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Thermal Efficiency
In thermodynamics, the thermal efficiency (\eta_) is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, steam turbine, steam engine, boiler, furnace, refrigerator, ACs etc. For a heat engine, thermal efficiency is the ratio of the net work output to the heat input; in the case of a heat pump, thermal efficiency (known as the '' coefficient of performance'' or COP) is the ratio of net heat output (for heating), or the net heat removed (for cooling) to the energy input (external work). The efficiency of a heat engine is fractional as the output is always less than the input while the COP of a heat pump is more than 1. These values are further restricted by the Carnot theorem. Overview In general, energy conversion efficiency is the ratio between the useful output of a device and the input, in energy terms. For thermal efficiency, the input, Q_, to the device is heat, or the heat-content of a fuel that is c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic System
A thermodynamic system is a body of matter and/or radiation separate from its surroundings that can be studied using the laws of thermodynamics. Thermodynamic systems can be passive and active according to internal processes. According to internal processes, passive systems and active systems are distinguished: passive, in which there is a redistribution of available energy, active, in which one type of energy is converted into another. Depending on its interaction with the environment, a thermodynamic system may be an isolated system, a Closed system#In thermodynamics, closed system, or an Open system (systems theory), open system. An isolated system does not exchange matter or energy with its surroundings. A closed system may exchange heat, experience forces, and exert forces, but does not exchange matter. An open system can interact with its surroundings by exchanging both matter and energy. The physical condition of a thermodynamic system at a given time is described by its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ratio
In mathematics, a ratio () shows how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ratio 4:3). Similarly, the ratio of lemons to oranges is 6:8 (or 3:4) and the ratio of oranges to the total amount of fruit is 8:14 (or 4:7). The numbers in a ratio may be quantities of any kind, such as counts of people or objects, or such as measurements of lengths, weights, time, etc. In most contexts, both numbers are restricted to be Positive integer, positive. A ratio may be specified either by giving both constituting numbers, written as "''a'' to ''b''" or "''a'':''b''", or by giving just the value of their quotient Equal quotients correspond to equal ratios. A statement expressing the equality of two ratios is called a ''proportion''. Consequently, a ratio may be considered as an ordered pair of numbers, a Fraction (mathematic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waste Heat
Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility (or in thermodynamics lexicon a lower exergy or higher entropy) than the original energy source. Sources of waste heat include all manner of human activities, natural systems, and all organisms, for example, incandescent light bulbs get hot, a refrigerator warms the room air, a building gets hot during peak hours, an internal combustion engine generates high-temperature exhaust gases, and electronic components get warm when in operation. Instead of being "wasted" by release into the ambient environment, sometimes waste heat (or cold) can be used by another process (such as using hot engine coolant to heat a vehicle), or a portion of heat that would otherwise be wasted can be reused in the same process if make-up heat is added to the sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Energy
In physical sciences, mechanical energy is the sum of macroscopic potential and kinetic energies. The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is constant. If an object moves in the opposite direction of a conservative net force, the potential energy will increase; and if the speed (not the velocity) of the object changes, the kinetic energy of the object also changes. In all real systems, however, nonconservative forces, such as frictional forces, will be present, but if they are of negligible magnitude, the mechanical energy changes little and its conservation is a useful approximation. In elastic collisions, the kinetic energy is conserved, but in inelastic collisions some mechanical energy may be converted into thermal energy. The equivalence between lost mechanical energy and an increase in temperature was discovered by James Prescott Joule. Many devices are us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnot Heat Engine 2
Carnot may refer to: People * Carnot Posey (1818–1863), American lawyer and military officer People with the surname *Lazare Carnot (1753-1823), French mathematician and politician of the French Revolution * Louis Carnot (born 2001), French French footballer *Nicolas Léonard Sadi Carnot (1796-1832), French military scientist and physicist; son of Lazare Carnot, namesake of Carnot Cycle. * Hippolyte Carnot (1801-1888), French politician; son of Lazare Carnot * Marie François Sadi Carnot (1837-1894), French politician; President of France from 1887 to 1894 and son of Hippolyte Carnot * Marie-Adolphe Carnot (1839-1920), French mining engineer and chemist; son of Hippolyte Carnot *Paul Carnot (1869-1957), French physician; son of Marie-Adolphe Carnot * Stéphane Carnot (born 1972), former French footballer Places * Carnot, Central African Republic, a city * Carnot, Wisconsin, United States * Carnot-Moon, Pennsylvania, United States Other uses *Carnot cycle, in thermodynamics *C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Figure Of Merit
A figure of merit (FOM) is a performance metric that characterizes the performance of a device, system, or method, relative to its alternatives. Examples *Absolute alcohol content per currency unit in an alcoholic beverage *accurizing, Accuracy of a rifle *Audio amplifier figures of merit such as gain or efficiency *Battery life of a laptop computer New York Times, June 25, 2009 *Calories per serving *Clock rate of a CPU is often given as a figure of merit, but is of limited use in comparing between different architectures. FLOPS may be a better figure, though these too are not completely representative of the performance of a CPU. *Contrast ratio of an LCD *Frequency response of a Loudspeaker, speaker *Fill factor (solar cell), Fill factor of a solar cell *Image resolutio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combined Cycle
