This document summarizes a seminar presentation on magnetic refrigeration given by Mr. Hardik N Kothiya. The presentation was given in partial fulfillment of a Bachelor of Engineering degree from the University of Pune, India. The seminar covered the history of magnetic refrigeration, the magneto-caloric effect, how magnetic refrigeration systems work, comparisons to conventional refrigeration, applications, advantages and disadvantages. Key topics included the discovery of the magneto-caloric effect in 1881, the first demonstration of magnetic refrigeration to reach 0.25 K in 1933, and recent developments in room temperature magnetic refrigeration.
It is a technolgy by which we can produce cooling Effect Using MAgnets and Magnetic Materials......
For any other enquiry u can contact me on +919540278218....
and can join my Page www.facebook.com/engineeringindia
This document is a seminar report on magnetic refrigeration submitted for the degree of Bachelor of Technology in Mechanical Engineering. It discusses magnetic refrigeration, which uses the magnetocaloric effect exhibited by solid materials like gadolinium compounds. When these materials are magnetized, their temperature increases due to entropy reduction, and when demagnetized, their temperature decreases due to entropy increase. This effect allows for cooling applications. The report covers the working principle, construction requirements, practical applications and advantages of magnetic refrigeration over conventional vapor compression refrigeration cycles.
This document provides an overview of magnetic refrigeration. It discusses the history and principles of magnetic refrigeration, describing the magnetocaloric effect and the thermodynamic cycle used. The components required for a magnetic refrigerator are outlined. Applications are discussed, along with advantages such as high efficiency and compactness compared to vapor-compression refrigeration. Some challenges are also noted, such as limited temperature changes and availability of materials. In conclusion, while further development is needed, magnetic refrigeration shows promise as an environmentally-friendly cooling technology.
This document discusses magnetic refrigeration, which provides cooling through the magnetocaloric effect. It begins by introducing magnetic refrigeration and the magnetocaloric effect. It then covers the basic principles and mechanism of magnetic refrigeration, including the thermodynamic cycle and components required. Potential magnetocaloric materials are discussed. Applications for magnetic refrigeration include household appliances, buildings, transportation, food storage, and electronics cooling. Benefits include higher efficiency and lower environmental impact compared to traditional refrigeration. Further research is still needed to improve temperature changes and develop stronger permanent magnets for widespread commercial use.
The document summarizes Ganesh Pralhad Bharambe's seminar on magnetic refrigeration presented under the guidance of Prof. A. M. Patil. It discusses the basic principles of magnetic refrigeration, the thermodynamic cycle involved, suitable working materials including developments in materials science, and applications of the technology.
What Is Magnetic refrigeration
he magnetocaloric effect (MCE, from magnet and calorie) is a magneto-thermodynamic phenomenon in which a temperature change of a suitable material is caused by exposing the material to a changing magnetic field. This is also known by low temperature physicists as adiabatic demagnetization. In that part of the refrigeration process, a decrease in the strength of an externally applied magnetic field allows the magnetic domains of a magnetocaloric material to become disoriented from the magnetic field by the agitating action of the thermal energy (phonons) present in the material. If the material is isolated so that no energy is allowed to (re)migrate into the material during this time, (i.e., an adiabatic process) the temperature drops as the domains absorb the thermal energy to perform their reorientation. The randomization of the domains occurs in a similar fashion to the randomization at the curie temperature of a ferromagnetic material, except that magnetic dipoles overcome a decreasing external magnetic field while energy remains constant, instead of magnetic domains being disrupted from internal ferromagnetism as energy is added.
One of the most notable examples of the magnetocaloric effect is in the chemical element gadolinium and some of its alloys. Gadolinium's temperature increases when it enters certain magnetic fields. When it leaves the magnetic field, the temperature drops. The effect is considerably stronger for the gadolinium alloy (Gd
5Si
2Ge
2).[8] Praseodymium alloyed with nickel (PrNi
5) has such a strong magnetocaloric effect that it has allowed scientists to approach to within one milliKelvin, one thousandth of a degree of absolute zero.[9]
This document discusses magnetic refrigeration, which uses the magnetocaloric effect to provide cooling. It works by applying and removing a magnetic field from magnetocaloric materials, causing their temperature to change. The document outlines the components, thermodynamic cycle steps, requirements, examples of prototypes, advantages like efficiency and sustainability, and challenges like initial costs. It also covers potential applications like household refrigeration and compares magnetic refrigeration to current technologies under development.
This document summarizes a presentation on magnetic refrigeration. It introduces the magnetocaloric effect where certain magnetic materials experience a temperature change when exposed to a changing magnetic field. It then describes how magnetic refrigeration works by using this effect to remove heat from a substance, replacing the gas compression/expansion process with magnetizing and demagnetizing the magnetic material. Finally, it discusses suitable magnetic materials, the advantages of magnetic refrigeration over conventional refrigeration like higher efficiency and being environmentally friendly, and potential applications of the technology.
It is a technolgy by which we can produce cooling Effect Using MAgnets and Magnetic Materials......
For any other enquiry u can contact me on +919540278218....
and can join my Page www.facebook.com/engineeringindia
This document is a seminar report on magnetic refrigeration submitted for the degree of Bachelor of Technology in Mechanical Engineering. It discusses magnetic refrigeration, which uses the magnetocaloric effect exhibited by solid materials like gadolinium compounds. When these materials are magnetized, their temperature increases due to entropy reduction, and when demagnetized, their temperature decreases due to entropy increase. This effect allows for cooling applications. The report covers the working principle, construction requirements, practical applications and advantages of magnetic refrigeration over conventional vapor compression refrigeration cycles.
This document provides an overview of magnetic refrigeration. It discusses the history and principles of magnetic refrigeration, describing the magnetocaloric effect and the thermodynamic cycle used. The components required for a magnetic refrigerator are outlined. Applications are discussed, along with advantages such as high efficiency and compactness compared to vapor-compression refrigeration. Some challenges are also noted, such as limited temperature changes and availability of materials. In conclusion, while further development is needed, magnetic refrigeration shows promise as an environmentally-friendly cooling technology.
This document discusses magnetic refrigeration, which provides cooling through the magnetocaloric effect. It begins by introducing magnetic refrigeration and the magnetocaloric effect. It then covers the basic principles and mechanism of magnetic refrigeration, including the thermodynamic cycle and components required. Potential magnetocaloric materials are discussed. Applications for magnetic refrigeration include household appliances, buildings, transportation, food storage, and electronics cooling. Benefits include higher efficiency and lower environmental impact compared to traditional refrigeration. Further research is still needed to improve temperature changes and develop stronger permanent magnets for widespread commercial use.
The document summarizes Ganesh Pralhad Bharambe's seminar on magnetic refrigeration presented under the guidance of Prof. A. M. Patil. It discusses the basic principles of magnetic refrigeration, the thermodynamic cycle involved, suitable working materials including developments in materials science, and applications of the technology.
What Is Magnetic refrigeration
he magnetocaloric effect (MCE, from magnet and calorie) is a magneto-thermodynamic phenomenon in which a temperature change of a suitable material is caused by exposing the material to a changing magnetic field. This is also known by low temperature physicists as adiabatic demagnetization. In that part of the refrigeration process, a decrease in the strength of an externally applied magnetic field allows the magnetic domains of a magnetocaloric material to become disoriented from the magnetic field by the agitating action of the thermal energy (phonons) present in the material. If the material is isolated so that no energy is allowed to (re)migrate into the material during this time, (i.e., an adiabatic process) the temperature drops as the domains absorb the thermal energy to perform their reorientation. The randomization of the domains occurs in a similar fashion to the randomization at the curie temperature of a ferromagnetic material, except that magnetic dipoles overcome a decreasing external magnetic field while energy remains constant, instead of magnetic domains being disrupted from internal ferromagnetism as energy is added.
One of the most notable examples of the magnetocaloric effect is in the chemical element gadolinium and some of its alloys. Gadolinium's temperature increases when it enters certain magnetic fields. When it leaves the magnetic field, the temperature drops. The effect is considerably stronger for the gadolinium alloy (Gd
5Si
2Ge
2).[8] Praseodymium alloyed with nickel (PrNi
5) has such a strong magnetocaloric effect that it has allowed scientists to approach to within one milliKelvin, one thousandth of a degree of absolute zero.[9]
This document discusses magnetic refrigeration, which uses the magnetocaloric effect to provide cooling. It works by applying and removing a magnetic field from magnetocaloric materials, causing their temperature to change. The document outlines the components, thermodynamic cycle steps, requirements, examples of prototypes, advantages like efficiency and sustainability, and challenges like initial costs. It also covers potential applications like household refrigeration and compares magnetic refrigeration to current technologies under development.
This document summarizes a presentation on magnetic refrigeration. It introduces the magnetocaloric effect where certain magnetic materials experience a temperature change when exposed to a changing magnetic field. It then describes how magnetic refrigeration works by using this effect to remove heat from a substance, replacing the gas compression/expansion process with magnetizing and demagnetizing the magnetic material. Finally, it discusses suitable magnetic materials, the advantages of magnetic refrigeration over conventional refrigeration like higher efficiency and being environmentally friendly, and potential applications of the technology.
