Air distribution in buildings

264 Pages·2014·26.906 MB·English

by  E E Khalil

Mechanical engineering
Air Distribution Air Distribution
in Buildings
in Buildings
Air Distribution in Buildings is a concise and practical guide to air distribution
system design and managing air conditioning systems in buildings. Making
use of 40 years of experience in the design of air conditioning and ventilation
systems, and other electromechanical services, this structured reference
for built environment engineering offers in-depth coverage of air distribution
technology. The text brings together a wide range of information and offers
technical guidance on the design, calculation, and efficient operation of air
distribution in buildings.
The text highlights the special characteristics of air distribution in individual
spaces. It presents the basic and fundamental concepts of air distribution
as it relates to grilles and outlets, room space, and buildings. It focuses on air
distribution systems in large buildings, starting with simple rooms and then
moving on to more complex configurations. It also sums up the latest standards
and best practices in air conditioning engineering.
• Includes knowledge of the new trends in buildings’ air distribution
• Provides systematic analyses of the air flow regimes, heat transfer,
and relative humidity in a collection of special built environments
• Presents energy analyses of the air conditioning systems for operating
theaters and sporting facilities in unusual and severe climatic conditions
• Offers a description of flow characteristics in archeological monuments
with emphasis on combating excessive moisture
• Introduces examples of very dense occupancy built environments,
moisture sensitive environments, and open space air conditioning
• Details advanced treatment of flow characterization in large
public buildings
This text serves as an ideal resource for air conditioning engineers, contractors,
and consultants. It also benefits mechanical and architectural engineering
students.
Essam E. Khalil
K20683
ISBN-13: 978-1-4665-9463-0
90000
9 781466 594630
K20683_Cover_mech.indd All Pages 10/15/13 10:18 AM
Air Distribution
in Buildings
Essam E. Khalil
Boca Raton London New York
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
MECHANICAL and AEROSPACE ENGINEERING
Frank Kreith & Darrell W. Pepper
Series Editors
RECENTLY PUBLISHED TITLES
Air Distribution in Buildings, Essam E. Khalil
Alternative Fuels for Transportation, Edited by Arumugam S. Ramadhas
Computer Techniques in Vibration, Edited by Clarence W. de Silva
Distributed Generation: The Power Paradigm for the New Millennium,
Edited by Anne-Marie Borbely and Jan F. Kreider
Elastic Waves in Composite Media and Structures: With Applications to Ultrasonic
Nondestructive Evaluation, Subhendu K. Datta and Arvind H. Shah
Elastoplasticity Theory, Vlado A. Lubarda
Energy Audit of Building Systems: An Engineering Approach, Moncef Krarti
Energy Conversion, Edited by D. Yogi Goswami and Frank Kreith
Energy Management and Conservation Handbook, Edited by Frank Kreith and
D. Yogi Goswami
The Finite Element Method Using MATLAB®, Second Edition, Young W. Kwon and
Hyochoong Bang
Fluid Power Circuits and Controls: Fundamentals and Applications, John S. Cundiff
Fuel Cells: Principles, Design, and Analysis, Shripad Revankar and Pradip Majumdar
Fundamentals of Environmental Discharge Modeling, Lorin R. Davis
Handbook of Energy Efficiency and Renewable Energy, Edited by Frank Kreith and
D. Yogi Goswami
Heat Transfer in Single and Multiphase Systems, Greg F. Naterer
Heating and Cooling of Buildings: Design for Efficiency, Revised Second Edition,
Jan F. Kreider, Peter S. Curtiss, and Ari Rabl
Intelligent Transportation Systems: Smart and Green Infrastructure Design, Second
Edition, Sumit Ghosh and Tony S. Lee
Introduction to Biofuels, David M. Mousdale
Introduction to Precision Machine Design and Error Assessment, Edited by Samir Mekid
Introductory Finite Element Method, Chandrakant S. Desai and Tribikram Kundu
Large Energy Storage Systems Handbook, Edited by Frank S. Barnes and Jonah G. Levine
Machine Elements: Life and Design, Boris M. Klebanov, David M. Barlam, and
Frederic E. Nystrom
Mathematical and Physical Modeling of Materials Processing Operations,
Olusegun Johnson Ilegbusi, Manabu Iguchi, and Walter E. Wahnsiedler
Mechanics of Composite Materials, Autar K. Kaw
Mechanics of Fatigue, Vladimir V. Bolotin
Mechanism Design: Enumeration of Kinematic Structures According to Function,
Lung-Wen Tsai
Mechatronic Systems: Devices, Design, Control, Operation and Monitoring,
Edited by Clarence W. de Silva
The MEMS Handbook, Second Edition (3 volumes), Edited by Mohamed Gad-el-Hak
MEMS: Introduction and Fundamentals
MEMS: Applications
MEMS: Design and Fabrication
Multiphase Flow Handbook, Edited by Clayton T. Crowe
Nanotechnology: Understanding Small Systems, Second Edition, Ben Rogers, Sumita
Pennathur, and Jesse Adams
Nuclear Engineering Handbook, Edited by Kenneth D. Kok
Optomechatronics: Fusion of Optical and Mechatronic Engineering, Hyungsuck Cho
Practical Inverse Analysis in Engineering, David M. Trujillo and Henry R. Busby
Pressure Vessels: Design and Practice, Somnath Chattopadhyay
Principles of Solid Mechanics, Rowland Richards, Jr.
