enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. 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 ...

  3. Energy conversion efficiency - Wikipedia

    en.wikipedia.org/wiki/Energy_conversion_efficiency

    A water electrolysis unit operating with a higher voltage that 1.48 V and at a temperature of 25 °C would have to have heat energy removed in order to maintain a constant temperature and the energy efficiency would be less than 0.83.

  4. NTU method - Wikipedia

    en.wikipedia.org/wiki/NTU_Method

    The number of transfer units (NTU) method is used to calculate the rate of heat transfer in heat exchangers (especially parallel flow, counter current, and cross-flow exchangers) when there is insufficient information to calculate the log mean temperature difference (LMTD). Alternatively, this method is useful for determining the expected heat ...

  5. Coefficient of performance - Wikipedia

    en.wikipedia.org/wiki/Coefficient_of_performance

    A realistic indication of energy efficiency over an entire year can be achieved by using seasonal COP or seasonal coefficient of performance (SCOP) for heat. Seasonal energy efficiency ratio (SEER) is mostly used for air conditioning. SCOP is a new methodology that gives a better indication of expected real-life performance, using COP can be ...

  6. Seasonal energy efficiency ratio - Wikipedia

    en.wikipedia.org/wiki/Seasonal_energy_efficiency...

    The SEER rating of a unit is the cooling output during a typical cooling-season divided by the total electric energy input during the same period. The higher the unit's SEER rating the more energy efficient it is. In the U.S., the SEER is the ratio of cooling in British thermal units (BTUs) to the energy consumed in watt-hours.

  7. R-value (insulation) - Wikipedia

    en.wikipedia.org/wiki/R-value_(insulation)

    R-value is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the warmer surface and colder surface of a barrier under steady-state conditions. The measure is therefore equally relevant for lowering energy bills for heating in the winter, for cooling in the summer, and for general comfort.

  8. Power plant efficiency - Wikipedia

    en.wikipedia.org/wiki/Power_plant_efficiency

    A heat rate value of 4 MJ/MJ gives an efficiency factor of 25%. For other units, make sure to use a corresponding conversion factor for the units. For example, if using Btu/kWh, use a conversion factor of 3,412 Btu per kWh to calculate the efficiency factor. For example, if the heat rate is 10,500 Btu/kWh, the efficiency is 32.5% (since 3,412 ...

  9. Heat transfer coefficient - Wikipedia

    en.wikipedia.org/wiki/Heat_transfer_coefficient

    It is used in calculating the heat transfer, typically by convection or phase transition between a fluid and a solid. The heat transfer coefficient has SI units in watts per square meter per kelvin (W/(m 2 K)). The overall heat transfer rate for combined modes is usually expressed in terms of an overall conductance or heat transfer coefficient ...