This document provides information about a project report on refrigeration using a Peltier module. It includes an abstract, introduction, chapters on the basic theory of Peltier devices, materials used, construction and design, working and performance, advantages and disadvantages, cost analysis, and conclusion. The basic theory chapter describes the history of Peltiers, their structure, principles, specifications, applications, heat transport method, doping of semiconductors, and thermoelectric performance factors. It explains how a Peltier module uses the Peltier effect to absorb heat on one side and release it on the other side when a DC current is applied.
Heat transfer enhancement by nanofluid Suhail Patel
The purpose of this paper is to look into the present aspects of “Nanotechnology”. This gives a brief description of how heat transfer enhances using Nanofluid And its application in various fields viz. heat transportation, military applications, medical, etc. This paper focuses one explaining the basic mechanisms of improvement in heat transfer by addition nanoparticles.
This document summarizes a student project report on designing a mini compressor-less Peltier refrigerator. It begins with acknowledgements to the student's project guide and department head for their support and guidance. It then provides a project certificate signed by the internal and external guides. The document outlines the objectives of studying Peltier cooling technology and designing a refrigerator. It describes the materials used, including an aluminum evaporator box and a 12V water pump for cooling the hot side of the Peltier module. The remaining chapters will cover the refrigerator's construction, working principle, cost analysis, and conclusions.
This document presents a thermoelectric refrigeration system project. It discusses the milestones, realization of the idea, introduction to thermoelectric refrigeration and the Peltier effect. It describes the materials used, working of the project including dimensions, advantages, drawbacks, applications, cost analysis, new opportunities, and concludes that the objective of long term cooling in power failures was achieved with a retention time of 57 minutes.
This document summarizes a seminar presentation on thermoelectric cooling systems. It introduces thermoelectric coolers and their basic principles, including the Peltier effect whereby applying a voltage creates a heat pump effect. Common materials used are bismuth telluride semiconductors. Multistage cooler designs can improve performance by decreasing the minimum cold side temperature. Thermoelectric coolers have advantages over vapor compression systems like no moving parts, quick response time, and lower power usage. Applications include electronics cooling, refrigeration, medical and laboratory equipment.
This document provides an overview of thermoacoustic refrigeration (TAR). It begins with introductions and basics of refrigeration and TAR. It then explains the main parts of TAR including the driver, resonator, stack, and heat exchangers. The document presents a case study on the Space Thermoacoustic Refrigerator launched in 1992. It discusses advantages and applications of TAR as well as challenges. In conclusion, TAR provides environmentally friendly refrigeration without ozone depleting chemicals or moving parts.
Magnetic refrigeration uses the magnetocaloric effect to achieve cooling through a thermodynamic cycle that involves magnetizing and demagnetizing a material. It was discovered in 1881 and further developed in the 1920s-1930s to achieve temperatures below 1K. Recent research has focused on materials with giant magnetocaloric effects and developing practical refrigerator designs. Magnetic refrigeration offers higher efficiency and lower costs than vapor compression refrigeration, with benefits for the environment and new technologies. Further development is still needed to address challenges like improving magnetocaloric materials and precision moving parts.
This document discusses phase change materials (PCMs) which can store and release large amounts of thermal energy during phase transitions between solid and liquid states. PCMs provide high energy storage density with small temperature changes. Thermal energy storage methods include sensible heat storage based on temperature change and latent heat storage using phase change. PCMs are classified as organic, inorganic, or eutectic and are selected based on properties like melting temperature and thermal stability. Applications of PCMs include construction materials, textiles, food/medical packaging, and automobiles.
This document presents information on a thermoelectric refrigerator. It includes an abstract that describes how thermoelectric modules can be used to produce refrigeration without CFCs. It then discusses the principles of thermoelectric refrigeration including the Peltier effect. It provides descriptions of the key components of the refrigerator like the thermoelectric module, heat sinks, fans, and temperature indicator. It also includes specifications, power calculations, comparisons to normal refrigerators, advantages, applications and concludes that thermoelectric refrigerators are portable, compact and environmentally friendly alternatives for some cooling applications.
Magneto hydro dynamic power generation( PDPU)Pratibha Singh
This document discusses magneto hydrodynamic (MHD) power generation. It begins with an introduction to MHD, which involves studying electrically conducting fluids in magnetic fields. An MHD generator directly converts heat energy to electrical energy without a conventional generator. The principle is that an induced voltage and current are generated when an ionized gas flows at high velocity through a magnetic field. The document describes open-cycle and closed-cycle MHD systems, advantages including higher efficiency and smaller size compared to conventional power plants, and challenges needing further development.
Micro machining involves removing material at the micro/nano scale to create small features and high precision surfaces. Key techniques include photolithography, which uses light passing through masks to pattern photoresist, and various etching methods like wet, dry, and plasma etching to remove material. Other important microfabrication processes are bulk micromachining, which etches the silicon substrate, surface micromachining which builds structures in layers, and LIGA which uses X-rays to create high aspect ratio metal parts through electroplating. These micro machining techniques enable manufacturing of complex micro-scale parts for applications like MEMS devices and biomedical tools.
Report on Solar Air heater by Hardik RamaniHardik Ramani
The document discusses advances in solar air heaters. It begins by providing background on solar air heating technology, including its basic principles of using a solid collector surface to absorb solar radiation and transfer heat to air via convection. Different types of solar air heaters are described, including porous and non-porous designs. The document then presents experimental results from testing various solar air heater designs under both summer and winter conditions to analyze temperature rise, thermal efficiency, and instantaneous thermal efficiency at varying air flow rates. It finds that designs with double glazing and packed beds performed better than single glazing. Finally, the conclusion discusses efficiency improvement through roughness additions to collector surfaces.
This document provides a literature review on thermoelectric cooling systems. It discusses the history of thermoelectric discoveries from 1820 to present. Several studies are summarized that examined using thermoelectric cooling modules for industrial enclosures, vehicles like cars and trucks, and personal cooling applications like a cooling helmet. The advantages of thermoelectric coolers are highlighted over traditional vapor-compression refrigeration systems, as thermoelectric coolers have no moving parts, refrigerants, or water requirements. The document also discusses software tools for selecting thermoelectric modules and references previous work developing thermoelectric cooling systems and prototypes.
The document reviews heat transfer enhancement techniques using twisted tape inserts. It discusses heat exchangers and classifications. Twisted tape is described as a passive enhancement method that induces swirl and turbulence to disrupt the thermal boundary layer. Attributes of twisted tape like pitch, twist ratio and shape are examined. Using twisted tape can increase heat transfer rate in a heat exchanger by up to 188% but also increases friction loss. Different tape configurations are evaluated and it is found that optimization of parameters like twist ratio can improve thermal performance.
Nanofluids are now developing technology in main purpose heat transfer stream. In paper has brief information on the introduction and preparation methods of nanofluids. This paper prepared from the study of online resources
Selective Laser Sintering is one of the most used processes of Rapid Prototyping. It is a powder based process where powder of different metals/materials get sintered by LASER.
The document discusses the design of a thermoelectric generator project to convert waste heat from a car engine into electricity. It aims to develop a system that is economical, easy to implement, and does not reduce engine efficiency. The document covers the basic principles of thermoelectric generation using the Seebeck and Peltier effects. It describes thermoelectric generator components like heat exchangers and materials like bismuth telluride. The document discusses performance metrics and advantages like utilizing wasted heat and having no moving parts. It also notes disadvantages like low conversion efficiency and outlines automotive and other applications of thermoelectric generators.
Magneto Hydro Dynamic Power Generation uses the principle that an electrical current is induced when a conductive fluid passes through a magnetic field at high velocity. There are two main types of MHD systems - open cycle systems which use combustion gases and closed cycle systems which reuse gases or use liquid metals. MHD has advantages like high efficiency around 50% and smaller plant size but also limitations like materials challenges from high temperatures and corrosion. Overall MHD is still in development for power generation applications.
Thermal energy based machining processes like electron beam machining (EBM), laser beam machining (LBM), and plasma arc machining (PAM) work by concentrating heat energy on a small area of the workpiece to melt and vaporize material. EBM uses a beam of high velocity electrons, LBM uses a focused laser beam, and PAM uses a high temperature plasma jet, all to remove tiny bits of workpiece material through localized heating and repetition of the process. While each has advantages like precision and lack of mechanical contact, they also have disadvantages like high equipment costs and low material removal rates.
Magnetic refrigeration has been viewed as primarily a cryogenic technology because the necessary high magnetic fields are most easily provided by superconducting magnets.
aseminar report on magnetic refrigerationhardik9343
This document summarizes a seminar presentation on magnetic refrigeration. It discusses the history of magnetic refrigeration dating back to 1881 when the magneto-caloric effect was discovered. It then provides an overview of how magnetic refrigeration works using the magneto-caloric effect found in solid state refrigerants. The objectives of magnetic refrigeration are to develop more efficient and cost effective small scale hydrogen liquefiers as an alternative to traditional vapor-compression cycles.
