ANALYSIS OF ENVIRONMENTAL IMPACTS ON THE PERFORMANCE OF PV MODULES
by
Gaurav Kumar Singh Centre for Energy studies
Submitted
infulfillment of the requirements of the degree of
Doctor of Philosophy to the
Indian Institute of Technology Delhi
February, 2013
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Certificate
This is to certify that the thesis entitled “Analysis of Environmental Impacts on the Performance of PV Modules”, being submitted by Gaurav Kumar Singh to the Indian Institute of Technology Delhi, is worthy of consideration for the award of the degree of ‘Doctor of Philosophy’ and is a record of the original bonafide research work carried out by him under our guidance and supervision. The results contained in the thesis have not been submitted in part or full, to any other University or Institute for the award of any degree or diploma.
Dr. G. N. Tiwari Dr.V.K.Kaul Dr. H. N. Singh
Professor General Manager Asst. Professor (D.O.P.)
C.E.S., IIT Delhi C.E.L., Sahibabad R.S.S. (P.G.) College, Hauz Khas, New Delhi Ghaziabad (U.P.) Pilkhuwa, Hapur, U.P.
Date: February, 2013
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Acknowledgements
I wish to express my deep sense of gratitude to my supervisor Dr. G. N. Tiwari, Professor, Centre for Energy Studies for his practical approach in almost every aspect of life including research and development work. His vast knowledge of the subject and logical way of thinking has been of great value for me. Their stimulating discussions, constructive criticism and personal guidance on various aspects have provided a great basis for dealing with the subject problems and many other personal problems of life. I am immensely thankful to him for his wonderful co-operation, constant encouragement, proper guidance and fruitful academic discussions for carrying out my research work.
It gives me indeed a great pleasure to express my heartfelt gratitude to my co- supervisor Dr. V. K. Kaul, General Manager, Central Electronics Limited, Sahibabad, U. P.
for his constant and consistent encouragement.
I am also deeply indebted to my co-supervisor Dr. H. N. Singh, for his constant and consistent guidance. His expert guidance, untiring efforts and valuable suggestions were a great help throughout my research work.
I also express my gratitude to Prof. R. P. Sharma, Head; Prof. T. S. Bhatti, and Dr.
Subodh Kumar and other faculty members at Centre for Energy Studies and Prof. I. P. Singh, IDDC for providing moral support and encouragement for the present Ph.D. research work.
Many of my friends have contributed in significant ways to the completion of this work. I have no words to my colleague Mr. Vivek Tomar for their continuous support. I am especially thankful to my colleagues Mr. Rajeev Mishra, Dr.Sanjay agrawaal, Mr. C. S.
Rajoria for their positive criticism and moral support. I am also thankful to Dr. S. C. Solanki, Dr. Manoj Gaur, Mr. R.P. Agrahari, Mr. Shyam and Mr. Madhusudan and other colleagues for their support.
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I am also thankful to Mr. Lakhmi Chand (Junior Technical Superintendent) for their kind support during experimental work.
There are no words that will suffice to thank my friends Ashish Kushwaha, Sunita Sanwaria, Dr. Kapil, S. Balyan, Vedpal, Shivendra, and Amit who always stood beside me in any kind of situation throughout my research work.
I express my deep heartfelt gratitude to my respected parents, Smt. Vimala Singh and Shri Shiv Raj Singh for their blessings, which helped me to reach this target. I express my deep heartfelt respect to my respected brothers Dr. Ashish Kumar Singh and Dr. Alok Kumar Singh for their mental support, which helped me to fulfill my research work without any problem.
Date: February, 2013 (Gaurav Kumar Singh)
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Abstract
Renewable energy (RE) resources have enormous potential and can meet the present world energy demand. They can enhance diversity in energy supply markets, secure long- term sustainable energy supply, and reduce local and global atmospheric emissions. They can also provide commercially attractive options to meet specific needs for energy services, especially in developing countries and rural areas).
Photovoltaic is the field of technology and research related to the application of solar cells as solar energy. A solar cell or photovoltaic (PV) cell is a device that converts solar energy into electricity by the photovoltaic effect. Sometimes the term ‘solar cell’ is reserved for devices intended specifically to capture energy from sunlight, while the term
‘photovoltaic cell’ is used when the source is unspecified. Photovoltaic generation of power is caused by radiation that separates positive and negative charge carriers in absorbing material. In the presence of an electric field, these charges can produce a current for use in an external circuit. Such fields exist permanently at junctions or in homogeneities in materials as
‘built-in’ electric fields and provide the required EMF for useful power production.
