ThermoAcoustic Refrigeration - Annual 2003 Arman

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Copyright 2001, Praxair Technology, Inc. All rights reserved. Copyright 2003 Praxair Technology, Inc.

ThermoacousticThermoacoustic

RefrigerationRefrigeration

Bayram Arman, Ph.D.Praxair, Inc.

Tonawanda, NY

Presented at ASHRAE Annual Meeting

Kansas City, MO, June 29, 2003


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June 2003 -- B Arman 2

Disclaimer

THIS INFORMATION WAS PRESENTED AT AN ASHRAE SEMINAR HELD

AT THE 2003 SUMMER MEETING IN KANSAS CITY, MO. THE SEMINAR

FORMAT IS TO PRESENT INFORMATION OF CURRENT INTEREST AND

TO PROVIDE A VENUE FOR INTERACTION BETWEEN ASHRAEMEMBERS. THESE SEMINARS SHOULD NOT BE CONSIDERED PEER-

REVIEWED (OR THE FINAL WORD ON ANY SUBJECT). ASHRAE HAS

NOT INVESTIGATED, AND ASHRAE EXPRESSLY DISCLAIMS ANY DUTY

TO INVESTIGATE ANY PRODUCT, SERVICE, PROCESS, PROCEDURE,

DESIGN, OR THE LIKE WHICH MAY BE DESCRIBED HEREIN. THEAPPEARANCE OF ANY TECHNICAL DATA OR EDITORIAL MATERIAL

IN THIS PRESENTATION DOES NOT CONSTITUTE ENDORSEMENT,

WARRANTY, OR GUARANTY BY ASHRAE OF ANY PRODUCT, SERVICE,

PROCESS, PROCEDURE, DESIGN, OR THE LIKE. NEITHER ASHRAE,

THE AUTHORS OR THEIR EMPLOYERS WARRANT THAT THE

INFORMATION IN THIS PRESENTATION IS FREE OF ERRORS. THEENTIRE RISK OF THE USE OF ANY INFORMATION IN THIS

PRESENTATION IS ASSUMED BY THE USER. BEFORE MAKING ANY

DECISION OR TAKING ANY ACTION ON THIS SUBJECT, YOU SHOULD

CONSULT A QUALIFIED PROFESSIONAL ADVISOR.


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Definitions

Thermoacoustic refrigerator is a device that converts acousticpower into refrigeration

Linear motor is a device that produces linear oscillatorymotion in a gas or acoustic power

Thermoacoustic engine is a device that produces linearoscillatory motion or acoustic power utilizing heat


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Outline

Introduction

Drive Options

Linear Motor Compressors

Standing Wave Thermoacoustic Coolers

No Feedback Thermoacoustic Cryocoolers (Orifice Pulse

Tubes)

Full Feedback Thermoacoustic Coolers

Free-Piston Stirling Coolers & Cryocoolers

Closure


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Introduction

New Opportunities

0

1

50

100

150

200

250

300

10 100 1000 10000 100000 1000000 10000000

Cold

Temperature(K)

Cooling Power (watt)

PHYSICS,

MEDICAL

RESEARCH

AIR SEPARATION & LNG

AIR CONDITIONING

RESIDENTIAL COMMERCIAL INDUSTRIAL

REFRIGERATION & FREEZING

VENDINGRESIDENTIAL

COMMERCIAL

New Markets

Vacuum TrapsMedical OxygenHigh Temperature SuperconductorsSensorsSmall LNGVOC RecoveryBiofreezing


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Introduction

Thermoacoustic Coolers

Robust, Static Cold Parts

Make it Reliable

Integral, Efficient Drivers

Make it Practical

Efficient, Scalable, Stirling Gas Cycle

Makes it Possible


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P

V

Qhot

Qcold

Introduction

Stirling Efficiency, Ideal & Real

Unlike the ideal cycle, the real machines

operate in a sinusoidal manner -- rounded P-V

for smooth operation

Qreg

Similar to any other real cycle, it has losses

associated

Adiabatic spaces

HX Temperature Differences

Mechanical Losses

Stirling cycle is made up of four reversible

process -- time-varying P-V in enclosed gas

The ideal cycle performance is Carnot

equivalent -- Tc/(Th-Tc) 9.0 @ 0C/30C, 0.3 @ 73K/30C


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Introduction

Thermoacoustic Refrigerators Are Acoustically-

Phased Stirling Systems

No Feedback (Orifice Pulse Tube):

Ideal Efficiency Tc/Th:0.9 @ 0C/30C, 0.24 @ 73K/30C

Same Cooling Physics, Frequency

Dependent Trade ideal efficiency for

mechanical simplicity

Real efficiencies similar under

100K!

