ENERGY AND EXERGY ANALYSIS OF N-PARTIALLY COVERED PHOTOVOLTAIC THERMAL COMPOUND PARABOLIC CONCENTRATOR (PVT-CPC) COLLECTOR ROHIT TRIPATHI

Transcription

1 ENERGY AND EXERGY ANALYSIS OF N-PARTIALLY COVERED PHOTOVOLTAIC THERMAL COMPOUND PARABOLIC CONCENTRATOR (PVT-CPC) COLLECTOR ROHIT TRIPATHI CENTRE FOR ENERGY STUDIES INDIAN INSTITUTE OF TECHNOLOGY DELHI OCTOBER 2017

2 Indian Institute of Technology Delhi (IITD), New Delhi, 2017

3 ENERGY AND EXERGY ANALYSIS OF N-PARTIALLY COVERED PHOTOVOLTAIC THERMAL COMPOUND PARABOLIC CONCENTRATOR (PVT-CPC) COLLECTOR by ROHIT TRIPATHI Centre for Energy Studies Submitted in fulfilment of the requirements of the degree of Doctor of Philosophy to the Indian Institute of Technology Delhi OCTOBER 2017

4 Certificate This is to certify that the thesis entitled Energy and exergy analysis of N-partially covered of photovoltaic thermal compound parabolic concentrator (PVT-CPC) collector, being submitted by Mr. Rohit Tripathi 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 bona fide research work carried out by him under my 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 President Bag Energy Research Society (BERS) Plot No. 51, Park -2, Mahamana Nagar Karaundi Varanasi, U.P India Website: Dr. T. S. Bhatti Professor Centre for Energy Studies Indian Institute of Technology Delhi Hauz Khas, New Delhi India Dr. V. K. Dwivedi Professor and Director Department of Mechanical Engineering Galgotias College of Engineering & Tech. Greater Noida, U.P. India i

5 Acknowledgements First, I would like to express my sincere gratitude to my supervisors Prof. G. N. Tiwari and Prof. T.S. Bhatti, Professor, Centre for Energy Studies, IIT Delhi and Prof. V. K. Dwivedi, Director and Professor, Galgotias College of Engineering & Technology, for their continuous encouragement and guidance, for their systematic guidance. Their guidance helped me all the time during research and writing of this thesis. My sincere gratitude to Head of Centre Professor Viresh Dutta, Centre for Energy Studies, for providing moral support and encouragement for the present Ph.D research work. Besides my supervisor, I would like to thank and convey my gratitude to my colleagues: Dr. Shyam, Dr. Madhu Sudan, Dr. Desh Bandhu Singh, Dr. J. K. Yadav, Mr. Vivek Tomer, Mr. Lovedeep Sahota, Ms. Poonam Joshi, Mr. Pramod Rajput, Mr. Gaurav K. Mishra, Mr. Sumit Tiwari and Mr. Arjun Deo for their insightful comments and encouragement. I am also thankful to Mr. Lakhmi Chand, Junior Technical Superintendent for his support during the experimental work. Apart from this, special thanks to my family. Words cannot express how grateful I am to my brother (Mr. Amit Tripathi), mother (Smt. Usha Tripathi), father (Shri A. k. Tripathi), brother-inlaw (Mr. Anurag and Paritosh), sisters (Shalini and Priyanka), sister-in-law (Mrs. Aparna Tripathi), mother and father-in-law (Smt. & Shri K. C. Trivedi). Your prayers for me were what sustained me thus far. I would also like to thank my wife (Mrs. Nidhi Tripathi) especially for supporting me from all directions throughout doing research work, writing this thesis. Last but not least, I would like to express appreciation to my loving son Yashvardhan who missed me a lot when I was busy in doing my research. Finally, I solicit the blessing of God for prosperity with good health. (Rohit Tripathi) ii

