The Dehumidification Handbook

1 The Dehumidification Handbook Third edition ISBN 0-9717887-0-7 Copyright 1989, 2002 and 2019 Munters CorporationThe Dehumidification HandbookThird EditionCopyright 1989, 2002 and 2019 Munters CorporationReuse Of This MaterialFor book reviews and personal educational and professional use, readers are encouraged to excerpt or photocopy and distribute any useful portion of this Handbook , provided that the source of the material is appropriately referenced and the Munters copyright is acknowledged. For electronic distribution or if the material will be included in any printed publication, Munters Corporation must provide written authorization in advance of publication. For those uses, please contact Munters Corporation Marketing Department by mail at 79 Monroe Street, Amesbury, MA 01913, or by email at great care has been taken in the compilation and publication of this book, no warranties either expressed or implied are given in connection with the material.

2 Neither the contributors nor the publisher take any responsibility whatsoever for any claims arising from its use. The entire risk of the use of this information is assumed by the user. However, to improve future editions, the publisher welcomes any and all comments, corrections or suggestions from would like to express our gratitude to Lew G. Harriman III as editor of the first two editions of this book and for guiding this work with interest. Also, we would like to thank the following original contributors and 1989 Editorial Advisory Board members for their work; Enno Abel, Nick Baranov, Bruce Bonner, Steven Brickley, Luiz Felipe de Carvalho, Douglas Kosar, Hansi Kruger, Ralph Lahmon, Milton Meckler, Mohamed Moledina, Terry Penny, Ing. Eugenio E. Sanchez, Daniel Schroeder, James Staunton, Steven Toth, Kenneth Welter, Sumner Weisman, Roland Wimmerstedt, and Jose addition, we d like to acknowledge and give special thanks to Steve Brickley, Jim Judge and Lindsay Judge for their content work and contributions to this (Third) edition of the book.

3 We also extend special thanks to Doug Des Champs for the cover design and book layout of this (Third) edition and Inc. for the printing and CorporationTABLE OF CONTENTS1. 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 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.

4 40 Choosing between desiccant and cooling 444. APPLICATIONS .. 46 Corrosion Prevention .. 48 Military storage .. 49 Electronics protection .. 49 Power plant 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.

5 58 Supermarkets .. 59 Hotels and motels .. 59 Sick buildings .. 59 Advanced HVAC systems .. 595. MOISTURE LOAD 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.

6 1037. SYSTEM DESIGN .. 106 Passive storage - Museum Example .. 109 Step One Define the purpose of the project .. 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 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.

7 167 System 4 - Eliminate all pre-cooling and remove all moisture with desiccants .. 168 Comparing 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 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.

8 189 Resistance moisture sensors .. 191 Microwave absorption .. 192 Radio frequency (capacitance) sensors .. 192 General Observations .. 194 Sensor placement .. 194 Measuring moisture below 10% relative humidity .. 194 Environmental 19510. MINIMIZING COSTS & MAXIMIZING BENEFITS .. 196 Identifying & Quantifying Economic Benefits .. 198 Operational cost reduction .. 198 Reducing cost of capital 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.

9 225 HoneyCombe Dehumidifier Performance Curves .. 226 Photo Credits .. 227 Moisture Load Calculation Sheets .. 228 Psychrometric Chart .. Fold-out Sheet1 INTRODUCTION1 INTRODUCTION2 PSYCHROMETRICS3 METHODS OF DEHUMIDIFICATION4 APPLICATIONS5 MOISTURE LOAD CALCULATIONS6 DESICCANT DEHUMIDIFIER PERFORMANCE7 SYSTEM DESIGN8 OPTIMIZING MIXED SYSTEMS9 HUMIDITY AND MOISTURE INSTRUMENTATION10 MINIMIZING COST & MAXIMIZING BENEFITSAAPPENDIX11 INTRODUCTION This Handbook explains how and why to dehumidify air. It is written for the engineer who has a basic understanding of building heating and cooling systems, or who operates a building or process which is influenced by atmospheric humidity. The text assumes the reader is interested in the technology, and has a need to apply it to gain some economic benefit.

10 The text also assumes the reader is interested in specific examples as well as the theory of dehumidification. These assumptions guide the necessary compromises any book must make between accuracy and clarity, and between details which illustrate a specific case and those which illustrate general, abstract of the information collected here comes from other technical references which deal incidentally with dehumidification in discussions of related topics. The American Society of Heating, Air Conditioning and Refrigerating Engineers (ASHRAE) has provided helpful information through its Handbook series. In addition, many industries have provided data which can assist the dehumidification engineer working in other primary information source is the collected experience of hundreds of engineers who deal with dehumidification and humidity control on a daily basis.