The latest weather report states that the temperature is 24ᵒC
and the relative humidity 50%.
a) Use the psychometric chart to estimate the absolute
humidity, humid volume, specific enthalpy, wet-bulb
temperature, and dew-point temperature of the air.
b) A thermometer is mounted on the back porch of your
house. What temperature would it read?
c) A sample of outside air is cooled at constant pressure. At
what temperature would condensation begin?
d) You step out of your neighborhood pool and feel quite cold
until you dry off. Explain why. Estimate your skin
temperature while you were still wet. Explain your answer.
What would be different if the relative humidity were 98%?
Absolute humidity = 0.009 kg water/kg DA
Humid Volume = 0.855 m3/kg DA
Specific enthalpy = 48 kJ/kg DA
Wet-bulb temperature = 17ᵒC
Dew point temperature= 13ᵒC
b) The temperature would be 24ᵒC
c) Condensation will be at the dew point which is 13ᵒC.
d) => When your skin is wet the evaporation of the moisture
takes heat away from your skin and makes you feel
=> As evaporation is taking place on your skin temperature
will be approximately at dew point which is 13ᵒC
=> If the relative humidity is at 98%, the rate of
evaporation would be slower. Thus, skin temperature
would not drop as much.