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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), or heat .
Just as with the internal energy version of the fundamental equation, the chain rule can be used on the above equations to find k+2 equations of state with respect to the particular potential. If Φ is a thermodynamic potential, then the fundamental equation may be expressed as:
Energy efficiency may refer to: Energy efficiency (physics), the ratio between the useful output and input of an energy conversion process Electrical efficiency, useful power output per electrical power consumed; Mechanical efficiency, a ratio of the measured performance to the performance of an ideal machine
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 ...
A Magic Triangle image mnemonic - when the terms of Ohm's law are arranged in this configuration, covering the unknown gives the formula in terms of the remaining parameters. It can be adapted to similar equations e.g. F = ma , v = fλ , E = mcΔT , V = π r 2 h and τ = rF sin θ .
Electric kettle: more than 90% [citation needed] (comparatively little heat energy is lost during the 2 to 3 minutes a kettle takes to boil water). A premium efficiency electric motor: more than 90% (see Main Article: Premium efficiency). A large power transformer used in the electrical grid may have efficiency of more than 99%. Early 19th ...
In mechanical engineering, mechanical efficiency is a dimensionless ratio that measures the efficiency of a mechanism or machine in transforming the power input to the device to power output. A machine is a mechanical linkage in which force is applied at one point, and the force does work moving a load at another point.
The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels, electrical energy or food energy. [ 9 ] [ 10 ] The energy efficiency is also occasionally known as energy intensity . [ 11 ]