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Useful output energy is always lower than input energy. Efficiency of power plants, world total, 2008. Energy conversion efficiency (η) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, as well as the useful output may be chemical, electric power, mechanical work, light (radiation ...
Power in mechanical systems is the combination of forces and movement. In particular, power is the product of a force on an object and the object's velocity, or the product of a torque on a shaft and the shaft's angular velocity. Mechanical power is also described as the time derivative of work.
A large power transformer used in the electrical grid may have efficiency of more than 99%. Early 19th century transformers were much less efficient, wasting up to a third of the energy passing through them. [citation needed] A steam power plant used to generate electricity may have 30-40% efficiency. [citation needed]
The red curve shows the power in the load, normalized relative to its maximum possible. The dark blue curve shows the efficiency η. The efficiency η is the ratio of the power dissipated by the load resistance R L to the total power dissipated by the circuit (which includes the voltage source's resistance of R S as well as R L):
The useful power of an engine with shaft power output can be calculated using a dynamometer to measure torque and rotational speed, with maximum power reached when torque multiplied by rotational speed is a maximum. For jet engines the useful power is equal to the flight speed of the aircraft multiplied by the force, known as net thrust ...
Exergy, often referred to as "available energy" or "useful work potential", is a fundamental concept in the field of thermodynamics and engineering.It plays a crucial role in understanding and quantifying the quality of energy within a system and its potential to perform useful work.
While performance per watt is useful, absolute power requirements are also important. Claims of improved performance per watt may be used to mask increasing power demands. For instance, though newer generation GPU architectures may provide better performance per watt, continued performance increases can negate the gains in efficiency, and the ...
The broken magenta line shows the cumulative power transmission within radius r, half of which flows inside the geometric mean of R 1 and R 2. The center conductor is held at voltage V and draws a current I toward the right, so we expect a total power flow of P = V · I according to basic laws of electricity. By evaluating the Poynting vector ...