Principles of Sustainable Energy Systems, Second Edition, Edited by Frank Kreith with
Susan Krumdieck, Co-Editor
Thermodynamics for Engineers, Kau-Fui Vincent Wong
Vibration and Shock Handbook, Edited by Clarence W. de Silva
Vibration Damping, Control, and Design, Edited by Clarence W. de Silva
Viscoelastic Solids, Roderic S. Lakes
Weatherization and Energy Efficiency Improvement for Existing Homes: An Engineering
Approach, Moncef Krarti
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2014 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Version Date: 20130930
International Standard Book Number-13: 978-1-4665-9465-4 (eBook - PDF)
This book contains information obtained from authentic and highly regarded sources. Reasonable efforts
have been made to publish reliable data and information, but the author and publisher cannot assume
responsibility for the validity of all materials or the consequences of their use. The authors and publishers
have attempted to trace the copyright holders of all material reproduced in this publication and apologize to
copyright holders if permission to publish in this form has not been obtained. If any copyright material has
not been acknowledged please write and let us know so we may rectify in any future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmit-
ted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented,
including photocopying, microfilming, and recording, or in any information storage or retrieval system,
without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.
com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood
Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and
registration for a variety of users. For organizations that have been granted a photocopy license by the CCC,
a separate system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used
only for identification and explanation without intent to infringe.
Visit the Taylor & Francis Web site at
http://www.taylorandfrancis.com
and the CRC Press Web site at
http://www.crcpress.com
Contents
Preface ...................................................................................................................xiii
Acknowledgments ................................................................................................xv
About the Author ...............................................................................................xvii
1 Air Distribution Systems ..............................................................................1
1.1 Airflow Patterns ....................................................................................1
1.1.1 General ......................................................................................1
1.1.2 Practical Configurations .........................................................3
1.1.2.1 Grilles and Diffusers ...............................................3
1.1.2.2 Square Ceiling Diffuser with a Circular
Duct Connection .......................................................8
1.1.2.3 Wall-Mounted Supply Grille ..................................8
1.1.2.4 Ceiling Architectural Diffuser ...............................9
1.1.2.5 Square Ceiling Diffuser.........................................10
1.1.2.6 High Ceiling Diffusers ..........................................10
1.1.2.7 Fixed Swirl Diffusers for Ceiling Installations ....10
1.2 Airflow Efficiency in Rooms .............................................................11
1.3 Noise Criteria .......................................................................................15
1.4 Air Handling Units .............................................................................18
1.4.1 Casing ......................................................................................18
1.4.2 Mixing Box ..............................................................................19
1.4.3 Filter Sections .........................................................................19
1.4.4 Coil Section Two-Pipe System ..............................................19
1.4.5 Electric Heater Section ..........................................................19
1.4.6 Fan Section ..............................................................................20
References .......................................................................................................20
2 Mathematical Modeling Technique .........................................................23
2.1 Governing Equations ..........................................................................23
2.1.1 Conservation of Mass: The Continuity Equation ..............23
2.1.1.1 Derivation of the Continuity Equation ...............23
2.1.1.2 Differential Form of the Continuity Equation ....24
2.1.2 Newton’s Second Law: The Linear Momentum
Equation ..................................................................................26
2.1.2.1 Derivation of the Linear Momentum Equation ....26
2.1.2.2 Description of Forces Acting on
Differential Element ...............................................28
2.1.2.3 Equations of Motion ...............................................30
2.1.2.4 Viscous Flow ...........................................................30
2.1.2.5 Stress–Deformation Relationships .......................30
© 2008 Taylor & Francis Group, LLC v
vi Contents
2.1.2.6 Navier–Stokes Equations ......................................31
2.1.3 First Law of Thermodynamics: The Energy Equation .....32
2.1.3.1 Derivation of the Energy Equation ......................32
2.1.3.2 Differential Form ....................................................32
2.2 Numerical Procedure .........................................................................33
2.2.1 Differential Equations of Motion .........................................33
2.2.2 Turbulence Model ..................................................................36
2.2.3 Wall Functions........................................................................39
2.2.4 Numerical Solution Procedure ............................................41
2.2.5 Finite Difference Equations ..................................................43
2.2.6 Solution Algorithm ................................................................44
2.2.6.1 Convergence and Stability ....................................45
2.3 Conclusions ..........................................................................................45
References .......................................................................................................46
3 Airflow Regimes and Thermal Comfort in a Room ..............................47
3.1 Numerical Model ................................................................................47
3.1.1 Case Geometry .......................................................................47
3.1.2 Boundary Conditions ............................................................48
