The Dehumidification Handbook - Carl Munters

1 The Dehumidification Handbook Second Edition ISBN 0-9717887-0-7 Copyright 1989 and 2002 Munters CorporationMUNTERS CORPORATIONDEHUMIDIFICATION DIVISION79 MONROE STREETAMESBURY, MA 01913-0640 USATEL (978) 241-1100 FAX (978) G. Harriman IIIE ditorThe Dehumidification Handbook Second EditionCopyright 1989 and 2002 - Munters CorporationEditions Of The Dehumidification HandbookThe first edition of The Dehumidification Handbook was published in1982 by Cargocaire Engineering Corporation, an earlier name for whatis now the Dehumidification Division of Munters Corporation. That firstedition was reprinted seven times between 1982 and 1989. The secondedition was a totally new and greatly expanded book, written in 1989and reprinted three times between 1989 and 2002.

2 This recompositionof the second edition was accomplished in 2002 and includes new ty-pography and approximately 10% revised Of This MaterialFor book reviews and personal educational and professional use, read-ers are encouraged to excerpt or photocopy and distribute any usefulportion of this Handbook , provided that the source of the material isappropriately referenced and the Munters copyright is electronic distribution or if the material will be included in anyprinted publication, Munters Corporation must provide written authori-zation in advance of publication. For those uses, contact Munters Cor-poration Corporate Communications Department by mail at 79 MonroeSt., Amesbury, MA 01913 USA or by fax at (978) 241-1215 or by emailat great care has been taken in the compilation and publicationof this book, no warranties either expressed or implied are given inconnection with the material.

3 Neither the editors nor the publisher takeany responsibility whatsoever for any claims arising from its use. Theentire risk of the use of this information is assumed by the user. How-ever, to improve future editions, the publisher welcomes any and allcomments, corrections or suggestions from G. Harriman III EDITOR1989 EDITORIAL ADVISORY BOARDEnno AbelProfessor of Mechanical EngineeringChalmers University of TechnologyGoteborg, SwedenNick BaranovTechnical Executive, Mechanical EngineeringGlaxo , United KingdomBruce BonnerPresidentBonner SystemsChelmsford, MA USAS teven BrickleyDirector of R&DMunters Dehumidification DivisionAmesbury, MA USALuiz Felipe de CarvalhoProfessor Emeritus of Thermal TechnologyUniversity of Rio de JaneiroRio de janeiro, BrasilDouglas KosarSenior Project Manager, Desiccant TechnologyGas Technology InstituteChicago, IL USAH ansi Kr gerGeneral ManagerMunters MexicoRalph LahmonArchitecture & Engineering ServicesEastman KodakRochester, NY USAM ilton MecklerPresidentThe Meckler GroupVentura.

4 CA USAM ohamed MoledinaSenior Process EngineerAtomic Energy Commission of CanadaMississauga, ONT CanadaTerry PennyManager, Building Research BranchUS DOE National Renewable Energy LaboratoryGolden, Colorado USAIng. Eugenio E. SanchezEngineering ManagerMidas ConsultoresCaracas, VenezuelaDaniel SchroederNaval Aviation Protection ProgramUS Navy Aviation DepotSan Diego, CA USAJ ames StauntonMachine Process EngineeringEastman KodakRochester, NY USAS teven TothChief Mechanical EngineerMiles PharmaceuticalsElkhart, IN USAK enneth WelterChief Mechanical EngineerStop & Shop SupermarketsBoston, MA USAS umner WeismanDirector of Application EngineeringGeneral Eastern InstrumentsWoburn, MA USAR oland WimmerstedtProfessor of Chemical EngineeringLund UniversityLund, SwedenJos ZuluetaMechanical Engineering Project ManagerPfizer PharmaceuticalsNew York, NY USATABLE OF CONTENTS1.

5 INTRODUCTION .. 102. PSYCHROMETRICS .. 12 Dry Bulb Temperature Degrees Fahrenheit .. 15 Relative humidity - Percent of saturation .. 15 Humidity Ratio - Grains of water vapor .. 16 Vapor pressure - Inches of mercury .. 17 Dew point temperature - Degrees Fahrenheit .. 18 Enthalpy - Btu s per pound of air .. 18 Wet-bulb temperature - Degrees Fahrenheit .. 193. METHODS OF Dehumidification .. 22 cooling -based Dehumidification .. 24 Desiccant Dehumidifiers .. 29 Liquid spray-tower .. 32 Solid packed tower .. 34 Rotating horizontal bed .. 36 Multiple vertical bed .. 38 Rotating Honeycombe .. 39 Comparing desiccant dehumidifiers .. 40 Choosing between desiccant and cooling dehumidifiers .. 444. APPLICATIONS .. 46 Corrosion Prevention .. 48 Military storage.