This document provides information about a project report on refrigeration using a Peltier module. It includes an abstract, introduction, chapters on the basic theory of Peltier devices, materials used, construction and design, working and performance, advantages and disadvantages, cost analysis, and conclusion. The basic theory chapter describes the history of Peltiers, their structure, principles, specifications, applications, heat transport method, doping of semiconductors, and thermoelectric performance factors. It explains how a Peltier module uses the Peltier effect to absorb heat on one side and release it on the other side when a DC current is applied.
Heat transfer enhancement by nanofluid Suhail Patel
The purpose of this paper is to look into the present aspects of “Nanotechnology”. This gives a brief description of how heat transfer enhances using Nanofluid And its application in various fields viz. heat transportation, military applications, medical, etc. This paper focuses one explaining the basic mechanisms of improvement in heat transfer by addition nanoparticles.
This document summarizes a student project report on designing a mini compressor-less Peltier refrigerator. It begins with acknowledgements to the student's project guide and department head for their support and guidance. It then provides a project certificate signed by the internal and external guides. The document outlines the objectives of studying Peltier cooling technology and designing a refrigerator. It describes the materials used, including an aluminum evaporator box and a 12V water pump for cooling the hot side of the Peltier module. The remaining chapters will cover the refrigerator's construction, working principle, cost analysis, and conclusions.
This document presents a thermoelectric refrigeration system project. It discusses the milestones, realization of the idea, introduction to thermoelectric refrigeration and the Peltier effect. It describes the materials used, working of the project including dimensions, advantages, drawbacks, applications, cost analysis, new opportunities, and concludes that the objective of long term cooling in power failures was achieved with a retention time of 57 minutes.
This document summarizes a seminar presentation on thermoelectric cooling systems. It introduces thermoelectric coolers and their basic principles, including the Peltier effect whereby applying a voltage creates a heat pump effect. Common materials used are bismuth telluride semiconductors. Multistage cooler designs can improve performance by decreasing the minimum cold side temperature. Thermoelectric coolers have advantages over vapor compression systems like no moving parts, quick response time, and lower power usage. Applications include electronics cooling, refrigeration, medical and laboratory equipment.
This document provides an overview of thermoacoustic refrigeration (TAR). It begins with introductions and basics of refrigeration and TAR. It then explains the main parts of TAR including the driver, resonator, stack, and heat exchangers. The document presents a case study on the Space Thermoacoustic Refrigerator launched in 1992. It discusses advantages and applications of TAR as well as challenges. In conclusion, TAR provides environmentally friendly refrigeration without ozone depleting chemicals or moving parts.
Magnetic refrigeration uses the magnetocaloric effect to achieve cooling through a thermodynamic cycle that involves magnetizing and demagnetizing a material. It was discovered in 1881 and further developed in the 1920s-1930s to achieve temperatures below 1K. Recent research has focused on materials with giant magnetocaloric effects and developing practical refrigerator designs. Magnetic refrigeration offers higher efficiency and lower costs than vapor compression refrigeration, with benefits for the environment and new technologies. Further development is still needed to address challenges like improving magnetocaloric materials and precision moving parts.
This document discusses phase change materials (PCMs) which can store and release large amounts of thermal energy during phase transitions between solid and liquid states. PCMs provide high energy storage density with small temperature changes. Thermal energy storage methods include sensible heat storage based on temperature change and latent heat storage using phase change. PCMs are classified as organic, inorganic, or eutectic and are selected based on properties like melting temperature and thermal stability. Applications of PCMs include construction materials, textiles, food/medical packaging, and automobiles.
This document presents information on a thermoelectric refrigerator. It includes an abstract that describes how thermoelectric modules can be used to produce refrigeration without CFCs. It then discusses the principles of thermoelectric refrigeration including the Peltier effect. It provides descriptions of the key components of the refrigerator like the thermoelectric module, heat sinks, fans, and temperature indicator. It also includes specifications, power calculations, comparisons to normal refrigerators, advantages, applications and concludes that thermoelectric refrigerators are portable, compact and environmentally friendly alternatives for some cooling applications.
Magneto hydro dynamic power generation( PDPU)Pratibha Singh
This document discusses magneto hydrodynamic (MHD) power generation. It begins with an introduction to MHD, which involves studying electrically conducting fluids in magnetic fields. An MHD generator directly converts heat energy to electrical energy without a conventional generator. The principle is that an induced voltage and current are generated when an ionized gas flows at high velocity through a magnetic field. The document describes open-cycle and closed-cycle MHD systems, advantages including higher efficiency and smaller size compared to conventional power plants, and challenges needing further development.
Micro machining involves removing material at the micro/nano scale to create small features and high precision surfaces. Key techniques include photolithography, which uses light passing through masks to pattern photoresist, and various etching methods like wet, dry, and plasma etching to remove material. Other important microfabrication processes are bulk micromachining, which etches the silicon substrate, surface micromachining which builds structures in layers, and LIGA which uses X-rays to create high aspect ratio metal parts through electroplating. These micro machining techniques enable manufacturing of complex micro-scale parts for applications like MEMS devices and biomedical tools.
Report on Solar Air heater by Hardik RamaniHardik Ramani
The document discusses advances in solar air heaters. It begins by providing background on solar air heating technology, including its basic principles of using a solid collector surface to absorb solar radiation and transfer heat to air via convection. Different types of solar air heaters are described, including porous and non-porous designs. The document then presents experimental results from testing various solar air heater designs under both summer and winter conditions to analyze temperature rise, thermal efficiency, and instantaneous thermal efficiency at varying air flow rates. It finds that designs with double glazing and packed beds performed better than single glazing. Finally, the conclusion discusses efficiency improvement through roughness additions to collector surfaces.
This document provides a literature review on thermoelectric cooling systems. It discusses the history of thermoelectric discoveries from 1820 to present. Several studies are summarized that examined using thermoelectric cooling modules for industrial enclosures, vehicles like cars and trucks, and personal cooling applications like a cooling helmet. The advantages of thermoelectric coolers are highlighted over traditional vapor-compression refrigeration systems, as thermoelectric coolers have no moving parts, refrigerants, or water requirements. The document also discusses software tools for selecting thermoelectric modules and references previous work developing thermoelectric cooling systems and prototypes.
The document reviews heat transfer enhancement techniques using twisted tape inserts. It discusses heat exchangers and classifications. Twisted tape is described as a passive enhancement method that induces swirl and turbulence to disrupt the thermal boundary layer. Attributes of twisted tape like pitch, twist ratio and shape are examined. Using twisted tape can increase heat transfer rate in a heat exchanger by up to 188% but also increases friction loss. Different tape configurations are evaluated and it is found that optimization of parameters like twist ratio can improve thermal performance.
Nanofluids are now developing technology in main purpose heat transfer stream. In paper has brief information on the introduction and preparation methods of nanofluids. This paper prepared from the study of online resources
Selective Laser Sintering is one of the most used processes of Rapid Prototyping. It is a powder based process where powder of different metals/materials get sintered by LASER.
The document discusses the design of a thermoelectric generator project to convert waste heat from a car engine into electricity. It aims to develop a system that is economical, easy to implement, and does not reduce engine efficiency. The document covers the basic principles of thermoelectric generation using the Seebeck and Peltier effects. It describes thermoelectric generator components like heat exchangers and materials like bismuth telluride. The document discusses performance metrics and advantages like utilizing wasted heat and having no moving parts. It also notes disadvantages like low conversion efficiency and outlines automotive and other applications of thermoelectric generators.
Magneto Hydro Dynamic Power Generation uses the principle that an electrical current is induced when a conductive fluid passes through a magnetic field at high velocity. There are two main types of MHD systems - open cycle systems which use combustion gases and closed cycle systems which reuse gases or use liquid metals. MHD has advantages like high efficiency around 50% and smaller plant size but also limitations like materials challenges from high temperatures and corrosion. Overall MHD is still in development for power generation applications.
Thermal energy based machining processes like electron beam machining (EBM), laser beam machining (LBM), and plasma arc machining (PAM) work by concentrating heat energy on a small area of the workpiece to melt and vaporize material. EBM uses a beam of high velocity electrons, LBM uses a focused laser beam, and PAM uses a high temperature plasma jet, all to remove tiny bits of workpiece material through localized heating and repetition of the process. While each has advantages like precision and lack of mechanical contact, they also have disadvantages like high equipment costs and low material removal rates.
Magnetic refrigeration has been viewed as primarily a cryogenic technology because the necessary high magnetic fields are most easily provided by superconducting magnets.
aseminar report on magnetic refrigerationhardik9343
This document summarizes a seminar presentation on magnetic refrigeration. It discusses the history of magnetic refrigeration dating back to 1881 when the magneto-caloric effect was discovered. It then provides an overview of how magnetic refrigeration works using the magneto-caloric effect found in solid state refrigerants. The objectives of magnetic refrigeration are to develop more efficient and cost effective small scale hydrogen liquefiers as an alternative to traditional vapor-compression cycles.
