Solar and Infrared Radiation Measurements

Description

The rather specialized field of solar and infrared radiation measurements has become increasingly important due to the increased demands by the renewable energy and climate change research communities for data with higher accuracy and increased temporal and spatial resolutions. Recent advances in radiometry, measurement systems, and information dissemination also have increased the need for refreshing the literature available for this topic. This book provides the reader with an up-to-date review of the important aspects of solar and infrared radiation measurements: radiometer design; equipment installation, operation, maintenance, and calibration; data quality assessment parameters; and the knowledge necessary to properly interpret and apply the measured data to a variety of topics. Each of the authors has more than 40　years of experience with this subject, primarily as the result of developing and operating multiple measurement stations, working with the industry to improve radiometry, and conducting various research projects. The book's scope and subject matter have been designed to help a wide audience gain a general understanding of this subject and to serve as a technical reference. A student new to the field will benefit from the review of terminology and the historical perspective for radiometry before addressing more detailed topics in radiometry that we hope will be of interest to the more experienced reader.  Describes the strengths and weaknesses of irradiance instruments  Provides detailed information on how to assess uncertainty in measurements  Offers comprehensive background information needed to understand the use of solar instrumentation  Discusses design concepts for shadowband radiometers, sky imagers, and satellite-based estimates of solar irradiance at the Earth's surface  Includes chapter-end questions, references, and useful links Cover Half Title Title Page Copyright Page Dedication Table of Contents Preface to the Second Edition Preface to the First Edition Acknowledgments Authors Chapter 1: Measuring Solar and Infrared Radiation Questions References Chapter 2: Definitions and Terminology 2.1 Introduction 2.2 The Sun 2.3 Extraterrestrial Radiation 2.4 Solar Coordinates 2.5 Zenith, Azimuth, and Hour Angles 2.6 Solar, Universal, and Local Standard Time 2.7 Solar Position Calculation Example 2.8 Sunrise and Sunset Times 2.9 Global, Direct Normal, and Diffuse Irradiance 2.10 Solar Radiation on Tilted Surfaces 2.11 The Spectral Nature of Solar Radiation 2.12 Fundamentals of Thermodynamics and Heat Transfer 2.12.1 Conduction 2.12.2 Convection 2.12.3 Radiative Heat Transfer 2.13 Photodiodes and Solar Cell Characteristics 2.14 Models Questions References Chapter 3: Historic Milestones in Solar and Infrared Radiation Measurement 3.1 Introduction 3.2 Earliest Observations of the Sun and the Nature of Light 3.3 Nineteenth-Century Radiometers 3.3.1 Pouillet’s Pyrheliometer (1837) 3.3.2 Campbell-Stokes Sunshine Recorder (1853, 1879) 3.3.3 Ångström Electrical Compensation Pyrheliometer (1893) 3.3.4 Callendar Pyranometer (1898) 3.3.5 Ångström and Tulipan Pyrgeometers (1899) 3.4 Operational Radiometers of the Twentieth Century 3.4.1 Abbot Silver-Disk Pyrheliometer (1906) 3.4.2 Smithsonian Water-Flow Pyrheliometer (1910) 3.4.3 Marvin Pyrheliometer (1910) 3.4.4 Ångström Pyranometer (1919) 3.4.5 Kipp & Zonen Solarimeter (1924) 3.4.6 Robitzsch Bimetallic Actinograph (1932) 3.4.7 Eppley 180° Pyrheliometer (1930) 3.4.8 Eppley Model PSP (1957) 3.4.9 Yanishevsky Pyranometer (1957) 3.4.10 Eppley Model NIP (1957) 3.4.11 Eppley Model Precision Infrared Radiometer (PIR) (1968) 3.4.12 Primary Absolute Cavity Radiometer (PACRAD) (1969) 3.4.13 Eppley Model 8-48 (1969) 3.4.14 LI-COR Model LI-200SA (1971) 3.4.15 Rotating Shadowband Radiometer (1975) 3.4.16 World Standard Group (1979) 3.5 Recent Advances in Solar Measurements 3.5.1 Automatic Hickey–Frieden Cavity Radiometer 3.5.2 Total Irradiance Monitor (TIM) 3.5.3 Cryogenic Solar Absolute Radiometer-Measure the Integral Transmittance (CSAR-MITRA) 3.6 Summary Questions References Chapter 4: Direct Normal Irradiance 4.1 Overview of Direct Normal Irradiance 4.2 Pyrheliometer Geometry 4.3 Operational Thermopile Pyrheliometers 4.4 Absolute Cavity Radiometers 4.5 Uncertainty Analysis for Pyrheliometer Calibration 4.6 Uncertainty Analysis for Operational Thermopile Pyrheliometers 4.6.1 Window Transmittance, Receiver Absorptivity, and Temperature Sensitivity 4.6.2 Solar Zenith Angle Dependence 4.7 Uncertainty Analysis for Rotating Shadowband Radiometer Estimates of Direct Normal Irradiance 4.8 Direct Normal Irradiance Models 4.8.1 Ground-Based Modeling 4.8.2 Satellite Model Estimates 4.9 Historical and Current Surface-Measured Direct Normal Irradiance Data 4.10 Current Issues Regarding Direct Normal Irradiance Measurements Questions References Chapter 5: Broadband Global Irradiance 5.1 Introduction to Global Horizontal Irradiance Measurements 5.2 Black-Disk Thermopile Pyranometers 5.2.1 Thermal Offsets 5.2.2 Nonlinearity 5.2.3 Spectral Response 5.2.4 Angle of Incidence Response 5.2.5 Response Degradation 5.2.6 Temperature Dependence 5.2.7 Ice and Snow on Dome—Ventilators 5.2.8 An Optical Anomaly 5.3 Black-and-White Pyranometers 5.3.1 Characteristics of Black-and-White Pyranometers 5.3.2 Lack of Thermal Offset 5.4 Photodiode-Based Pyranometers 5.4.1 Characterizing a Photodiode Pyranometer 5.4.2 Removing Biases in Photodiode Pyranometer Measurements 5.4.3 Reference Solar Cells 5.5 Calibration of Pyranometers 5.5.1 Shade–Unshade Calibration Method 5.5.2 Summation Method Calibration 5.6 Pyranometer Calibration Uncertainties 5.6.1 Uncertainty Analysis Applied to Pyranometer Calibration 5.6.2 An Example of the GUM Procedure Applied to the Calibration Uncertainties of a Pyranometer 5.6.3 Importance of Understanding Limitations of Percent Uncertainties Questions References Useful Links Chapter 6: Diffuse Irradiance 6.1 Introduction 6.2 Atmospheric Scattering Concepts 6.3 Measuring Diffuse Irradiance 6.3.1 Fixed Shadowband Measurements of Diffuse Irradiance 6.3.2 Calculated Diffuse Irradiance versus Shading Disk Diffuse 6.3.3 Rotating Shadowband Diffuse Measurements 6.4 Calibration of Diffuse Pyranometers 6.5 Value of Accurate Diffuse Measurements Questions References Chapter 7: Solar Spectral Measurements 7.1 Introduction 7.2 The Extraterrestrial Solar Spectrum 7.3 Atmospheric Interactions 7.3.1 Rayleigh Scattering 7.3.2 Aerosol Scattering and Absorption 7.3.3 Gas Absorption 7.3.4 Transmission of the Atmosphere 7.4 Broad Filter Radiometry 7.4.1 Photometry 7.4.2 Photosynthetically Active Radiation (PAR) 7.4.3 UVA and UVB 7.5 Narrow-Band Filter Radiometry 7.5.1 Aerosol Optical Depth 7.5.2 Water Vapor 7.5.3 Sun Radiometers 7.6 Spectrometry 7.6.1 Spectrometers 7.6.2 Spectral Models 7.6.3 Discrete Spectral Measurements and Modeling Combined Questions References Chapter 8: Albedo 8.1 Introduction 8.2 Broadband Albedo 8.3 Spectral Albedo 8.4 Bidirectional Reflectance Distribution Function 8.5 Albedo Measurements 8.5.1 Broadband Albedo 8.5.2 Spectral Albedo Questions References Chapter 9: Measuring Solar Radiation on a Tilted Surface 9.1 Introduction 9.2 Effect of Tilt on Single Black Detector Pyranometers 9.3 Effect of Tilt on Black-and-White Pyranometers 9.4 Effect of Tilt on Photodiode Pyranometers 9.5 Recommendations for Tilted Irradiance Measurements 9.6 Modeling Photovoltaic