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Read and Download Ebook 2009 Ashrae Handbook: Fundamentals, I-P Edition PDF. 2009 Ashrae Handbook: Fundamentals, I-P Edition Review. Annotation The 2009 ASHRAE Handbook'Fundamentals covers basic principles and data used in the HVAC & R industry. Updated with research sponsored by ASHRAE and others. 2009 ASHRAE® HANDBOOK FUNDAMENTALS Inch-Pound EditionAmerican Society of Heating, Refrigerating and Air-Conditioning En.
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2009 ashrae handbook-fundamentals(inch-poundedition)(ashrae,2009). 1. 2009 ASHRAE® HANDBOOK FUNDAMENTALS Inch-Pound EditionAmerican Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
1791 Tullie Circle, N.E., Atlanta, GA 30329 (404) 636-8400. ©2009 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers,Inc. All rights reserved. DEDICATED TO THE ADVANCEMENT OF THE PROFESSION AND ITS ALLIED INDUSTRIES No part of this publication may be reproduced without permission in writing fromASHRAE, except by a reviewer who may quote brief passages or reproduce illustrations ina review with appropriate credit; nor may any part of this book be reproduced, stored in aretrieval system, or transmitted in any way or by any means—electronic, photocopying,recording, or other—without permission in writing from ASHRAE. Requests for permis-sion should be submitted at www.ashrae.org/permissions. Volunteer members of ASHRAE Technical Committees and others compiled the infor-mation in this handbook, and it is generally reviewed and updated every four years.
Com-ments, criticisms, and suggestions regarding the subject matter are invited. Any errors oromissions in the data should be brought to the attention of the Editor. Additions and correc-tions to Handbook volumes in print will be published in the Handbook published the yearfollowing their verification and, as soon as verified, on the ASHRAE Internet Web site. DISCLAIMER ASHRAE has compiled this publication with care, but ASHRAE has not investigated,and ASHRAE expressly disclaims any duty to investigate, any product, service, process,procedure, design, or the like that may be described herein.
The appearance of any technicaldata or editorial material in this publication does not constitute endorsement, warranty, orguaranty by ASHRAE of any product, service, process, procedure, design, or the like.ASHRAE does not warrant that the information in this publication is free of errors. Theentire risk of the use of any information in this publication is assumed by the user. ISBN 978-1-933742-54-0 ISSN 1523-7222 The paper for this book is both acid- and elemental-chlorine-free and was manufactured with pulp obtained from sources using sustainable forestry practices. The printing used soy-based inks. ASHRAE Research: Improving the Quality of Life The American Society of Heating, Refrigerating and Air- annually, enabling ASHRAE to report new data about materialConditioning Engineers is the world’s foremost technical society in properties and building physics and to promote the application ofthe fields of heating, ventilation, air conditioning, and refrigeration. Innovative technologies.Its members worldwide are individuals who share ideas, identify Chapters in the ASHRAE Handbook are updated through theneeds, support research, and write the industry’s standards for test- experience of members of ASHRAE Technical Committees anding and practice. The result is that engineers are better able to keep through results of ASHRAE Research reported at ASHRAE meet-indoor environments safe and productive while protecting and pre- ings and published in ASHRAE special publications and inserving the outdoors for generations to come.
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Preface The 2009 ASHRAE Handbook—Fundamentals covers basic prin-. Chapter 20, Space Air Diffusion, has been completely rewritten tociples and data used in the HVAC&R industry.
The ASHRAE Tech- harmonize with related chapters in other volumes, with major sec-nical Committees that prepare these chapters strive not only to tions on fully mixed, partially mixed, stratified, and task/ambientprovide new information, but also to clarify existing information, systems and the principles behind their design and operation.delete obsolete materials, and reorganize chapters to make the Hand-. Chapter 21, Duct Design, has new data for round and rectangularbook more understandable and easier to use. An accompanying CD- fittings in agreement with the ASHRAE Duct Fitting Database, asROM contains all the volume’s chapters in both I-P and SI units. Well as new content on duct leakage requirements, spiral duct This edition includes a new chapter (35), Sustainability, which roughness, and flexible duct pressure loss correction.defines this concept for HVAC&R and describes the principles,.
