Thermo acoustic refrigeration is an innovative alternative for cooling that is both clean and inexpensive. The refrigeration effect is achieved by using sound waves and an inert gas which will not cause any damage to the atmosphere. Thermo acoustic engines and refrigerators were already being considered a few years ago for specialized applications. Their simplicity, lack of lubrication and sliding seals, and their use of environmentally harmless working fluids were adequate compensation for their lower efficiencies.

1. A
SEMINAR
ON
“ STUDY OF THERMO ACOUSTIC REFRIGERATION
SYSTEM”
Department Of Mechanical Engineering,
BABASAHEB NAIK COLLEGE OF ENGINEERING,
PUSAD- 445215 (M.S.)
2018-19
06-10-2018 1
Submitted By
Mr. PAVAN U.SHELKE
Final Year
MECHANICAL ENGINEERING
Guided By
Dr.K.K.JADHAO
(Project & Seminar Guide)
(Associate Prof. Mech.Engg.Deptt.)

2.  INTRODUCTION
 BASIC OF CONVENTIONAL REFRIGERATION
 WHAT IS THERMOACOUSTICS?
 BASIC COMPONENTS OF THERMO ACOUSTIC REFRIGERATOR (TAR)
 WORKING OF TAR SYSTEM
 COMPARISON OF TAR SYSTEM WITH OTHER REFRIGERATION SYSTEMS
 ADVANTAGES
 DISADVANTAGES
 IMPROVEMENTS CAN BE MADE
 APPLICATIONS
 CONCLUSION
 REFERENCES
CONTENTS
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3.  Conventional refrigerators use Ozone Depleting Substances like
Chlorofluorocarbons (CFCs) and Hydro fluorocarbons (HFCs) as refrigerants,
which depletes the ozone layer.
 Acoustics deals with study of sound production, transmission, and effects.
Thermo acoustic deals with thermal effects of the sound waves and the inter
conversion of sound energy and heat. Sound waves travel in a longitudinal fashion.
INTRODUCTION
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4. BASIC OF CONVENTIONAL REFRIGERATION
 The compressor is the heart of the system. It compresses the low pressure
refrigerant vapour into high pressure refrigerant vapour.
 The condenser removes heat from the refrigerant.
 The expansion devices control the flow of the liquid refrigerant to the next
component.
 The evaporator absorbs the heat in the system.
Fig. Conventional basic of refrigeration
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5. Process 1to 2 Isentropic Compression in a compressor
Process 2 to 3 Constant-pressure heat rejection in the Condenser
Process 3 to 4 Expansion (Throttling)
Process 4 to 1 Evaporation i.e. heat absorbed in the evaporator.
Continue……
Fig:: P-h Diagram for Refrigeration Cycle
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6. WHAT IS THERMOACOUSTICS?
 Thermo acoustics combines the branches of acoustics and thermodynamics
together to move heat by using sound.
 Thermo acoustics focuses on the microscopic temperature oscillations that
accompany these pressure changes.
 This results in a large temperature difference between the hot and cold sides of
the device and causes refrigeration.
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7. BASIC COMPONENTS OF THERMO ACOUSTIC
REFRIGERATOR (TAR)
1. Working Gas
2. Acoustic Driver
3. Acoustic Resonator
4. Stack
5. Heat Exchanger
6. Coolants
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8. WORKING GAS
 To achieve high efficiency inert gases like Helium, Xenon etc, are preferred.
 Resulting in high utilization of gas molecules to participate in heat transfer.
 Inert gases have certain issues like leakages; cost, refilling, etc. therefore air
with high pressure can also be used as a working medium.
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9. ACOUSTIC DRIVER
 The sound waves required for the refrigerator are produced by an acoustic driver
fitted at one end of resonator tube.
 Basically it converts electrical power into acoustic power.
 The driver consists of a commercial moving-coil Loudspeaker. The choice of the
driver is based on requirements like compactness, lightweight, low losses.
Fig : Acoustic Driver06-10-2018 9

10. ACOUSTIC RESONATOR
Fig: Acoustic Resonator
 A resonator tube is a long hollow pipe
which is a cylindrical tube having an air
column
 The purpose of the resonance Tube in a
Thermo Acoustic Refrigeration (TAR) is to
contain the Working fluid and to cause it to
have a desired natural frequency.
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11. STACK
The most important piece of a
thermo acoustic device is the stack
The purpose of the stack is to
provide a medium where the walls are
close enough so that each time a
packet of gas moves,
Low thermal conductivity, Mylar
material is chosen. Because of the
difficulty of construction of the parallel-
plate stack. Fig: Stack
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12. HEAT EXCHANGER
 Heat exchangers are devices used to transfer
heat energy from one fluid to another. Heat
exchangers can be of copper or aluminium tubing.
Fins can be added to increase the contact area with
the gas and stack.
Fig: Heat Exchanger06-10-2018 12