A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turbine (CCGT) plant, which is a kind of gas-fired power plant. The same principle is also used for marine propulsion, where it is called a combined gas and steam (COGAS) plant. Combining two or more thermodynamic cycles improves overall efficiency, which reduces fuel costs. The principle is that after completing its cycle in the first engine, the working fluid (the exhaust) is still hot enough that a second subsequent heat engine can extract energy from the heat in the exhaust. Usually the heat passes through a heat exchanger so that the two engines can use different working fluids. By generating power from multiple streams of work, the overall efficiency can be increased by 50–60%. That is, from an overall efficiency of the system of say ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wärtsilä-Sulzer RTA96-C
The Wärtsilä RT-flex96C is a two-stroke turbocharged low-speed diesel engine designed by the Finnish manufacturer Wärtsilä. It is designed for large container ships that run on heavy fuel oil. Its largest 14-cylinder version is high, long, weighs over , and produces . It is the largest reciprocating engine in the world. The 14-cylinder version first entered commercial service in September 2006 aboard the '' Emma Mærsk''. The design is similar to the older RTA96C engine, but with common rail technology (in place of traditional camshaft, chain gear, fuel pump and hydraulic actuator systems). This provides maximum performance at lower revolutions per minute (rpm), reduces fuel consumption and emits lower levels of harmful emissions. The engine has crosshead bearings so the always-vertical piston rods create a tight seal under the pistons. Consequently, the lubrication of the engine is split: the cylinders and the crankcase use different lubricants, each being specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formula 1
Formula One (F1) is the highest class of worldwide racing for open-wheel single-seater formula Auto racing, racing cars sanctioned by the Fédération Internationale de l'Automobile (FIA). The FIA Formula One World Championship has been one of the world's premier forms of motorsport since its 1950 Formula One season, inaugural running in 1950 and is often considered to be the pinnacle of motorsport. The word ''Formula racing, formula'' in the name refers to Formula One regulations, the set of rules all participant cars must follow. A Formula One season consists of a series of races, known as List of Formula One Grands Prix, Grands Prix. Grands Prix take place in multiple countries and continents on either purpose-built List of Formula One circuits, circuits or closed roads. A List of Formula One World Championship points scoring systems, points scoring system is used at Grands Prix to determine two annual World Championships: List of Formula One World Drivers' Champions, one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second Law Of Thermodynamics
The second law of thermodynamics is a physical law based on Universal (metaphysics), universal empirical observation concerning heat and Energy transformation, energy interconversions. A simple statement of the law is that heat always flows spontaneously from hotter to colder regions of matter (or 'downhill' in terms of the temperature gradient). Another statement is: "Not all heat can be converted into Work (thermodynamics), work in a cyclic process."Young, H. D; Freedman, R. A. (2004). ''University Physics'', 11th edition. Pearson. p. 764. The second law of thermodynamics establishes the concept of entropy as a physical property of a thermodynamic system. It predicts whether processes are forbidden despite obeying the requirement of conservation of energy as expressed in the first law of thermodynamics and provides necessary criteria for spontaneous processes. For example, the first law allows the process of a cup falling off a table and breaking on the floor, as well as allowi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Law Of Thermodynamics
The first law of thermodynamics is a formulation of the law of conservation of energy in the context of thermodynamic processes. For a thermodynamic process affecting a thermodynamic system without transfer of matter, the law distinguishes two principal forms of energy transfer, heat and thermodynamic work. The law also defines the internal energy of a system, an extensive property for taking account of the balance of heat transfer, thermodynamic work, and matter transfer, into and out of the system. Energy cannot be created or destroyed, but it can be transformed from one form to another. In an externally isolated system, with internal changes, the sum of all forms of energy is constant. An equivalent statement is that perpetual motion machines of the first kind are impossible; work done by a system on its surroundings requires that the system's internal energy be consumed, so that the amount of internal energy lost by that work must be resupplied as heat by an external e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Work (thermodynamics)
Thermodynamic work is one of the principal kinds of process by which a thermodynamic system can interact with and transfer energy to its surroundings. This results in externally measurable macroscopic forces on the system's surroundings, which can cause mechanical work, to lift a weight, for example,Kittel, C. Kroemer, H. (1980). ''Thermal Physics'', second edition, W.H. Freeman, San Francisco, or cause changes in electromagnetic,Guggenheim, E.A. (1985). ''Thermodynamics. An Advanced Treatment for Chemists and Physicists'', seventh edition, North Holland, Amsterdam, .Jackson, J.D. (1975). ''Classical Electrodynamics'', second edition, John Wiley and Sons, New York, .Konopinski, E.J. (1981). ''Electromagnetic Fields and Relativistic Particles'', McGraw-Hill, New York, . or gravitationalNorth, G.R., Erukhimova, T.L. (2009). ''Atmospheric Thermodynamics. Elementary Physics and Chemistry'', Cambridge University Press, Cambridge (UK), . variables. Also, the surroundings can perform t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