Full Feedback = Full Stirling

Critical for high temperatures

Carnot equivalent ideal efficiencyTc/(Th-Tc)

Net mass flow in the feedback loopis detrimental


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Compressor

Heat ofCompression

Regenerator

QQ

Cold HeatExchanger

Pulse Tube

Q

Reservoir

Hot HeatExchanger

Orifice

Aftercooler

Piston moves down and adiabatically compress PT gas

PT gas flows through the orifice into reservoir and exchanges heat. Flow stops when PPT= Pave

Piston moves up and adiabatically expands gas in the PT

Cold low P gas in the PT is forced toward the cold end by gas flow from the reservoir

Refrigeration load is picked up by the cold gas and flow stops when PPT> Pave

Regenerator precools the incoming high P gas before reaches the cold end

Proper gas motion in phase with pressure is achieved by the use of orifice and reservoir volume tostore the gas at half cycle

Gas is in the pulse tube could be divided into three segments with middle segment is acting like adisplacer to insulate both ends

Gas in the pulse tube functions to transmit hydrodynamic power in oscillating gas system from one endto the other across a temperature gradient with a minimum power dissipation and entropy generation

Introduction

No Feedback Refrigerator (OPTR)

Tambient

Tcold


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Introduction

History of Development

Giffo

rd

Mc

Mahon

(1960s)

GM Refrigerator

Giffo

rd

&

Lon

gsw

otrth

(1960s

)

LANL

(198

0s)

Taco

nisOscilla

tions

&Rott

Standing Wave

Radebaugh & NISTTeam (1984-1995)

M

ikulin

M

BTI(1983)

No Feedback (Orifice Pulse Tube)

Low & High Frequency105K 60K

LANL(1997)

Garret (02)

Full Feedback

Free Piston StirlingPh

ilipsC

o.

(1946)

Herschel (1834)

Kirk (1861)

Stirling (1816)

Stirling Refrigerator


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Introduction

Practical Limits of Thermoacoustic Coolers

Capacity scales withcross section

Regenerator flow uniformity

0

50

100

150

200

250

300

1 10 100 1000 10000 100000 1000000 1000000

Cold

Temperature(K)


AIR CONDITIONING

RESIDENTIALCOMMERCIALINDUSTRIAL

PHYSICS,MEDICALRESEARCH

AIR SEPARATION & LNG


VENDINGRESIDENTIAL

COMMERCIAL

New MarketsVacuum TrapsMedical OxygenHigh Temperature SuperconductorsSensorsSmall LNG

VOC RecoveryBiofreezing

Frequency

Temperature: Fixed heat transfer length

High T

Acoustic Dissipation Penalty Regenerator low-T heat capacity


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Drive Options

Linear Motor (Electrodynamic)

Most Common Input Many Types

Burner

Engine

Refrigerators

Thermoacoustic Engine

Large Systems

Solid State (piezoelectric)

Low Efficiency, Stroke


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Drive Options

Electrodynamic Drives

Static Coil (Motor)

More Copper Fits! Efficiency w/o Large Moving Mass

Moving Magnet or Iron

Many Morphologies

One Type Spans The Opportunity Range There are many manufacturers

Moving Coil (Loudspeaker)

Cheap, less efficient

Better for low power

Standard for Military Cryocoolers (


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N S

S N

#1

#2

N S

S N

#1

#2

MID-STROKE, Showing Internal Cancellationand External Balanced Influences

FULL STROKE, ShowingResidual Cancellation

from Out Magnet

A

A

B

B

Drive Options

Linear Motor Drive Family

Moving Magnets on Small Core

Requires Rotational Control

True 1-D Zero-Wear Flexure

Enables Compact Plan, Scale-up

Standard Electric Motor Mfg Methods

100 to 10,000 Watt Developed


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Radially-Rigid Suspension

Easy Clearance Seals

Shock Proofing

Completely Sealed in Vessels ZERO Contamination

Modulating Operation

Low-Load Maintenance

Quick Cool-Down

Twin-STAR Arrangement

Near-zero Vibration

Drive Options

Linear Motors


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Family of PWGs 2x100 (2s114W)

2x300 (2s160W)

2x2000 (2s241W*) 2x5000 (2s297W)

2x10000 (2s362W)

*two housing styles

Drive Options

Picture of Pressure Wave Generators


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Drive Options

Linear Motor Based Compressors

When fitted with Reed valves the linear motor drivesbecome oil-free compressors

One manufacturer is developing first prototypes forcompressors up to 20kW input power

Another manufacturer commercialized small compressors(200W) for mechanical refrigeration

For the 200W compressors, a substantial efficiencyimprovement over the conventional compressortechnologies is reported!


