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
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 3, Problem 3.52P
Under normal operating conditions a zone has a total cooling load of 120,000 Btu/hr (35 kW) with a SHF of 0.8. The space is to be maintained at 74 F (23 C) db and 50% relative humidity (RH). However, there are periods when the latent load is high and the SHF is estimated to be as low as 0.6. Assume that air enters the cooling coil at 8 F (29 C) db and 71 F (22 C) wb and the coil apparatus dew point is 48 F (9 C). (a) Devise a system and the associated psychrometric processes to cover the necessary range of operation. b) Define the various air states and show the processes on Chart ia. (c) Compute air-flow rate, coil load, minimum zone load, and any reheat that may be required. Assume constant air flow and standard sea-level pressure.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Required information
NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to
return to this part.
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°C. Air enters the heating section at 10°C and 70 percent relative humidity at a rate
of 32 m /min, and it leaves the humidifying section at 20°C and 60 percent relative
humidity. Use data from the tables.
Sat. vapor
100°C
Heating
coils
Humidifier
10°C
Air
20°C
70%
60%
ymYmin
P=1 atm
Determine the temperature and relative humidity of air when leaves the heating section.
The temperature is
°C.
The relative humidity is
%.
In an uncomfortable summer day, the air is at 87OF and 80% relative humidity. A laboratory air conditioner is to deliver 1.00 x 103ft3/min of air at 55OF in order to maintain the interior air at an average temperature of 75OF and relative humidity of 40%.a. If the vent switch on the air conditioner is turned to the open position, outside air enters the unit as shown belown the air conditioner, the air is cooled to a temperature low enough to condense the necessary amount of water and reheated to 55OF, at which point it has the same absolute humidity as the room air. Determine the rate (lb/min) at which water is condensed, the temperature to which the air must be cooled to condense water at this rate, and the net tons of cooling required (Q), where 1 ton of cooling = -12,000 Btu/h.
Assume A = 87 οF, B = 80 %, C = 55 οF.
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
coils
Loooooooo
10°C
70%
35 m³/min
AIR
P = 1 atm
Sat. vapor
100°C
Humidifier
€
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
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...
Additional Engineering Textbook Solutions
Find more solutions based on key concepts
Figure 4-3212 shows a class list for Millennium College. Convert this user view to a set of 3NF relations using...
Modern Database Management
For the circuit shown, use the node-voltage method to find v1, v2, and i1.
How much power is delivered to the c...
Electric Circuits. (11th Edition)
Why is the booting process necessary?
Computer Science: An Overview (13th Edition) (What's New in Computer Science)
42. A container holding 1.5 moles [mol] of oxygen (formula: O2, molecular weight = 32 grams per mole [g/mol]) a...
Thinking Like an Engineer: An Active Learning Approach (4th Edition)
Why does the cutting force Fc increase with increased feed or DOC?
Degarmo's Materials And Processes In Manufacturing
Find the error in each of the following code segments, and explain how to correct it: 1 for (k = 0.1; k != 1.0;...
Java How to Program, Early Objects (11th Edition) (Deitel: How to Program)
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.Similar questions
- The design condition for a space is 77oF db and 50% relative humidity with 55oF db supply air at 90% relative humidity. A 50-ton, constant-volume space air- conditioning system uses face and bypass and water temperature control. Outdoor air is supplied at 95oF db, 60% relative humidity with a ratio of 1 lbm to 5 lbm re-circulated air. A part-load condition exists where the total space load is decreased by 50% and the SHF is increased to 90%. The outdoor air condition changes to 85oF db and 70% relative humidity. Assume sea-level conditions. a) At full – load conditions:a. Show all the processes on a psychrometric chart.b. Determine the temperature must the air be supplied to the space at fullload conditions.c. Determine the apparatus dew point temperature at full load conditions. b)At part – load conditions:a. Show all the processes on a psychrometric chart.b. Determine the temperature must the air be supplied to the space at partload conditions.c. Determine the apparatus dew point…arrow_forwardAir Conditioning Thermo Fluidarrow_forwardA space is to be maintained at 75 F db and 40% relative humidity. The total heat gain to the space is 62,000 Btu/hr with a SHF of 0.8. The outdoor air requirement is 500 cfm. The outdoor air has a temperature of 90 F and 50% relative humidity. Assume that the supply air has a temperature of 50 F db. Determine the following: a. Quantity of supplied air b. Capacity of the cooling coil c. Rate of moisture removal from the dehumidification elementarrow_forward
- P=19 Moist air goes into air-conditioning unit at a degree-30 C and 70% relative humidity, and it is cooled to 20-degree C and 20% relative humidity at a constant pressure of 1.01325 bar. The mass flow rate of dry air is mda=63 kg/s The unit applies refrigerant R-134a as the cooling fluid that enters inside the tubes of the cooling coil at 3.6 bar with a quality of 0.2 and leaves as a saturated vapor at the same pressure of 3.6 bar. Use the psychometric chart to determine: a) Mass flow rate of condensed water in kg/s b) The heat transfer rate from the air to the cooling coil in kW (Use the psychometric chart) c) The mass flow rate of R-134a that is needed in kg/sarrow_forwardThermo Fluid help needed air conditionerarrow_forwardASHRAE standard 62.2 states that the minimum acceptable rate of airflow into and out of a room is 15cfm (cubic feet per minute). If air is supplied at 68°F with a relative humidity of 45%, how many gallons of water (minimum) must be added to a portable room humidifier before you go to sleep if you would like to maintain the room at 65% humidity for 7 hours?arrow_forward
- Problem 2: 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 coils Leeeeeeee 10°℃ 70% 35 m³/min AIR P = 1 atm Sat. vapor 100°C Humidifier 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 sectionarrow_forwardA space is to be maintained at 22C and 50% relative humidity. The sensible heat load is 100 kW, and the latent heat load is 15 kW. Outside air is at 38C DB and 25C WB temp. Air is supplied to the space at 13C. If all-outside air system (no recirculation) is to be implemented, determine: (a) the cooling capacity in tons; (b) capacity of supply air fan in cmh; and (c) the coil bypass factor.arrow_forwardAir Conditionarrow_forward
- Help needed for Air Conditioning pleasearrow_forwardPick the right combination of True Statements. 1. As the by-pass factor (BPF) of the cooling coil increases, temperature difference between air at the outlet of the coil and coil ADP decreases. 2. As the by-pass factor (BPF) of the cooling coil increases, temperature difference between air at the outlet of the coil and coil ADP increases. 3. During cooling and humidification process, the enthalpy of air may increase, decrease or remain constant depending upon the temperature of the wet surface. 4. During sensible cooling of air, dry bulb temperature decreases but wet bulb temperature remains constant 5. The sensible heat factor for a sensible heating process is 1.0arrow_forwardplease answer do not image formatarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University Press
Mechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSON
Thermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEY
Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning
Engineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY
The Refrigeration Cycle Explained - The Four Major Components; Author: HVAC Know It All;https://www.youtube.com/watch?v=zfciSvOZDUY;License: Standard YouTube License, CC-BY