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  2. Conversion of units - Wikipedia

    en.wikipedia.org/wiki/Conversion_of_units

    Conversion of units is the conversion of the unit of measurement in which a quantity is expressed, typically through a multiplicative conversion factor that changes the unit without changing the quantity. This is also often loosely taken to include replacement of a quantity with a corresponding quantity that describes the same physical property.

  3. List of conversion factors - Wikipedia

    en.wikipedia.org/wiki/List_of_conversion_factors

    Conversions between units in the metric system are defined by their prefixes (for example, 1 kilogram = 1000 grams, 1 milligram = 0.001 grams) and are thus not listed in this article. Exceptions are made if the unit is commonly known by another name (for example, 1 micron = 10 −6 metre).

  4. Energy factor - Wikipedia

    en.wikipedia.org/wiki/Energy_factor

    The energy factor metric only applies to residential water heaters, which are currently defined by fuel, type, and input capacity. [5] Generally, the EF number represents the thermal efficiency of the water heater as a percentage, since it is an average of the ratio of the theoretical heat required to raise the temperature of water drawn to the amount of energy actually consumed by the water ...

  5. Energy conversion efficiency - Wikipedia

    en.wikipedia.org/wiki/Energy_conversion_efficiency

    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 ...

  6. Thermal efficiency - Wikipedia

    en.wikipedia.org/wiki/Thermal_efficiency

    Output (mechanical) energy is always lower than input energy. 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, , to the device is heat, or the heat-content of a fuel that is consumed.

  7. Ecological efficiency - Wikipedia

    en.wikipedia.org/wiki/Ecological_efficiency

    The rest of the energy input into cultivating feed is respired or egested by the livestock and unable to be used by humans. Out of a total of 28,400 terawatt-hours (96.8 × 10 ^ 15 BTU ) of energy used in the US in 1999, 10.5% was used in food production, [ 3 ] with the percentage accounting for food from both producer and primary consumer ...

  8. Power plant efficiency - Wikipedia

    en.wikipedia.org/wiki/Power_plant_efficiency

    This thermal energy input of 1 kWh = 3.6 MJ = 3,412 Btu 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.

  9. Cost of transport - Wikipedia

    en.wikipedia.org/wiki/Cost_of_transport

    where is the energy input to the system, which has mass , that is used to move the system a distance , and is Standard gravity. Alternatively, one can use the power input to the system used to move the system at a constant velocity . The cost of transport is non-dimensional.