The document discusses magnetic refrigeration, which uses magneto caloric materials to produce refrigeration through magnetic fields. The objective is to develop more efficient small-scale hydrogen liquefiers using this technique. Magnetic refrigeration offers benefits over traditional vapor-compression cycles like higher efficiency, reduced costs, compactness and reliability. Current activities involve developing optimized magnetic refrigerants and designing a magnetic liquefier. Magnetic refrigeration could provide a more efficient and environmentally friendly alternative to traditional gas-compression refrigeration systems.
This short document does not contain any meaningful information to summarize. It consists of formatting characters without any words or sentences of substance. In 3 sentences or less, there is no essential information that can be extracted from the given text to create a useful summary.
The document summarizes the working principles of magnetic refrigeration systems. It begins with an introduction to different refrigeration methods and outlines the advantages of magnetic refrigeration over conventional vapor compression systems. It then describes the key concepts of magnetocaloric effect and magnetic refrigeration cycles. Specifically:
1) Magnetic refrigeration utilizes the magnetocaloric effect where applying/removing a magnetic field causes certain materials to heat up/cool down. This replaces the need for compressors and refrigerants.
2) The document explains the temperature changes associated with magnetizing/demagnetizing magnetocaloric materials like gadolinium and illustrates the temperature-entropy diagram of magnetic refrigeration cycles.
3) It provides an overview of
This document summarizes the history of wireless power transmission (WPT). It discusses how Maxwell's equations predicted radio waves in 1864 and experiments in the late 1800s provided early evidence of wireless transmission. Nikola Tesla conducted the first WPT experiment in 1899, but it had low efficiency due to long wavelength. Development of higher frequency microwaves in the 1930s allowed for more efficient concentration of power. W.C. Brown pioneered microwave power transmission research from the 1960s, including powering a helicopter wirelessly in 1964. Many laboratory and field experiments using 2.45GHz and 5.8GHz frequencies followed in subsequent decades, advancing WPT technology.
1. The document discusses different types of recyclable building boards and papers that can be used in construction, including plywood, hardboard, insulating fiberboard, chipboard, particle board, gypsum board, strawboard, asbestos-cement board, corkboard, paperboard, and mineral fiberboard.
2. It provides details on the composition and manufacturing process for each type of board. For example, it explains that plywood is made by bonding thin layers of wood at right angles, and each layer is called a veneer.
3. The document outlines common applications of these boards in architecture, as furniture, ceiling designs, building structures, and interiors. Building boards offer various benefits
Gravitational waves are ripples in spacetime predicted by Einstein's theory of general relativity that are generated by accelerating masses. The LIGO project uses laser interferometry across 4km arms to detect passing gravitational waves. Sources include merging black holes and neutron stars. Detection of gravitational waves will allow observation of astrophysical events like supernovae and provide a new way to study the early universe and test general relativity in strong gravitational fields.
This document provides an overview of the fibreboard manufacturing process. It describes how fibres are produced from lignocellulosic materials through refining processes like attrition milling. Fibreboards can be made through dry or wet processes. The wet process involves forming fibres into a mat using water, while the dry process uses air-laid mat formation similar to particleboard. Key steps include refining, forming, pressing, humidifying, and trimming. The document also covers raw material requirements, properties specified in Indian standards, and references for further information.
USAT Certified Coach Dave Jimenez did a tailored presentation at TriShop in Plano, TX on Monday, June 22, 2015 for athletes planning on racing Ironman 70.3 Buffalo Springs in Lubbock, TX on June 28, 2015.
In this presentation, Dave helps plan your logistics and race strategy to have your best 70.3 yet. Dave covered important things to do the days leading up to the event, race morning, the weather and how it may impact your approach to the race, the swim, bike and run courses including strategies about how to race the course and have efficient transitions.
El glaucoma es una enfermedad de los ojos causada por un aumento de la presión intraocular que puede llevar a la pérdida de la vista. Existen dos tipos principales: glaucoma de ángulo cerrado y glaucoma de ángulo abierto. Los factores de riesgo incluyen la edad, antecedentes familiares de glaucoma, y ascendencia africana o asiática. La prevención requiere exámenes regulares de la vista y el seguimiento del tratamiento médico.
The document is copyrighted to Six Apart, Ltd. and contains repeated copyright notices and blank lines. It notes that server performance and environment are subject to change and includes partner and copyright information.
SURVEY AND DESIGN OF A HEADLIGHT CIRCUIT TO REDUCE POWER CONSUMPTIONIAEME Publication
All the components in an automobile are powered by internal combustion engines and thereby reducing its mechanical efficiency. Battery in an automobile is charged with an internal combustion engine with the conversion of mechanical to electrical energy by an alternator also known as generator. Most of the people often forget to turn off their light in the morning which reduces mechanical efficiency of an engine.
This document is a seminar report on traffic induced vibrations submitted by a civil engineering student. It discusses various factors that influence traffic vibrations such as road conditions, vehicle weight and speed, soil type, and season. It also describes how vibrations propagate from the source (vehicles) through the soil to nearby structures. Common methods for measuring vibrations and typical vibration levels from road traffic, construction, and trains are presented. Potential damage to buildings from vibrations and annoyance to inhabitants are addressed. The report concludes with suggested preventative measures such as road maintenance, traffic control, soil improvement, isolation systems, and sufficient distance between roads and buildings.
Thermodynamics of magnetic refrigeration cycles are discussed. Key points:
1. Magnetic refrigeration uses the magnetocaloric effect where applying/removing a magnetic field causes materials to heat up/cool down.
2. Cyclic magnetic refrigeration processes are analyzed using thermodynamic potentials and the first law of thermodynamics. Formulas for work, heat, enthalpy and entropy are presented.
3. Common thermodynamic cycles for magnetic refrigeration like Brayton, Ericsson and Carnot cycles are examined. Cascade and regeneration principles can be applied to widen the achievable temperature range.
In this PPT you know about the SELF HEALING technology in spacecrafts
This technology is still under research in NASA.
This technology can be also implement on Aircrafts.So it is very simple concept it includes some basic knowledge about Composites materials and its properties.
This presentation provides an overview of wind power generation. It discusses that wind energy comes from the sun and is influenced by surface roughness up to 100 meters. There are two main types of wind turbines - horizontal axis and vertical axis. The design of the wind turbine, including the number of blades and size of the generator, impacts efficiency. India has over 20,000 MW of installed wind power capacity as of 2013 and is the fifth largest producer, with Tamil Nadu having the most installations. The future of wind energy depends on government policies and subsidies to encourage its growth.
The document summarizes a seminar on magnetic refrigeration presented by Ganesh Pralhad Bharambe. It discusses the basic principles of using magnetocaloric effects to generate cooling, describing the thermodynamic cycle of adiabatic magnetization, isomagnetic enthalpic transfer, adiabatic demagnetization, and isomagnetic entropic transfer. It also covers potential working materials for magnetic refrigeration like gadolinium alloys, and developments in materials science to improve efficiency, such as amorphous alloys and nanostructured composites.
The document is a seminar report on utilizing a hybrid PV-wind energy system. It discusses the need for hybrid power plants due to the disadvantages of conventional combustion generators like pollution. It then explains hybrid power systems using examples like solar-wind. The report focuses on a solar-wind hybrid power station, providing block diagrams of the system components and an overview of how solar and wind energy work. It discusses combining wind turbines and solar panels in a hybrid system for increased reliability. The conclusion is that a hybrid PV-wind system can provide stable power supply by maximizing the strengths of both solar and wind energy sources.
The magnetic refrigeration at room temperature is an emerging technology that has
attracted the interest of researchers around the world (Bouchekara, 2008). Such a technology
applies the magnetocaloric effect which was first discovered by Warburg (Bohigas, 2000;
Zimm, 2007).
DESIGN AND TESTING OF PROTOTYPE MAGNETIC REFRIGERATION Muhammad Usman
Magnetic refrigeration is considered as a more reliable and sustainable source to generate cooling and effect in the working fluid using a hysteresis effect. Magnetically soft material with less hysteresis loop area has been recommended for this project.
This document summarizes magnetic refrigeration technology. It discusses how magnetic refrigeration uses the magnetocaloric effect to produce cooling through applying and removing a magnetic field to magnetic materials. The document outlines the basic thermodynamic cycle of magnetic refrigeration and compares it to a vapor compression cycle. It also discusses some promising magnetocaloric materials and challenges to overcome like reducing costs and improving efficiency to enable widespread commercial applications of magnetic refrigeration.
Magnetic refrigeration is a cooling technology based on the magnetocaloric effect where magnetocaloric materials are used to attain low temperatures below 1 Kelvin or for common refrigeration. The magnetic refrigeration cycle is analogous to vapor compression refrigeration, where a magnetocaloric material is placed in and out of a magnetic field to transfer heat instead of compressing and expanding a gas. While magnetic refrigeration offers benefits like higher efficiency and reduced costs compared to traditional vapor compression refrigeration, developing high performance magnetocaloric materials and protecting electronics from magnetic fields remain challenges to the technology.