6 Abstract In the present thesis, the performance of N-partially covered photovoltaic thermal compound parabolic concentrator (PVT-CPC) collector connected in series have been analyzed on annual basis. Two mode of operation have been considered for the performance evaluation as namely (i) constant mass flow rate and (ii) constant collection temperature mode. An analytical expression for outlet fluid temperature and temperature dependent electrical efficiency at N th collector of PVT-CPC collector at constant flow rate mode as a function of climatic and design parameters have been derived. The mass flow rate of fluid and number of collectors have been optimized for desired outlet fluid temperature at N th collector. The analytical results of proposed N partially covered PVT-CPC collector have been compared. It is observed that when number of collector increases, the outlet fluid temperature also increases and when mass flow rate increases, the outlet fluid temperature decreases. The number of collector has been optimized N=6 for obtaining maximum water temperature around C at mass flow rate kg/s with collector area of 1 m 2. A software program has been developed in MATLAB 2013a to determine the outlet fluid temperature at N th collector of partially covered photovoltaic thermal compound parabolic concentrator (PVT-CPC) collector for New Delhi climate conditions, India. Here, two cases or two weather conditions has been considered to compare the performance of proposed system as Case (i): January (winter season) and Case (ii): June (summer season). Here, mass flow rate and number of collector have been optimized as kg/s at number of collectors (N=6) for 97 0 C outlet water temperature at N th collector of PVT-CPC for both seasons. It is also observed that case (i) is chosen best for maximum outlet water temperature due to high ambient air temperature in summer season. iii

7 Further, a fully covered photovoltaic thermal compound parabolic concentrator (PVT- CPC) water collector at (N=1) constant flow rate has been experimentally validated for Delhi climate under clear sky condition. Here, two different cases have been considered to compare the thermal and electrical performance of proposed system. The cases have been named as case (i): fixed (non-tracking) collector and case (ii): manual-maximum power point tracking (M-MPPT) collector. It is observed that case (ii) is dominated to case (i) to achieve maximum overall exergy. It has been found that a fair agreement between theoretical and experimental results through correlation coefficient and percentage error. After validation analysis, the four series connected PVT collector have been compared to analyze the thermal and electrical performance, overall energy and exergy. Here, four cases have been discussed as series connected: case (i): N partially covered PVT-CPC collector, case (ii): partially covered PVT collector, case (iii): N-Convectional CPC collector and case (iv): N- flat plate collector. Here, two fluids: water and molten salt have been compared to evaluate the performance of proposed cases. It is observed that case (iii): N-convectional CPC has been chosen best for obtaining overall energy and exergy. But, this system is not self-sustainable due to absence of PV module. Due to this, N- partially covered PVT-CPC collector has been chosen best to obtain maximum overall thermal energy. Annual performance evaluation of proposed N partially covered PVT-CPC collector connected in series has been further discussed at constant collection mode. Here, the analytical expression for mass flow rate in term of outlet fluid temperature has been derived to consider climate parameters of proposed system. Two cases/systems have been considered to compare as namely viz: case (i): N partially covered PVT-CPC collector and case (ii): N- convectional CPC collector. Here, one other fluid has been chosen, named as ethylene glycol. The effects of water iv

8 and ethylene glycol have been obtained. It is observed that N- convectional CPC has been selected for maximum overall energy and exergy but it is not self-sustainable system. In this study, all weather conditions ( a, b, c and d types) of New Delhi, India have been considered to evaluate the annual performance of proposed system by considering four different cases on the basis of packing factor. Four cases have been named viz: case (i): 25% of collector area is covered by PV module, case (ii): 50% of collector area is covered by PV module, case (iii): 75% of collector area is covered by PV module and 100% of collector area is covered by PV module. Different types of fluids (water, molten salt) have been chosen to obtain maximum outlet fluid temperature and thermal gain which will be most useful for space heating of buildings to conserve fossil fuel to sustain environment. Based on numerical computation and analysis methods, it has been found that case (i) and case (iv) of proposed system are best suited to obtain maximum overall thermal energy and overall exergy, respectively. v

