Dew Water (River Publishers Series in Chemical, Environmental, and Energy Engineering)

The world's ever-increasing need for fresh water has led to the use of non-conventional sources such as rain and fog water collection. Although rain water collection is relatively simple, the supply is often erratic. Passive fog water collection has been used in several parts of the world but is only relevant to certain geographical locations. Dew occurrence, however, is far more widespread, can form in most climates and geographic settings, show high frequency and prevalence throughout the year. During the past 20 years, dew collection has therefore been investigated as a serious supplemental source of fresh water. Dew Water offers a thorough review of dew, its formation characteristics and potential for dew collection, for audiences that include policy-makers, non-governmental organizations involved in development aid and sustainable development, engineers, urban planners, researchers and students. After providing a background on atmospheric water, humid air, and sky and materials emissivity, the book deals with dew formation and its estimation with a focus on the use of meteorological data. Dew measurement techniques are reviewed and discussed as well as dew collection by passive means. Computational fluid dynamics technique is described for better design of dew collectors. Dew quality (chemistry, biology) is assessed in view of potable water quality. Costs and economic aspects are also considered. -- from back cover Front Cover Half Title Page RIVER PUBLISHERS SERIES IN CHEMICAL,ENVIRONMENTAL, AND ENERGY ENGINEERING Title Page Copyright Page Contents Forewords Preface Participants of the Reviewing Process Glossary List of Figures List of Tables List of Abbreviations Chapter 1 - History Chapter 2 - Water on Earth 2.1 Water Cycle 2.2 Water Repartition 2.3 Atmospheric Water 2.3.1 Atmosphere Composition 2.3.2 Water Repartition 2.4 Contribution and Role of Dew 2.4.1 General 2.4.2 Dew and Plants 2.4.3 Dew Water for Humans Chapter 3 - Atmosphere and Materials Radiative Properties 3.1 Radiative Properties of Materials 3.1.1 Definitions 3.1.2 Planck’s Law and Black Body 3.1.3 Stefan–Boltzmann Law 3.1.4 Kirchhoff’s Law of Thermal Radiation 3.1.5 Gray Body 3.1.6 Atmospheric Radiation 3.2 Long Wave Radiative Transfer in Atmosphere 3.2.1 Clear Sky Emissivity: Radiation Deficit 3.2.2 Clear Sky Emissivity: Angular Dependence 3.2.3 Cloudy Sky Emissivity 3.2.4 Dry and Wet Substrate Emissivities Chapter 4 - Humid Air 4.1 Humid Air Characteristics 4.1.1 Dalton’s Law 4.1.2 Humid Air Equation of State 4.1.3 Humid Air Density 4.1.4 Saturated Vapor Pressure 4.2 Specific Quantities 4.2.1 Moisture Content, Humidity Ratio, Mass Mixing Ratio, Absolute and Specific Humidity 4.2.2 Relative Humidity 4.2.3 Dew Point Temperature and Relative Humidity 4.2.4 Dew-point Depression Temperature and Relative Humidity 4.2.5 Degree of Saturation 4.2.6 Specific Volume 4.2.7 Specific Enthalpy 4.2.8 Wet-Bulb Temperature: Psychrometric Constant 4.2.9 Mollier Diagram. Psychometric Chart 4.2.10 Moisture Harvesting Index 4.2.11 The Vapor Concentration􀀀Vapor Pressure Relation Chapter 5 - Dew Nucleation and Growth 5.1 Nucleation 5.1.1 Homogeneous Nucleation 5.1.2 Heterogeneous Nucleation 5.2 Boundary Layer 5.3 Growth Regimes 5.3.1 Basic Equations 5.3.2 Single Droplet Growth Law 5.3.3 Individual Drop Growth in a Pattern 5.3.4 Drop Pattern Evolution with Coalescence 5.3.5 Effect of Edges and Borders 5.3.6 Contact Angle Hysteresis and Surface Coverage 5.3.7 New Drop Generation 5.3.8 Effects of Gravity 5.4 Spatio-temporal Fluctuations 5.5 Condensation on Micro-patterned Substrates 5.5.1 Micro-pillars 5.5.2 Grooves and Stripes 5.6 Liquid and Liquid-Imbibed Substrate 5.7 Melting Substrate 5.8 Thermal Aspects 5.8.1 Drop Surface 5.8.2 Radiative Versus Conductive Cooling: Planar Substrate 5.8.3 Radiative Versus Conductive Cooling: Bumpy Substrate 5.8.4 Condensation Rates of Bumpy Substrates Chapter 6 - Dew Collection by Gravity 6.1 Smooth Substrates 6.1.1 Filmwise 6.1.2 Dropwise 6.2 Edge Effects 6.3 Textured Substrates 6.3.1 Filmwise 6.3.2 Dropwise 6.4 Rough and Porous Substrate 6.4.1 Enhanced Roughness 6.4.2 Porous Substrate (Fibrocement) 6.5 Oil-Imbibed Micro-substrate Chapter 7 - Dew Yield Estimation 7.1 Artificial Neural Networks 7.1.1 Model Inputs