# 2-4.Relative humidity RH

### Relative humidity RH

Relative humidity is the ratio of the partial pressure of water vapor in an air-water mixture to the saturated vapor pressure of water at a prescribed temperature. The relative humidity of air depends on temperature and the pressure of the system of interest.

RH Relative humidity
mw mass of water vapor in the air(g/m3)
mw max Saturated water vapor amount(g/m3)

The unit of volume used as a standard is 1 m3.
The unit of weight of the water used as a standard is 1g.

When temperature changes, even when relative humidity is same, content amount of water changes.

◎Content amount of water which is 80% of relative humidity in case the temperature in equipment is 30℃

The above-mentioned formula is changed.

mw = mwmax X RH/100

mwmax = 30.4g
RH = 80%

mw = 30.4 x 80/100 = 24.32g/m3

◎ Content amount of water which is 80% of relative humidity in case the temperature in equipment is 60℃ similarly

mwmax = 129.9g
RH = 80%

mw = 129.9 x 80/100 = 103.92g/m3

◎ Content amount of water which is 80% of relative humidity in case the temperature in equipment is 90℃ similarly

mwmax = 421.5g
RH = 80%

mw = 421.5 x 80/100 = 337.2g/m3

#### << Content water vapor content of 80% of relative humidity >>

That is, if temperature is raised to 90℃ from 30℃, maintaining 80% of relative humidity for equipment with 1-m capacity three, moisture of 312.88 g is absorbable from a subject at the maximum.