(a) Explanation Express the partial pressure of dry air. P a = P − P ν = P − P sat@20°C (I) Here, partial pressure of air is P a , environmental pressure is P , vapor pressure is P ν and saturation pressure at temperature of 20°C is P sat@20°C . Express the mass of the dry air. m a = P a ν R a T (II) Here, volume is ν , universal gas constant is R a and temperature is T . Conclusion: Refer Table A-2, “ideal-gas specific heats of various common gases”, and write the gas constant of air. R a = 0.287 kPa ⋅ m 3 / kg ⋅ K Refer Table A-4, “saturated water-temperature table”, and write the saturation pressure at temperature of 20 ° C . P sat@20°C = 2.3392 kPa Substitute 90 kPa for P and 2.3392 kPa for P sat@20°C in Equation (I). P a = 90 kPa − 2.3392 kPa = 87.66 kPa Substitute 87.66 kPa for P a , 1 .8 m 3 for ν , 0 (b) To determine The specific humidity. (c) To determine The enthalpy of the air per unit mass of the dry air.

9th Edition

ISBN: 8220106796979

Author: CENGEL

Publisher: YUZU

See similar textbooks

Videos

Question

Chapter 14.7, Problem 122RP

(a)

To determine

The mass of the dry air.

(b)

To determine

The specific humidity.

(c)

To determine

The enthalpy of the air per unit mass of the dry air.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Chapter 14.7, Problem 121RP

Chapter 14.7, Problem 124RP

Students have asked these similar questions

The air in an area (30.5°C and 30% humidity) has a volume of 96.6 cubic meters which must be replaced every 5 minutes. Outside air at 38.0°C and 70% humidity is chilled to remove some of its water content and then dehumidified to the required temperature. What is the volumetric flow rate (in m3/min) of the humid air entering the chiller?

Air at a temperature of 26.7C and a total pressure of 200 kPa contains water vapor with a partial pressure of 2.8 kPa. Determine: (a) the percentage humidity, (b) relative humidity, (c) absolute humidity (d) humid heat in kJ/kg-K (e) wet bulb temperature, and (f) humid volume. Ans: (a) 79.7% (b) 80% (c) 0.00881 (d) 1.0215 (e) 21.2C (f) 0.4435 m3/kg d.a.

The air in a room (24.0°C and 30% humidity) with a volume of 96.6 m3 must be replaced every 5 minutes. Outside air at 38.0°C and 70% humidity is chilled to remove some of its water content and then dehumidified to the required temperature. What is the volumetric flow rate (in m3/min) of the humid air entering the chiller?

Chapter 14 Solutions

EBK THERMODYNAMICS: AN ENGINEERING APPR

Ch. 14.7 - What is the difference between dry air and...Ch. 14.7 - What is vapor pressure?Ch. 14.7 - What is the difference between the specific...Ch. 14.7 - Can the water vapor in air be treated as an ideal...Ch. 14.7 - Explain how vapor pressure of the ambient air is...Ch. 14.7 - Is the relative humidity of saturated air...Ch. 14.7 - Moist air is passed through a cooling section...Ch. 14.7 - How will (a) the specific humidity and (b) the...Ch. 14.7 - Prob. 9P Ch. 14.7 - Consider a tank that contains moist air at 3 atm...

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.

The mass of the dry air.

Solution Summary: The author explains the mass of the dry air and the gas constant of air in Table A-2.

Videos

The mass of the dry air.

The specific humidity.

The enthalpy of the air per unit mass of the dry air.

Want to see the full answer?

Chapter 14 Solutions