Design, Fabrication and Analysis of Thermo-Acoustic Refrigeration System – A ...IRJET Journal
This document provides a review of thermo-acoustic refrigeration systems. It discusses the basic principles of how these systems work using sound waves to transfer heat without harmful refrigerants. The document summarizes several research papers that studied ways to optimize the design and efficiency of thermo-acoustic refrigerators, such as by varying the stack design and material or operating parameters like frequency and pressure. While thermo-acoustic refrigerators currently have a lower coefficient of performance than conventional systems, the document concludes that ongoing research aims to improve performance and make these environmentally-friendly refrigeration systems more competitive.
This document summarizes research on magnetic refrigeration. It describes the development of magnetic refrigeration technology over time, including early experiments in the late 19th century and key advances in the late 20th century. It then discusses several studies that have designed and tested different types of magnetic refrigeration devices, including reciprocating and rotating systems, and investigated how to optimize performance by studying various design and operating parameters. The document focuses on a study in Iraq that constructed the first magnetic refrigerator in the country to experimentally investigate its performance and the effects of different operational parameters.
Review of magnetic refrigeration system as alternative to conventional refrig...Naji Abdullah
The refrigeration system is one of the most important systems in industry.
Developers are constantly seeking for how to avoid the damage to the environment. Magnetic
refrigeration is an emerging, environment-friendly technology based on a magnetic solid that
acts as a refrigerant by magneto-caloric effect (MCE). In the case of ferromagnetic materials,
MCE warms as the magnetic moments of the atom are aligned by the application of a magnetic
field. There are two types of magnetic phase changes that may occur at the Curie point: first
order magnetic transition (FOMT) and second order magnetic transition (SOMT). The
reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative cycle),
where the magnetic material matrix works both as a refrigerating medium and as a heat
regenerating medium, while the fluid flowing in the porous matrix works as a heat transfer
medium. Regeneration can be accomplished by blowing a heat transfer fluid in a reciprocating
fashion through the regenerator made of magnetocaloric material that is alternately magnetized
and demagnetized. Many magnetic refrigeration prototypes with different designs and software
models have been built in different parts of the world. In this paper, the authors try to shed
light on the magnetic refrigeration and show its effectiveness compared with conventional
refrigeration methods.
Cryogenic Treatment and Cryogenic Cooling in Die Sink Electric Discharge Mach...IJERA Editor
Integration of Cryogenic Treatment and Cryogenic Cooling with EDM process results in a newer process called as the Cryogenically Assisted Electric Discharge Machining (CEDM) process. It is one of very recent developments for the enhancement of process capabilities of EDM. In this technique, either the tool or the workpiece, or tool and workpiece both, may be, cryogenically treated down to sub zero temperatures or the EDM tool is cryogenically cooled with an objective to modify their properties. The modifications in properties result in the reduction of tool wear rate (TWR) and surface roughness (SR) and to increase material removal rate (MRR). An experimental set up for both the variants of CEDM has been discussed in the presented paper
This document discusses magnetic refrigeration. It begins by introducing magnetic refrigeration and the magnetocaloric effect. It then explains the thermodynamic cycle of magnetic refrigeration, which involves adiabatic magnetization, isomagnetic heat transfer, adiabatic demagnetization, and isomagnetic entropy transfer. Common working materials like gadolinium and its alloys are mentioned. Advantages discussed include being more environmentally friendly than vapor-compression refrigeration by avoiding hazardous chemicals and ozone-depleting refrigerants.
Suspended nanoparticles in conventional fluids,
called nanofluids, have been the subject of intensive study
worldwide since pioneering researchers recently discovered the
anomalous thermal behavior of these fluids. The heat transfer from
smaller area is achieved through microchannels. The heat transfer
principle states that maximum heat transfer is achieved in
microchannels with maximum pressure drop across it. In this
research work the experimental and numerical investigation for
the improved heat transfer characteristics of serpentine shaped
microchannel heat sink using Al2O3/water nanofluid is done. The
fluid flow characteristics is also analyzed for the serpentine
shaped micrchannel. The experimental results of the heat
transfer using Al2O3 nanofluid is compared with the numerical
values. The calculations in this work suggest that the best heat
transfer enhancement can be obtained by using a system with an
Al2O3–water nanofluid-cooled micro channel with serpentine
shaped fluid flow
ENHANCEMENT OF THERMAL EFFICIENCY OF NANOFLUID FLOWS IN A FLAT SOLAR COLLECTO...Barhm Mohamad
Flat plate solar collector (FPSC) is popular for their low cost, simplicity, and ease of installation and operation. In this work, FPSC thermal performance was analyzed. It's compared to diamond/H2O nanofluids. The volume percentage and kind of nanoparticles are analyzed numerically that validation with experimental data available in the literature. The hot climate of Iraq is employed to approximate the model. The numerical study is performed by using ANSYS/FLUENT software to simulate the case study of problem. Due to less solar intensity after midday, temperatures reduction. The greatest collector thermal efficiency is 68.90% with 1% ND/water nanofluid, a 12.2% increase over pure water. The efficiency of 1% nanofluid is better than other concentrations because of a change in physical properties and an increase in thermal conductivity. Since the intensity of radiation affects the outlet temperature from the solar collector and there is a direct link between them, this increases the efficiency of the solar collector, especially around 12:30 pm at the optimum efficiency.
This document summarizes research on cooling systems for high heat flux electronics. It discusses direct and indirect liquid cooling systems using single or two-phase flow. Direct systems use coolants like dielectric fluids in contact with chips, while indirect systems use a liquid loop and secondary refrigeration loop. Two-phase microchannel and spray cooling can remove over 800 W/cm2. Refrigeration systems maintain low chip temperatures below 125°C even at over 1000 W/cm2. Flow instabilities are a challenge, and active control methods are needed for transient applications. Advanced modeling and control strategies may enable effective cooling of future high-power electronics.
Magnetic refrigeration is a technology that has proven to
be environmentally safe. Computer models have shown
25% efficiency improvement over vapor compression
systems.
Introduction to Magnetic RefrigerationSamet Baykul
DATE: 2019.05.12
We have given a lecture to the class in the course of "Refrigeration Systems" in ODTÜ.
● Introduction
● History and Developments
● Physical Phenomenas
● Thermodynamics of Magnetic Refrigeration
● Magnetocaloric Materials
● Future of Magnetic Refrigeration
● Developments
● Usage Areas
● Conclusion
Enhancement of rate of heat transfer using nano fluidsSharathKumar528
Nano fluids as coolants and lubricants is still very primitive in technology. This presentation explores the future of nano fluids for enhanced heat transfer.
The field of thermoelectrics has been growing steadily due to its ability to convert heat directly into electricity and to develop cost
effective, pollution free forms of energy conversion, aiming at efficiencies as high as possible. Low-dimensional structures have proved to be promising candidates for enhancing the thermoelectric properties of semiconductors. Here, we discuss the idea of implementation of dense arrays of armchair graphene nanoribbons in microfabricated structures to develop planar unileg thermoelectric microgenerators to convert heat fl ow into electrical energy. This paper is a discussion on energy scavenging to provide power autonomy to devices on a human body i.e., thermoelectric conversion of human heat and thereby summarizes the advantages of this material for commercial use because of its extra ordinary thermo electric performance.
IRJET- Design and Fabrication of Thermo Acoustic RefrigeratorIRJET Journal
This document describes the design and fabrication of a thermoacoustic refrigerator. Some key points:
1. Thermoacoustic refrigeration uses sound waves to alternately compress and relax gas particles in a tube, transferring heat without moving parts.
2. The refrigerator consists of a resonator tube containing a stack of closely spaced surfaces through which a sound wave oscillates. Heat is transferred between the gas and stack surfaces.
3. Experiments investigated different stack geometries and materials to optimize heat transfer and the refrigerator's performance. Temperature sensors measured the temperature difference created.
This document discusses cryogenic heat treatment of metals. It provides background on the history of cryogenics beginning in the late 1800s. It then discusses the process of cryogenic treatment, which involves cooling metals to below -190°C to improve properties like wear resistance, corrosion resistance, and reducing residual stresses. The effects of cryogenic treatment are explained, including transforming retained austenite to martensite and precipitating carbides to enhance properties.
Waste Heat Recovery From Refrigeration PlantIRJET Journal
This document summarizes waste heat recovery from a refrigeration plant condenser. It discusses how the waste heat from a condenser, which is currently released into the environment, can instead be captured and used for applications like water heating. The document then provides technical details on heat transfer methods, refrigerants, and vapor compression refrigeration systems. It analyzes using the condenser waste heat from a 30-ton refrigeration plant to heat water up to 50°C, which could then be used for low-temperature household or industrial purposes. Capturing this waste heat improves overall system efficiency and reduces environmental impacts.
This presentation discusses thermoelectric effects on magnetic nanostructures and their application in magnetic refrigeration. It explains that magnetic refrigeration is based on the magnetocaloric effect and the varying magnetic entropy of magnetic materials. Magnetic refrigeration has advantages over traditional vapor compression cycles, including lower costs, less electricity usage, no compressor or refrigerant gases. While initial investment is higher for magnetic refrigeration, it provides safer, more environmentally friendly cooling. The goal is to develop efficient magnetic refrigeration technology for standard home refrigerators.