9 स र श वर तम न थ स म, एन-आ स क र प कवर सकए गए फ ट व ल ट इक थमतल क प उ ड परवलस क कन स ट र क टर (प व ट - प ) कल क टर क श र खल म ज ड व क सवश ल षण व सषतक आध र पर सक ग ह ऑपर न क द म ड क प रद तन म ल कन क सलए म न ग ह, अथ तर (i) सनर र र म सहक प रव ह दर और (ii) लग र र ग रह र पम न म ड जलव और सडज इन म नक क एक म र ह क र प म लग र र प रव ह दर म ड पर प व ट - प कल क टर क एनथ कल क टर क आउटल ट र रल र पम न और र पम न पर सनर तर सवद र दक षर क सलए एक सवश ल षण त मक असर व यक त ल गई ह र रल पद थत क द रव यम न प रव ह दर और कल क टर क ख य एनथ कल क टर पर व स र आउटल ट र रल र पम न क सलए अन क सलर सक ग ह प रस त सवर एन क सवश ल षण त मक पररण म आ स क र प प व ट - प कल क टर क र लन क गई ह ह द ख ज र ह सक जब कल क टर क ख य बढ ज र ह, र आउटल ट द रव क र पम न र बढ ज र ह और जब द रव यम न प रव ह क दर बढ ज र ह, र आउटल ट द रव क र पम न कम ह ज र ह कल क टर क ख य क असधकर म प रव ह क र पम न C क आ प जन प रव ह दर सकल ग र म प रसर क ड पर प र प त करन क सलए एन = 6 अन क सलर सक ग ह नई सदल ल जलव पररक तथथसर, र रर क सलए आ स क र प कवर फ ट व क तल टक थमतल क प उ ड परवलस क कन स ट र क टर (प व ट - प ) कल क टर क एनथ कल क टर पर आउटल ट द रव क र पम न सनध तररर करन क सलए मर लब 2013 म एक फ टव र प र ग र म सवकस र सक ग ह ह, द म मल द म म क तथथसर क प रस त सवर प रण ल क प रद तन क र लन क (i): जनवर ( सदत क म म) और म मल (ii): ज न (गम क म म) क र प म करन क सलए म न ग ह ह, द न जन क सलए प व ट - प क एनथ कल क टर पर 97 0 C आउटल ट प न क र पम न क सलए कल क टर क ख य पर जन प रव ह दर और कल क टर क ख य क सकल ग र म प रसर क ड क र प म अन क सलर सक ग ह (एन = 6) ह र द ख ज र ह सक गम क म म म उच च पररव व र पम न क क रण म मल (i) असधकर म आउटल ट जल र पम न क सलए वतश ष ठ च न ज र ह इ क अल व, एक प णतर कवर फ ट व ल ट इक थमतल क प उ ड परवलस क क न ट र क टर (प व ट - प ) प न कल क टर (एन = 1) सनर र र प रव ह दर पर प र ग सक ज र ह, ज सक सदल ल क व र वरण क सलए स पष ट र प आक क क तथथसर क र हर म न य ह ह, प रस त सवर प रण ल क थमतल और इल क तक टर कल प रद तन क र लन करन क सलए द अलग-अलग म मल पर सवच र सक ग ह म मल क म मल (i) क र प म न समर सक ग ह : सफक स ड (न न-टर सक ग) कल क टर और क (ii): म न अल-असधकर म प वर प व इ ट टर सक ग (एम-एमप प ट ) कल क टर ह द ख ग ह सक म मल (ii) म मल पर ह व ह (i) असधकर म मग र प दर प र प त करन क सलए ह प ग ह सक ह ब ध ग ण क और प रसर र त र सट क ब च द सर क और प र सगक पररण म क ब च एक उसचर मझ र ह त य पन सवश ल षण क ब द, प व ट कल क टर ज ड च र श र खल ओ क र लन थमतल और इल क तक टर कल प रद तन, मग र ऊज त और प क सवश ल षण क गई ह म मल म (i): एन आ स क र प कवर सक ग प व ट - प कल क टर, म मल (ii): एन आ स क र प प व ट कल क टर, म मल (iii): एन- कन व क शनल प कल क टर और क (iv): एन फ ल ट प ल ट कल क टर ह, च र म मल क अलग अलग श र खल ज ड ह आ ह एन-फ ल ट प ल ट कल क टर ह, द र रल पद थत: प रस त सवर म मल क प रद तन क