Chapter 23, Insulation for Mechanical Systems, has added tablesdesign considerations, and detailed evaluations needed in designing from ASHRAE Standard 90.1-2007, and a new section on writingsustainable HVAC&R systems. Also new for this volume, chapter order and groupings have been.
Chapter 24, Airflow Around Buildings, has added a detailed dis-revised for more logical flow and use. Some of the other revisions cussion on computational evaluation of airflow, plus new refer-and additions to the volume are as follows: ences including updated versions of design standards and manuals of practice. Chapter 1, Psychrometrics, has new information on the composi-.
Chapters 25, 26, and 27 carry new titles, reorganized as chapters tion of dry air, and revised table data for thermodynamic proper- on Heat, Air, and Moisture Control Fundamentals, Material Prop- ties of water and moist air. Erties, and Examples, respectively, with updated content through-. Chapter 6, Mass Transfer, has added examples on evaluating diffu- out. Sion coefficients, and on heat transfer and moisture removal rates. Chapter 29, Refrigerants, has new content on stratospheric ozone. Chapter 7, Fundamentals of Control, includes new content on depletion, global climate change, and global environmental char- dampers, adaptive control, direct digital control (DDC) system acteristics of refrigerants.
Architecture and specifications, and wireless control. Chapter 30, Thermophysical Properties of Refrigerants, has up-. Chapter 9, Thermal Comfort, has a new section on thermal com- dated data for R-125, R-245fa, R-170, R-290, R-600, and R-600a. Fort and task performance, based on multiple new studies done in. Chapter 36, Measurement and Instruments, has revised content on laboratory and office environments. Measurement of air velocity, infiltration, airtightness, and outdoor. Chapter 10, Indoor Environmental Health, was reorganized to air ventilation, plus new information on particle image velocime- describe hazard sources, health effects, exposure standards, and try (PIV) and data acquisition and recording.
Exposure controls. New and updated topics include mold, Legio- nella, indoor air chemistry, thermal impacts, and water quality This volume is published, both as a bound print volume and in standards. Electronic format on a CD-ROM, in two editions: one using inch-. Chapter 14, Climatic Design Information, has new climate data pound (I-P) units of measurement, the other using the International for 5564 stations (an increase of 1142 new stations compared to System of Units (SI). 2005 Fundamentals) on the CD-ROM accompanying this book. Corrections to the 2006, 2007, and 2008 Handbook volumes can A subset of data for selected stations is also included in the be found on the ASHRAE Web site at and in printed chapter for convenient access.
The Additions and Corrections section of this volume. Corrections. Chapter 15, Fenestration, has been revised to include new exam- for this volume will be listed in subsequent volumes and on the ples of solar heat gain coefficient (SHGC) calculations, and new ASHRAE Web site. Research results on shading calculations and U-factors for various Reader comments are enthusiastically invited. To suggest im- specialized door types. Provements for a chapter, please comment using the form on the.
Chapter 16, Ventilation and Infiltration, has new, detailed exam- ASHRAE Web site or, using the cutout page(s) at the end of this vol- ples, updates from ASHRAE Standards 62.1 and 62.2, discussion ume’s index, write to Handbook Editor, ASHRAE, 1791 Tullie Cir- of relevant LEED® aspects, and new information on airtightness cle, Atlanta, GA 30329, or fax 678-539-2187, or e-mail mowen@ and ventilation rates for commercial buildings. Ashrae.org. Chapter 18, Nonresidential Cooling and Heating Load Calcu- lations, has been updated to reflect new ASHRAE research results on climate data and on heat gains from office equipment, lighting, Mark S. Owen and commercial cooking appliances. Editor. The four-volume ASHRAE Handbook is a reference for engineers working in HVAC&R and for professionals in allied fields.
The print edition isrevised on a four-year cycle, with one volume published each year. Tables of contents for the four most recent volumes appear on these pages, and acomposite index is at the end of this volume. In addition to the CD-ROM accompanying this book, ASHRAE publishes a HandbookCD+ containingall four volumes plus supplemental material and features. The Society also produces educational materials, standards, design guides, databases, andmany other useful publications. See the online bookstore of the ASHRAE Web site (www.ashrae.org) for information on these publications.
