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  2. Heat pump and refrigeration cycle - Wikipedia

    en.wikipedia.org/wiki/Heat_pump_and...

    Thermodynamic heat pump cycles or refrigeration cycles are the conceptual and mathematical models for heat pump, air conditioning and refrigeration systems. [1] A heat pump is a mechanical system that transmits heat from one location (the "source") at a certain temperature to another location (the "sink" or "heat sink") at a higher temperature ...

  3. Thermal efficiency - Wikipedia

    en.wikipedia.org/wiki/Thermal_efficiency

    In the United States, in everyday usage the SEER is the more common measure of energy efficiency for cooling devices, as well as for heat pumps when in their heating mode. For energy-conversion heating devices their peak steady-state thermal efficiency is often stated, e.g., 'this furnace is 90% efficient', but a more detailed measure of ...

  4. List of conversion factors - Wikipedia

    en.wikipedia.org/wiki/List_of_conversion_factors

    cycle per second: cps ≡ 1 Hz = 1 cps = 1 Hz degree per second: deg/s ≡ 1 °/s ≡ 1/360 Hz = 0.002 7 Hz hertz (SI unit) Hz ≡ One cycle per second = 1 Hz = 1/s radian per second: rad/s ≡ 1/(2π) Hz ≈ 0.159 155 Hz: revolution per minute: rpm ≡ One rpm equals one rotation completed around a fixed axis in one minute of time. ≈ 0.104 ...

  5. Heating seasonal performance factor - Wikipedia

    en.wikipedia.org/wiki/Heating_seasonal...

    For instance, a system which delivers an HSPF of 7.7 will transfer 2.25 times as much heat as electricity consumed over a season. [5] In Europe the term Seasonal Performance Factor ("SPF") is used to mean the same as the average COP over the heating season. A system which transfers 2.25 times as much heat as the electricity consumed is said to ...

  6. Carnot cycle - Wikipedia

    en.wikipedia.org/wiki/Carnot_cycle

    A Carnot cycle is an ideal thermodynamic cycle proposed by French physicist Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s. By Carnot's theorem, it provides an upper limit on the efficiency of any classical thermodynamic engine during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference through ...

  7. Glossary of HVAC terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_HVAC_terms

    The hourly ventilation rate divided by the volume of a space. For perfectly mixed air or laminar flow spaces, this is equal to the number of times per hour that the volume the space is exchanged by mechanical and natural ventilation. Also called air change rate or air exchange rate. Abbreviated ACH or ac/hr. air conditioner

  8. Conversion of units - Wikipedia

    en.wikipedia.org/wiki/Conversion_of_units

    For example, 10 miles per hour can be converted to metres per second by using a sequence of conversion factors as shown below: = . Each conversion factor is chosen based on the relationship between one of the original units and one of the desired units (or some intermediary unit), before being rearranged to create a factor that cancels out the ...

  9. Central heating - Wikipedia

    en.wikipedia.org/wiki/Central_heating

    A central heating system provides warmth to a number of spaces within a building from one main source of heat. It is a component of heating, ventilation, and air conditioning (short: HVAC) systems, which can both cool and warm interior spaces. A central heating system has a furnace that converts fuel or electricity to heat.