10 म ल कन करन क सलए प न और क र लन क गई ह ह द ख ग ह सक म मल (iii): एन-कन वक शतनल प क मग र ऊज त और प दर प र प त करन क सलए वतश ष ठ च न ग ह ल सकन, प व म ड य ल क अन पक तथथसर क क रण ह प रण ल आत मसनर तर नह ह इ वजह, एन-आ स क र प कवर सकए गए प व ट - प कल क टर क असधकर म मग र र प ऊज त प र प त करन क सलए वतश ष ठ च न ग ह श र खल म ज ड प रस त सवर एन आ स क र प कवर सकए गए प व ट - प कल क टर क व सषतक प रद तन म ल कन क लग र र ग रह म ड म आग चच त क गई ह ह, आउटल ट र रल र पम न क अवसध म जन प रव ह दर क सलए सवश ल षण त मक असर व यक त प रस त सवर प रण ल क जलव म नक पर सवच र करन क सलए ल गई ह द म मल / प रण सल क र लन करन क सलए म न ज र ह ज सक: म मल (i): एन आ स क र प प व ट - प कल क टर और म मल (ii): एन-कन वक शतनल प कल क टर ह, एक अन य र रल पद थत क च न ग ह, सज इथ इल न ग ल इक ल कह ज र ह प न और इथ इल न ग ल इक ल क प रर व प र प त सकए गए ह ह द ख ग ह सक एन-कन वक शतनल प क असधकर म मग र ऊज त और प दर क सलए च न ग ह ल सकन ह स व -थथ प रण ल नह ह इ अध य न म, नई सदल ल, र रर क र म म पररक तथथसर ('ए', 'ब ', ' ' और 'ड ') क आध र पर च र अलग-अलग म मल पर सवच र करक प रस त सवर प रण ल क व सषतक प रद तन क म ल कन करन क सलए सवच र सक ग ह प सक ग क रक म मल (i): कल क टर क ष त र क 25% प व म ड य ल, क (ii) कल क टर क ष त र क 50% प व म ड य ल, क (iii) कल क टर क ष त र क 75% ह ज प व म ड य ल द व र कवर सक ग ह और (iiv) कल क टर क ष त र क 100% प व म ड य ल द व र कवर सक ग ह सवसर न न प रक र क र रल पद थत (प न, म ल ट न ल ट) क असधकर म आउटल ट र रल र पम न और थमतल ल र प र प त करन क सलए च न ग ह ज प तवरण व र वरण क बन ए रखन क सलए ज व श म ई धन क रक षण क सलए इम रर क अ र ररक ष ह सट ग क सलए ब उप ग ह ग ख य त मक गणन और सवश ल षण सवसध क आध र पर, ह प ग ह सक म मल (i) और प रस त सवर प रण ल क म मल (iv) म क स प र प त करन क सलए ब उप ह

11 Table of contents Certificate Acknowledgements Abstract Table of content List of figures List of tables Nomenclature i ii iii vii xii xix xx CHAPTER I General Introduction 1.1 Introduction Photovoltaic thermal (PVT) collector Historical background of photovoltaic thermal (PVT) system Classification and applications Solar concentrator Classification of solar concentrator Based on design Based on solar tracking Working principal and review of Compound parabolic concentrator 13 (CPC) Conventional compound parabolic concentrator (CCPC) Photovoltaic thermal compound parabolic concentrator 16 (PVT-CPC) 1.4 Challenges Objectives Organization of chapters 19 vi

12 CHAPTER II Thermal modeling of N identical partially covered photovoltaic thermal compound parabolic concentrator (PVT- CPC) collector connected in series: A constant flow rate mode 2.1 Introduction Working principle of the proposed system Thermal modeling Results and discussion Summary 36 CHAPTER III An experimental validation of a fully covered photovoltaic thermal compound parabolic concentrator (PVT-CPC) water collector 3.1 Introduction Systems description Fixed concentrated PVT collector [case (i)] Manual (M)-MPPT concentrated PVT collector[case (ii)] 44 Thermal modeling Thermal energy and exergy Instantaneous thermal efficiency Electrical gain Overall energy and exergy Experiment Setup Statistical Analysis Methodology 54 vii