and Architecture 7.1.2 Model Optimization 7.1.3 Results 7.2 Energy Balance Models 7.2.1 Basic Equations 7.2.2 Semi-empirical Models 7.3 Analytical Model with Simple Meteorological Data 7.3.1 Approximations in the Energy Equation 7.3.2 Laboratory Tests 7.3.3 Wind Influence 7.3.4 Radiation Deficit 7.3.5 Dew Yield 7.3.6 Comparison with Measured Dew Yields 7.4 CFD-based Extrapolation to Non-planar Condensers 7.5 Dew Maps Chapter 8 - Computational Fluid Dynamics 8.1 Principles of the Simulation 8.2 Dew Yield and Cooling Temperature 8.3 Radiative Cooling 8.3.1 Radiative Modules 8.3.2 Mimicking Radiation by Surface-like Heat Flux 8.4 Program Setup 8.5 Study of Structures 8.5.1 Planar Structures 8.5.2 Roofs 8.5.3 Hollow Ridges 8.5.4 Hollow Cones 8.5.5 Positive Cones and Pines 8.5.6 Calibrations Chapter 9 - Dew Measurement and Collection 9.1 Optical Means 9.1.1 Observation-based Methods 9.1.2 Light Transmission or Reflection 9.1.3 Change of Spectral Reflectance 9.2 Electrical Means: Leaf-Wetness Sensors 9.3 Direct Weighing 9.4 Evaluation by Gravity Flow Collection 9.4.1 Scraping 9.4.2 Boundary Effects 9.5 General Effect of Materials and Forms 9.6 Enhanced Dew Condensation and Collection 9.7 Dew Measurement Standard 9.8 Super Absorbing Hydrogels 9.9 Massive Dew Condensers 9.10 Review of Large Dew Condensers Chapter 10 - Dew Water Quality 10.1 Chemical Characteristics 10.1.1 Catchment Techniques and Data Analyses 10.1.2 Electric Conductivity. Total Dissolved Solids 10.1.3 Major and Minor Ions 10.1.4 pH 10.1.5 Ion Source Characterization (Correlations, Enrichment Factor, Air Mass Trajectory, Isotope Analysis) 10.1.6 Urban Environment 10.2 Biological Features 10.2.1 Dew on Plants 10.2.2 Dew on Inert Substrates 10.2.3 Sterilization by Dew Condensation Chapter 11 - Economic Aspects 11.1 Mirleft (SW Morocco) 11.2 Coquimbo Region (S-center Chile) 11.3 Kothara (NW India) Appendix A - Slab and Hemisphere Emissivities Appendix B - The Clausius–Clapeyron Equation Appendix C - Relation between Vapor and Heat Transfer Coefficients C.1 Vapor Transfer C.2 Heat Transfer C.3 Ratio of Transfer Coefficients Appendix D - Volume of a Spherical Cap Appendix E - Wetting and Super Wetting Properties E.1 Ideal Surface E.2 Rough and Micro-patterned Surfaces E.2.1 Rough Substrate E.2.2 Micro-patterned Substrate. Cassie Baxter and Wenzel States Appendix F - Sand Blasting Roughness F.1 Roughness Amplitudes F.2 Wenzel Roughness Factor Appendix G - Meniscus in a Groove Appendix H - The Penman–Monteith Equation H.1 The Penman–Monteith Equation H.2 Aerodynamic Resistance ra H.3 (Bulk) Surface Aerodynamic Resistance rs H.4 Reference Surface Appendix I - Relation between Dew Yield and Dry Air Cooling Bibliography Index About the Author Back Cover The world's ever-increasing need for fresh water has led to the use of non-conventional sources such as rain and fog water collection. Although rain water collection is relatively simple, the supply is often erratic. Passive fog water collection has been used in several parts of the world but is only relevant to certain geographical locations. Dew occurrence, however, is far more widespread, can form in most climates and geographic settings, show high frequency and prevalence throughout the year. During the past 20 years, dew collection has therefore been investigated as a serious supplemental source of fresh water. Dew Water offers a thorough review of dew, its formation characteristics and potential for dew collection, for audiences that include policy-makers, non-governmental organizations involved in development aid and sustainable development, engineers, urban planners, researchers and students.After providing a background on atmospheric water, humid air, and sky and materials emissivity, the book deals with dew formation and its estimation with a focus on the use of meteorological data. Dew measurement techniques are reviewed and discussed as well as dew collection by passive means. Computational fluid dynamics technique is described for better design of dew collectors. Dew quality (chemistry, biology) is assessed in view of potable water quality. Costs and economic aspects are also considered.Topics include: dew, dew water, sky emissivity, materials emissivity, passive cooling, dew formation, dew collection, computational fluid dynamics, dew chemistry, dew biology, and dew economics