Magnetic Refrigeration
ABSTRACT
Refrigeration is a process in which heat is removed from an enclosed space and given to the surrounding. Refrigeration technology is not new but centuries old only the thing is that methods of refrigeration are changed. The refrigerants used in the conventional systems pollute the environment by depleting the ozone layer. By the depletion of ozone layer the harmful rays from sun i.e. UV rays, infrared rays may cause skin cancer to human beings. So there is a need to build a new refrigeration system so that it is environment friendly. This led to the discovery of new technique for refrigeration known as “ MAGNETIC REFRIGERATION ”.
An attempt has been made I this paper to bring about the advantages of Magnetic Refrigeration system over conventional Refrigeration system. The first chapter gives a brief introduction to Conventional Refrigeration system. In the second topic we have the introduction to Magnetic Refrigeration system, its basic working system and refrigerants used for the system.
The third chapter gives the prototype working of “AMRR” (Active Magnetic Regenerative Refrigerator). Further in this chapter the experimental results on this system are discussed.
Chapter four gives the enhancement of magnetocaloric effect, which is the basis of magnetic refrigeration. In the next chapter comparison has been made between Magnetic Refrigeration and Conventional Refrigeration systems. The applications and conclusions are discussed in the chapter 6 and 7 respectively.
Though the technique is at experimental stage, the results obtained from the prototype gives an indication that it will soon hit the domestic market in next 5 – 10 years. So watch out this new system that will soon enter your kitchen.
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Friday, April 1, 2011
A FUTURE ENERGY SOURCE - LIQUID HYDROGEN
A FUTURE ENERGY SOURCE - LIQUID HYDROGEN
ABSTRACT
The conversion to Liquid Hydrogen as an alternative fuel would allow for independence on fuel cost and supply, as Hydrogen is globally accessible. The biggest obstacle to using Hydrogen is its very low density, a property that even combined with Hydrogen’s high heat of combustion still results in very large fuel tanks. Liquid Hydrogen (LH2) with its higher density would still require a larger volume than other fuels like petrol, diesel, LPG to achieve the same mission. Another problem by using Liquid Hydrogen is its cryogenic nature, a property that requires complicated fuel tanks and more careful fueling. A design study has been conducted for this report to determine the feasibility of using Liquid Hydrogen.
Liquid Hydrogen has been proposed as an alternate fuel for various applications to supplant dwindling and increasingly costly, insecure hydrocarbon fuels. It is plentiful in supply, recyclable after combustion, low ion pollutant and toxic product, high energy content per unit mass and compatible with state of the art engine technology. Its low density, storage and handling problems, uncertain cost and safety aspects are facets that have to be dealt with before wide spread application is accepted.
INTRODUCTION
Of all the uncertainties the future of energy sector, the most serious are the future availability and price of the fuel. Recent temporary shortages of petroleum have driven up prices and prompted industrial nations to take conservation measures. Total production of oil is leveling off and is expected to begin declining over the next decade.
If limitations are imposed upon industrial fuel supplies in the future or prices rise too high, the projected growth of industry over the next 30 years may not materialize. This, in turn, would restrict any major expansion in the market, which would have higher fuel consumption rate.
It is timely that positive, aggressive action be taken to select a fuel for future. The choice would be made in full recognition of all the economic, sociological and technological ramifications which will be involved. Particularly, global aspects need to be considered. Local advantages or short term benefits which might require another change within a few decades should not be allowed to dominate the considerations.
With its tremendous fossil resources, there is strong incentive in the world to continue using kerosene type fuel for as long as it can be made available on an economic basis. The path of least resistance is to continue using the current fuel as long as it is available, broaden the specification to achieve a greater yield of usable product per barrel of crude oil. This minimizes the problem of changeover of equipments and facilities. Unfortunately, this option simply trades short term and local advantages for long term world wide problems.
On the basis of conceptual design studies and theoretical analysis Liquid Hydrogen has been shown to be a very attractive candidate compared with other alternative fuels like liquid methane synthetic jet A. Characteristics such as high energy content, clean burning, high cooling capacity and universal availability have made Liquid Hydrogen as a potential fuel for various applications.
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http://www.enjineer.com/forum
ABSTRACT
The conversion to Liquid Hydrogen as an alternative fuel would allow for independence on fuel cost and supply, as Hydrogen is globally accessible. The biggest obstacle to using Hydrogen is its very low density, a property that even combined with Hydrogen’s high heat of combustion still results in very large fuel tanks. Liquid Hydrogen (LH2) with its higher density would still require a larger volume than other fuels like petrol, diesel, LPG to achieve the same mission. Another problem by using Liquid Hydrogen is its cryogenic nature, a property that requires complicated fuel tanks and more careful fueling. A design study has been conducted for this report to determine the feasibility of using Liquid Hydrogen.
Liquid Hydrogen has been proposed as an alternate fuel for various applications to supplant dwindling and increasingly costly, insecure hydrocarbon fuels. It is plentiful in supply, recyclable after combustion, low ion pollutant and toxic product, high energy content per unit mass and compatible with state of the art engine technology. Its low density, storage and handling problems, uncertain cost and safety aspects are facets that have to be dealt with before wide spread application is accepted.
INTRODUCTION
Of all the uncertainties the future of energy sector, the most serious are the future availability and price of the fuel. Recent temporary shortages of petroleum have driven up prices and prompted industrial nations to take conservation measures. Total production of oil is leveling off and is expected to begin declining over the next decade.
