A number of significant changes have occurred in Advances in Solar Energy since Volume 1 appeared in 1982. The delays in publication of the second volume are the result of reorganization of the American Solar Energy Society, and the negotiation of a new publishing arrangement. Beginning with this volume, Advances is now published jointly by the Society and Plenum Press. The Editorial Board has been enlarged to be more representative of the different fields of solar energy conversion. Production of Advances is being expedited through the use of modern word processing equipment and the 'lEX typesetting-editing program. We have gone to a single-column format to ease the problems of presenting long equations, and we expect that the user of the volume will find it easy to read. The use of 'lEX will make last minute updates possible. The external appearance of the volume matches that of Volume 1. We expect that future volumes of this annual will be proceeding on schedule. We invite comments from users and correspondence from prospective authors of critical reviews. Karl W. Boer John A. Duffie CONTENTS CHAPTER 1 The Measurement of Solar Radiation Ronald Stewart, Daniel W. Spencer and Richard Perez 1.1 Abstract 1 1.2 Characteristics of Pyranometers ....................................... . 2 1.3 General Features of a Pyranometer ................................... . 3 1.3.1 Instrument Sensitivity 4 1.3.2 Response with Time 4 1.3.3 Sensitivity 4 1.3.4 Responsivity ................................................. .

1 The Measurement of Solar Radiation.- 1.1 Abstract.- 1.2 Characteristics of Pyranometers.- 1.3 General Features of a Pyranometer.- 1.3.1 Instrument Sensitivity.- 1.3.2 Response with Time.- 1.3.3 Sensitivity.- 1.3.4 Responsivity.- 1.3.5 Temperature Coefficient of Sensitivity.- 1.3.6 Thermal Transient Response.- 1.3.7 Linearity.- 1.3.8 Angular Dependence of Sensitivity.- 1.3.9 Leveling.- 1.3.10 Spectral Response.- 1.3.11 Stability.- 1.3.12 Pyranometer Sensitivity Function.- 1.4 Pyranometers.- 1.4.1 Clear-Sky Analysis.- 1.4.2 Installation of the Instrument.- 1.4.3 Thermopile Construction.- 1.4.4 Moisture.- 1.4.5 Deposition.- 1.4.6 Negative Values.- 1.4.7 Readings Which Exceed the Values for Extraterrestrial Insolation.- 1.4.8 Diffuse Solar Radiation.- 1.4.9 Shadowband Orientation.- 1.5 Pyrheliometers.- 1.5.1 Calibration.- 1.5.2 Temperature Correction.- 1.5.3 Spectral Measurements Using Broadband Filters.- 1.5.4 Time Constant of the Pyrheliometer.- 1.5.5 Tracking.- 1.5.6 Importance of the Solar Aureole.- 1.5.7 Pyrheliometer Tracker Wiring.- 1.5.8 Quality Control of Data.- 1.5.9 Solar Radiation Instruments.- 1.5.9.1 The Pyrheliometers.- 1.5.9.2 The Pyranometers.- 1.5.9.3 Duration of Sunshine Instruments.- Appendix 1.1 Historical Perspectives.- 1.1.1 Historical Perspectives-From Sundials to Satellites.- References.- 2 Environmental Requirements for Anaerobic Digestion of Biomass.- 2.1 Abstract.- 2.2 Introduction.- 2.3 Microbiology of Methanogens.- 2.3.1 Interspecies H2 Transfer.- 2.3.2 Methanogenic Reactions.- 2.3.3 Characteristics of Methanogenic Species in Pure Culture.- 2.3.4 Methanothrix Soehngenii.- 2.3.5 Biochemical Mechanisms and Pathways.- 2.3.6 Predominance of Species.- 2.3.7 Fermentative Bacteria.- 2.4 Nutrient Requirements.- 2.4.1 Nitrogen.- 2.4.2 Phosphorus.- 2.4.3 Sulfur.- 2.4.4 Trace Metals.- 2.5 Toxicity Response.- 2.5.1 Acclimation and Metabolism.- 2.5.2 Microbial Kinetics and Toxicity.- 2.5.3 Toxicity in Anaerobic Digestion Studies.- 2.6 Alkalinity.- 2.6.1 Alkalinity Concentration Required.- 2.6.2 Choice of Purchased Alkalinity.- 2.7 Modeling of the Anaerobic Digestion Process.- 2.7.1 Cellular Synthesis of Organic Substrate.- 2.7.2 Rate-Limiting Step in Anaerobic Digestion.- 2.7.2.1 Lipids and Acetate.- 2.7.2.2 Cellulose.- 2.7.3 Kinetics.- 2.7.4 Stoichiometry.- 2.7.5 Calculations of Methane Production.- 2.8 Design Prerequisites.- 2.8.1 Solids Concentration in Feed Sludge.- 2.8.2 Batch versus Continuous Feeding.