2009 FUNDAMENTALSPRINCIPLES 21. Duct DesignChapter 1.
Psychrometrics 22. Pipe Sizing 2. Thermodynamics and Refrigeration Cycles 23. Insulation for Mechanical Systems 3.
Fluid Flow 24. Airflow Around Buildings 4. Heat Transfer 5. Two-Phase Flow BUILDING ENVELOPE 6. Mass Transfer Chapter 25. Heat, Air, and Moisture Control in Building 7. Fundamentals of Control Assemblies—Fundamentals 8.
Sound and Vibration 26. Heat, Air, and Moisture Control in Building Assemblies—Material PropertiesINDOOR ENVIRONMENTAL QUALITY 27. Heat, Air, and Moisture Control in BuildingChapter 9. Thermal Comfort Assemblies—Examples 10. Indoor Environmental Health 11. Air Contaminants MATERIALS 12. Odors Chapter 28.
Combustion and Fuels 13. Indoor Environmental Modeling 29.
Refrigerants 30. Thermophysical Properties of RefrigerantsLOAD AND ENERGY CALCULATIONS 31. Physical Properties of Secondary Coolants (Brines)Chapter 14. Climatic Design Information 32. Sorbents and Desiccants 15. Fenestration 33.
Physical Properties of Materials 16. Ventilation and Infiltration 17. Residential Cooling and Heating Load Calculations GENERAL 18.
Nonresidential Cooling and Heating Load Chapter 34. Energy Resources Calculations 35.
Sustainability 19. Energy Estimating and Modeling Methods 36. Measurement and Instruments 37. Abbreviations and SymbolsHVAC DESIGN 38. Units and ConversionsChapter 20. Space Air Diffusion 39. Codes and Standards 2008 HVAC SYSTEMS AND EQUIPMENTAIR-CONDITIONING AND HEATING SYSTEMS HEATING EQUIPMENT AND COMPONENTSChapter 1.
HVAC System Analysis and Selection Chapter 30. Automatic Fuel-Burning Systems 2. Decentralized Cooling and Heating 31. Central Heating and Cooling 32. Air Handling and Distribution 33. Residential In-Space Heating Equipment 5.
In-Room Terminal Systems 34. Chimney, Vent, and Fireplace Systems 6. Panel Heating and Cooling 35. Hydronic Heat-Distributing Units and Radiators 7. Combined Heat and Power Systems 8. Applied Heat Pump and Heat Recovery Systems 36.
Solar Energy Equipment 9. Small Forced-Air Heating and Cooling Systems COOLING EQUIPMENT AND COMPONENTS 10. Steam Systems 11. District Heating and Cooling Chapter 37. Compressors 12. Hydronic Heating and Cooling 38. Condensers 13.
Condenser Water Systems 39. Cooling Towers 14. Medium- and High-Temperature Water Heating 40. Evaporative Air-Cooling Equipment 15. Infrared Radiant Heating 41. Liquid Coolers 16. Ultraviolet Lamp Systems 42.
Liquid-Chilling Systems 17. Combustion Turbine Inlet Cooling GENERAL COMPONENTSAIR-HANDLING EQUIPMENT AND COMPONENTS Chapter 43. Centrifugal PumpsChapter 18. Duct Construction 44. Motors, Motor Controls, and Variable-Speed Drives 19. Room Air Distribution Equipment 45. Pipes, Tubes, and Fittings 20.
Humidifiers 47. Heat Exchangers 22. Air-Cooling and Dehumidifying Coils 23. Desiccant Dehumidification and Pressure-Drying PACKAGED, UNITARY, AND SPLIT-SYSTEM Equipment EQUIPMENT 24. Mechanical Dehumidifiers and Related Components 25. Air-to-Air Energy Recovery Equipment Chapter 48. Unitary Air Conditioners and Heat Pumps 26.
Air-Heating Coils 49. Room Air Conditioners and Packaged Terminal Air 27.
Unit Ventilators, Unit Heaters, and Makeup Air Conditioners Units 28. Air Cleaners for Particulate Contaminants GENERAL 29.
Industrial Gas Cleaning and Air Pollution Control Chapter 50. Thermal Storage Equipment 51. Codes and Standards. CD-ROM with all content from 2009 Fundamentals inside back cover 2007 HVAC APPLICATIONSCOMFORT APPLICATIONS ENERGY-RELATED APPLICATIONSChapter 1. Residences Chapter 32. Geothermal Energy 2.
