Thermo acoustic refrigeration uses high intensity sound waves in a pressurized gas tube to pump heat from one place to another and produce a refrigeration effect without lubricants, resulting in 40% less energy consumption. It takes advantage of sound waves reverberating within devices to convert a temperature differential into mechanical energy or vice versa. Applications include liquefying natural gas, chip cooling, refrigerating food, and air conditioning buildings.

1. Thermo acoustic refrigeration

2. CONTENTS
ABSTRACT.
INTRODUCTION.
BASIC FUNCTIONING.
THERMO ACOUSTIC EFFECT.
SPACE TA REFRIGERATOR.
MERITS OF TECHNOLOGY.
APPLICATIONS.
CONCLUSION.

3. ABSTRACT
Thermo acoustic refrigeration is a
phenomenon that uses high intensity
sound waves in a pressurized gas tube
to pump heat from one place to other to
produce refrigeration effect.
This system completely eliminates the
need for lubricants and results in 40%
less energy consumption

4. INTRODUCTION
Thermo acoustic devices take advantage of sound
waves reverberating within them to convert a
temperature differential into mechanical energy or
mechanical energy into a temperature differential.
Thermo acoustic devices perform best with inert
gases.
They do not produce the harmful environmental
effects such as global warming or stratospheric
ozone depletion.

5. BASIC FUNCTIONING
A thermo acoustic refrigerator uses
acoustic power to pump heat from a
cool source to a hot sink.
These devices perform best when they
employ noble gases as their
thermodynamic working fluids.

6. BASIC FUNCTIONING
The principle can be imagined as a loud
speaker creating high amplitude sound
waves that can compress refrigerant
allowing heat absorption.
sound waves travel by compressing
and expanding the gas they are
generated in.

7. BASIC FUNCTIONING
Suppose the wave is traveling through
a tube, a temperature gradient can be
generated by putting a stack of plates in
the right place in the tube, in which
sound waves are bouncing around.
Some plates in the stack will get hotter
while the others get colder

8. THERMO ACOUSTIC EFFECT
Acoustic or sound waves can be utilized to produce
cooling.
The pressure variations in the acoustic wave are
accompanied by temperature variations due to
compressions and expansions of the gas.
As expansion and compression in an acoustic wave
are inherently associated with a displacement, a net
transport of heat results.
To fix the direction of heat flow, a standing wave
pattern is generated in an acoustic resonator.

9. Theoretical Basics
Thermoacoustic refrigerator is a special
kind of device that uses energy of sound
waves or acoustic energy to pump heat
from low temperature reservoir to a high
temperature reservoir.

10. Standing wave
Thermoacoustic Refrigerator
Working
• Hot compressed gas at the
right end of stack.
• Heat loss to stack. Stack
temperature rises
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stack

11. • Gas expands while moving to
left and cools.
Working (contd..)
• Cold gas takes heat from stack.
Stack becomes colder.

12. Working (contd..)
Temp gradient across the stack
is established.
To
exhaust
To cold
system
• Circulating fluid
picks up/loses heat
at the heat
exchangers.
Very cold Very

13. Space TA Refrigerator
The refrigerator is driven by a modified
compression driver that is coupled to a
quarter-wavelength resonator using a
single-convolution electroformed metal
bellow.
The resonator contains the heat
exchangers and the stack. The stack is
3.8 cm in diameter and 7.9 cm in length.

15. MERITS OF TECHNOLOGY
No moving parts for the process, so very reliable and
a long life span.
Environmentally friendly working medium (air, noble
gas)
The use of air or noble gas as working medium offers
a large window of applications because there are no
phase transitions.
Use of simple materials with no special requirements,
which are commercially available in large quantities
and therefore relatively cheap.
On the same technology base a large variety of
applications can be covered.

16. APPLICATIONS
Liquefaction of natural gas
Chip cooling.
Electronic equipment cooling on naval ships.
Electricity from sunlight.
Cogeneration (combined heat and power).
Upgrading industrial waste heat.

17. CONCLUSION
Thermo acoustic engines and refrigerators have
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.
the design of high power, single frequency loud
speakers and reciprocating electric generators can
be used to power hybrid electric vehicles, capture
solar energy, refrigerate food, air condition buildings,
liquefy industrial gases.