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An enthalpy–entropy chart, also known as the H–S chart or Mollier diagram, plots the total heat against entropy, [1] describing the enthalpy of a thermodynamic system. [2] A typical chart covers a pressure range of 0.01–1000 bar , and temperatures up to 800 degrees Celsius . [ 3 ]
The scale for APHA color goes from 0 to 500 in units of parts per million of platinum cobalt to water. Zero on this scale represents distilled water, or what is more commonly called white water. APHA standards can be used for both visual comparison and instrumental measurements.
A Fixture Unit is not a flow rate unit but a design factor. A fixture unit is equal to 1 cubic foot (0.028 m 3) of water drained in a 1 + 1 ⁄ 4 inches (32 mm) diameter pipe over one minute. [2] One cubic foot of water is roughly 7.48 US gallons (28.3 L; 6.23 imp gal). A Fixture Unit is used in plumbing design for both water supply and waste ...
An air purge heating unit is used to ensure that the purge air remains at a temperature above the acid dew-point. This temperature is typically around 20 °C/68 °F. [2] If temperatures are below this point, the controls will be corroded by condensation of compounds in the flue gas. Heated air ensures that controls are dry during startup. [3]
The dimensionless humidity ratio is typically expressed as grams of water per kilogram of dry air, or grains of water per pound of air (7000 grains equal 1 pound). Specific enthalpy , symbolized by h , is the sum of the internal (heat) energy of the moist air in question, including the heat of the air and water vapor within.
Variable air volume (VAV) is a type of heating, ventilating, and/or air-conditioning system. Unlike constant air volume (CAV) systems, which supply a constant airflow at a variable temperature, VAV systems vary the airflow at a constant or varying temperature.
Air bled from the engine fan is blown across the pre-cooler, located in the engine strut, and absorbs excess heat from the service bleed air. A fan air modulating valve (FAMV) varies the cooling airflow to control the final air temperature of the service bleed air. Notably, the Boeing 787 does not use bleed air to pressurize the cabin.
Absolute humidity is defined as water mass per volume of air. A given mass of air will grow or shrink as the temperature or pressure varies. So the absolute humidity of a mass of air will vary due to changes in temperature or pressure, even when the proportion of water in that mass of air (its specific humidity) remains constant.