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  2. Electrical efficiency - Wikipedia

    en.wikipedia.org/wiki/Electrical_efficiency

    As a result of the maximum power theorem, devices transfer maximum power to a load when running at 50% electrical efficiency. This occurs when the load resistance (of the device in question) is equal to the internal Thevenin equivalent resistance of the power source. This is valid only for non-reactive source and load impedances.

  3. Energy conversion efficiency - Wikipedia

    en.wikipedia.org/wiki/Energy_conversion_efficiency

    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), or heat. The resulting value, η (eta), ranges ...

  4. Betz's law - Wikipedia

    en.wikipedia.org/wiki/Betz's_law

    The power coefficient [9] C P (= P/P wind) is the dimensionless ratio of the extractable power P to the kinetic power P wind available in the undistributed stream. [ citation needed ] It has a maximum value C P max = 16/27 = 0.593 (or 59.3%; however, coefficients of performance are usually expressed as a decimal, not a percentage).

  5. Power usage effectiveness - Wikipedia

    en.wikipedia.org/wiki/Power_usage_effectiveness

    As of the end of Q2 2015, Facebook's Prineville data center had a power usage effectiveness (PUE) of 1.078 and its Forest City data center had a PUE of 1.082. [15] In October 2015, Allied Control has a claimed PUE ratio of 1.02 [16] through the use of two-phase immersion cooling using 3M Novec 7100 fluid.

  6. Power-flow study - Wikipedia

    en.wikipedia.org/wiki/Power-flow_study

    In power engineering, the power-flow study, or load-flow study, is a numerical analysis of the flow of electric power in an interconnected system. A power-flow study usually uses simplified notations such as a one-line diagram and per-unit system, and focuses on various aspects of AC power parameters, such as Voltage, voltage angles, real power and reactive power.

  7. Flywheel energy storage - Wikipedia

    en.wikipedia.org/wiki/Flywheel_energy_storage

    NASA G2 flywheel. Flywheel energy storage (FES) works by accelerating a rotor to a very high speed and maintaining the energy in the system as rotational energy.When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the system correspondingly results in an increase in the speed of the ...

  8. Power plant efficiency - Wikipedia

    en.wikipedia.org/wiki/Power_plant_efficiency

    Therefore, the heat rate of a 100% efficient plant is simply 1, or 1 kWh/kWh, or 3.6 MJ/kWh, or 3,412 Btu/kWh; To express the efficiency of a generator or power plant as a percentage, invert the value if dimensionless notation or same unit are used. For example: A heat rate value of 5 gives an efficiency factor of 20%.

  9. Coefficient of performance - Wikipedia

    en.wikipedia.org/wiki/Coefficient_of_performance

    [1] [2] Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs. The COP is used in thermodynamics . The COP usually exceeds 1, especially in heat pumps, because instead of just converting work to heat (which, if 100% efficient, would be a COP of 1), it pumps additional heat from a heat source to ...