User:KoKo KonatA/sandbox/Thermal Engineering

Thermal Engineering is a specialized sub-discipline of mechanical engineering that deals with heat energy, which can be transformed between two mediums or transferred into other forms of energy.

Thermal engineering became more important during the Industrial Revolution in Europe in the 17th century, when people started having the desire of improving the efficiency of steam engines. Now it has been extended into a broader subject discipline as humans began to need more energy in different forms in automotive manufacturing industry, commercial construction, and Heating Ventilation and Cooling industry as well as living.

Thermal engineering has a variety of applications in different industries. Development in thermal engineering will help people build engines with higher efficiency and power for cars, air planes, and rockets. Air conditioning system will enable people to change their living conditions. Thermal engineers can help plants generate more power with fewer fuel consumed.

Thermal engineers usually have training in various subjects so that they can know how energy is generated(often by burning fuels) and they need to make machines work in a cost-effective way, and they are also required to design new thermal systems.

History
The development of thermal engineering has always been a decisive factor in human being's productive force and mode of life.

In the 17th century, Newcomer's steam engine established England as the major industrial force in the world. Later steam engines were improved in energy consumption and efficiency. Significant improvements in this kind of machine are widespread and this technology has played an important role in the production process since the start of the industrial revolution. About the same time, people studied concepts such as latent heat, specific heat, ideal gas and conductive and convective heat transfer, which allowed engineers and scientists to make the next two centuries quite fruitful in the field of thermal engineering. The improved steam engine also enabled people to have more ways of transportation, like trains and steam ships. With them, people could travel for a longer distance fast.

In 1807, French engineers Nicéphore Niépce and Claude Niépce ran a prototype internal combustion engine, using controlled dust explosions, the Pyréolophore. This engine powered a boat on the Saône river, France. The same year, the Swiss engineer François Isaac de Rivaz built an internal combustion engine ignited by an electric spark. In 1823, Samuel Brown patented the first internal combustion engine to be applied industrially. This advancement in thermal engineering revolutionized people's daily life and warfare, because the invention of internal combustion engine were followed by the invention of cars, tanks and air jets.

During the mid-1800s, Carnot and his contemporaries combined many ideas and created the basis of the Second Law of Thermodynamics. Gouy and Stodola drew up those ideas and made the initial contribution related to topics such as exergy, availability, maximum and several other names. Little interest other than theoretical development was made in the early 1990s.

In the 1930s and 1940s engineers and scientists began to apply analytical tools more intensely. The numbers of tools and the understanding of their application began to grow. Much of the focus was on how to make the overall processes better by trying to define ultimate performance limitations.

After the 1970s, the use of analytical tools became much concentrated and powerful. Both the analysis techniques and the tools to carry them out on a large scale were to have a profound effect on engineering design, even though engineering design was still in the developing stage. These tools could help engineers with many what-if questions, and help them pick the most suitable solution for their problem. Thus, thermal engineers built more power plants and more people started using household appliances like televisions.

The oil embargoes of the 1970s called engineers' attention on the efficient use of energy. Engineers like Moran(1982), and Szargut et al(1988) fleshed out approaches to determine the ultimate energy value of chemical process, heat transfer, power generation, and various other physical processes. About that time, courses in the design of thermal systems were being developed at universities, and several textbooks were developed for these courses.

Now, with computer-aided design, graphical interface is continuously being enhanced. Plug-in modules and more user-friendly codes allow engineers to design and perform tests more conveniently. Artificial intelligence is also becoming a big factor in thermal engineering that made it possible for engineers to specify the desired output and limitation of input, evaluate the efficiency, and reduce costs.

Tools
Thermal engineers usually use several tools to build a thermal system, including heat exchanger, compressor, pumps and fans.

Heat exchanger
Heat exchangers are usually used by thermal engineers when they are building power plants or car engines.