A photovoltaic (PV) cell or solar cell is a device that converts solar energy into electricity by the photovoltaic effect. A photovoltaic module is a packaged interconnected assembly of photovoltaic cells. An installation of photovoltaic modules or panels is known as a photovoltaic array or a solar panel. Photovoltaic cells typically require protection from the environment. For cost and practicality reasons, a number of cells are connected electrically and packaged in a photovoltaic module, while a collection of these modules that are mechanically fastened together, wired, and designed to be a field-installable unit, sometimes with a glass covering and a frame and backing made of metal, plastic or fiberglass, are known as a photovoltaic panel or simply solar panel. A photovoltaic installation unit typically
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includes an array of photovoltaic modules or panels, an inverter, batteries (for off grid) and interconnection wiring. The final cost of any PV system ultimately depends on PV array size, battery bank size and on the other components required for the specific application. Hence, the lack of PV system design results in high design costs for PV power system projects
The performance of the PV system depends upon several factors, especially the meteorological conditions such as solar radiation, ambient temperature and dust along aging effect.
In present thesis, an attempt has been made to study the effect of environmental degradation and dust on the performance of PV modules in outdoor and indoor conditions. In order to show the dusting effects on PV modules in indoor conditions, four PV modules M1
(CEL: A-0286, Opaque, 1990), M2(CEL: P-15292, Opaque, 2008), M3 (SIEMENS: 020854, Opaque, 2008) and M4 (CEL: S-6224, Semitransparent, 1010) have been considered and tested with the help of a solar simulator at various dusting levels and solar intensities. In indoor experiments, it has been observed that the efficiency of PV modules decreases by 5.33% to 45.23% for increased thickness of dust layer (0.08µm to 0.55µm) for all PV modules. Later on, dusting effects on PV modules in outdoor conditions are also examined.
The experiments in this study have been carried out for a standalone PV (SAPV) system installed at Solar Energy Park, IIT Delhi for both summer and winter season. It has been observed that efficiency of PV module is more sensitive in summer season as compare to winter.
Further, an analysis has been made to evaluate performance of PV Module with and without air duct in terms of energy and exergy. Along with, a comparative study has been carried out for summer and winter seasons. In this regard, four different cases, case A (semitransparent PV module without duct), case B (semitransparent PV module with duct), case C (Opaque PV module without duct) and case D (Opaque PV module with duct) are
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considered for the study. Outdoor experiments have been conducted for all cases. It has been observed that electrical efficiency is higher for cases B and D (with air duct) respectively in comparison to cases A and C (without air duct) respectively.
An attempt has been made to study the effect of aging on the performance of solar hut at CEL, Sahibabad (UP) and the SAPV system at Solar Energy Park, IIT Delhi. For present study, an experimental data collected in the past have been used. It is found that electrical efficiency of Solar Hut has been decreased by 61.18% in its operational life of 28 years and average annual rate of decrease in efficiency is 3.6% per year. Also, it has been observed that the rate of decrease in efficiency is constantly slowing down. The performance of SAPV system installed at Solar Energy Park also has been evaluated. For this purpose, experiments have been carried out for two years. It is found that electrical efficiency of SAPV System has been decreased by 5.3% in 3 years of operational life and average annual rate of decrease in efficiency is 1.8% per year. It has also been observed that the rate of decrease in efficiency has lowering trend.
In the last part, life cycle assessment studies aim at comparing and analyzing environmental impacts and services of the systems. The life cycle cost analysis and energy matrices namely, energy payback time (EPBT), electricity production factor (EPF) and life cycle conversion efficiency (LCCE) based on electrical energy output from the SAPV and roof top PV system have been evaluated for outdoor conditions. As per the norms of Kyoto protocol, the annual carbon credits earned by both the systems have been calculated. It has been found in this study that EPF and LCCE are higher and EPBT and cost of electricity produced is lower for the roof top system.