13. COOLANTS
 Like a conventional refrigeration system, the thermo acoustic
system would require coolants to circulate through pipes.
 One coolant loop would remove heat from the cooled space and
bring it to the cooled side of the stack while another would remove
heat from the hot side and discard it into the surroundings.
 The coolants required would include water & glycol mixtures.
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14. WORKING OF TAR SYSTEM
 Mainly consist of a loudspeaker attached to an acoustic resonator (tube)
filled with a gas
 The loudspeaker acts as the driver,
 The gas, which is cooled due to expansion absorbs heat from the cold side
of the stack.
Fig: Working of TAR System
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15. Comparison Of Tar System With Other Refrigeration Systems
1. On The Basis Of Type Of Refrigerant
The Absorption Refrigeration uses a binary mixture of refrigerant
and absorbent like Water/ammonia or LiBr/water.
Thermo-electric and Thermo acoustic Refrigeration Systems do not
use any refrigerant.
2. On The Basis Of Working Cycle
Vapour Absorption Refrigeration is a two stage process. The
vapour refrigerant is absorbed in a binary solution which then
regenerates the refrigerant on heating externally.
The Thermo acoustic Refrigeration System is powered by either a
heat engine running on waste heat or an electric source. Due to
compression and expansion of air packets heat transfer across two
mediums is made possible.
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16. ADVANTAGES
 Harmful chemicals like CFC’s, HFC’s, and HCFC’s are not released
into atmosphere.
 No moving parts for the process, so very reliable and a long life span.
Environmentally friendly working medium (air, noble gas).
 Use of simple materials with no special requirements, which are
commercially available in large quantities and therefore relatively cheap.
 Thermo acoustic refrigeration works best with inert gases such as
helium and argon, which are harmless, non-flammable, nontoxic, non-ozone
depleting or global warming and is judged inexpensive to manufacture.
 The system is not bulky. It doesn’t use any refrigerant and hence has no
polluting effects
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17. DISADVANTAGES
 Thermo acoustic refrigeration is currently less efficient than the traditional
refrigerators. Lack of suppliers producing customized components.
 Lack of interest and funding from the industry due to their concentration on
developing alternative gases to CFCs. COP is less when compared with the present
refrigerating systems.
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18. IMPROVEMENTS CAN BE MADE
In order to improve the efficiency, regenerators are used. The function of a
regenerator is to store thermal energy during part of the cycle and return it later.
This component can increase the thermodynamic efficiency to impressive
levels. Increasing the level of temperature gradient setup thereby providing more
refrigeration effect.
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19. APPLICATIONS
 Thermo acoustic have broad applications in households and commercial
industries
 Since most of the noise generating electronic components, e.g.
semiconductor devices, operate faster and more effectively at lower
temperatures.
 Future applications of Thermo acoustic cooling devices would not be
restricted to industrial uses only but also could provide inexpensive heating and
cooling for homes.
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20. CONCLUSION
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21. REFERENCES
[1]. Russell D.A and Weilbull P., “Tsabletop Thermo Acoustic Refrigerator for
demonstration”.American journal of physics Volume 10, Issue 5 December
2002, (PP. 70-80).
[2]. Viswa Mohan Pedagopu & Khannaji Pattapu, “A novel approach to design
and fabrication of Thermo-Acoustic Refrigerator using high amplitude sound
waves”, IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-
ISSN: 2278- 1684,p-ISSN: 2320-334X, Volume 8, Issue 6 (Sep. - Oct. 2013),
(PP 15-24).
[3]. Ratish Sawant “Design and Fabrication of Thermo Acoustic Refrigerator”
International Journal of Research in Advent Technology, Vol.3, No.4, April
2015 E-ISSN: 2321-9637 (PP 104-106).
[4]. Pranav Mahamuni “A Study of Thermo Acoustic Refrigeration
System”International Journal of Innovative Research in Advanced Engineering
(IJIRAE) ISSN: 2349-2163 Issue 2, Volume 2 (February 2015) (PP 160-160).
TEXT BOOKS
[1]. A text book of Refrigeration and Air-Conditioning by R.S.KHURMI and
J.K.GUPTA (PP. 109-269).
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22. THANK YOU
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