Retail Facilities 33. Solar Energy Use 3.
Commercial and Public Buildings 34. Thermal Storage 4. Places of Assembly 5. Hotels, Motels, and Dormitories BUILDING OPERATIONS AND MANAGEMENT 6. Educational Facilities Chapter 35. Energy Use and Management 7. Health Care Facilities 36.
Owning and Operating Costs 8. Justice Facilities 37.
Testing, Adjusting, and Balancing 9. Automobiles and Mass Transit 38. Operation and Maintenance Management 10. Computer Applications 11.
Building Energy MonitoringINDUSTRIAL APPLICATIONS 41. Supervisory Control Strategies and Optimization 42. HVAC CommissioningChapter 12. Industrial Air Conditioning 13.
Enclosed Vehicular Facilities GENERAL APPLICATIONS 14. Laboratories 15. Engine Test Facilities Chapter 43. Building Envelopes 16. Clean Spaces 44.
Building Air Intake and Exhaust Design 17. Data Processing and Electronic Office Areas 45. Control of Gaseous Indoor Air Contaminants 18. Printing Plants 46. Design and Application of Controls 19. Textile Processing Plants 47. Sound and Vibration Control 20.
Photographic Material Facilities 48. Water Treatment 21. Museums, Galleries, Archives, and Libraries 49. Service Water Heating 22. Environmental Control for Animals and Plants 50. Snow Melting and Freeze Protection 23. Drying and Storing Selected Farm Crops 51.
Evaporative Cooling 24. Air Conditioning of Wood and Paper Product 52. Fire and Smoke Management Facilities 53. Radiant Heating and Cooling 25. Power Plants 54. Seismic and Wind Restraint Design 26. Nuclear Facilities 55.
Electrical Considerations 27. Mine Air Conditioning and Ventilation 56. Room Air Distribution 28.
Industrial Drying Systems 57. Integrated Building Design 29. Ventilation of the Industrial Environment 58. Chemical, Biological, Radiological, and Explosive 30.
Industrial Local Exhaust Systems Incidents 31. Kitchen Ventilation 59. Codes and Standards 2006 REFRIGERATIONREFRIGERATION SYSTEM PRACTICES 29. Chocolates, Candies, Nuts, Dried Fruits, and DriedChapter 1. Liquid Overfeed Systems Vegetables 2 System Practices for Halocarbon Refrigerants DISTRIBUTION OF CHILLED AND FROZEN FOOD 3. System Practices for Ammonia and Carbon Dioxide Refrigerants Chapter 30.
Cargo Containers, Rail Cars, Trailers, and Trucks 4. Secondary Coolants in Refrigeration Systems 31.
Marine Refrigeration 5. Refrigerant System Chemistry 32. Air Transport 6. Control of Moisture and Other Contaminants in Refrigerant Systems INDUSTRIAL APPLICATIONS 7. Lubricants in Refrigerant Systems Chapter 33.
Insulation Systems for Refrigerant Piping 8. Refrigerant Containment, Recovery, Recycling, and 34. Ice Manufacture Reclamation 35. Ice Rinks 36. Concrete Dams and Subsurface SoilsFOOD STORAGE AND EQUIPMENT 37. Refrigeration in the Chemical IndustryChapter 9.
Thermal Properties of Foods 10. Cooling and Freezing Times of Foods LOW-TEMPERATURE APPLICATIONS 11. Commodity Storage Requirements Chapter 38.
Cryogenics 12. Food Microbiology and Refrigeration 39. Ultralow-Temperature Refrigeration 13.
Refrigeration Load 40. Biomedical Applications of Cryogenic Refrigeration 14. Refrigerated-Facility Design 15. Methods of Precooling Fruits, Vegetables, and REFRIGERATION EQUIPMENT Cut Flowers Chapter 41. Absorption Cooling, Heating, and RefrigerationFOOD REFRIGERATION Equipment 42.
Forced-Circulation Air CoolersChapter 16. Industrial Food-Freezing Systems 43. Component Balancing in Refrigeration Systems 17. Meat Products 18. Poultry Products 44.