13 3.7 Results and discussion Summary 63 CHAPTER IV Comparison of thermal performance of various series connected: photovoltaic thermal (PVT) systems at constant flow rate 4.1 Introduction Systems description Thermal modelling Proposed cases Thermal energy and exergy of cases Electrical gain Overall energy and exergy Methodology Results and discussion Summary 83 CHAPTER V Comparative study for N-partially covered photovoltaic thermal compound parabolic concentrator (PVT- CPC) and convectional compound parabolic concentrator (CPC) collector: A constant collection temperature mode 5.1 Introduction System description Thermal modelling N-partially covered photovoltaic thermal compound parabolic concentrator (PVT-CPC) collector connected in series N-convectional compound parabolic concentrator (CPC) collector connected in series viii

14 5.4 Thermal analysis Electrical analysis Overall thermal energy and exergy analysis Enviroeconomic (carbon mitigation and credits) analysis Results and discussion Summary 102 CHAPTER VI Energy and exergy performance of N partially covered photovoltaic thermal compound parabolic concentrator (PVT-CPC) collector connected in series. 6.1 Introduction Descriptions: systems, fluids and weather conditions N-Partially covered (25% PV covered area on collector) PVT-CPC collector connected in series [Case (i)] N-Partially covered (50% PV covered area on collector) PVT-CPC collector connected in series [Case (ii)] N-Partially covered (75% PV covered area on collector) PVT-CPC collector connected in series [Case (iii)] N-fully covered (25% PV covered area on collector) PVT-CPC collector connected in series [Case (iv)] Annual overall energy and exergy analysis CO2 mitigation and carbon credits analysis Carbon dioxide (CO2) mitigation Carbon credits Methodology Results and discussion 110 ix

15 6.6 Summary 118 CHAPTER VII Conclusions and recommendations 7.1 Conclusions Future scope and recommendations 122 References 123 Appendix 143 List of publications 154 Brief bio-data of the author 160 x

16 List of figures Figure No. Figure Caption Page No. Figure 1.1: Flow diagram of solar energy utilization. 3 Figure 1.2 (a): Horizontal cut section of photovoltaic thermal (PVT) collector 5 Figure 1.2 (b): Vertical cut section of photovoltaic thermal (PVT) collector. 5 Figure 1.2 (c): Picture of photovoltaic thermal (PVT) collector. 5 Figure 1.3: Classification of photovoltaic thermal (PVT) systems 11 Figure 1.4 (a): Schematic cross section of a compound parabolic concentrator. 14 Figure 1.5: Figure 2.1 (a): Figure 2.1 (b): Figure 2.2 (a): Figure 2.2 (b): Figure 2.3: Actual picture of fully covered photovoltaic thermal compound parabolic concentrator (PVT-CPC) collector. Cross section side view of proposed partially covered PVT-CPC system Cut-sectional front view at XX of proposed partially covered PVT- CPC collector. Proposed system-arrangement of N-PVT-CPC water collector connected in series at cut section. Proposed system of N-PVT-CPC water collector connected in series at cut section with different arrangement of connecting method. Hourly variation of beam radiation and ambient air temperature for a typical day in month of January and June Figure 2.4: Hourly variation of outlet water temperature for partially covered N- 32 Figure 2.5 (a): PVT-CPC water collector for a typical day in month of January and June. Hourly variation of average flowing water temperature, T f for partially covered N-PVT-CPC water collector for a typical day in month of January and June. 33 xi

17 Figure 2.5 (b): Figure 2.5 (c): Figure 2.6: Figure 2.7 (a): Figure 2.7 (b): Figure 2.8: Figure 3.1: Figure 3.2: Figure 3.3 (a): Figure 3.3 (b): Hourly variation of average absorber plate temperature, T p for partially covered N-PVT-CPC water collector for a typical day in month of January and June Hourly variation of average solar cell temperature, T c for partially covered N-PVT-CPC water collector for a typical day in month of January and June. Hourly variation of electrical efficiency and solar cell temperature for partially covered N-PVT-CPC water collector for a typical day in month of June Hourly variation of outlet water temperature, T fon with different values of mass flow rate, for partially covered N-PVT-CPC water collector for a typical day in month of January Hourly variation of outlet water temperature, T fon with different values of mass flow rate, for partially covered N-PVT-CPC water collector for a typical day in month of June. Variation of maximum outlet water temperature at N th collector of partially covered PVT-CPC with varying number of collectors at constant mass flow rate Experimental setup for a (N=1) fully covered photovoltaic thermalcompound parabolic concentrator (PVT-CPC) water collector in forced mode. Internal diagram for collector of fully covered photovoltaic thermalcompound parabolic concentrator (PVT-CPC) Actual photograph of experiment set up (front view) for fully covered (PVT-CPC) water collector in forced mode [case (i)] Actual photograph of experiment set up (side and top view) for fully covered PVT-CPC water collector in forced mode [case(i)] xii

