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A typical coal-fired power plant works at 10,500 Btu/kWh (3.1 kWh/kWh), an efficiency of 32–33%. [25] The centigrade heat unit (CHU) is the amount of heat required to raise the temperature of one pound (0.45 kg) of water by one Celsius degree. It is equal to 1.8 Btu or 1,899 joules. [26]
The therm (symbol, thm) is a non-SI unit of heat energy equal to 100,000 British thermal units (BTU), [1] and approximately 105 megajoules, 29.3 kilowatt-hours, 25,200 kilocalories and 25.2 thermies. One therm is the energy content of approximately 100 cubic feet (2.83 cubic metres) of natural gas at standard temperature and pressure .
For some usage examples, consider the conversion of 1 SCCM to kg/s of a gas of molecular weight , where is in kg/kmol. Furthermore, consider standard conditions of 101325 Pa and 273.15 K, and assume the gas is an ideal gas (i.e., Z n = 1 {\displaystyle Z_{n}=1} ).
[1] Compressed natural gas (CNG), for example, is a gas rather than a liquid. It can be measured by its volume in standard cubic feet (ft 3 ) at atmospheric conditions , by its weight in pounds (lb), or by its energy content in joules (J), British thermal units (BTU), or kilowatt-hours (kW·h).
≡ 13 595.1 kg/m 3 × 1 ft × g 0: ≈ 4.063 666 × 10 4 Pa [33] foot of water (39.2 °F) ftH 2 O ≈ 999.972 kg/m 3 × 1 ft × g 0: ≈ 2.988 98 × 10 3 Pa [33] inch of mercury (conventional) inHg ≡ 13 595.1 kg/m 3 × 1 in × g 0: ≈ 3.386 389 × 10 3 Pa [33] inch of water (39.2 °F) inH 2 O ≈ 999.972 kg/m 3 × 1 in × g 0: ≈ 249.082 ...
The SI unit of volumetric heat capacity is joule per kelvin per cubic meter, J⋅K −1 ⋅m −3. The volumetric heat capacity can also be expressed as the specific heat capacity (heat capacity per unit of mass, in J⋅K −1 ⋅kg −1) times the density of the substance (in kg/L, or g/mL). [1] It is defined to serve as an intensive property.
Quantity (common name/s) (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
The change of atmospheric pressure with altitude can be obtained from this equation: [2] P a = 0.9877 a {\displaystyle P_{a}=0.9877^{a}} Given an atmospheric pollutant concentration at an atmospheric pressure of 1 atmosphere (i.e., at sea level altitude), the concentration at other altitudes can be obtained from this equation: