Moist air exists at 80 *F dry-bulb temperature, 0.0150 lbm water/ lbm air humidity ratio, and 14.696 psia pressure.  Through the use of table A.4 and fundameltal relations, determine: a) the dew-point temperature b)relative humidity c) Volume in ft^3?lbm air d) the enthalpy in Btu/ lbm air Solution Table used http://www.engineeringtoolbox.com/moist-air-properties-d_1256.html Psychometric Chart used: http://web.uconn.edu/poultry/NE-127/NewFiles/psychrometric_inset.html Temperature = 80 F Humidity Ratio = 0.0150 lbm water/ lbm air Pressure = 14.696 psi From the psychometric chart we see, at humidity ratio of 0.015 and T = 80 F Wet Bulb temperature = 69 F Using dew point chart http://docs.engineeringtoolbox.com/documents/682/dry_wet_bulb_dew_point_deg_F.pdf, we get Dew Point Temperature = 65 F Relative humidity = 70 % (Approximately) Specific Volume = 13.9 ft^3/lbm dry air Enthalpy = 36 Btu/lbm dry air .

1. Moist air exists at 80 *F dry-bulb temperature, 0.0150 lbm water/ lbm air humidity ratio, and
14.696 psia pressure.  Through the use of table A.4 and fundameltal relations, determine:
a) the dew-point temperature
b)relative humidity
c) Volume in ft^3?lbm air
d) the enthalpy in Btu/ lbm air
Solution
Table used http://www.engineeringtoolbox.com/moist-air-properties-d_1256.html
Psychometric Chart used: http://web.uconn.edu/poultry/NE-
127/NewFiles/psychrometric_inset.html
Temperature = 80 F
Humidity Ratio = 0.0150 lbm water/ lbm air
Pressure = 14.696 psi
From the psychometric chart we see,
at humidity ratio of 0.015 and T = 80 F
Wet Bulb temperature = 69 F

2. Using dew point chart
http://docs.engineeringtoolbox.com/documents/682/dry_wet_bulb_dew_point_deg_F.pdf,
we get
Dew Point Temperature = 65 F
Relative humidity = 70 % (Approximately)
Specific Volume = 13.9 ft^3/lbm dry air
Enthalpy = 36 Btu/lbm dry air