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Table of Contents
Certificate i
Acknowledgement ii
Abstract iv
List of Figures xiii
List of Tables xix
Nomenclature xxi
Chapter - 1 General introduction
1.1 Introduction 1
1.2 Photovoltaic effect 2
1.3 Solar cells 3
1.3.1 Basics of solar cell 3
1.3.2 Basic parameters of a solar cell 8
1.3.2.1 Overall current (I) 8
1.3.2.2 Short circuit current (Isc) 8 1.3.2.3 Open circuit voltage (Voc) 8 1.3.2.4 I-V Characteristics 8 1.3.2.5 Fill factor (FF) 9 1.3.2.6 Maximum power (Pmax) 9 1.3.2.7 Efficiency of a solar cell 10
1.3.2.8 Specifications of the silicon solar cell 10
1.4 Photovoltaic (PV) module 11
1.4.1 Types of photovoltaic module 11
1.4.1.1. Opaque PV module 11
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1.4.1.2. Semitransparent PV module 12 1.4.2 Basic parameters of PV module 12
1.4.2.1 Packing factor (PF) 12
1.4.2.2 Electrical efficiency of PV module 12 1.4.2.3 Temperature dependent electrical efficiency
of PV module 13
1.4.3 Electrical connections of the cells 13 1.4.3.1. Series connection of cells 13 1.4.3.2. Parallel connection of cells 14 1.4.4 Working and performance factors of PV modules 15 1.4.5 Specifications of a single standard PV module 17
1.5 Photovoltaic thermal (PVT) air collector 17
15.1 Thermal efficiency 17
1.5.2 Overall gain 18
1.5.3 Overall efficiency 19
1.6 Historical review of research in PV modules 20
1.6.1 Environmental impacts on PV module 20
1.6.2 Photovoltaic thermal (PVT) air collectors 21
1.6.3 Standalone and roof top PV system 22
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1.7 Statistical analysis 23
1.8 Objectives of research work 24
1.9 Thesis outline 25
Chapter - 2 Experimental setup and observations
2.1 Introduction 26
2.2 Indoor experimental setup 26
2.3 Outdoor experimental setup 27
2.3.1 Stand alone PV system at Solar Energy Park, I.I.T. Delhi. 28 2.3.2 Roof top PV system of Solar Hut, CEL, Sahibabad,
U.P. (India) 30
2.3.3 Glazed hybrid PVT module air collector 31
2.3.4 Roof top PV system at Sodha BERS Complex, Varanasi,
U.P. (India) 32
2.4 Experimental methodologies 35
2.4.1 Methodology to study effect of dusting on performance
of PV modules 35
2.4.2 Methodology to study effect of air duct on performance
of PV modules 35
2.4.3 Methodology to study effect of aging on performance of
PV modules 36
2.4.4 Methodology for energy and economic analysis of PV modules 37
2.5 Observations 37
2.5.1 Observational parameters 37
2.5.2 Instrumentation 38
2.5.3 Typical observations 38
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Chapter: 3 Study of Dusting Effect on the Performance of PV Modules
3.1 Introduction 41
3.2 Effect of dusting in indoor conditions 44
3.2.1 System description 44
3.2.2 Methodology used and working principle 47
3.2.3 I-V Characteristics 50
3.2.4 Result and discussion 56
3.3 Effect of dusting in outdoor conditions 62
3.3.1 System description 62
3.3.2 Methodology used and observations 63
3.3.3 Result and discussion 66
3.4 Conclusion 70
Chapter: 4 Energy and exergy of PV modules with and without air duct
4.1 Introduction 72
4.2 System description and working principle 75
4.2.1 System description 75
4.2.2 Working principle 78
4.3 Experimental procedure and observations 80
4.4 Results and discussion 81
4.5 Conclusion 90
Chapter: 5 Study of aging effect on the performance of solar hut and stand alone PV system
5.1 Introduction 91
5. 2 System description and working methodology 93
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5.2.1 System description 93
5.2.2 Methodology and observations 94
5.3 Result and discussion 96
5.3.1 Results and discussion of solar hut RTPV system 96
5.3.2 Results and discussion of SAPV system 103
5.3.2.1 Siemens Modules 103
5.3.2.2 CEL Modules 106
5.3.2.3 Stand alone PV system 110
5.4 Conclusion 114
Chapter: 6 Energy and economic analysis of standalone PV and roof top PV system
6.1 Introduction 116
6.2 Methodology 119
6.3 Embodied energy 120
6.4 Energy matrices 120
6.4.1 Energy payback time (EPBT) 121
6.4.2 Electricity production factor (EPF) 121
6.4.3 Life cycle conversion efficiency (LCCE) 122
6.5 Life cycle cost analysis 122
6.6 Roof top PV system at Sodha BERS Complex, Varanasi, U.P. (India) 124
6.6.1 Experimental observations 124
6.6.2 Calculation of annual electrical energy produced by RTPV system 125 6.6.3 Calculation of embodied energy of RTPV system 126 6.6.4 Calculation of energy matrices of RTPV system 128 6.6.5 Analysis of CO2 emission in RTPV system 128 6.6.6 Economic analysis of RTPV system 128
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6.7 Stand alone PV system at Solar Energy Park, I I T, Delhi, New Delhi 129
6.7.1 Experimental observations 129
6.7.2 Calculation of annual electrical energy produced by SAPV system 130 6.7.3 Calculation of embodied energy of SAPV system 131 6.7.4 Calculation of energy matrices of SAPV system 133
6.7.5 Carbon credit earned by SAPV system 133
6.7.6 Economic analysis of SAPV system 134
6.8 Results and discussion 136
6.9 Conclusion 139
Chapter: 7 Conclusion and recommendations
7.1 Conclusion 141
7.2 Recommendations 143
References 144
Appendices
Appendix – I 152
Appendix – II 165
Appendix – III 167
Appendix – IV 179
List of Publication 182
Brief Bio-data of the Author 184
