Dewpoint temperature, Td, is the temperature at which the water vapor contained in a gas starts to condense when cooled.

露點溫度 (T d ) 是氣體中的 水蒸汽在冷卻過程中開始凝結結露時的溫度。

Dewpoint is defined as the temperature at which a moist gas is saturated with respect to a plane surface of pure liquid water.

露點被定義為在濕氣體達到飽 和狀態并在平面表面產生純液態水時的溫度 P w = P ws (Td)

Pw is partial water vapor pressure 水蒸汽分壓

• Pws is water vapor ' s saturation pressure. 飽和水蒸汽壓力

• Td is dew point temperature 露點溫度

At this state condensation and evaporation are at an equilibrium and take place at the same rate.

在這種狀態時水的凝結和蒸發達到平衡狀態并且以相 同的速度進行。

• proportional only to the pressure of water vapour (T n , m, A are constants) 只和水 蒸汽壓力相關

• measurement sensitive to pressure changes 測量對壓力變化非常敏感

Dewpoint is not temperature dependent but only pressure dependent parameter.

露點是只和壓力相關 , 并不和溫度相關 的一個參數。