A heat exchanger is a device designed to transfer the internal thermal energy (enthalpy) between two or more fluids or between solid surfaces or particles and a fluid in thermal contact within a given system. The fluid inside heat exchangers can be pure substances or mixtures, and they may be liquid or both liquid and gas.

A heat exchanger can be used to heat, cool, vaporize, or condensate a fluid stream. Its objects may also be sterilizing, passteurizing, distilling, or crystallizing the process fluid. Heat exchangers can be classified by many ways, like its function, construction and heat-transfer mechanics, etc.

Compressor
With compressors, thermal engineers can build air conditioners and refrigerators that enable people to monitor their living condition and preserve food for a longer time.

A compressor is a mechanical device that reduces the volume of gases to increase the pressure of them. It's used for many purposes in different fields like industry, commerce and residential applications. Generally speaking, compressors perform two kinds of tasks:


 * Compressors are widely used for refrigeration, air conditioning and heat pumping applications in vapor compression cycles.
 * Compressors are often used to compress air.

Although many gas compressors look similar, they are designed in different ways for different tasks. They are commonly designed specifically to meet the pressure, temperature or flow, and they have to be able to adapt gases or gas mixtures used in tasks.

=== Fans === Fans are used widely in thermal engineering. For example, they are essential parts of  computers’ cooling systems.

Fans are devices that impart air movement due to rotation of an impeller inside a fixed casing. They can be used in many engineering systems. Fans, along with the chiller and boilers, are the heart of heating, ventilating and air-conditioning systems. Many types of fans are also found in power plants. Large fans can be utilized to furnish air to the boiler and to draw air through cooling towers. Automobiles also have several fans in them. There are four kinds of fans that are commonly used: axial flow fan, centrifugal fan, mixed-flow fan and cross-flow fan.

Important aspects that are issues in choosing fans include efficiency and noise generation. Because of the great engineering importance of fans, several organizations publish rating and testing criteria, like ASME, 1990.

Applications
Thermal engineering has a variety of applications in different industries, including food industry, petroleum industry, and medical industry.

=== Drying of materials === Drying is one of the most common processes in thermal engineering. It is one of the unit operations to decrease the mass of products and reduce the cost of transportation, and its main goals also include improving mechanical and physicochemical properties and increase shelf life of products. It's widely used in chemical, pharmaceutical, food and ceramic, and textile industries.

To successfully utilize drying technology, thermal engineers are required to have a good understanding of properties of humid air, wet materials, drying curves, heat and mass transfer. These are the principles of the theory of drying.

In recent years, relatively few new technologies have been successfully implemented into practice, because drying is an old and well-established technology. One of the examples of novel drying methods is steam drying.

=== Air-conditioning system === Thermal Engineers are usually required to monitor the temperature in a system, and they need air-conditioning systems.

The term "air conditioning" refer to all equipment and processes used to maintain comfortable and healthy indoor air suitable for human's living. However, in thermal engineering, an air-conditioning system's tasks include heating, ventilating, air conditioning and refrigerating. Consequently, air conditioning is not restricted to cooling and dehumidifying of air, and not even restricted to modify the condition of indoor air.

To design and utilize an air conditioning system, engineers need to learn about the behavior of the air and water vapor mixture, which is known as psychrometry.

=== Thermal energy storage === Sometime, thermal engineers need to store the thermal energy from machines or the nature, and they need thermal energy storage technology.

Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used at a later time for heating and cooling applications and power generation. The applications of this technology plays an important role in energy conservation in buildings. It is assisted by the incorporation of latent heat(the heat required to change the phase of materials, like from liquid to gas) storage (LHS) in various building components and mechanical systems. These building components that can store excess heat and reduce space-conditioning(integration of a building's heating, ventilating and air conditioning) energy consumption. These functions of the building components are achieved by the use of different phase change materials (PCM).

=== Cooling tower === In power plants, thermal engineers use cooling tower to keep the machine working in appropriate temperatures.

