The inside temperature of a wall in a dwelling is 19°C. If the air in the...

The inside temperature of a wall in a dwelling is 19°C. If the air in the room is at 21°C, what is the maximum relative humidity, in percent, the air can have before condensation occurs on the wall?

Solutions

Expert Solution

The set of formulas assumes a standard atmospheric pressure. These formulas will calculate saturation vapor pressure(Es) and actual vapor pressure(E) in millibars.

Es=6.11*10.0**(7.5*Tc/(237.7+Tc) = 6.11*10.0**(7.5*21/(237.7+21) =37.198 mbar

E=6.11*10.0**(7.5*Tdc/(237.7+Tdc) = 6.11*10.0**(7.5*19/(237.7+19) 33.917 mbar

where Tdc= dewpoint temperature in degrees Celsius

Tc= air temperature in degrees Celsius

Es= saturation vapor pressure

E= actual vapor pressure

Once you have the saturation vapor pressure and the actual vapor pressure, relative humidity can be computed by dividing the actual vapor pressure by the saturation vapor pressure and then multiplying by 100 to convert the quantity to a percent.

Relative Humidity(RH) in percent =(E/Es)*100

= (33.197/37.198)*100 = 91.118 %

Note: Due to the rounding of decimal places, answer may be slightly different from the above answer, but it should be within 2%

samet mamat answered 1 year ago

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