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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 ...
The SI unit is watt (W). Another unit common in non-metric regions or sectors is the ton of refrigeration, which describes the amount of water at freezing temperature that can be frozen in 24 hours, equivalent to 3.5 kW or 12,000 BTU/h. [1] [2] [3]
It was originally defined as the rate of heat transfer that results in the freezing or melting of 1 short ton (2,000 lb; 907 kg) of pure ice at 0 °C (32 °F) in 24 hours. [1] [2] The modern definition is exactly 12,000 Btu IT /h (3.516853 kW). Air-conditioning and refrigeration equipment capacity in the U.S. is often specified in "tons" (of ...
For a water electrolysis unit operating at a constant temperature of 25 °C without the input of any additional heat energy, electrical energy would have to be supplied at a rate equivalent of the enthalpy (heat) of reaction or 285.830 kJ (0.07940 kWh) per gram mol of water consumed. [6] It would operate at a cell voltage of 1.48 V.
1 ton of cooling, a common unit in North American refrigeration and air conditioning applications, is 12,000 Btu/h (3.52 kW). It is the rate of heat transfer needed to freeze 1 short ton (907 kg) of water into ice in 24 hours.
Energy; system unit code (alternative) symbol or abbrev. notes sample default conversion combinations SI: yottajoule: YJ YJ 1.0 YJ (2.8 × 10 17 kWh) zettajoule: ZJ ZJ 1.0 ZJ (2.8 × 10 14 kWh)
So, for a boiler that produces 210 kW (or 700,000 BTU/h) output for each 300 kW (or 1,000,000 BTU/h) heat-equivalent input, its thermal efficiency is 210/300 = 0.70, or 70%. This means that 30% of the energy is lost to the environment. An electric resistance heater has a thermal efficiency close to 100%. [8]
A hot fluid's heat capacity rate can be much greater than, equal to, or much less than the heat capacity rate of the same fluid when cold. In practice, it is most important in specifying heat-exchanger systems, wherein one fluid usually of dissimilar nature is used to cool another fluid such as the hot gases or steam cooled in a power plant by a heat sink from a water source—a case of ...