taf(thermal accoustic refregeraton)

8/13/2019 Taf(thermal accoustic refregeraton)

1/45


2/45

Trevor Bourgeois

Mike Horne Peter Smith

Erin MacNeil

SupervisorDr. Murat Koksal

Team Members


3/45

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


4/45

Main Prototype Components

Speaker

Gas

Tube

Stack

Heat Exchangers


5/45

Speaker

Considerations Power Capacity

Frequency Response

Choice 10 inch

Operates At LowFrequencies (100 Hz)

400 W Maximum Power


6/45

Gas Medium

Considerations Physical Properties

Sealing

Cost

Choice Air

Atmospheric Pressure


7/45

Tube

Considerations Length

Diameter

Sound Reflection

Low Acoustic Losses

Sound Transmission

Choice 1.5 PVC Tube

Flat End

f

cl

2


8/45

Considerations Gap Size

Material properties

Material thickness

Location

Length

Does not impede wave

Choice Paper

Aluminum Screen

Stack


9/45

Heat Exchangers

Considerations Material

Type

Choice Aluminum

Water Circulated


10/45

Solid Porous Material

Give And Takes Heat From Gas

Heat Transfer

DT Across

Stack


11/45

Gap Size

Solid Thickness

Position

Length

Ability Of Sound To Pass Through

Physical Properties

Design Considerations


12/45

Foil

Paper

Foam

Lexan

Screen

Stack Designs


13/45

Foil

Aluminum Foil

Crimped

Rolled Up AroundCentre Post


14/45

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


15/45

Paper

Couragrated Paper

Rolled Up


16/45

Paper


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


17/45

Foam

Open Cell Foam

Cut To ApproximateShape

Tape To Hold TwoPieces Together


18/45

Foam


Length 54.04 mm

Gap Size 0.5 mm

PLASTIC FOAM STACK


19/45

Lexan

Strips Thin Lexan

Monofilament FishingLine Used As Spacers

Rolled Up Around APencil


20/45

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


21/45

Screen

Aluminum Screen

Punch To Cut Circles

Many Layers


22/45

Screen


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


23/45

Experimental Setup

P

ressureTransducers

Thermocouples


24/45

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


25/45

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


26/45

Stack Temperature Results


27/45

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


28/45

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


29/45


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


30/45


Pros:Few manufacturing stepsLow cost operation

Cons: Long enough drill bitPossible tool wandering

Drill Thru Channel Design


31/45


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


32/45


Pros:Greater heat transfer rate

Cons:Higher manufacturing costsLonger build time

Sealing

Larger pump ( )

Tube Flow Design

4

1

RP


33/45


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


34/45


Pros:Better rate of heat transferthan the first design.

Lower machining costs than

the second design.

Cons:Sealing

CNC Milled Channel Design


35/45

ReservoirWooden Cartridge

Heat Exchanger Setup



Large Reservoir to keepwater at a constant

temperature


36/45

Wooden Cartridge

Heat Exchanger Setup



ColdSpace

Represents our refrigerating capacity


37/45

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


38/45


4.8C in 30 minutes 1.2C in 30 minutes

ColdSpace

Cooling from atmosphereCooling From Prototype

ColdSpace


39/45


3.6C in 30 minutes

Cooling From Prototype

ColdSpace

Heat removal rate of 16.7W

Speaker drawing power at 90.25W

COP = 0.185


40/45

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)


41/45

Recommendations

Theoretical Work

Calculate Operating Frequency

Heat Exchanger Calculations


42/45

Recommendations

Theoretical Work

Experimentation Stack Gap Size

Stack Location

Stack Length


43/45

Recommendations

Theoretical Work Experimentation

Equipment Improvements

Pressure Transducers

Signal Generator


44/45

Recommendations

Theoretical Work Experimentation

Equipment Improvements

Design Changes

Speaker Funneling

Helium Heat Exchangers

Insulation (thermal, acoustic)

Mechanical Resonator


45/45

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

taf(thermal accoustic refregeraton)

Documents