In a wet cooling, water is evaporated into vapor to cool the water stream. Both natural-draft cooling towers and mechanical-draft towers are popular. Natural-draft cooling towers are in larger size and are used in power plants for cooling the water supply to the condenser. In a natural-draft tower, the air flows upward due to the buoyancy of the warm, moist air leaving the top of the packing. Mechanical-draft towers are smaller and are preferred for oil refineries and other process industries, as well as for central air-conditioning systems and refrigeration plants. In a mechanical-draft tower, the flow is forced or induced by a fan. Since the air inlet temperature is usually lower than the water inlet temperature, the water is cooled both by evaporation and by sensible heat(Sensible heat is heat exchanged by a body or thermodynamic system in which the exchange of heat changes the temperature of the body or system) loss. To operate normally, the evaporative heat loss is considerably larger than the sensible heat loss.

=== Solar distillation technology === The sun can be a good source of energy for thermal engineers, and with the help of the sun, they can help with the water shortage.

According to the United Nations(2004) report, about 2/3rd of the world will face a shortage of water from 2025 onward. Solar distillation technology is a promising solution among several water treatment technologies, because it takes input as sunlight and it can effectively many impurities, such as salts and microorganisms.

Solar distillation technology uses solar radiation as the source of heat to obtain potable water with the help of a device called solar still. Solar energy falls on the surface of brackish/saline water will increase the temperature of water. Water gets evaporated and the vapor condenses and distillate will come as an output.

Solar distillation technology requires relatively simple technology, low maintenance and only sunshine to operate. It is suitable for places where hot climatic conditions exist during the major part of the year and is in drought.

== Job description and education ==

Job description
Having a good command of theories of energy and energy transfer, thermal engineers can design, develop and test products and machinery. They are also responsible for estimating costs, supervising product manufacturing and evaluating the quality, safety and cost of the product. Although thermal engineers usually work in offices, labs or industrial plants, they visit manufacturing sites to monitor production.

Education
Although universities and colleges often offer programs focused on thermal engineering, most of them offer courses closely related to thermal engineering, like chemical engineering and mechanical engineering. A bachelor’s degree may be adequate for the beginning of a career in engineering, but to get an advanced position, people are required to get a graduate’s degree with a concentration in thermal dynamics.

Certificate programs
Graduate-level certificate programs are typically designed for professional engineers who need a solid foundation in the practical applications of thermofluids. Prior coursework requirements may include mathematics, heat transfer and basic thermodynamics. These programs are generally 16 credit-hours and feature coursework in statistical and equilibrium thermodynamics, gas dynamics and fluid mechanics.

Master's degree programs
A master's degree program in thermal engineering includes courses such as heat transfer, fluid dynamics, energy conversion, combustion and engineering instrumentation. Students also need to take core classes in mechanical engineering and applied mathematics. Most master's degree programs take about two years to complete, and in some school students can take programs combined with master's degree program and Ph.D. program.

Ph.D. programs
Doctoral programs in thermal engineering are designed for engineers who are interested in research. These programs typically require bachelor's and master's degrees in engineering and applicants may be required to take a series of oral and written comprehension examinations. Ph.D. students will spend a large amount of time performing laboratory research in thermodynamic areas, such as heat transfer, combustion and energy dynamics.

Entry-level positions in this industry typically require a bachelor's degree in a discipline such as mechanical or chemical engineering; however, in order to advance to a higher position within the field of thermodynamic engineering, a master's or doctoral degree is needed because thermodynamics is not taught as a concentration in undergraduate studies.

Associations

 * American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
 * American Society of Mechanical Engineers (ASME)
 * Pi Tau Sigma (Mechanical Engineering honor society)
 * Society of Automotive Engineers (SAE)
 * Society of Women Engineers (SWE)
 * Institution of Mechanical Engineers (IMechE) (British)
 * Chartered Institution of Building Services Engineers (CIBSE) (British)
 * Verein Deutscher Ingenieure (VDI) (Germany)

Wikibooks

 * Engineering Thermodynamics
 * Fluid mechanics
 * Heat Transfer
 * Engineering Mechanics