14-05-2012, 02:07 PM
THERMO-ACOUSTIC REFRIGERATION
[attachment=21996]
ABSTRACT
This paper explores the basic principles of thermo-acoustic refrigeration. Combined with an understanding of the underlying thermodynamics, the model enables us to spread awareness of the viability of thermo-acoustic as cooling devices.
From creating comfortable home environments to manufacturing fast and efficient electronic devices, air conditioning and refrigeration remain expensive, yet essential, services for both homes and industries. However, in an age of impending energy and environmental crises, current cooling technologies continue to generate greenhouse gases with high-energy costs.
Thermo-acoustic refrigeration is an innovative alternative for cooling that is both clean and inexpensive. Through the construction of a functional model, we will demonstrate the effectiveness of thermo-acoustic for modern cooling.
INTRODUCTION
In the word thermo-acoustic, thermo means heat and acoustic means sound. So technology based upon the purposeful use of high-pressure sound waves to provide cooling is thermo-acoustic refrigeration.
Refrigeration relies on two major thermodynamic principles. First, a fluid’s temperature rises when compressed and falls when expanded. Second, when two substances are placed in direct contact, heat will flow from the hotter substance to the cooler one. While conventional refrigerators use pumps to transfer heat on a macroscopic scale, Thermo-acoustic refrigerators rely on sound to generate waves of pressure that alternately compress and relax the gas particles within the tube.
The apparent benefits and commercial opportunity of developing Thermo-acoustic refrigeration and air conditioning applications becomes evident when evaluated against conventional technologies. The following table compares Thermo-acoustics to conventional vapor compression technologies, including the industry's recent advances in adopting carbon dioxide and hydrocarbons as alternative refrigerant gases.
CAMPONENTS USED
Thermo-acoustic requires very few components for its construction and some components as accessories and devices for increasing performance and reading purpose. The components are as follows,
STACK:-
In the last twenty years of the 20th century, much research and design was dedicated to so call “Thermo-acoustic" machines that utilized an oscillating gas with nominally standing wave phasing in the presence of a stack of closely spaced, rather non-conducting plates (Swift, 1988). This stack of plates was designed with a plate-to-plate spacing about a few thermal penetration depths, or the acoustic thermal boundary layer thickness. This acoustic boundary layer is called a “penetration depth" because it is the distance that heat can diffuse in one acoustic cycle.
Stacks form the core of a thermo-acoustic refrigerator and are the in general designed first. Its properties are chosen iteratively until a suitable compromise between the various performance characteristics is achieved. Design of a low cost thermo-acoustic refrigerator starts with placing constraints upon the stack material and its geometry. Readily available to the automotive industry for use in catalytic converters and particulate filters, ceramic substrates present a highly-desirable rectangular pore cross-section configuration, excellent cell rigidity, reasonable thermal conductivity, and wall thicknesses down to 0.064mm. Compared to stacks, which are in part or wholly hand-assembled, the precision and consistency of ceramic substrate geometry is excellent.
ACRYLIC TUBE: -
Acrylic tube is a fabric tube around which the whole arrangement placed. On the one side of it the loudspeaker is placed and on the other side the stack is fixed in tube. Acrylic tube is a transparent tube in which whole arrangement in placed and cooling will perform.
[attachment=21996]
ABSTRACT
This paper explores the basic principles of thermo-acoustic refrigeration. Combined with an understanding of the underlying thermodynamics, the model enables us to spread awareness of the viability of thermo-acoustic as cooling devices.
From creating comfortable home environments to manufacturing fast and efficient electronic devices, air conditioning and refrigeration remain expensive, yet essential, services for both homes and industries. However, in an age of impending energy and environmental crises, current cooling technologies continue to generate greenhouse gases with high-energy costs.
Thermo-acoustic refrigeration is an innovative alternative for cooling that is both clean and inexpensive. Through the construction of a functional model, we will demonstrate the effectiveness of thermo-acoustic for modern cooling.
INTRODUCTION
In the word thermo-acoustic, thermo means heat and acoustic means sound. So technology based upon the purposeful use of high-pressure sound waves to provide cooling is thermo-acoustic refrigeration.
Refrigeration relies on two major thermodynamic principles. First, a fluid’s temperature rises when compressed and falls when expanded. Second, when two substances are placed in direct contact, heat will flow from the hotter substance to the cooler one. While conventional refrigerators use pumps to transfer heat on a macroscopic scale, Thermo-acoustic refrigerators rely on sound to generate waves of pressure that alternately compress and relax the gas particles within the tube.
The apparent benefits and commercial opportunity of developing Thermo-acoustic refrigeration and air conditioning applications becomes evident when evaluated against conventional technologies. The following table compares Thermo-acoustics to conventional vapor compression technologies, including the industry's recent advances in adopting carbon dioxide and hydrocarbons as alternative refrigerant gases.
CAMPONENTS USED
Thermo-acoustic requires very few components for its construction and some components as accessories and devices for increasing performance and reading purpose. The components are as follows,
STACK:-
In the last twenty years of the 20th century, much research and design was dedicated to so call “Thermo-acoustic" machines that utilized an oscillating gas with nominally standing wave phasing in the presence of a stack of closely spaced, rather non-conducting plates (Swift, 1988). This stack of plates was designed with a plate-to-plate spacing about a few thermal penetration depths, or the acoustic thermal boundary layer thickness. This acoustic boundary layer is called a “penetration depth" because it is the distance that heat can diffuse in one acoustic cycle.
Stacks form the core of a thermo-acoustic refrigerator and are the in general designed first. Its properties are chosen iteratively until a suitable compromise between the various performance characteristics is achieved. Design of a low cost thermo-acoustic refrigerator starts with placing constraints upon the stack material and its geometry. Readily available to the automotive industry for use in catalytic converters and particulate filters, ceramic substrates present a highly-desirable rectangular pore cross-section configuration, excellent cell rigidity, reasonable thermal conductivity, and wall thicknesses down to 0.064mm. Compared to stacks, which are in part or wholly hand-assembled, the precision and consistency of ceramic substrate geometry is excellent.
ACRYLIC TUBE: -
Acrylic tube is a fabric tube around which the whole arrangement placed. On the one side of it the loudspeaker is placed and on the other side the stack is fixed in tube. Acrylic tube is a transparent tube in which whole arrangement in placed and cooling will perform.