If limitations are imposed upon industrial fuel supplies in the future or prices rise too high, the projected growth of industry over the next 30 years may not materialize. This, in turn, would restrict any major expansion in the market, which would have higher fuel consumption rate.
It is timely that positive, aggressive action be taken to select a fuel for future. The choice would be made in full recognition of all the economic, sociological and technological ramifications which will be involved. Particularly, global aspects need to be considered. Local advantages or short term benefits which might require another change within a few decades should not be allowed to dominate the considerations.
With its tremendous fossil resources, there is strong incentive in the world to continue using kerosene type fuel for as long as it can be made available on an economic basis. The path of least resistance is to continue using the current fuel as long as it is available, broaden the specification to achieve a greater yield of usable product per barrel of crude oil. This minimizes the problem of changeover of equipments and facilities. Unfortunately, this option simply trades short term and local advantages for long term world wide problems.
On the basis of conceptual design studies and theoretical analysis Liquid Hydrogen has been shown to be a very attractive candidate compared with other alternative fuels like liquid methane synthetic jet A. Characteristics such as high energy content, clean burning, high cooling capacity and universal availability have made Liquid Hydrogen as a potential fuel for various applications.
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http://www.enjineer.com/forum
JUST IN TIME
JUST IN TIME
ABSTRACT
Just In Time (JIT)
Just-in-time (JIT) is a management philosophy that strives to eliminate sources of manufacturing waste by producing the right part in the right place at the right time. Waste results from any activity that adds cost without adding value , such as moving and storing. JIT (also known as lean production or stockless production) improves profits and return on investment by reducing inventory levels (increasing the inventory turnover rate), reducing variability, improving product quality, reducing production and delivery lead times, and reducing other costs (such as those associated with machine setup and equipment breakdown). In a JIT system, underutilized (excess) capacity is used instead of buffer inventories to hedge against problems that may arise.
JIT applies primarily to repetitive manufacturing processes in which the same products and components are produced over and over again. The general idea is to establish flow processes (even when the facility uses a jobbing or batch process layout) by linking work centers so that there is an even, balanced flow of materials throughout the entire production process, similar to that found in an assembly line. To accomplish this, an attempt is made to reach the goals of driving all queues toward zero and achieving the ideal lot size of one unit.
INTRODUCTION
Just in Time originated in Japan. It was introduced as a technique, philosophy, and/or way of working in manufacturing after the Japanese had viewed the inefficiencies of the Ford Motor Company in the United States. It is generally associated with the Toyota Motor Company, because their Chief Engineer at the time in the 1950’s, Taiichi Ohno, developed the technique. The beginnings of this production system are rooted in the historical situation that Toyota faced. After the Second World War the president of Toyota said "Catch up with America in three years, otherwise the automobile industry of Japan will not survive”. Ohno began to examine the American industry and found that American manufacturers made great use of economic order quantities - the traditional idea that it is best to make a "lot" or "batch" of an item before switching to a new item. They also made use of economic order quantities in terms of ordering and stocking the many parts needed to assemble a car. Ohno decided that waste that happened in America would have to be decreased if he were to develop a technique for Japan, so he proposed decreasing waste by making it were items only move through production when they are demanded, and that they would have to set up a program where inspection for problems would occur and stop the process until they were repaired, thereby reducing waste.
Download full seminar papers At
http://www.enjineer.com/forum
ABSTRACT
Just In Time (JIT)
Just-in-time (JIT) is a management philosophy that strives to eliminate sources of manufacturing waste by producing the right part in the right place at the right time. Waste results from any activity that adds cost without adding value , such as moving and storing. JIT (also known as lean production or stockless production) improves profits and return on investment by reducing inventory levels (increasing the inventory turnover rate), reducing variability, improving product quality, reducing production and delivery lead times, and reducing other costs (such as those associated with machine setup and equipment breakdown). In a JIT system, underutilized (excess) capacity is used instead of buffer inventories to hedge against problems that may arise.
JIT applies primarily to repetitive manufacturing processes in which the same products and components are produced over and over again. The general idea is to establish flow processes (even when the facility uses a jobbing or batch process layout) by linking work centers so that there is an even, balanced flow of materials throughout the entire production process, similar to that found in an assembly line. To accomplish this, an attempt is made to reach the goals of driving all queues toward zero and achieving the ideal lot size of one unit.
INTRODUCTION
Just in Time originated in Japan. It was introduced as a technique, philosophy, and/or way of working in manufacturing after the Japanese had viewed the inefficiencies of the Ford Motor Company in the United States. It is generally associated with the Toyota Motor Company, because their Chief Engineer at the time in the 1950’s, Taiichi Ohno, developed the technique. The beginnings of this production system are rooted in the historical situation that Toyota faced. After the Second World War the president of Toyota said "Catch up with America in three years, otherwise the automobile industry of Japan will not survive”. Ohno began to examine the American industry and found that American manufacturers made great use of economic order quantities - the traditional idea that it is best to make a "lot" or "batch" of an item before switching to a new item. They also made use of economic order quantities in terms of ordering and stocking the many parts needed to assemble a car. Ohno decided that waste that happened in America would have to be decreased if he were to develop a technique for Japan, so he proposed decreasing waste by making it were items only move through production when they are demanded, and that they would have to set up a program where inspection for problems would occur and stop the process until they were repaired, thereby reducing waste.
Download full seminar papers At
http://www.enjineer.com/forum
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