System Performance with Data from Photodiode Pyranometers Questions References Chapter 10: Shadowband Radiometers 10.1 Introduction 10.2 Introduction to the Rotating Shadowband Radiometer 10.3 Rotating Shadowband Radiometer Using Silicon Detector 10.4 Multifilter Rotating Shadowband Radiometer 10.5 SPN1 Sunshine Pyranometer Questions References Chapter 11: Infrared Measurements 11.1 Introduction 11.2 Pyrgeometers 11.3 Calibration 11.4 Improved Calibrations 11.5 Other Pyrgeometer Manufacturers 11.6 Operational Considerations Questions References Chapter 12: Net Radiation Measurements 12.1 Introduction 12.2 Single-Sensor (All-Wave) Net Radiometers 12.3 Two-Sensor Net Radiometers 12.4 Four-Sensor Net Radiometers 12.5 Accuracy of Net Radiometers 12.6 A Better Net Radiation Standard 12.7 Net Radiometer Sources Questions References Chapter 13: Radiometer Calibrations 13.1 Introduction 13.1.1 What Is Calibration? 13.1.2 Why Is Calibration Needed? 13.1.3 How Frequently Should a Radiometer Be Calibrated? 13.2 Broadband Shortwave Radiometer Calibration 13.3 Broadband Longwave Radiometer Calibration 13.4 Spectral Calibrations 13.4.1 The Measurement Equation 13.4.2 Standard Lamps 13.4.3 Langley Plots Questions References Chapter 14: Ancillary Measurements 14.1 Introduction 14.2 Ambient Temperature 14.2.1 Types of Temperature Sensors 14.2.2 Response Times 14.2.3 Measuring Temperature 14.3 Wind Speed and Wind Direction 14.3.1 Sensor Terminology 14.3.2 Anemometer 14.3.3 Cup Anemometers 14.3.4 Propeller Anemometers 14.3.5 Sonic Anemometers 14.3.6 Installing Anemometers 14.3.7 Wind Vanes 14.4 Relative Humidity 14.5 Atmospheric Water Vapor 14.5.1 Using GPS Satellites to Measure Precipitable Water Vapor 14.5.2 Installing a Global Positioning System Antenna 14.6 Pressure 14.6.1 Aneroid Displacement Transducers 14.6.2 Piezoresistive Barometers 14.6.3 Piezocapacitance Barometers 14.7 Sky-Imaging Systems 14.7.1 Site Surveys 14.7.2 Sky Conditions 14.8 Circumsolar Instruments 14.8.1 Sun and Aureole Measurement 14.8.2 Attempts to Automatically and Continuously Monitor the Circumsolar Irradiance 14.8.3 Use of the Sky Imager to Measure Circumsolar Irradiance 14.8.4 Use of the Rotating Shadowband Radiometer 14.9 Recommended Minimum Accuracies for Operational Instruments Questions References Chapter 15: Solar Monitoring Station Best Practices 15.1 Introduction 15.2 Choosing a Site 15.3 Grounding and Shielding 15.4 Data Logger and Communications 15.5 Measurement Interval 15.6 Cleaning and Maintenance 15.7 Record Keeping 15.8 Importance of Reviewing Data 15.9 Quality Control of Data 15.10 Field Calibrations 15.11 Physical Layout of a Solar-Monitoring Station Questions References Chapter 16: Solar Radiation Estimates Derived from Satellite Images and Auxiliary Measurements 16.1 Introduction 16.2 Geostationary Satellites 16.3 Deriving Irradiance from Satellites 16.3.1 Physical Models 16.3.2 Empirical Models 16.3.3 Global Irradiance 16.3.4 Pixel-to-Cloud Index Conversion 16.3.5 Cloud Index to Global Horizontal Irradiance Conversion 16.3.6 Direct Irradiance 16.3.7 Diffuse Irradiance 16.3.8 Tilted Irradiance 16.4 Status of Satellite Irradiance Models 16.5 Comments on Modeling and Measurement Questions References Appendix A: Measurement Uncertainty Principles Appendix B: Modeling Solar Radiation Appendix C: Sunshine Duration Appendix D: Sun Path Charts Appendix E: Solar Position Algorithms Appendix F: Useful Conversion Factors Appendix G: Sources for Equipment Appendix H: BORCAL Report Appendix I: Failure Modes Appendix J: How to Build a Pyranometer with a Solar Cell or Photodiode Appendix K: Content Required for a Comprehensive Datafile Appendix L: Solar Radiation Databases Answers to Chapter Questions Index