Nonimaging Optics in Solar Energy Synthesis Lectures on Energy and the Environment Technology S

Joseph J. O’Gallagher9781598293302, 1598293303

Nonimaging optics is a subdiscipline of optics whose development over the last 35–40 years was led by scientists from the University of Chicago and other cooperating individuals and institutions. The approach provides a formalism that allows the design of optical devices that approach the maximum physically attainable geometric concentration for a given set of optical tolerances. This means that it has the potential to revolutionize the design of solar concentrators. In this monograph, the basic practical applications of the techniques of nonimaging optics to solar energy collection and concentration are developed and explained. The formalism for designing a wide variety of concentrator types, such as the compound parabolic concentrator and its many embodiments and variations, is presented. Both advantages and limitations of the approach are reviewed. Practical and economic aspects of concentrator design for both thermal and photovoltaic applications are discussed as well. The whole range of concentrator applications from simple low-concentration nontracking designs to ultrahigh-concentration multistage configurations is covered. Table of Contents: Introduction / CPCs / Practical Design of CPC Thermal Collectors / Practical Design of CPC PV Concentrators / Two-Stage Nonimaging Concentrators for Solar Thermal Applications / Two-Stage Nonimaging Concentrators for Solar PV Applications / Selected Demonstrations of Nonimaging Concentrator Performance / The Importance of Economic Factors in Effective Solar Concentrator Design / Ultrahigh Concentration / Bibliography

---

Table of contents :
Nonimaging Optics in Solar Energy……Page 2
Keywords……Page 5
Acknowledgments……Page 6
Important Note……Page 8
Contents……Page 10
1.1 WHAT IS “NONIMAGING OPTICS?”……Page 14
1.3.1 Concentration and the Thermodynamic Limit……Page 15
1.4 THE ROLE OF CONCENTRATION IN SOLAR ENERGY CONVERSION……Page 17
2.1 BASIC GEOMETRY……Page 20
2.3 THE “EDGE-RAY PRINCIPLE”……Page 23
2.4 SOLUTIONS FOR NONFLAT ABSORBERS……Page 24
2.5 THE “GAP-LOSS” PROBLEM……Page 27
2.6 CPC SOLAR GEOMETRY……Page 30
2.7 CPC DEPLOYMENT FLEXIBILITY……Page 31
2.8 THE DIELECTRIC TOTALLY INTERNALLY REFLECTING CPC……Page 32
2.9 SUMMARY OF CPC FEATURES……Page 33
3.1.1 The External Reflector CPC……Page 36
3.1.1.1 Generic Model for Nonimaging Evacuated Solar Thermal Collectors……Page 37
Simple model for XCPC optical performance……Page 38
Concentration and thermal performance for evacuated CPCs……Page 39
3.1.2 Comparison of Early and Recent XCPC Embodiments……Page 40
3.1.3 The Integrated CPC……Page 44
3.1.3.1 A “Manufacturable Design”……Page 46
3.2 CPCs WITH NONEVACUATED ABSORBERS……Page 48
3.2.1 Performance Model for Nonevacuated CPCs……Page 49
4.1 ECONOMIC CONSIDERATIONS FOR PV APPLICATIONS……Page 52
4.2 PERFORMANCE EFFECTS IN CPCs FOR PV APPLICATIONS……Page 53
5.1 BASIC CONCEPTS……Page 60
5.2 GEOMETRIC CONSIDERATIONS……Page 61
5.3 CONCENTRATION, OPTICAL QUALITY, AND THERMAL PERFORMANCE OF TWO-STAGE DISH CONCENTRATORS……Page 64
5.3.1 Effect of Slope Error and Operating Temperature……Page 66
5.3.2 Effect of Focal Ratio……Page 67
5.3.3 Off-Track Tolerances With and Without Secondaries……Page 68
5.4 PERFORMANCE BENEFITS FOR SECONDARIES COMBINED WITH SPHERICAL MIRRORS……Page 69
5.5 SUMMARY OF ADVANTAGES OF TWO-STAGE NONIMAGING CONFIGURATIONS……Page 70
5.6.1 CPCs and CECs……Page 71
5.6.2 Flowline or Trumpet Concentrators……Page 72
5.6.3 TERCs……Page 74
5.7 SOME GENERAL OBSERVATIONS……Page 75
5.8 PRACTICAL CONSIDERATIONS AND AN OPERATIONAL TEST……Page 76
5.8.1 The Importance of Maintaining the Optical Performance of the Primary……Page 77
6.1 MULTIELEMENT CONCENTRATOR ARRAYS……Page 80
6.1.1 Geometric Considerations……Page 81
6.1.2 Secondary Designs……Page 84
6.2 SINGLE LARGE-SCALE PV CONCENTRATORS USED WITH A MULTICELL ARRAY……Page 86
7.1 THE BREADSPRINGS INDIAN SCHOOL NONEVACUATED CPC PROJECT……Page 90
7.2 THE UNIVERSITY OF CHICAGO EVACUATED XCPC ARRAY……Page 91
7.3 THE SACRAMENTO ICPC SOLAR COOLING PROJECT……Page 97
8.1 A RATIONAL MODEL FOR COST PERFORMANCE OPTIMIZATION……Page 102
8.1.1 The Model……Page 103
8.1.2 Conclusions……Page 106
8.2.2 A Simple Model……Page 107
8.2.3 Discussion……Page 109
9.1.2 Limits to Central Receiver Concentration……Page 112
9.1.2.2 Field Size……Page 114
9.1.2.3 Nonsurround Field Designs……Page 115
9.1.3 Summary and Conclusions……Page 118
9.2 SOME EXOTIC APPLICATIONS FOR ULTRAHIGH SOLAR FLUXES……Page 119
9.2.1 Using Highly Concentrated Sunlight in Space……Page 120
9.2.3 Solar Thermal Propulsion in Space……Page 121
Bibliography and References……Page 124
Author Biography……Page 132