A thermoacoustic refrigerator driven bya low temperature differential, high-efficiency multistage thermoacoustic engine

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A thermoacoustic refrigerator driven by

a low temperature differential, high-

efficiency multistage thermoacoustic

engine

S. Hasegawa, T. Yamaguchi, Y. Oshinoya(Elsvier, Received 24 July 2012, Accepted 16 April 2013

Available online 2 May 2013)

Advisor: Prof. Akiyoshi Iida

Assistant Prof. Hiroshi Yokoyama

Student: Subhan Ullah

Student ID: M135117

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Table of contents

Introduction

Background

Previous research

Objective

Methodology

Design parameters

Calculation methodology

Results

Summary

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Introduction

Background

Previous research

Objective

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Background

Roughly one-thirdof the energy consumed by industry isdischarged as thermal losses

Most of this waste energy, however, is of low quality (i.e.,below 300 F (260 C) and is typically not practical oreconomical to recover with current technology

To solve this problem, a multistage double loopthermoacoustic engine that can lower the critical onsettemperature upto 110K has been proposed

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Previous research

T. Jin et al. (A thermoacoustically driven pulse

tube refrigerator capable of working below

120K)a minimum of 117.6K is achieved.

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Objective

Numerical calculation for modelingthermoacoustic (TA) cooler driven by TAengine.

To determine configuration that enables low-temp. oscillation and high efficiency.

To derive thermal efficiency when temp. ratioof the prime mover is changed.

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Methodology

Analysis model & design parameters Calculation methodology

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Analysis model

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Design parameters

Length(m) Diameter(mm)

Apertureratio(%)

r(mm)

Ambient HX 1 0.031 100 72 1.3

Regenerator 1 0.06 100 83.4 r1=0.125

Hot HX1 0.026 100 72 1.3

Ambient HX 2 0.031 100 72 1.3

Regenerator 2 0.06 100 83.4 r2=0.075

Hot HX 2 0.026 100 72 1.3

Ambient HX 3 0.031 100 72 1.3

Regenerator 3 0.06 100 83.4 r3=0.1

Hot HX 3 0.026 100 72 1.3

Ambient HX 4 0.031 100 72 1.3

Regenerator 4 0.08 100 75 r4=0.055

Cold HX 0.026 100 72 1.310/25/2013 9


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Calculation methodology

The method devised by Rott, based on the

first-order differential equation,

If we calculate Eigenvalues and Eigenvectorsof matrix A in above equation, leads to

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Solving simultaneous equations by eliminating

p and U gives us,

The operating conditions can be determined

without reference to such terms

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Also,

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The 2ndlaw efficiency for engine is calculated

by;

The 2ndlaw efficiency for refrigerator is

calculated by;

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The second law efficiency of the entire apparatus

COP is the value obtained by dividing all Q values,which is the total sum of each engines heat inputby heat output Qout.

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Results

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summary

It is shown that a multistage type thermoacousticengine, optimized using numerical calculationsproposed in this research produces oscillations at

110.8 K, which is equivalent to a typical industrialwaste heat temperature

And second law efficiency of the entire apparatusis over 21%.

The results show that using multistage type canproduce a low temperature oscillationcompatible with high efficiency.

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Documents

A thermoacoustic refrigerator driven bya low temperature differential, high-efficiency multistage thermoacoustic engine