exchanger
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Heat Exchanger Evolution
Heat exchanger must becompatible with our
present design
Four Bolt Holes
Floating fastener assembly
Center Hole
To hold part of the stack
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Heat Exchanger Evolution
Manufacturing
Drill three thru holes
Intersect at right angles
Four ends tapped and plugged Front two ends tapped for a
1/8 NPT thread
Drill Thru Channel Design
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Heat Exchanger Evolution
Pros:Few manufacturing stepsLow cost operation
Cons: Long enough drill bitPossible tool wandering
Drill Thru Channel Design
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Heat Exchanger Evolution
Tube Flow Design
Manufacturing CNC machine a pocket for the
tube insert
Tube insert Machined block
Connects five 1/16 diametertubes.
Seal with silicone
Drill and tap two ends for a 1/8NPT threadTube Insert
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Heat Exchanger Evolution
Pros:Greater heat transfer rate
Cons:Higher manufacturing costsLonger build time
Sealing
Larger pump ( )
Tube Flow Design
4
1
RP
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Heat Exchanger Evolution
CNC Milled Channel Design
Manufacturing CNCend mill curved profile
Thickness of wall is 2mm
Front two ends drill and tap fora 1/8 NPT thread
oiy PPba
a
22
2
21
max
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Heat Exchanger Evolution
Pros:Better rate of heat transferthan the first design.
Lower machining costs than
the second design.
Cons:Sealing
CNC Milled Channel Design
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ReservoirWooden Cartridge
Heat Exchanger Setup
Hot Side Heat Exchanger
Cold Side Heat Exchanger
Large Reservoir to keepwater at a constant
temperature
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Wooden Cartridge
Heat Exchanger Setup
Hot Side Heat Exchanger
Cold Side Heat Exchanger
ColdSpace
Represents our refrigerating capacity
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Heat Exchanger Experiments
H.E. Experiment (Aluminum Screen)
0
5
10
15
20
25
30
35
40
45
50
0 20 40 60 80 100 120
Time (s)
Temperature(C)
Cold Side - No Pump Hot Side - No Pump Ambient
Cold Side - Hot Side Pump Hot Side - Hot Side Pump
-ve Slope
-ve Slope
+veSlope
+ve Slope
5.5C
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Heat Exchanger Experiments
4.8C in 30 minutes 1.2C in 30 minutes
ColdSpace
Cooling from atmosphereCooling From Prototype
ColdSpace
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Heat Exchanger Experiments
3.6C in 30 minutes
Cooling From Prototype
ColdSpace
Heat removal rate of 16.7W
Speaker drawing power at 90.25W
COP = 0.185
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Less than meter long, less than 20lb
DT of 5-10C below ambient
Sound Insulation
Introduce Heat Exchangers
10-20 Watts Cooling
Build for less than $2,000.00
Users Manual
Comparison with Project Goals
(17 C)
(16.7 W)
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Recommendations
Theoretical Work
Calculate Operating Frequency
Heat Exchanger Calculations
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Recommendations
Theoretical Work
Experimentation Stack Gap Size
Stack Location
Stack Length
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Recommendations
Theoretical Work Experimentation
Equipment Improvements
Pressure Transducers
Signal Generator
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Recommendations
Theoretical Work Experimentation
Equipment Improvements
Design Changes
Speaker Funneling
Helium Heat Exchangers
Insulation (thermal, acoustic)
Mechanical Resonator
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Built prototype with variable stacks
Performed comprehensive set of experiments Determined optimum stack
Designed Heat Exchanger
Heat Exchanger tests performed
16.7 W cooling power
Coefficient of Performance 0.185
Term Summary