3.1.2.1 Walls .........................................................................48
3.1.2.2 Interior .....................................................................48
3.1.2.3 Supply Grilles .........................................................48
3.1.2.4 Light Heat Load ......................................................49
3.1.2.5 Human Body ...........................................................49
3.1.2.6 Return Grilles .........................................................50
3.1.2.7 Television Heat Load .............................................50
3.2 Flow Pattern and Thermal Behavior ................................................51
3.2.1 General ....................................................................................51
3.2.2 Design Alternatives ...............................................................51
3.2.2.1 Design 1 ...................................................................51
3.2.2.2 Design 2: Square Diffuser (60–30–15°) ................53
3.2.2.3 Design 3: Square Diffuser (90–60–30°) ................53
3.2.2.4 Design 4: Circular Diffuser (90–60–30°) .............56
3.2.2.5 Design 5: Swirl Flow ..............................................59
3.2.2.6 Design 6: Side Return ............................................61
3.2.2.7 Design 7: Side Supply .............................................64
3.3 Conclusions ..........................................................................................67
References .......................................................................................................68
4 Airflow Regimes and Thermal Pattern in
Archeological Monuments .........................................................................69
4.1 Historical Background .......................................................................70
4.1.1 General ....................................................................................70
4.1.1.1 External Factors ......................................................70
4.1.1.2 Internal Factors .......................................................70
© 2008 Taylor & Francis Group, LLC
Contents vii
4.1.2 Main Factors Affecting Human Comfort ...........................73
4.2 Background ..........................................................................................73
4.2.1 General ....................................................................................73
4.2.2 Ventilation in Archeological Tombs of Valley of the
Kings, Luxor ...........................................................................73
4.2.2.1 Omar Abdel-Aziz and Khalil (2005) ....................73
4.2.2.2 Ezzeldin and Khalil (2006) ....................................77
4.3 Proposed Design Calculation Methodology ...................................81
4.3.1 General ....................................................................................81
4.3.2 Classification of Tombs .........................................................82
4.3.2.1 Rameses VII Tomb (KV1) ......................................83
4.3.2.2 Rameses IV Tomb (KV2) ........................................84
4.3.2.3 Bay Tomb (KV13) ....................................................84
4.3.2.4 Seti II Tomb (KV15) ................................................85
4.3.3 Mesh Generation ....................................................................88
4.3.4 Computational Design Studies ............................................89
4.3.5 Boundary Conditions ............................................................91
4.3.5.1 Inlet Air Conditions ...............................................91
4.3.5.2 Outlets ......................................................................91
4.3.5.3 Walls .........................................................................91
4.3.5.4 Visitors .....................................................................91
4.4 Proposed Solution ...............................................................................92
4.4.1 Investigate Decay Mechanisms and Causes ......................92
4.4.2 Design and Construction of Effective
Ventilation System for Protection and Preservation .........95
4.5 Conclusions ..........................................................................................97
References .......................................................................................................97
Recommended Readings ..............................................................................98
5 Airflow in Places of Worship ...................................................................101
5.1 People and Comfort ..........................................................................102
5.1.1 Comfort Criteria ...................................................................102
5.1.2 Effect of Air Movement .......................................................102
5.1.3 Acceptable Comfort Zone ...................................................102
5.2 Climatic Factors .................................................................................102
5.2.1 Climatic Elements Affecting Natural Cooling ................102
5.2.2 Extrapolating Regional Weather Data to Specific Sites ....103
5.2.2.1 Humidity ...............................................................103
5.2.2.2 Solar Radiation .....................................................103
5.2.2.3 Temperature ..........................................................103
5.2.2.4 Wind .......................................................................103
5.3 Air Conditioning of Mosques: Ceiling Designs ...........................103
5.4 Air Conditioning of Churches: Ceiling Designs ..........................106
5.4.1 Model Architecture (Structure) .........................................107
5.4.1.1 Inlet Air Conditions .............................................107
© 2008 Taylor & Francis Group, LLC
viii Contents
5.4.1.2 Air Inlets and Outlets ..........................................109
5.4.1.3 Walls .......................................................................109
5.4.1.4 Visitors’ Bodies and Faces ...................................109
5.4.2 Velocity Predictions .............................................................109
5.5 Air Distribution in Mosques: Free-Stand Units ............................117
5.6 Conclusions ........................................................................................122
References .....................................................................................................122
6 Airflow Patterns in Healthcare Facilities ...............................................123
6.1 Airflow Characteristics for Comfort ..............................................123
6.2 Early Practice of Airflow Design ....................................................124