Similar to a seminar report magnetic refrigeration (20)
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
Leonard Jayamohan, Partner & Generative AI Lead, Deloitte
This keynote will reveal how Deloitte leverages Neo4j’s graph power for groundbreaking digital twin solutions, achieving a staggering 100x performance boost. Discover the essential role knowledge graphs play in successful generative AI implementations. Plus, get an exclusive look at an innovative Neo4j + Generative AI solution Deloitte is developing in-house.
GraphRAG for Life Science to increase LLM accuracyTomaz Bratanic
GraphRAG for life science domain, where you retriever information from biomedical knowledge graphs using LLMs to increase the accuracy and performance of generated answers
AI 101: An Introduction to the Basics and Impact of Artificial IntelligenceIndexBug
Imagine a world where machines not only perform tasks but also learn, adapt, and make decisions. This is the promise of Artificial Intelligence (AI), a technology that's not just enhancing our lives but revolutionizing entire industries.
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!SOFTTECHHUB
As the digital landscape continually evolves, operating systems play a critical role in shaping user experiences and productivity. The launch of Nitrux Linux 3.5.0 marks a significant milestone, offering a robust alternative to traditional systems such as Windows 11. This article delves into the essence of Nitrux Linux 3.5.0, exploring its unique features, advantages, and how it stands as a compelling choice for both casual users and tech enthusiasts.
Infrastructure Challenges in Scaling RAG with Custom AI modelsZilliz
Building Retrieval-Augmented Generation (RAG) systems with open-source and custom AI models is a complex task. This talk explores the challenges in productionizing RAG systems, including retrieval performance, response synthesis, and evaluation. We’ll discuss how to leverage open-source models like text embeddings, language models, and custom fine-tuned models to enhance RAG performance. Additionally, we’ll cover how BentoML can help orchestrate and scale these AI components efficiently, ensuring seamless deployment and management of RAG systems in the cloud.
UiPath Test Automation using UiPath Test Suite series, part 5DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 5. In this session, we will cover CI/CD with devops.
Topics covered:
CI/CD with in UiPath
End-to-end overview of CI/CD pipeline with Azure devops
Speaker:
Lyndsey Byblow, Test Suite Sales Engineer @ UiPath, Inc.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Speck&Tech
ABSTRACT: A prima vista, un mattoncino Lego e la backdoor XZ potrebbero avere in comune il fatto di essere entrambi blocchi di costruzione, o dipendenze di progetti creativi e software. La realtà è che un mattoncino Lego e il caso della backdoor XZ hanno molto di più di tutto ciò in comune.
Partecipate alla presentazione per immergervi in una storia di interoperabilità, standard e formati aperti, per poi discutere del ruolo importante che i contributori hanno in una comunità open source sostenibile.
BIO: Sostenitrice del software libero e dei formati standard e aperti. È stata un membro attivo dei progetti Fedora e openSUSE e ha co-fondato l'Associazione LibreItalia dove è stata coinvolta in diversi eventi, migrazioni e formazione relativi a LibreOffice. In precedenza ha lavorato a migrazioni e corsi di formazione su LibreOffice per diverse amministrazioni pubbliche e privati. Da gennaio 2020 lavora in SUSE come Software Release Engineer per Uyuni e SUSE Manager e quando non segue la sua passione per i computer e per Geeko coltiva la sua curiosità per l'astronomia (da cui deriva il suo nickname deneb_alpha).
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
“An Outlook of the Ongoing and Future Relationship between Blockchain Technologies and Process-aware Information Systems.” Invited talk at the joint workshop on Blockchain for Information Systems (BC4IS) and Blockchain for Trusted Data Sharing (B4TDS), co-located with with the 36th International Conference on Advanced Information Systems Engineering (CAiSE), 3 June 2024, Limassol, Cyprus.
1. 1
A
Seminar
On
“MAGNETIC REFRIGERATION”
By
MR. HARDIK N KOTHIYA
Under The Guidance Of
Prof. J. R. MAHAJAN
Submitted In Partial Fulfillment of the Requirement For
Bachelor of Engineering (Mechanical)Degree
of
University of Pune
Department of Mechanical Engineering
Late G.N. SapkalCollege of Engineering,
Anjaneri, Nashik-422212
2013-2014
2. 2
Kalyani Charitable Trust’s
Late G. N. Sapkal College of Engineering
Sapkal Knowledge Hub, Kalyani Hills, Anjaneri, Trimbakeshwar Road,
Nashik – 422 212, Maharashtra State, India
CERTIFICATE
This is to certify that Mr. HARDIK N KOTHIYAhas successfully
completed his Seminaron the topic“MAGNETIC REFRIGERATION”,
under the able guidance of Prof. J. R. MAHAJANtowards the partial
fulfillment ofThird YearofMechanical Engineering as laid down
byUniversity of Pune during academic year 2013-14.
Prof. Prof. T.Y. Badgujar
[Seminar Guide] [ H.O.D. Mechanical ]
Dr. Basavaraj S. Balapgol
[Examiner] Principal
3. 3
CONTENT
ACKNOWLEDGEMENT
ABSTRACT
INDEX
Sr.
No.
Description Page
No.
1 Introduction 7
2 History 8
3 Refrigeration 9
3.1 Magnetic Refrigeration 9
4 Objective Of Magnetic Refrigeration 10
5 Magneto-caloric Effect 10
6 Working Of Magnetic Refrigeration 12
6.1 Magnetic Refrigeration System 12
6.2 Refrigerator’s Configuration 13
7 Comparison Between Magnetic Refrigeration
& Conventional Refrigeration
14
8 Components 16
9 Application 17
9.1 A Rotary AMR Liquefier 17
9.2 Future Application 17
10 Techinical Benefits 18
11 Advantages 18
12 Disadvantages 19
13 Current & Future Uses 20
14 Conclusion 21
15 Reference 21
4. 4
FIGURE INDEX
FIGURE NO. TITLE PAGE NO.
2.1 Emil Warburg Gabriel 8
5.1 Magneto-Caloric Effect 11
5.2 Process of Magneto-Caloric Effect 11
6.1 Flow Process Diagram A 12
6.2 Flow Process Diagram B 13
7.1
Comparison Between Magnetic
Refrigeration & Conventional Refrigeration
14
7.2
Refrigeration Cycle For Conventional Gas
Compression & Magnetic Refrigeration
15
8.1 Components 16
9.1 A Rotary AMR Liquefier 17
5. 5
ACKNOWLEDGEMENT
I take this opportunity to express our deep sense of gratitude and respecttowards
our guide MR. J. R. MAHAJAN, Department of Mechanical Engineering,Late G N
Sapkal College Of Engineering , NASHIK. I am very much indebted to his for the
generosity, expertise and guidance; I have received from him while collecting data on this
seminar and throughout our studies. Without his support and timely guidance,the
completion of my seminar would have seemed a far fetched dream. In this respect I find
ourselves lucky to have his as our guide. He has guided us not only with the subject
matter, but also taught us the proper style and technique of working and presentation. It is
a great pleasure for me to express my gratitude towards those who are involved in the
completion of my seminar report. I whole-heartedly thank to our HOD Mr. T. Y.
BADGUJAR for their guidance. I am also indebted to all Sr. Engineers and others who
gave me their valuable time and guidance. The various information and sources I used
during my report completion findplace in my report.
I am also grateful to Senior Seminar Coordinators respected sir’s.
HARDIK N KOTHIYA
III year, VSem
Deptt. Of Mechanical Engineering (L.G.N.S.COE, Nashik) Magnetic Refrigeration
6. 6
ABSTRACT
The objective of this effort is to study the Magnetic Refrigeration which uses solid
materials asthe refrigerant. These materials demonstrate the unique property known as
magneto caloric effect, which means that they increase and decrease in temperature
whenmagnetized/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.
Magnetic refrigeration is an emerging technology that exploits the magneto-
caloric effectfound in solid state refrigerants. The combination of solid-state refrigerants,
water based heat transfer fluids and high efficiency leads to environmentally desirable
products with minimal contribution to global warming. Among the numerous application
of refrigeration technology air conditioning applications provide the largest aggregate
cooling power and use of the greatest quantity of electric energy.
7. 7
1. INTRODUCTION
Refrigeration is the process of removing heat from matter which may be a solid, a
liquid, or agas. Removing heatfrom the matter cools it, or lowers its temperature. In the
mechanical refrigeration a refrigerant is a substance capable of transferring heat that it
absorbs at low temperatures and pressures to a condensing medium; inthe region of
transfer, the refrigerant is at higher temperatures and pressures. By means of expansion,
compression, and a cooling medium, such as air or water, the refrigerant removes heat
from a substance and transfers it to the cooling medium.
Our society is highly dependent on reliable cooling technology. Refrigeration
iscritical toour health and the global economy. Consumer application includes air
conditioning, food preservation, air dehumidification, beverage dispensing and ice
making without refrigerant ion the food supply wood still be seasonal and limited to
locally produced non-perishable items.
Modern refrigeration is almost entirely based on a compression/
expansionrefrigerationcycle. It is a mature, reliable & relatively low cost technology.