Refrigerant-Control Devices 19. Fishery Products 45. Factory Dehydrating, Charging, and Testing 20. Dairy Products UNITARY REFRIGERATION EQUIPMENT 21. Eggs and Egg Products 22. Deciduous Tree and Vine Fruit Chapter 46. Retail Food Store Refrigeration and Equipment 23.
Citrus Fruit, Bananas, and Subtropical Fruit 47. Food Service and General Commercial 24. Vegetables Refrigeration Equipment 25.
Fruit Juice Concentrates and Chilled-Juice Products 48. Household Refrigerators and Freezers 26. Beverages 27. Processed, Precooked, and Prepared Foods GENERAL 28.
Bakery Products 49. Codes and Standards.
LICENSE AGREEMENT 2009 ASHRAE Handbook—Fundamentals CD-ROM The 2009 ASHRAE Handbook—Fundamentals is distributed with an accompanying CD-ROM, which provides electronic access to the volume’s content. The License for this CD-ROM is for personal use only; this CD-ROM may not be used on aLAN or WAN. Using the CD-ROM indicates your acceptance of the terms and conditions of this agree-ment. If you do not agree with them, you should not use this CD-ROM. The title and all copyrights and ownership rights in the program and data are retained byASHRAE.
You assume responsibility for the selection of the program and data to achieve yourintended results and for the installation, use, and results obtained from the program and data. You may use the program and data on a single machine. You may copy the program anddata into any machine-readable form for back-up purposes in support of your use of the programor data on a single machine. You may not copy or transfer the program or data except asexpressly provided for in this license.
To do so will result in the automatic termination of yourlicense, and ASHRAE will consider options available to it to recover damages from unauthor-ized use of its intellectual property. Specifically, you may not copy nor transfer the program or data onto a machine other thanyour own unless the person to whom you are copying or transferring the program or data also hasa license to use them. Distribution to third parties of ASHRAE intellectual property in print or electronic formfrom this CD-ROM is also prohibited except when authorized by ASHRAE.
If you wish to reprint data from this CD-ROM in print or electronic form (such as postingcontent on a Web site), visit www.ashrae.org/permissions and go to Handbook Reprint Permis-sions. CONTENTSContributors viiASHRAE Technical Committees, Task Groups, and Technical Resource Groups ixASHRAE Research: Improving the Quality of Life xPreface xPRINCIPLESChapter 1. Psychrometrics (TC 1.1, Thermodynamics and Psychrometrics, TC 8.3, Absorption and Heat- Operated Machines) 1.1 2. Thermodynamics and Refrigeration Cycles (TC 1.1) 2.1 3.
Fluid Flow (TC 1.3, Heat Transfer and Fluid Flow) 3.1 4. Heat Transfer (TC 1.3) 4.1 5. Two-Phase Flow (TC 1.3) 5.1 6.
2009 Ashrae Fundamentals Handbook Pdf
Mass Transfer (TC 1.3) 6.1 7. Fundamentals of Control (TC 1.4, Control Theory and Application) 7.1 8. Sound and Vibration (TC 2.6, Sound and Vibration Control) 8.1INDOOR ENVIRONMENTAL QUALITYChapter 9. Thermal Comfort (TC 2.1, Physiology and Human Environment) 9.1 10.
Indoor Environmental Health (Environmental Health Committee) 10.1 11. Air Contaminants (TC 2.3, Gaseous Air Contaminants and Gas Contaminant Removal Equipment) 11.1 12.
Odors (TC 2.3) 12.1 13. Indoor Environmental Modeling (TC 4.10, Indoor Environmental Modeling) 13.1LOAD AND ENERGY CALCULATIONSChapter 14. Climatic Design Information (TC 4.2, Climatic Information) 14.1 15. Fenestration (TC 4.5, Fenestration) 15.1 16.
Ventilation and Infiltration (TC 4.3, Ventilation Requirements and Infiltration ) 16.1 17. Residential Cooling and Heating Load Calculations (TC 4.1, Load Calculation Data and Procedures) 17.1 18. Nonresidential Cooling and Heating Load Calculations (TC 4.1) 18.1 19. Energy Estimating and Modeling Methods (TC 4.7, Energy Calculations) 19.1HVAC DESIGNChapter 20. Space Air Diffusion (TC 5.3, Room Air Distribution) 20.1 21.
Duct Design (TC 5.2, Duct Design) 21.1. 22. Pipe Sizing (TC 6.1, Hydronic and Steam Equipment and Systems) 22.1 23. Insulation for Mechanical Systems (TC 1.8, Mechanical Systems Insulation) 23.1 24. Airflow Around Buildings (TC 4.3) 24.1BUILDING ENVELOPEChapter 25. Heat, Air, and Moisture Control in Building Assemblies—Fundamentals (TC 4.4, Building Materials and Building Envelope Performance) 25.1 26. Heat, Air, and Moisture Control in Building Assemblies—Material Properties (TC 4.4) 26.1 27.
Heat, Air, and Moisture Control in Insulated Assemblies—Examples (TC 4.4) 27.1MATERIALSChapter 28. Combustion and Fuels (TC 6.10, Fuels and Combustion) 28.1 29.
Refrigerants (TC 3.1, Refrigerants and Secondary Coolants) 29.1 30. Thermophysical Properties of Refrigerants (TC 3.1) 30.1 31. Physical Properties of Secondary Coolants (Brines) (TC 3.1) 31.1 32. Sorbents and Desiccants (TC 8.12, Dessicant Dehumidification Equipment and Components) 32.1 33. Physical Properties of Materials (TC 1.3) 33.1GENERALChapter 34.
Ashrae Fundamentals 2009 Download
Energy Resources (TC 2.8, Building Environmental Impacts and Sustainability) 34.1 35. Sustainability (TC 2.8) 35.1 36. Measurement and Instruments (TC 1.2, Instruments and Measurements) 36.1 37. Abbreviations and Symbols (TC 1.6, Terminology) 37.1 38. Units and Conversions (TC 1.6) 38.1 39. Codes and Standards 39.1INDEX I.1 Composite index to the 2006 Refrigeration, 2007 HVAC Applications, 2008 HVAC Systems and Equipment, and 2009 Fundamentals volumes. CHAPTER 1 PSYCHROMETRICSComposition of Dry and Moist Air.
1.1 Thermodynamic Wet-Bulb and Dew-Point Temperature. Standard Atmosphere. 1.1 Numerical Calculation of Moist Air Properties. 1.13Thermodynamic Properties of Moist Air.
1.2 Psychrometric Charts. 1.14Thermodynamic Properties of Water at Saturation. 1.2Humidity Parameters. 1.2 Typical Air-Conditioning Processes. 1.15Perfect Gas Relationships for Dry and Transport Properties of Moist Air.
1.19 Moist Air. 1.12 Symbols. 1.19P SYCHROMETRICS uses thermodynamic properties to ana- lyze conditions and processes involving moist air. This chapterdiscusses perfect gas relations and their use in common heating, flat interface surface between moist air and the condensed phase. Saturation conditions change when the interface radius is very small (e.g., with ultrafine water droplets). The relative molecular mass ofcooling, and humidity control problems. Formulas developed by water is 18.015268 on the carbon-12 scale.
The gas constant forHerrmann et al. (2009) may be used where greater precision is water vapor isrequired. Hyland and Wexler (1983a, 1983b), Nelson and Sauer (2002), Rw = 1545.368 = 85.780 ftlbf /lbw °R (2)and Herrmann et al. (2009) developed formulas for thermodynamicproperties of moist air and water modeled as real gases.
However,perfect gas relations can be substituted in most air-conditioning U.S. STANDARD ATMOSPHEREproblems.
(1998) showed that errors are less than 0.7%in calculating humidity ratio, enthalpy, and specific volume of sat- The temperature and barometric pressure of atmospheric air varyurated air at standard atmospheric pressure for a temperature range considerably with altitude as well as with local geographic andof 60 to 120°F. Furthermore, these errors decrease with decreasing weather conditions.
