HEATING, VENTILATING,+AC ANAL...EBOOK>I<
6th Edition
ISBN: 2819480255750
Author: Mcquiston
Publisher: INTER WILE
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Chapter 3, Problem 3.51P
A multizone air handler provides air to several zones. One interior zone contains computer equipment with only a sensible load. The coil in the unit cools air from 85 F (29 C) db and 70 F (21 C) wb to 53 F (12 C) db and 90% relative humidity (RH). (a) If the zone is to be maintained at 75 F (24 C) and 50% RH, what proportion of the supply air to the zone bypasses the coil? The amount of air supplied to the zone is 2,500 cfm (1.18 m3/s). (b) What is the cooling load for the zone? Assume standard sea-level pressure.
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In a place where a summer air-conditioning plant will be installed, 40% of the air entering the air-conditioning plant is the fresh air, and 60% is the return (bypass) air. The sensible heat gain of the place is 10 kW. and the latent heat gain is 2.5 kW.> Outdoor conditions: 32 °C DB, %50 RH.> Indoor conditions: 20 °C DB. %50 RH.> Take the relative humidity of the air passing through the cooling coil 90% at the coil outlet.
> The total air flow rate in the mixing chamber is 3000 m3/h> Take the density of the air as 1.2 kg/m3Based on the above.a) Show the process on a psychrometric diagram. b) Calculate the amount of fresh air. c) What is the value of enthalpy of blowing air. d) Calculate the ratio of by-pass air at cooling coil. e) Calculate the flow rate of by-passed air.
In a place where a summer air-conditioning plant will be installed, 40% of the air entering the air-conditioning plant is the fresh air, and 60% is the return (bypass) air. The sensible heat gain of the place is 10 kW. and the latent heat gain is 2.5 kW.> Outdoor conditions: 32 °C DB, %50 RH.> Indoor conditions: 20 °C DB. %50 RH.> Take the relative humidity of the air passing through the cooling coil 90% at the coil outlet.
> The total air flow rate in the mixing chamber is 3000 m3/h> Take the density of the air as 1.2 kg/m3Based on the above.
Calculate the amount of fresh air. What is the value of enthalpy of blowing air. Calculate the ratio of by-pass air at cooling coil. Calculate the flow rate of by-passed air.
A summer air-conditioning shown below is required to maintain a certain room at specified conditions. The layout of the system is indicated on the next page and the specifications are listed below.System specifications:Required room temperature: 23⁰C, 50% Relative humidityAtmospheric pressure: 101 kPaOutside air conditions: 30⁰C, 80% Relative humidity Sensible heat gain: 5 kWLatent heat gain: 4 kWTemperature rise across fan: 1.5⁰CTemperature of air leaving cooler: 12⁰CTemperature of air entering room: 18⁰CApparatus dew point of cooler: 7⁰C
Chapter 3 Solutions
HEATING, VENTILATING,+AC ANAL...EBOOK>I<
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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