Over the years ,all parts of a conventional refrigerator were considerably improved due to
extended research and development efforts. Furthermore, some liquids used as
refrigerants arehazardous chemicals, while other eventually escape into the environment
contributingtowards ozone layer depletion and global warming and therefore,
conventionalrefrigeration ultimately promotes deleterious trends in the global climate.
Magnetic refrigerator, which has advantages in refrigeration efficiency, reliability,
lownoise and environmental friendliness with respect to the conventional gas
refrigerators, is becoming a promising technology to replace the conventional technique.
The development of the magnetic material, magnetic refrigeration cycles, magnetic field
and the refrigerator of room temperature magnetic refrigeration is introduced.
8. 8
2. HISTORY
Fig. 2.1Emil WarburgGabriel
The effect was discovered in pure iron in 1881 by E. Warburg. Originally, the
cooling effect varied between 0.5 to 2 K/T. Major advances first appeared in the late
1920s when cooling via adiabatic demagnetization was independently proposed by two
scientists: Debye (1926) and Giauque(1927).
The process was demonstrated a few years later when Giauque and MacDougall in
1933used it to reach a temperature of 0.25 K. Between 1933 and 1997, a number of
advances in utilization of the MCE for cooling occurred.
This cooling technology was first demonstrated experimentally by chemist Nobel
Laureate William F. Giauque and his colleague Dr. D.P. MacDougall in 1933 for
cryogenic purposes (they reached 0.25 K) In 1997, the first near room temperature proof
of concept magnetic refrigerator was demonstrated by Prof. Karl A. Gschneidner, Jr. by
the Iowa State University at Ames Laboratory. This event attracted interest from
scientists and companies worldwide that started developing new kinds of room
temperature materials and magnetic refrigerator designs.
Refrigerators based on the magneto caloric effect have been demonstrated in
laboratories, usingmagnetic fields starting at 0.6 T up to 10 teslas. Magnetic fields above
2 T are difficult to produce with permanent magnets and are produced by a
superconducting magnet (1 tesla is about 20,000 times the Earth's magnetic field).
9. 9
3.REFRIGERATION
Refrigeration is the process of removing heat from an enclosed space, or from a
substance, andmoving it to a place where it is unobjectionable. The primary purpose of
refrigeration is lowering the temperature of the enclosed space or substance and then
maintaining that lower temperature. The term cooing refers generally to any natural or
artificial process by which heat is dissipated. The process of artificially producing
extreme cold temperatures is referred to as cryogenics. Cold is the absence of heat, hence
in order to decrease a temperature, one “removes heat", rather than "adding cold." In
order to satisfy the Second Law of Thermodynamics, some form of work must
be performed to accomplish this. This work is traditionally done by mechanical work but
can also be done by magnetism, laser or other means.
3.1MAGNETIC REFRIGERATION
Magnetic refrigeration, or adiabatic demagnetization, is a cooling technology
based on themagneto caloric effect, an intrinsic property of magnetic solids. The
refrigerant is often a paramagnetic salt, such as cerium magnesium nitrate. The active
magnetic dipoles in this case are those of the electron shells of the paramagnetic atoms.
A strong magnetic field is applied to the refrigerant, forcing its various magnetic
dipolesto align and putting these degrees of freedom of the refrigerant into a state of
lowered entropy. A heat sink then absorbs the heat released by the refrigerant due to its
loss of entropy. Thermal contact with the heat sink is then broken so that the system is
insulated, and the magnetic field is switched off. This increases the heat capacity of the
refrigerant, thus decreasing its temperature below the temperature of the heat sink.
Because few materials exhibit the needed properties at room temperature, applications
have so far been limited to cryogenics and research.
10. 10
4. OBJECTIVES OF MAGNETIC REFRIGERATION
To develop more efficient and cost effective small scale H2 liquefiers as an
alternative tovapor-compression cycles using magnetic refrigeration. With the help of
magnetic refrigeration our objective is to solve the problem of hydrogen storage as it
ignites on a very low temperature. Hydrogen Research Institute (HRI) is studying it
with the help of magnetic refrigeration. We provide the cooling for the hydrogen storage
by liquefying it.
The hydrogen can be liquefied at a low temperature and the low temperature is
achieved with the help of magnetic refrigeration.Thus, the magnetic refrigeration also
provides a method to store hydrogen by liquefying it. The term used for such a device is
magnetic liquefier.
5. MAGNETO CALORIC EFFECT
The Magneto caloric effect (MCE, from magnet and calorie) is a magneto-
thermodynamicphenomenon in which a reversible change in temperature of a suitable
material is caused by exposing the material to a changing magnetic field. This is also
known as adiabaticdemagnetization by low temperature physicists, due to the
application of the process specifically to affect a temperature drop. In that part of the
overall refrigeration process, a decrease in the strength of an externally applied magnetic
field allows the magnetic domains of a Chosen (magneto caloric) material to become
disoriented from the magnetic field by the agitating Action of the thermal energy
(phonons) present in the material. If the material is isolated so that no energy is allowed
to (e) migrate into the material during this time (i.e. an adiabatic process), the temperature
drops as the domains absorb the thermal energy to perform their reorientation.
One of the most notable examples of the magneto caloric effect is in the
chemicalelement gadolinium and some of its alloys. Gadolinium's temperature is
observed to increase when it enters certain magnetic fields. When it leaves the magnetic
11. 11
field, the temperature returns to normal. The effect is considerably stronger for the
gadolinium alloy Gd5 (Si2Ge2). Praseodymium alloyed with nickel (Pr Ni 5) has such a
strong magneto caloric effect that it has allowed scientists to approach within one
thousandth of a degree of absolute zero. Magnetic Refrigeration is also called as
Adiabatic Magnetization.
Fig. 5.1 Magneto-Caloric Effect
Fig. 5.2 Process of Magneto-Caloric Effect
12. 12
1. WORKING OF MAGNETIC REFRIGERATION SYSTEM
6.1 Magnetic Refrigeration system : -
Consists of two beds containing spherical powder of Gadolinium with water being
usedas the heat transfer fluid. The magnetic field for this system is 5 Wb/m2, providing a
temperature span of 38 K. The process flow diagram for the magnetic refrigeration
system is shown in Fig.
Fig.6.1 Flow process diagram A
A mixture of water and ethanol serves as the heat transfer fluid for the system.
The fluidfirst passes through the hot heat exchanger, which uses air to transfer heat to the
atmosphere. The fluid then passes through the copper plates attached to the no
magnetized cooler-magneto caloric beds and loses heat. A fan blows air over this cold
fluid into the freezer to keep the freezer temperature at approximately 0°F. The heat
transfer fluid then gets heated up to 80°F, as it passes through the copper plates adjoined
by the magnetized warmer magneto caloric beds, where it continues to cycle around the
loop. However, the magneto caloric beds simultaneously move up and down, into and out
of the magnetic field. The temperature of the refrigerator section is kept around 39°F.
6.2 Refrigerator Configuration :-
13. 13
The typical household refrigerator has an internal volume of 165-200 litres, where
thefreezer represents approximately 30% of this volume. Freezers are designed to
maintain at temperature of 0°F. Refrigerators maintain a temperature of 39°F. The
refrigerator will be insulated with polyurethane foam, one of the most common forms of
insulation available. The refrigerator is kept cool by forcing cold air from the freezer into
the refrigerator by using a small fan.
Fig. 6.2 Flow process diagram B
The control system for maintaining the desired internal temperatures consists of
twothermostats with on/off switches. The freezer thermostat regulates the temperature by
turning the compressor off when the temperature gets below 0°F. A second thermostat
regulates the fan that cools the refrigerator to 39°F. To maintain a frost-free environment
in the freezer, a defrost timer will send power to a defrost heater on the coils for a fifteen
minute time period every eight hours. In the first six minutes, the walls of the freezer will
be defrosted. The water will then drain into a pan at the base of the refrigerator. The next
nine minutes involve the safety factor of not reaching a temperature in the freezer that is
too high. Also, a safety thermostat keeps the liquid water from freezing as it drains.
The heat transfer fluid for the magnetic refrigeration system is a liquid alcohol
watermixture. The mixture used in the design consists of 60 % ethanol and 40 % water.
This mixture has a freezing point of –40°F, assuring that the mixture does not freeze at
operatingtemperatures. This heat transfer fluid is cheaper than traditional refrigerants and
also eliminatesthe environmental damage produced from these refrigerants.
14. 14
7. COMPARISON BETWEEN MAGNETIC REFRIGERATION
AND CONVENTIONAL REFRIGERATION
Fig. 7.1Comparison between Magnetic Refrigeration and Conventional Refrigeration
In Figure 2 the four basic steps of a conventional gascompression/ Expansion
refrigerationprocess are shown. These are a compression of a gas, extraction of heat,
Expansion of the gas, and injection of heat. The two Process steps extraction of heat and
expansion are Responsible for a cooling process in two steps. The main Cooling usually
occurs through the expansion of the gas.
The steps of a magnetic refrigeration process are Analogous. By comparing a with
b, inFigure.2 one can see That instead of compression of a gas, a magnetocaloric Material
is moved into a magnetic field and that instead of Expansion it is moved out of the field.