6 49 Electronics protection .. 49 Power plant layup .. 49 Lithium battery production .. 49 Condensation Prevention .. 50 Ice rinks .. 51 Water treatment plants .. 51 Surface preparation & coating .. 51 Injection molding .. 514. APPLICATIONS (CONTINUED) ..46 Mold/Fungus Prevention .. 52 Archival storage ..53 Seed storage .. 53 Cargo protection .. 53 Breweries .. 53 Moisture Regain Prevention .. 54 Candy packaging .. 55 Semiconductor and pharmaceutical clean rooms .. 55 Safety glass laminating .. 55 Composite manufacturing .. 55 Product Drying .. 56 Investment castings .. 57 Plastic resin drying ..57 Candy coating ..57 Fish drying .. 57 Dry cooling .. 58 Supermarkets ..59 Hotels and motels .. 59 Sick buildings .. 59 Advanced HVAC systems .. 595. MOISTURE LOAD CALCULATIONS.

7 60 Selecting design Conditions .. 62 Moisture Load Sources .. 64 Periodic vs. continuous loads .. 78 Fresh air moisture load .. 78 Sample moisture load calculations .. 81 Warehouse Dehumidification .. 82 Glass lamination room .. 866. DESICCANT DEHUMIDIFIER PERFORMANCE .. 92 Operating Variables .. 941. Process inlet moisture .. 962. Process inlet temperature .. 963. Air velocity through the process side .. 974. Air temperature entering reactivation .. 985. Moisture of air entering reactivation .. 996. Velocity of air through reactivation .. 1007. Amount of desiccant presented to the airstream .. 1028. Desiccant sorption and desorption characteristics .. 1037. SYSTEM design .. 106 Passive storage - Museum Example .. 109 Step One Define the purpose of the project.

8 109 Step Two Establishing control levels and tolerances .. 110 Step Three Calculate heat and moisture loads .. 110 Step Four Size the components to remove the loads .. 111 Step Five Select the control system .. 112 Passive Storage - Military Example .. 114 Active Storage - Refrigerated Warehouse Example .. 119 Commercial HVAC - Supermarket Example .. 129 Industrial HVAC - Pharmaceutical Tableting .. 139 Product Drying - Candy Coating Example .. 1508. OPTIMIZING MIXED SYSTEMS .. 162 Example Case Description .. 164 System 1 Dry the make-up air only .. 164 System 2 Pre-cool the make-up air and dry the blend with a desiccant unit .. 166 System 3 Pre-cool the blended air before it enters the desiccant unit .. 167 System 4 - Eliminate all pre- cooling and remove all moisture with desiccants.

9 168 Comparing Alternatives .. 1709. HUMIDITY & MOISTURE INSTRUMENTATION .. 174 Duty Cycle & Operating Environment .. 177 Instrument Functions .. 178 Repeatability vs. Accuracy .. 180 Relative Humidity Sensors .. 180 Mechanical expansion hygrometer .. 180 Electronic expansion hygrometer .. 181 Electronic capacitance sensor .. 182 Electronic resistive sensor .. 182 Psychrometric instruments .. 183 Absolute Humidity Sensors .. 185 Gravimetric train .. 185 Condensation hygrometers .. 185 Aluminum oxide sensors .. 186 Salt equilibrium sensors .. 187 Electrolytic hygrometers .. 188 Material Moisture Content Sensors .. 188 Coulombic Karl Fischer titration .. 188 Infrared absorption .. 189 Equilibrium moisture detectors .. 189 Resistance moisture sensors .. 191 Microwave absorption.

10 192 Radio frequency (capacitance) sensors .. 192 General Observations .. 194 Sensor placement .. 194 Measuring moisture below 10% relative humidity .. 194 Environmental chambers .. 19510. MINIMIZING COSTS & MAXIMIZING BENEFITS .. 196 Identifying & Quantifying Economic Benefits .. 198 Operational cost reduction .. 198 Reducing cost of capital investments .. 201 Improved profits through improved quality .. 203 Improving operational responsiveness .. 204 Minimizing costs .. 205 Minimizing first cost .. 205 Minimizing operating cost .. 208 Summary .. 213 Worksheets .. 215 APPENDIX .. 216 Weather design Data .. 217 Filter Selection Guide .. 221 Steam Data .. 222 Conversion Factors .. 223 Dew Points at Altitudes and High Pressure .. 225 HoneyCombe Dehumidifier Performance Curves.