dew point

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dew point:

see dewdew,
thin film of water that has condensed on the surface of objects near the ground. Dew forms when radiational cooling of these objects during the nighttime hours also cools the shallow layer of overlying air in contact with them, causing the condensation of some water vapor.
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Dew Point

 

the temperature at which air becomes saturated by water vapor when cooled at a given moisture content and a constant pressure. The condensation of water vapor begins when the dew point is reached in the air or on objects in contact with the air.

The dew point is one of the major characteristics of humidity and can be calculated from the temperature and humidity of the air or determined directly with a condensation hygrometer. If the relative humidity is less than 100 percent, the dew point is always less than the actual air temperature. The dew point decreases with decreasing relative humidity.

At saturation, that is, at a relative humidity of 100 percent, the actual temperature coincides with the dew point. Thus, at a temperature of 15°C, the relative humidities of 100, 80, 60, and 40 percent correspond to the dew points of 15.0°, 11.6°, 7.3°, and 1.5°C, respectively.

dew point

[′dü ‚pȯint]
(chemistry)
The temperature and pressure at which a gas begins to condense to a liquid.
(meteorology)
The temperature at which air becomes saturated when cooled without addition of moisture or change of pressure; any further cooling causes condensation. Also known as dew-point temperature.

dew point

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If the temperature is +30°C and there is 15 gm of water vapor per kg of dry air and the air is cooled to +20°C, saturation will occur. +20°C is the Dew point. Similarly, Dew point is +33°C if air with 5 gm of water vapor per kg is cooled till it becomes saturated.
The temperature to which a given parcel of air must be cooled at constant pressure and constant-water-vapor content for saturation to occur. It is the temperature at which the saturation vapor pressure of the parcel is equal to the actual vapor pressure of the contained water vapor. Any further cooling usually results in the formation of dew or frost. Also called the dew-point temperature. When this temperature is below 0°C, it is sometimes called the frost point.
References in periodicals archive ?
Dew Point Sensor--Generally the dew point sensor needs to be replaced yearly.
The dew point and wind speed were presented as daily averages, and precipitation was given as a daily total.
A flue gas stream typically has a dew point of 120 to 136[degrees]F (49 to 58[degrees]C).
Moreover, in addition to the usual objectives of improving quality control and yields, in these industries there is a new focus on energy saving - aimed at realizing a low-carbon society - and this is leading to a growing demand for finer measurement and control of dew point.
Hydrocarbon dew point (HCDP) in natural gas has always been operationally important.
The PF boiler test data obtained previously showed that the dew point of oil shale flue gas fluctuates between 75 and 80[degrees]C and does not depend on boiler thermal load or boiler design [3].
As it gets cooler and cooler through the night, it's getting closer to the dew point.
The air inlet dew point is another factor to affect the TMH performance.
The test apparatus was built around a Bureau of Mines chilled mirror dew point tester, which is accepted by the industry for use in assessing gas quality and dew points.
9+], along with well-known gas equations of state, a field-mounted pipeline gas chromatograph can be a reliable and economical tool for tracking hydrocarbon dew point and giving advance warning of liquid formation.
With proper equipment handling, one new sampling method was found to produce a representative sample of the flowing gas stream, when ambient conditions were both well above and well below the hydrocarbon dew point.
It uses a continuously turning wheel of desiccant that generally provides a very consistent dew point and temperature to the process.