As explained in the Previous section, these processes change the temperature Of the
material and heat may be extracted, respectively Injected just as in the conventional
process. There are Some differencesbetween the two processes. The heat Injection and
rejection in a gaseous refrigerant is a ratherFast process, because turbulent motion
15. 15
transports heat Very fast. Unfortunately, this is not the case in the solid Magneto-caloric
materials. Here, the transport mechanism For heat is slow molecular diffusion. Therefore,
at present fi Ligree porous structures are considered to be the best Solution to overcome
this problem. The small distances From the central regions of the material to an adjacent
fluid Domain, where a heat transport fluid captures the heat and Transports it out of the
material, are ideal to make the Magnetic cooling process faster. Furthermore, the not very
Large adiabatic temperature differences of magneto-caloric Materials will require more
often a design of cascade or Regenerative magnetic refrigerators than in conventional
Refrigerators and hence require additional heat transfer Steps. In the is the conventional
gascompression Process is driven by continuously repeating The four different basic
processes shown and is the Magnetic refrigeration cycle comparison. Compression is
Replaced by adiabatic magnetization and expansion by Adiabatic demagnetization.
Fig. 7.2 Refrigeration cycles for conventional gas compression and magnetic refrigeration
8. COMPONENTS
16. 16
Components required for construction :-
Fig. 8.1Components
1. Magnets : -
Magnets are the main functioning element of the magnetic refrigeration. Magnets
providethe magnetic field to the material so that they can lose or gain the heat to the
surrounding and from the space to be cooled respectively.
2. Hot Heat Exchanger : -
The hot heat exchanger absorbs the heat from the material used and gives off to
thesurrounding. It makes the transfer of heat much effective.
3. Cold Heat Exchanger :-
The cold heat exchanger absorbs the heat from the space to be cooled and gives it
to themagnetic material. It helps to make the absorption of heat effective.
4. Drive : -
Drive provides the right rotation to the heat to rightly handle it. Due to this heat
flows inthe right desired direction.
5. Magneto caloric Wheel : -
It forms the structure of the whole device. It joins both the two magnets to work properly.
9. APPLICATIONS
17. 17
9.1 A rotary AMR liquefier :-
The Cryofuel Systems Group is developing an AMR refrigerator for the purpose
of liquefyingnatural gas. A rotary configuration is used to move magnetic material into
and out of a superconducting magnet. This technology can also be extended to the
liquefaction of hydrogen.
Fig. 9.1 A Rotary AMR liquefier
9.2 Future Applications:-
In general, at the present stage of the development of magnetic refrigerators with
permanentmagnets, hardly any freezing applications are feasible. These results, because
large temperature spans occur between the heat source and the heat sink. Such are used
for freezing, e.g. in cooling plants in the food industry or in large marine freezing
applications. Some of the future applications are:
1. Magnetic household refrigeration appliances
2. Magnetic cooling and air conditioning in buildings and houses
3. Central cooling system
4. Refrigeration in medicine
5. Cooling in food industry and storage
6. Cooling in transportation
7. Cooling of electronics
10.TECHNICAL BENEFITS
18. 18
2. High efficiency: - As the magneto caloric effect is highly reversible, the thermo
dynamicefficiency of the magnetic refrigerator is high. It is somewhat 50% more
than Vapor Compression cycle.
3. Reduced operating cost: - As it eliminates the most inefficient part of today’s
refrigerator i.e.comp. The cost reduces as a result.
4. Compactness: - It is possible to achieve high energy density compact device. It is
due to thereason that in case of magnetic refrigeration the working substance is a
solid material (say gadolinium) and not a gas as in case of vapor compression
cycles.
5. Reliability: - Due to the absence of gas, it reduces concerns related to the emission
into theatmosphere and hence is reliable one.
11. ADVANTAGES
1. Environmental friendly: - Conventional refrigerator use refrigerant that contains
CFC or HCFC, which have been linked to Ozone depletion and global warming.
Some refrigerant like ammonia are toxic and inflammable.
2. Low running and operating cost:-There is no compressor in magnetic
refrigerator, which is most inefficient and costlier part. This leads in less energy
consumption and hence low running cost.
3. Higher efficiency:-Because it eliminates the need to expand and compressed the
liquid, magnetic refrigerator consume less energy and can operate at 60%
efficiency.
4. Wide temperature span: - Operating temperature of magnetic refrigerator can
easily be changed over a wide range from about 30 k to 290 k without losing the
magneto-caloric effect.
19. 19
5. Reliability: - High energy density and more compact device, less moving parts as
compared to traditional system hence more reliable.
6. Quite operation: - This refrigerator unit is substantially quite than traditional
refrigeration system.
12. DISADVANTAGES
On the other hand, some disadvantages include:
1. The initial investment is more as compared with conventional refrigeration.
2. The magneto caloric materials are rare earth materials hence their availability also
addsup an disadvantage in MAGNETIC REFRIGERATION.
GMCE materials need to be developed to allow higher frequencies of rectilinear
androtary magnetic refrigerators.
3. Protection of electronic components from magnetic fields. But notice that they
are static, of short range and may be shielded
4. Permanent magnets have limited field strength. Electromagnets and
superconductingmagnets are (too) expensive.
5. Temperature changes are limited. Multi-stage machines lose efficiency through
the heattransfer between the stages.
6. Moving machines need high precision to avoid magnetic field reduction due to
gapsbetween the magnets and the magneto caloric material.
20. 20
13. CURRENT AND FUTURE USES
There are still some thermal and magnetic hysteresis problems to be solved for
these first-orderphase transition materials that exhibit the MCE to become really useful;
this is a subject of current research. A useful review on magneto caloric materials
published in 2005 is entitled "Recent developments in magneto caloric materials" by Dr.
Karl A. Gschneidner, .This effect is currently being explored to produce better
refrigeration techniques, especially for use in spacecraft. This technique is already used to
achieve cryogenic temperatures in the laboratory setting (below 10K). As an object
displaying MCE is moved into a magnetic field, the magnetic spins align, lowering the
entropy. Moving that object out of the field allows the object to increase its entropy by
absorbing heat from the environment and disordering the spins. In this way, heat can be
taken from one area to another. Should materials be found to display this effect near room
temperature, refrigeration without the need for compression may be possible, increasing
energy efficiency.
In addition, magnetic refrigeration could also be used in domestic refrigerators. In
2006, aresearch group led by Karl Sandeman at the University of Cambridge made a new
alloy, composed of cobalt, manganese, silicon and germanium that can be used for
magnetic refrigeration. This has made the use of the expensive material gadolinium
redundant, and made the creation of domestic magnetic refrigerators possible. The use of
this technology for domestic refrigerators though is very remote due to the high efficiency
of current Vapor-compression refrigeration in the range of 60% of Carnots efficiency.
Gas molecules are responsible for heat transfer, they absorb heat in the inner side of the
refrigerator by expanding and release this heat in the outside by condensing. The work
provided to do this work is a cheap and highly efficient compressor, driven by an electric
motor that is more than 80% efficient. This technology could eventually compete with
other cryogenic heat pumps for gas liquefaction purposes.
21. 21
14. CONCLUSION
If we say future perspectives of room temperature Magnetic Refrigeration; It can
be seen fromthe earlier Description that main progresses have been made in America.
However, with the continual phasic progresses of Room temperature magnetic
refrigeration, the whole world Hasaccelerated in the research. Nevertheless, it is notable
that main work is concentrated Oninvestigations of magnetic materials, lack of
Experimental explorations of magnetic refrigerator. From The former results achieved by
researchers, it can be seen. At the end of this study we can say;
1. It is a technology that has proven to be environmentally safe.
2. In order to make the magnetic refrigerator commercially Viable, scientists need to
know how to achieve larger temperature swings and also permanent magnets
which canproduce strong magnetic fields of order 10 tesla.
3. There are still some thermal and magnetic hysteresis problems to be Solved for
thematerials that exhibit the MCE to become really useful.
4. Magnetic materials available for room Temperature magnetic refrigeration are
mainlyGd, Gdsige alloys, mnas-like materials, perovskitelike Materials,
5. Materials under development for room Temparature magnetic refrigeration are
La(fexsi1-X)13 and La(Fe0.88Si0.12)13Hy
6. Excellent behavior of regeneration and heat Transfer is required It can be use
household refrigerator, central Cooling systems, room air conditioners and
Supermarket refrigeration applications.
7. This technology must be universalized worldwide.
22. 22
15. REFERENCES
1. http://en.wikipedia.org/wiki/Magnetic_refrigeration
2. http://www.scribd.com/doc/19537314/Magnetic-Refrigeration
3. Lounasmaa, experimental principles and methods, academic press
4. Richardson and Smith, experimental techniques in condensed matter physics at low
temperature, Addison Wesley (2003)
5. A text book on cryogenic engineering by V.J.Johnson
6. “Refrigeration and Air conditioning” by Arora and Domkundwar
7. Magnetic Refrigeration, ASHRAE Journal (2007), by John Dieckmann, Kurt Roth and
James Brodrick