6.3 Present Observations ........................................................................125
6.4 Problem Analysis ..............................................................................126
6.5 Modeled Equations ...........................................................................127
6.6 Flow Pattern Analyses ......................................................................130
6.6.1 Experimental Facility ..........................................................131
6.6.2 Numerical Program .............................................................132
6.7 Conclusions ........................................................................................137
References .....................................................................................................139
Recommended Readings ............................................................................139
7 Examples of Typical Air Conditioning Projects ...................................143
7.1 Environmental Control ....................................................................143
7.1.1 Temperatures ........................................................................143
7.1.2 Relative Humidity Control .................................................143
7.1.3 Airflow Velocity Control .....................................................144
7.1.4 Ventilation .............................................................................144
7.2 Air Filtration ......................................................................................145
7.3 Pressure Relationships and Ventilation .........................................145
7.4 Air Movement ....................................................................................147
7.5 Air Quality .........................................................................................147
7.6 Smoke Control ...................................................................................148
7.7 Fire Control ........................................................................................148
7.8 Noise Criteria .....................................................................................149
7.9 Factors Affecting System Selection ................................................149
7.9.1 General Design Factors .......................................................149
7.9.2 Load Characteristics ............................................................150
7.9.3 Design Factors ......................................................................151
7.9.3.1 Comfort Level .......................................................151
7.9.3.2 Costs .......................................................................151
7.9.3.3 Local Conditions ..................................................152
7.9.3.4 Automatic Temperature Control ........................152
7.9.3.5 Fire, Smoke, and Odor Control ...........................152
7.10 HVAC Life Cycle Cost Analyses .....................................................152
7.10.1 Introduction ..........................................................................152
© 2008 Taylor & Francis Group, LLC
Contents ix
7.10.2 Owning Costs Analysis ......................................................154
7.10.3 Operating Costs Analysis ...................................................155
7.10.4 Maintenance Costs Analysis ..............................................156
7.10.5 Design Specifications ..........................................................156
7.11 Further Examples ..............................................................................157
7.12 Engineering Tips for Energy-Efficient Buildings .........................168
7.13 Conclusions ........................................................................................169
References .....................................................................................................170
8 Indoor Environmental Quality ................................................................171
8.1 Definitions ..........................................................................................171
8.2 IEQ Mandatory Provisions ..............................................................173
8.2.1 Indoor Air Quality ...............................................................174
8.2.2 Minimum Ventilation Rates ...............................................174
8.2.3 Outdoor Air Delivery Monitoring .....................................174
8.2.3.1 Spaces Ventilated by Mechanical Systems .......174
8.2.3.2 Naturally Ventilated Spaces ................................175
8.2.3.3 CO Sensors ...........................................................175
2
8.2.4 Filtration and Air Cleaner Requirements .........................176
8.2.4.1 Particulate Matter .................................................176
8.2.4.2 Ozone .....................................................................176
8.2.4.3 Bypass Pathways ..................................................176
8.2.5 Environmental Tobacco Smoke ..........................................176
8.2.6 Building Entrances ..............................................................176
8.2.6.1 Scraper Surface .....................................................177
8.2.6.2 Absorption Surface ..............................................177
8.2.6.3 Finishing Surface ..................................................177
8.3 Thermal Environmental Conditions for Human
Occupancy Comfort ..........................................................................177
8.4 Acoustical Control ............................................................................178
8.4.1 Exterior Sound ......................................................................178
8.4.2 Interior Sound ......................................................................178
8.4.3 Outdoor–Indoor Transmission Class and Sound
Transmission Class ..............................................................179
8.5 Daylighting by Top Lighting ...........................................................179
8.5.1 Minimum Daylight Zone by Top Lighting ......................179
8.5.2 Skylight Characteristics ......................................................179
8.6 Isolation of the Building from Pollutants in Soil ..........................180
8.7 Prescriptive Option ...........................................................................180
8.7.1 Daylighting by Side Lighting .............................................180
8.7.1.1 Minimum Effective Aperture .............................180
8.7.1.2 Office Space Shading ...........................................181
8.7.2 Materials ................................................................................182
8.7.2.1 Adhesives and Sealants .......................................182
8.7.2.2 VOC Content Requirements ...............................182
© 2008 Taylor & Francis Group, LLC