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  2. Coefficient of performance - Wikipedia

    en.wikipedia.org/wiki/Coefficient_of_performance

    The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work (energy) required. [1] [2] Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs. The COP is used in thermodynamics.

  3. Thermal efficiency - Wikipedia

    en.wikipedia.org/wiki/Thermal_efficiency

    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 ...

  4. Heat pump and refrigeration cycle - Wikipedia

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

    Applications that need to operate at a high coefficient of performance in very varied conditions, as is the case with heat pumps where external temperatures and internal heat demand vary considerably through the seasons, typically use a variable speed inverter compressor and an adjustable expansion valve to control the pressures of the cycle ...

  5. Carnot's theorem (thermodynamics) - Wikipedia

    en.wikipedia.org/wiki/Carnot's_theorem...

    It may seem odd that a hypothetical reversible heat pump with a low efficiency is used to violate the second law of thermodynamics, but the figure of merit for refrigerator units is not the efficiency, /, but the coefficient of performance (COP), [2] which is / where this has the sign opposite to the above (+ for work done to the engine).

  6. Energy conversion efficiency - Wikipedia

    en.wikipedia.org/wiki/Energy_conversion_efficiency

    It is not called efficiency, but the coefficient of performance, or COP. It is a ratio of useful heating or cooling provided relative to the work (energy) required. Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs.

  7. Exergy efficiency - Wikipedia

    en.wikipedia.org/wiki/Exergy_efficiency

    In thermal engineering, exergy efficiency (also known as the second-law efficiency or rational efficiency) computes the effectiveness of a system relative to its performance in reversible conditions. It is defined as the ratio of the thermal efficiency of an actual system compared to an idealized or reversible version of the system for heat ...

  8. Prisoners of Profit - The Huffington Post

    projects.huffingtonpost.com/prisoners-of-profit-2

    When the state evaluates current contractors, past performance counts for less than one-fourth of the total score. The bulk of the rating stems from the quality of the contractor’s technical proposal – its plans to staff the facility, for example, and its policies on security, escapes and training.

  9. Table of thermodynamic equations - Wikipedia

    en.wikipedia.org/wiki/Table_of_thermodynamic...

    (Common) symbol/s Defining equation SI unit Dimension Temperature gradient: No standard symbol K⋅m −1: ΘL −1: Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer P = / W ML 2 T −3: Thermal intensity I