The Dehumidification HandbookSecond EditionISBN 0-9717887-0-7Copyright 1989 and 2002 Munters CorporationLewis G. Harriman IIIEditorMUNTERS CORPORATIONDEHUMIDIFICATION DIVISION79 MONROE STREETAMESBURY, MA 01913-0640USATEL (978) 241-1100FAX (978) com

The Dehumidification HandbookSecond 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. This recompositionof the second edition was accomplished in 2002 and includes new typography and approximately 10% revised material.Reuse Of This MaterialFor book reviews and personal educational and professional use, readers 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 acknowledged.For electronic distribution or if the material will be included in anyprinted publication, Munters Corporation must provide written authorization in advance of publication. For those uses, contact Munters Corporation Corporate Communications Department by mail at 79 MonroeSt., Amesbury, MA 01913 USA or by fax at (978) 241-1215 or by emailat [email protected] great care has been taken in the compilation and publicationof this book, no warranties either expressed or implied are given inconnection with the material. 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. However, to improve future editions, the publisher welcomes any and allcomments, corrections or suggestions from readers.

Lewis G. Harriman III EDITORMohamed Moledina1989 EDITORIAL ADVISORY BOARDSenior Process EngineerAtomic Energy Commission of CanadaMississauga, ONT CanadaEnno AbelTerry PennyProfessor of Mechanical EngineeringChalmers University of TechnologyGoteborg, SwedenManager, Building Research BranchUS DOE National Renewable Energy LaboratoryGolden, Colorado USANick BaranovIng. Eugenio E. SanchezTechnical Executive, Mechanical EngineeringGlaxo Ltd.Stevenage, United KingdomEngineering ManagerMidas ConsultoresCaracas, VenezuelaBruce BonnerDaniel SchroederPresidentBonner SystemsChelmsford, MA USANaval Aviation Protection ProgramUS Navy Aviation DepotSan Diego, CA USASteven BrickleyJames StauntonDirector of R&DMunters Dehumidification DivisionAmesbury, MA USAMachine Process EngineeringEastman KodakRochester, NY USALuiz Felipe de CarvalhoSteven TothProfessor Emeritus of Thermal TechnologyUniversity of Rio de JaneiroRio de janeiro, BrasilChief Mechanical EngineerMiles PharmaceuticalsElkhart, IN USADouglas KosarKenneth WelterSenior Project Manager, Desiccant TechnologyGas Technology InstituteChicago, IL USAChief Mechanical EngineerStop & Shop SupermarketsBoston, MA USAHansi KrügerSumner WeismanGeneral ManagerMunters MexicoDirector of Application EngineeringGeneral Eastern InstrumentsWoburn, MA USARalph LahmonArchitecture & Engineering ServicesEastman KodakRochester, NY USARoland WimmerstedtProfessor of Chemical EngineeringLund UniversityLund, SwedenMilton MecklerPresidentThe Meckler GroupVentura, CA USAJosé ZuluetaMechanical Engineering Project ManagerPfizer PharmaceuticalsNew York, NY USA

TABLE OF CONTENTS1. INTRODUCTION . 102. PSYCHROMETRICS . 12Dry Bulb Temperature Degrees Fahrenheit . 15Relative humidity - Percent of saturation . 15Humidity Ratio - Grains of water vapor . 16Vapor pressure - Inches of mercury . 17Dew point temperature - Degrees Fahrenheit . 18Enthalpy - Btu’s per pound of air . 18Wet-bulb temperature - Degrees Fahrenheit . 193. METHODS OF DEHUMIDIFICATION . 22Cooling-based Dehumidification . 24Desiccant Dehumidifiers .29Liquid spray-tower . 32Solid packed tower . 34Rotating horizontal bed . 36Multiple vertical bed . 38Rotating Honeycombe . 39Comparing desiccant dehumidifiers . 40Choosing between desiccant and cooling dehumidifiers . 444. APPLICATIONS . 46Corrosion Prevention .48Military storage . 49Electronics protection . 49Power plant layup . 49Lithium battery production . 49Condensation Prevention .50Ice rinks . 51Water treatment plants . 51Surface preparation & coating . 51Injection molding . 51

4. APPLICATIONS (CONTINUED). 46Mold/Fungus Prevention .52Archival storage . 53Seed storage . 53Cargo protection . 53Breweries . 53Moisture Regain Prevention .54Candy packaging . 55Semiconductor and pharmaceutical clean rooms . 55Safety glass laminating . 55Composite manufacturing . 55Product Drying .56Investment castings . 57Plastic resin drying . 57Candy coating . 57Fish drying . 57Dry Cooling .58Supermarkets . 59Hotels and motels . 59Sick buildings . 59Advanced HVAC systems . 595. MOISTURE LOAD CALCULATIONS . 60Selecting Design Conditions .62Moisture Load Sources .64Periodic vs. continuous loads . 78Fresh air moisture load . 78Sample moisture load calculations .81Warehouse dehumidification . 82Glass lamination room . 86

6. DESICCANT DEHUMIDIFIER PERFORMANCE . 92Operating 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 . 106Passive storage - Museum Example . 109Step One — Define the purpose of the project . 109Step Two — Establishing control levels and tolerances . 110Step Three — Calculate heat and moisture loads . 110Step Four — Size the components to remove the loads . 111Step Five — Select the control system . 112Passive Storage - Military Example .114Active Storage - Refrigerated Warehouse Example . 119Commercial HVAC - Supermarket Example .129Industrial HVAC - Pharmaceutical Tableting . 139Product Drying - Candy Coating Example . 1508. OPTIMIZING MIXED SYSTEMS . 162Example Case Description . 164System 1 – Dry the make-up air only . 164System 2 – Pre-cool the make-up air and dry the blend with a desiccant unit . 166System 3 – Pre-cool the blended air before it enters the desiccant unit . 167System 4 - Eliminate all pre-cooling and remove all moisture with desiccants . 168Comparing Alternatives .170

9. HUMIDITY & MOISTURE INSTRUMENTATION . 174Duty Cycle & Operating Environment .177Instrument Functions .