The standard atmosphere gives a standard ofpressure. Reference for estimating properties at various altitudes. At sea level, standard temperature is 59°F; standard barometric pressure is COMPOSITION OF DRY AND MOIST AIR 14.696 psia or 29.921 in. Temperature is assumed to decrease linearly with increasing altitude throughout the troposphere (lower Atmospheric air contains many gaseous components as well as atmosphere), and to be constant in the lower reaches of the strato-water vapor and miscellaneous contaminants (e.g., smoke, pollen,and gaseous pollutants not normally present in free air far from pol- sphere. The lower atmosphere is assumed to consist of dry air thatlution sources). Behaves as a perfect gas. Gravity is also assumed constant at the Dry air is atmospheric air with all water vapor and contaminants standard value, 32.1740 ft/s2.
Table 1 summarizes property data forremoved. Its composition is relatively constant, but small variations altitudes to 30,000 ft.in the amounts of individual components occur with time, geo- Pressure values in Table 1 may be calculated fromgraphic location, and altitude.
Harrison (1965) lists the approximatepercentage composition of dry air by volume as: nitrogen, 78.084; p = 14.696(1 – 6.8754 10 –6Z) 5.2559 (3)oxygen, 20.9476; argon, 0.934; neon, 0.001818; helium, 0.000524;methane, 0.00015; sulfur dioxide, 0 to 0.0001; hydrogen, 0.00005; The equation for temperature as a function of altitude isand minor components such as krypton, xenon, and ozone, 0.0002.Harrison (1965) and Hyland and Wexler (1983a) used a value Table 1 Standard Atmospheric Data for Altitudes to 30,000 ft0.0314 (circa 1955) for carbon dioxide. Carbon dioxide reached0.0379 in 2005, is currently increasing by 0.00019 percent per year Altitude, ft Temperature, °F Pressure, psiaand is projected to reach 0.0438 in 2036 (Gatley et al. 2008; Keeling –1000 62.6 15.236and Whorf 2005a, 2005b). Increases in carbon dioxide are offset by –500 60.8 14.966decreases in oxygen; consequently, the oxygen percentage in 2036 0 59.0 14.696is projected to be 20.9352. Using the projected changes, the relative 500 57.2 14.430molecular mass for dry air for at least the first half of the 21st cen- 1,000 55.4 14.175tury is 28.966, based on the carbon-12 scale. The gas constant for 2,000 51.9 13.664dry air using the current Mohr and Taylor (2005) value for the uni- 3,000 48.3 13.173versal gas constant is 4,000 44.7 12.682 Rda = 1545.349/28.966 = 53.350 ftlbf /lbda °R (1) 5,000 41.2 12.230 6,000 37.6 11.778 Moist air is a binary (two-component) mixture of dry air and 7,000 34.0 11.341water vapor.
The amount of water vapor varies from zero (dry air) to 8,000 30.5 10.914a maximum that depends on temperature and pressure. Saturation 9,000 26.9 10.506is a state of neutral equilibrium between moist air and the condensed 10,000 23.4 10.108water phase (liquid or solid); unless otherwise stated, it assumes a 15,000 5.5 8.296 20,000 –12.3 6.758The preparation of this chapter is assigned to TC 1.1, Thermodynamics and 30,000 –47.8 4.371Psychrometrics. Source: Adapted from NASA (1976).
1.1. 1.2 2009 ASHRAE Handbook—Fundamentals t = 59 – 0.00356620Z (4) ln pws = C1/T + C2 + C3T + C4T 2 + C5T 3 + C6T 4 + C7 ln T (5)where where Z = altitude, ft C1 = 1.021 416 5 E+04 p = barometric pressure, psia C2 = 4.893 242 8 E+00 t = temperature, °F C3 = 5.376 579 4 E 03 Equations (3) and (4) are accurate from 16,500 ft to 36,000 ft. C4 = 1.920 237 7 E 07For higher altitudes, comprehensive tables of barometric pressure C5 = 3.557 583 2 E 10 C6 = 9.034 468 8 E 14and other physical properties of the standard atmosphere, in both SI C7 = 4.163 501 9 E 00and I-P units, can be found in NASA (1976). The saturation pressure over liquid water for the temperature rangeTHERMODYNAMIC PROPERTIES OF MOIST AIR of 32 to 392°F is given by Table 2, developed from formulas by Herrmann et al. (2009), lnpws = C8/T + C9 + C10T + C11T 2 + C12T 3 + C13 ln T (6)shows values of thermodynamic properties of moist air based on theInternational Temperature Scale of 1990 (ITS-90).