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19921990 1994 1996 1998 2000 2002

Linear Motor Driven OPTR (LOPTR) 0.1 kW @ 80KFirst Tested

No Feedback Thermoacoustic Cryocoolers

Linear Motor

Pressure WaveGenerator

OPTR


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80K OPTR -- Commercially Available


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30K OPTR -- being Developed

Warm HX

Transition

Cold HX

LN2 HX

Inertance

Pulse Tube

2nd Stage

19921990 1994 1996 1998 2000 2002

LOPTR20kW CFIC Driver

0.5kW @ 30KFirst Tests


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No Feedback Thermoacoustic Cryocooler

The Largest Thermoacoustic Engine Driven OPTR

TADOPTR

2.1 kW @ 125KAchieves World Record

Performance

19921990 1994 1996 1998 2000 2002

TADOPTR Achieves2kW at 130K (-225F)and over 20% of Carnotin both TAD and OPTR


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No Feedback Thermoacoustic Cryocooler

The Largest Thermoacoustic Engine

19921990 1994 1996 1998 2000 2002

TASHE-OPTR II8 kW @ 125K

Startup

PX/LANL

TASHE-OPTR I0.5 kW @ 125K

First TestedPX/LANL

3 OPTRs - 8 kW cooling power

@ -150 oC

TASHE - 60 kW acoustic power@ 50 oC

Natural gas burner - 150 kW heat

@ 700 oC


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Pulse tubes are commercially available.

0%

5%

10%

15%

20%

25%

10 100 1000 10000

Motor/Compressor Input Power (W)

TRW #126Raytheon #84

LMNIST

Sunpower

DRS #14

Sumitomo #83

Cryomech

PT -- Stirling Type

PT -- G-M Type

Stirling

G-M

MR J/T

Turbo-Brayton

Praxair

CarnotEfficiency%

80K


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Full Feedback Coolers

A university and an ice cream manufacturer are developingunits for ice cream display cases (Garret 2002)

Bellows Bounce (Compact) Vibro-Acoustic Design

No acoustic resonator, everything fits inside the bellows Motor mass resonates with bellows/gas stiffness Thermoacoustic-Stirling thermal core for higher efficiency


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Stirling Coolers & Cryocoolers

Helium working fluid

Light weight

Full turn down capability

High ambient operation

Good COPs

One manufacturer measured COP of 3 between 0 and30C

Development of units for cooling from ambient downto -80C is underway

A unit as cooler thermoelectric replacement iscommercialized by a Japanese manufacturer.

Stirling cryocoolers have been commercially available

Thermoaco stic Coolers and Cr ocoolers


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Thermoacoustic Coolers and CryocoolersAre Here! Reliable

Scalable

Efficient

Environmentally friendly

Full turndown

High ambient operation

Available Stirling coolers ambient down

to 70K

No feedback thermoacousticcryocoolers (pulse tubes) 150Kto 4K

0

50

100

150

200

250

300

1 10 100 1000 10000 100000 1000000 1000000

Cold

Temperature(K)


AIR CONDITIONING

RESIDENTIALCOMMERCIALINDUSTRIAL

PHYSICS,MEDICALRESEARCH

INDUSTRIAL GAS SEPARATIONLNG


VENDINGRESIDENTIAL

COMMERCIAL

New MarketsVacuum TrapsMedical OxygenHigh Temperature SuperconductorsSensorsSmall LNG

VOC RecoveryBiofreezing


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Linear Motor Compressors Are Here!

Reliable

Oil-free

Scalable Efficient

Full turndown

Commercially available

Linear Compressor

2x10kW Linear Motor


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Additional Slides


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Large Thermoacoustic Systems -- Introduction

Standing Wave Engine

Spontaneous acoustic oscillations occur onesa critical temperature gradient is established

A typical parcel of gas oscillates along the axis

During its travel it experiences changes intemperature caused by compression and

expansion of gas by the sound pressure andby heat exchange with solid wall

A thermodynamic cycle with the time phasingresults from the coupled pressure,

temperature, position and heat oscillations

Time phasing between gas motion andpressure is such that the gas moves hotward

while P is risingand coolward when pressureis falling

Deliberately imperfect heat transfer in order tointroduce a significant time delay between gas

motion and thermal expansion/contraction

TAMBIENT

THOT

QHeatSource

Stack

QSink

Resonator

StackTT

Blob Location

12

34

1

P

V

2

3 4

L Th i S I d i


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Large Thermoacoustic Systems -- Introduction

Traveling Wave Engine

TAMBIENT

THOT

Mass flux

suppressor

Thermal buffer tube

Feedback Inertance

Compliance

Regenerator

Resonator Conversion of heat to power

occurs in the regenerator

Good heat transfer between the

solid and gas is required Gas moves toward the hot HX

while the P is highand towardambient HX while P is low

Acoustic power must be injectedinto ambient end of theregenerator in order to amplify theacoustic power

Swift et al. at LANL introduced ajet pump or mass flux suppressorto get substantial powerproduction

RegenT

Blob Location

3

21

4

1

P

V

2

4

3

Heate

d

Coole

d

ThermoAcoustic Refrigeration - Annual 2003 Arman

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