- 2.8.3 Plug Flow versus CSTR.- 2.8.4 Temperature.- 2.8.5 Process Configuration.- 2.8.6 Soluble versus Sludge Feedstocks.- 2.8.7 Industrial Wastewaters Treated by Methane Fermentation.- 2.8.8 Screening Studies.- 2.8.9 Scale-Up Factors Affecting Performance.- 2.9 Future Directions.- References.- 3 Principles and Technology of Biomass Gasification.- 3.1 Abstract.- 3.2 Introduction.- 3.2.1 History of Biomass Gasification.- 3.2.2 Major References on Biomass Gasification.- 3.2.3 Gasification Research Centers.- 3.2.4 Gasification Meetings.- 3.3 Gasifier Technology.- 3.3.1 Types of Gasifiers.- 3.3.1.1 Charcoal Gasifiers.- 3.3.1.2 Updraft Gasifiers.- 3.3.1.3 Downdraft Gasifiers.- 3.3.1.4 Fluidized Bed Gasifiers.- 3.3.1.5 Suspension Gasifiers.- 3.3.1.6 Other Gasifiers.- 3.3.2 Gasifier Systems.- 3.3.3 Gasifier System Specifications.- 3.3.4 Producer Gas Use and Gas Conditioning.- 3.4 Principles of Gasification.- 3.4.1 Gasifier Fuels.- 3.4.2 Biomass versus Coal Gasification.- 3.4.3 Chemistry of Biomass Gasification.- 3.4.4 Global Thermodynamics of Biomass Gasification.- 3.4.5 The Gasification Reactions.- 3.4.5.1 Solid and Gas Pyrolysis.- 3.4.5.2 Kinetics of Solid Pyrolysis Reactions.- 3.4.5.3 Kinetics of Biomass Vapor Pyrolysis Reactions.- 3.4.5.4 Mechanisms of Charcoal Gasification.- 3.4.5.5 Kinetics of Charcoal Gasification.- 3.4.6 Modeling of Gasifier Operation.- 3.4.6.1 Updraft Gasifier Modeling.- 3.4.6.2 Downdraft Gasifier Modeling.- 3.4.6.3 Fluidized Bed Gasifier Modeling.- 3.4.6.4 Fast Pyrolysis Modeling.- 3.5 Conclusions.- 3.6 Acknowledgments.- Appendix 3.1 Units.- References.- 4 Biomass Pyrolysis: A Review of the Literature Part 2-Lignocellulose Pyrolysis.- 4.1 Abstract.- 4.2 Introduction.- 4.2.1 Scope.- 4.2.2 Goals.- 4.3 Pyrolysis of Carbohydrates.- 4.3.1 Low Temperature Phenomena.- 4.3.1.1 Products.- 4.3.1.2 Mechanisms and Kinetics.- 4.3.2 Moderate Temperature Phenomena.- 4.3.2.1 Products.- 4.3.2.2 Mechanisms and Kinetics.- 4.3.3 High Temperature Phenomena.- 4.3.3.1 Products.- 4.3.3.2 Mechanisms and Kinetics.- 4.3.4 Effects of Various Parameters.- 4.3.5 Summary and Critique.- 4.4 Pyrolysis of Lignin.- 4.4.1 Low Temperature Phenomena.- 4.4.2 Moderate Temperature Phenomena.- 4.4.2.1 Products.- 4.4.2.2 Mechanisms and Kinetics.- 4.4.3 High Temperature Phenomena.- 4.4.3.1 Products.- 4.4.3.2 Mechanisms and Kinetics.- 4.4.4 Effects of Various Parameters.- 4.4.4.1 Heating Rate.- 4.4.4.2 Pressure.- 4.4.4.3 Particle Size.- 4.4.4.4 Additives.- 4.4.4.5 Pyrolysis Medium.- 4.4.5 Summary and Critique.- 4.5 Pyrolysis of Lignocellulosic Materials.- 4.5.1 Low Temperature Phenomena.- 4.5.2 Moderate Temperature Phenomena.- 4.5.2.1 Products.- 4.5.2.2 Mechanisms and Kinetics.- 4.5.3 High Temperature Phenomena.- 4.5.3.1 Products.- 4.5.3.2 Mechanisms and Kinetics.- 4.5.4 Effects of Various Parameters.- 4.5.4.1 Heating Rate.- 4.5.4.2 Pressure.- 4.5.4.3 Particle Size.- 4.5.4.4 Gaseous Environment.- 4.5.4.5 Mineral Matter and Additives.- 4.5.5 Summary and Critique.- 4.6 Commercial Development.- 4.6.1 Generic Technologies.- 4.6.2 Generic Economics.- 4.6.3 State of the Art Reactors.- 4.6.3.1 Class I Reactors.- 4.6.3.2 Class II Reactors.- 4.6.3.3 Class III Reactors.- 4.6.3.4 Summary and Critique.- 4.7 Conclusions.- 4.8 Acknowledgments.- 4.9 Notation.- References.- 5 Thermal Comfort and Passive Design.- 5.1 Historical Notes.- 5.2 Physiological Basis.- 5.3 Summary.- 5.4 Empirical Studies.- 5.5 Analytical Work.- 5.6 The Bioclimatic Chart.- 5.7 Variability of Comfort.- 5.8 Psychological Extensions.- 5.9 Consequences.- 5.10 Behavioral and Clothing Differences.- 5.11 Acclimatization and Habit.- 5.12 Passive Heating Systems and Comfort.- 5.13 Summary.- 5.14 References.- 6 Earth Contact Buildings: Applications, Thermal Analysis and Energy Benefits.- 6.1 Abstract.- 6.2 Earth Contact Structures and Their Applicability.- 6.3 The General Advantages of Earth Contact Structures.- 6.3.1 Visual Impact /Aesthetics.- 6.3.2 Preservation of…