Relative Humidity

on . Posted in Fluid Dynamics

Relative humidity, abbreviated as RH, a dimensionless number, is a measure of the amount of moisture in the air with respect to the temperature.

 

Relative Humidity formula

\(\large{ RH = \frac{e}{e_s} \;100 }\) 
Symbol English Metric
\(\large{ RH }\) = relative humidity  \(\large{dimensionless}\) 
\(\large{ e }\) = actual vapor pressure \(\large{\frac{lbf}{in^2}}\) \(\large{Pa}\)
\(\large{ e_s }\) = saturated vapor pressure \(\large{\frac{lbf}{in^2}}\) \(\large{Pa}\)

 

Relative Humidity formula

\(\large{ RH = 100 \;  \left(  \frac{ 112 \; - \; 0.1 \; T \; + T_d }{ 112 \; + \; 0.9 \; T }   \right)^8   }\) 
Symbol English Metric
\(\large{ RH }\) = relative humidity  \(\large{dimensionless}\) 
\(\large{ T_d }\) = dewpoint \(\large{F}\) \(\large{C}\)
\(\large{ T }\) = temperature \(\large{F}\) \(\large{C}\)

 

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Tags: Temperature Equations HVAC Equations