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ABSTRACT
The objective of this effort is to study the Magnetic Refrigeration which uses solid materials as
the refrigerant. These materials demonstrate the unique property known as magneto caloric
effect, which means that they increase and decrease in temperature when
magnetized/demagnetized. This effect has been observed for many years and was used for
cooling near absolute zero. Recently materials are being developed which have sufficient
temperature and entropy change to make them useful for a wide range temperature applications.
Benefits of magnetic refrigeration are lower cost, longer life, lower weight and higher efficiency
because it only requires one moving part-the rotating disc on which the magneto caloric material
is mounted. The unit uses no gas compressor, no pumps, no working fluid, no valves and no
ozone destroying chlorofluorocarbons/hydro chlorofluorocarbons. potential commercial
applications include cooling of electronics, super conducting components used in
telecommunications equipment, home and commercial refrigerator ,heat pumps, air conditioning
for homes, offices and automobiles and virtually any places where refrigeration is needed.
Chapter 1
INTRODUCTION
Magnetic refrigeration is a cooling technology based on the magnetocaloric effect. This
technique can be used to attain extremely low temperatures (well below 1 kelvin), as well as the
ranges used in common refrigerators, depending on the design of the system. depending on the design of the system. The objective of this effort is to study the Magnetic Refrigeration which uses solid materials as the refrigerant. These materials demonstrate the unique property known as magneto caloric effect, which means that they increase and decrease in temperature when magnetized/demagnetized. This effect has been observed for many years and was used for cooling near absolute zero. Recently materials are being developed which have sufficient temperature and entropy change to make them useful for a wide range temperature applications. Benefits of magnetic refrigeration are lower cost, longer life, lower weight and higher efficiency because it only requires one moving part-the rotating disc on which the magneto caloric material is mounted. The unit uses no gas compressor, no pumps, no working fluid, no valves and no ozone destroying chlorofluorocarbons/hydro chlorofluorocarbons. potential commercial applications include cooling of electronics, super conducting components used in telecommunications equipment, home and commercial refrigerator ,heat pumps, air conditioning for homes, offices and automobiles and virtually any places where refrigeration is needed.
Magnetic refrigeration is a method of refrigeration based on the magnetocaloric effect.
This effect, discovered in 1881, is defined as the response of a solid to an applied magnetic field
which is apparent as a change in its temperature.
This effect is obeyed by all transition metals
and lanthanide-series elements. When a magnetic field is applied, these metals, known as
ferromagnets, tend to heat up. As heat is applied, the magnetic moments align. When the field is
removed, the ferromagnet cools down as the magnetic moments become randomly oriented.
Gadolinium, a rare-earth metal, exhibits one of the largest known magnetocaloric effects. It was
used as the refrigerant for many of the early magnetic refrigeration designs. The problem with
using pure gadolinium as the refrigerant material is that it does not exhibit a strong
magnetocaloric effect at room temperature. More recently, however, it has been discovered that
arc-melted alloys of gadolinium, silicon, and germanium are more efficient at room
temperature.
ABSTRACT
The objective of this effort is to study the Magnetic Refrigeration which uses solid materials as
the refrigerant. These materials demonstrate the unique property known as magneto caloric
effect, which means that they increase and decrease in temperature when
magnetized/demagnetized. This effect has been observed for many years and was used for
cooling near absolute zero. Recently materials are being developed which have sufficient
temperature and entropy change to make them useful for a wide range temperature applications.
Benefits of magnetic refrigeration are lower cost, longer life, lower weight and higher efficiency
because it only requires one moving part-the rotating disc on which the magneto caloric material
is mounted. The unit uses no gas compressor, no pumps, no working fluid, no valves and no
ozone destroying chlorofluorocarbons/hydro chlorofluorocarbons. potential commercial
applications include cooling of electronics, super conducting components used in
telecommunications equipment, home and commercial refrigerator ,heat pumps, air conditioning
for homes, offices and automobiles and virtually any places where refrigeration is needed.
Chapter 1
INTRODUCTION
Magnetic refrigeration is a cooling technology based on the magnetocaloric effect. This
technique can be used to attain extremely low temperatures (well below 1 kelvin), as well as the
ranges used in common refrigerators, depending on the design of the system. depending on the design of the system. The objective of this effort is to study the Magnetic Refrigeration which uses solid materials as the refrigerant. These materials demonstrate the unique property known as magneto caloric effect, which means that they increase and decrease in temperature when magnetized/demagnetized. This effect has been observed for many years and was used for cooling near absolute zero. Recently materials are being developed which have sufficient temperature and entropy change to make them useful for a wide range temperature applications. Benefits of magnetic refrigeration are lower cost, longer life, lower weight and higher efficiency because it only requires one moving part-the rotating disc on which the magneto caloric material is mounted. The unit uses no gas compressor, no pumps, no working fluid, no valves and no ozone destroying chlorofluorocarbons/hydro chlorofluorocarbons. potential commercial applications include cooling of electronics, super conducting components used in telecommunications equipment, home and commercial refrigerator ,heat pumps, air conditioning for homes, offices and automobiles and virtually any places where refrigeration is needed.
Magnetic refrigeration is a method of refrigeration based on the magnetocaloric effect.
This effect, discovered in 1881, is defined as the response of a solid to an applied magnetic field
which is apparent as a change in its temperature.
This effect is obeyed by all transition metals
and lanthanide-series elements. When a magnetic field is applied, these metals, known as
ferromagnets, tend to heat up. As heat is applied, the magnetic moments align. When the field is
removed, the ferromagnet cools down as the magnetic moments become randomly oriented.
Gadolinium, a rare-earth metal, exhibits one of the largest known magnetocaloric effects. It was
used as the refrigerant for many of the early magnetic refrigeration designs. The problem with
using pure gadolinium as the refrigerant material is that it does not exhibit a strong
magnetocaloric effect at room temperature. More recently, however, it has been discovered that
arc-melted alloys of gadolinium, silicon, and germanium are more efficient at room
temperature.
