Heating Ventilating and Air Conditioning: Analysis and Design
6th Edition
ISBN: 9780471470151
Author: Faye C. McQuiston, Jeffrey D. Spitler, Jerald D. Parker
Publisher: Wiley, John & Sons, Incorporated
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Textbook Question
Chapter 3, Problem 3.41P
A cooling system is being designed for use at high elevation (5000 ft or 1500 m) where the outdoor air is very dry. The space with a high latent load,
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P=19 Moist air goes into air-conditioning unit at a
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An air-conditioning system operates at a total pressure of 1 atm and consists of a heating
section and a humidifier that supplies wet steam (saturated water vapor) at 100 degrees
celsius. Air enters the heating section at 10 degrees celsius and 70 percent relative humidity
at a rate of 35 m^3/min, and it leaves the humidifying section at 20 degree celcius and 60
percent relative humidity.
Heating
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10°C
70%
35 m³/min
AIR
P = 1 atm
Sat. vapor
100°C
Humidifier
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20°C
60%
a. Humidity ratio at inlet
b. Relative humidity at the exit
c. Humidity ratio at exit
d. Rate at which water is added to humidifying section
Air at a dry bulb temperature of 20oC and relative humidity of 80% is to be heated and humidified to 40oC and 40% relative humidity. The following options are available for this objective: (a) by passing air through a heated water-spray air washer; (b) by preheating sensibly, and then passing through a water-spray washer with recirculated water until relative humidity rises to 95% and then again heating sensibly to the final required state. Determine for (a) and (b) the total heating required, the make-up water required in water-spray air washer, and the humidifying efficiency of the recirculated spray water.
Chapter 3 Solutions
Heating Ventilating and Air Conditioning: Analysis and Design
Ch. 3 - A space is at a temperature of 75 F (24 C), and...Ch. 3 - Determine the humidity ratio, enthalpy, and...Ch. 3 - Suppose the air of Problem 3-2 is at a pressure...Ch. 3 - What is the enthalpy of moist air at 70 F (20 C)...Ch. 3 - The inside surface temperature of a window in a...Ch. 3 - What is the mass flow rate of dry air flowing at a...Ch. 3 - Determine the dew point of moist air at 80 F (27...Ch. 3 - A room is to be maintained at 72 F (22 C) db. It...Ch. 3 - Air is cooled from 80 F db and 67 F wb until it is...Ch. 3 - Conditions in a room are measured to be 80 F db...
Ch. 3 - The environmental conditions in a room are to be...Ch. 3 - Air enters a cooling coil at the rate of 5000 cfm...Ch. 3 - Air flowing in a duct has dry and wet bulb...Ch. 3 - Air is humidified with the dry bulb temperature...Ch. 3 - Air at 38 C db and 20 C wb is humidified...Ch. 3 - Two thousand cfm (1.0 m3/s) of air at an initial...Ch. 3 - Air at 40 F (5 C) db and 35 F (2 C) wb is mixed...Ch. 3 - Rework Problem 3-25, using Chart 1a, with the...Ch. 3 - The design cooling load for a zone in a building...Ch. 3 - Assume that the air in Problem 3-22 is supplied to...Ch. 3 - The sensible heat loss from a space is 500,000...Ch. 3 - Air enters a refrigeration coil at 90 Fdb and 75...Ch. 3 - A building has a total heating load of 200,000...Ch. 3 - Reconsider Problem 3-36 for an elevation of 5000...Ch. 3 - The system of Problem 3-34 has a supply air fan...Ch. 3 - An evaporative cooling system is to be used to...Ch. 3 - A cooling system is being designed for use at high...Ch. 3 - Consider a space heating system designed as shown...Ch. 3 - A variable-air-volume VAV cooling system is a type...Ch. 3 - Rework Problem 3-43 for an elevation of 5000 feet...Ch. 3 - The design condition for a space is 77 F (25 C) db...Ch. 3 - Rework Problem 3-45 for an elevation of 5000 feet...Ch. 3 - It is necessary to cool and dehumidify air from 80...Ch. 3 - Conditions in one zone of a dual-duct conditioning...Ch. 3 - Rework Problem 3-48 for an elevation of 5000 ft...Ch. 3 - A water coil in Problem 3-48 cools return air to...Ch. 3 - A multizone air handler provides air to several...Ch. 3 - Under normal operating conditions a zone has a...Ch. 3 - An interior zone of a large building is designed...Ch. 3 - Outdoor air is mixed with room return air to...Ch. 3 - Consider an enclosed swimming pool. The pool area...Ch. 3 - One particular zone served by a multizone air...Ch. 3 - A research building requires 100 percent outdoor...Ch. 3 - A space requires cooling in the amount of 120,000...
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