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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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