Question

It is a hot, sunny day in Rochester when you decide to go for a walk along the lakefront. The temperature is 90°F with a relative humidity of 88%. After a while, you need to get out of the heat and decide to head back to your car. You crank up the A/C and allow the car to cool down to 72°F. During this time, approximately 75% of the water vapor in the air outside condenses in the car. Calculate the relative humidity in your car once cooled.

Answer 1

This question is based on temperature dependent factors.

I am giving step by step solution of this question in an image form.

(Page no-01 Relative humidity - 88% (at 90°F). water vapor in the cure = 75% Relative humidity at 72°F = ? The formula is; Relative Humidity % x 100 where; E = Saturation Vapor Pressure - Actual Vapor Pressure. E & Es is calculated as follows, - Es= 6.11 x e(243.5+T) E = 6.11 x 024031547) where; T = Ambient temperature in celsius. I To Dew point in celsius Now, Jemperature converted from of to c. 90-32 - 2000) of - 9 (c) +32 58 x 5 = °C go ) +32 [c = 32.227T (17.67 XT

(Page no-02! OF - (c) +32 72 - 900) +32 72-32 = () 40 x 5 = { c = 22.227 To (17.67 X 32.22 243.5+ 32.22% Es = 6.11 X 0(2-0648) — 6.11*7.8837 Es = 48.1695) Then; E = 6.1 X (17.67 X 22.22 243.5 +22.22 E = 6:11 x 41-4775) -6.11x4.3819 I E= 26.77 38) Now, Relative Humidity % = € x 100 Es RH = 26.7738 x100 48. 1695 (RH = 55.58% when Care become cool; the relative humidity will be 55.58%.