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  2. List of conversion factors - Wikipedia

    en.wikipedia.org/wiki/List_of_conversion_factors

    Conceptually, the length of time it takes for the Sun to return to the same position in the cycle of seasons, [Converter 1] approximately 365.242 19 d, each day being 86 400 SI seconds [28] ≈ 31.556 925 Ms

  3. Degree day - Wikipedia

    en.wikipedia.org/wiki/Degree_day

    The degree day is not an SI derived unit; although the day is acceptable for use in the SI, it is not a decimal multiple of its base unit, the second. (The degree, in Celsius and measured relative to a base temperature, is identical to the kelvin, the SI base unit). Expressed as a proper SI unit, a quantity of kelvin second is four orders of ...

  4. Rotational frequency - Wikipedia

    en.wikipedia.org/wiki/Rotational_frequency

    Its SI unit is the reciprocal seconds (s −1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). [ 1 ] [ a ] [ b ] Rotational frequency can be obtained dividing angular frequency , ω, by a full turn (2 π radians ): ν =ω/(2π rad).

  5. Heating degree day - Wikipedia

    en.wikipedia.org/wiki/Heating_degree_day

    Heating degree day (HDD) is a measurement designed to quantify the demand for energy needed to heat a building. HDD is derived from measurements of outside air temperature . The estimated average heating energy requirements for a given building at a specific location are considered to be directly proportional to the number of HDD at that location.

  6. Cooling load temperature difference calculation method

    en.wikipedia.org/wiki/Cooling_load_temperature...

    The second factor is the CLF, or the cooling load factor. This coefficient accounts for the time lag between the outdoor and indoor temperature peaks. Depending on the properties of the building envelope, a delay is present when observing the amount of heat being transferred inside from the outdoors.

  7. Frequency - Wikipedia

    en.wikipedia.org/wiki/Frequency

    The SI unit for the period, as for all measurements of time, is the second. [5] A traditional unit of frequency used with rotating mechanical devices, where it is termed rotational frequency, is revolution per minute, abbreviated r/min or rpm. [6] Sixty rpm is equivalent to one hertz. [7]

  8. Hertz - Wikipedia

    en.wikipedia.org/wiki/Hertz

    The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. [ 1 ] [ a ] The hertz is an SI derived unit whose formal expression in terms of SI base units is s −1 , meaning that one hertz is one per second or the reciprocal of one second . [ 2 ]

  9. Pulse-repetition frequency - Wikipedia

    en.wikipedia.org/wiki/Pulse-repetition_frequency

    Both are measured in terms of cycle per second, or hertz. The PRF is normally much lower than the frequency. The PRF is normally much lower than the frequency. For instance, a typical World War II radar like the Type 7 GCI radar had a basic carrier frequency of 209 MHz (209 million cycles per second) and a PRF of 300 or 500 pulses per second.