This ideal scale wherediffers slightly from practical temperature scales used for physical C8 = 1.044 039 7 E+04measurements. For example, the standard boiling point for water (at C9 = 1.129 465 0 E+0114.696 psia) occurs at 211.95°F on this scale rather than at the tra- C10 = 2.702 235 5 E 02ditional 212°F. Most measurements are currently based on the C11 = 1.289 036 0 E 05International Temperature Scale of 1990 (ITS-90) (Preston-Thomas C12 = 2.478 068 1 E 091990).
C13 = 6.545 967 3 E+00 The following properties are shown in Table 2: In both Equations (5) and (6), t = Fahrenheit temperature, based on the International Temperature pws = saturation pressure, psia Scale of 1990 (ITS-90) and expressed relative to absolute T = absolute temperature, °R = °F + 459.67 temperature T in degrees Rankine (°R) by the following relation: The coefficients of Equations (5) and (6) were derived from the T = t + 459.67 Hyland-Wexler equations, which are given in SI units. Because of Ws = humidity ratio at saturation; gaseous phase (moist air) exists in rounding errors in the derivations and in some computers’ calculat- equilibrium with condensed phase (liquid or solid) at given ing precision, results from Equations (5) and (6) may not agree pre- temperature and pressure (standard atmospheric pressure).
At cisely with Table 3 values. Given values of temperature and pressure, humidity ratio W can The vapor pressure ps of water in saturated moist air differs neg- have any value from zero to Ws. Ligibly from the saturation vapor pressure pws of pure water at the vda = specific volume of dry air, ft3/lbda. Same temperature. Consequently, ps can be used in equations in vas = vs vda, difference between specific volume of moist air at place of pws with very little error: saturation and that of dry air, ft3/lbda, at same pressure and temperature.
Ps = xws p vs = specific volume of moist air at saturation, ft3/lbda. Hda = specific enthalpy of dry air, Btu/lbda. In Table 2, hda has been where xws is the mole fraction of water vapor in saturated moist air assigned a value of 0 at 0°F and standard atmospheric pressure. At temperature t and pressure p, and p is the total barometric pressure has = hs hda, difference between specific enthalpy of moist air at of moist air. Saturation and that of dry air, Btu/lbda, at same pressure and temperature. Hs = specific enthalpy of moist air at saturation, Btu/lbda.
HUMIDITY PARAMETERS sda = specific entropy of dry air, Btu/lbda °R. In Table 2, sda is assigned a value of 0 at °F and standard atmospheric pressure. Basic Parameters ss = specific entropy of moist air at saturation Btu/lbda °R.
Ashrae 90.1 2009
Humidity ratio W (alternatively, the moisture content or mixing ratio) of a given moist air sample is defined as the ratio of the mass THERMODYNAMIC PROPERTIES OF of water vapor to the mass of dry air in the sample: WATER AT SATURATION W = Mw /Mda (7) Table 3 shows thermodynamic properties of water at saturationfor temperatures from 80 to 300°F, calculated by the formulations W equals the mole fraction ratio xw /xda multiplied by the ratio ofdescribed by IAPWS (2007). Symbols in the table follow standard molecular masses (18.015268/28.966 = 0.621945):steam table nomenclature. These properties are based on the Inter-national Temperature Scale of 1990 (ITS-90). The internal energy W = 0.621945xw /xda (8)and entropy of saturated liquid water are both assigned the valuezero at the triple point, 32.018°F. Between the triple-point and crit- Specific humidity is the ratio of the mass of water vapor toical-point temperatures of water, two states (saturated liquid and total mass of the moist air sample:saturated vapor) may coexist in equilibrium.
= Mw /(Mw + Mda) (9a) The water vapor saturation pressure is required to determinea number of moist air properties, principally the saturation humid- In terms of the humidity ratio,ity ratio. Soldier of fortune payback torrent iso. Values may be obtained from Table 3 or calculated fromthe following formulas (Hyland and Wexler 1983b).
The 1983 for- = W/(1 + W) (9b)mulas are within 300 ppm of the latest IAPWS formulations. Forhigher accuracy, developers of software and others are referred to Absolute humidity (alternatively, water vapor density) dv is theIAPWS (2007) and (2008).