Print the psychrometric chart for each problem and locate th

Print the psychrometric chart for each problem and locate the states and draw process lines (if there is any) on it. Total pressure in all problems is sea level pressure. The inside surface temperature of a window in a room is 40 F where the air has a temperature of 72 F db, and 50 percent relative humidity. Will moisture condense on the window glass?

Solution

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 given temperature. saturated vapor pressure at 22 C=2680 Pa ...

so partial pressure of water vapor = 0.50*2680 Pa = 1340 Pa ...

partial pressure of air = 100000-1340 = 98660 Pa

dew point temp for 1340 Pa = 52 F

so as the temp. of glass in less than 52 F , so yes moisture will form on surface