18 Figure 3.4 (a): Figure 3.4 (b): Figure 3.5 (a): Figure 3.5 (b): Figure 3.6: Figure 3.7: Figure 3.8: Figure 3.9: Figure 3.10 (a): Figure 3.10 (b): Front view diagram for manner of observation for manual MPPT of fully covered photovoltaic thermal-compound parabolic concentrator (PVT-CPC) collector [case (ii)] (from hr hr hr). Actual photograph of experiment set up (front view) for fully covered photovoltaic thermal-compound parabolic concentrator (PVT-CPC) collector in forced mode [case (ii)] (right to left - from hr [1] hr [2] hr [3] Hourly variation of beam radiation for theoretical and experimental for cases (i-ii) for clear sky condition in month of September Hourly variation of ambient air temperature for theoretical and experimental for cases (i-ii) for clear sky condition in month of September Hourly variation of outlet water temperature from the collector for theoretical and experimental for both cases in clear sky condition, month of September Hourly variation of water temperature in the tank for theoretical and experimental for both cases in clear sky condition, month of September Hourly variation of solar cell temperature for theoretical and experimental for both cases in clear sky condition, month of September Hourly variation of temperature dependent electrical efficiency of PV module for theoretical and experimental for both cases in clear sky condition, month of September. Hourly variation of temperature dependent electrical efficiency of PV module for theoretical and experimental for both cases in clear sky condition, month of September. Hourly variation of experimental instantaneous electrical efficiency for both cases (i-ii) in clear sky condition, month of September xiii

19 Figure 3.11 (a): Figure 3.11 (b): Figure 3.12 (a): Figure 3.12 (b): Figure 4.1 (a): Figure 4.1 (b): Figure 4.2 (a): Figure 4.2 (b): Figure 4.3 (a): Figure 4.3 (b): Figure 4.4 (a): Figure 4.4 (b): Monthly variation of beam radiation for theoretical and experimental for cases (i-ii) in a year. Monthly variation of experimental electrical gain for both cases (i-ii) in a year Monthly variation of experimental overall thermal energy gain for both cases (i-ii) in a year Monthly variation of experimental overall exergy for both cases (i-ii) in a year Series connected N number of partially covered Photovoltaic thermal (PVT) - compound parabolic concentrator (CPC) collectors [case (i)] Isometric view of partially covered N- photovoltaic thermalcompound parabolic concentrator (PVT-CPC) collectors connected in series. [Case (i)] Schematic diagram of partially covered N Photovoltaic thermal (PVT) collector connected in series [case (ii)] Isometric view of N-photovoltaic thermal (PVT) collector connected in series [Case (ii)] Schematic diagram of N-Compound parabolic concentrator (CPC) collectors connected in series [case (iii)] Isometric view of N-convectional compound parabolic concentrator (CPC) collectors connected in series. [Case (iii)] Schematic diagram of N Flat plate collector (FPC) connected in series [case (iv)] Isometric view of N-convectional flat plate collector (FPC) connected in series. [Case (iv)] Figure 4.5: Flow chart for annual analysis of proposed PVT systems 76 Figure 4.6: Hourly variation of total radiation, beam radiation and ambient air temperature for a clear day in month of January, New Delhi, India. 77 xiv

20 Figure 4.7: Figure 4.8: Figure 4.9: Figure 4.10: Figure 4.11: Figure 4.12 (a): Figure 4.12 (b): Figure 4.13 (a): Figure 4.13 (b): Figure 5.1 Figure 5.2: Figure 5.3: Figure 5.4: Hourly variation of outlet fluid temperature of four different systems (all cases) for a clear day in month of January, New Delhi, India Effect of collectors to maximum outlet fluid temperature for case (i) and case (ii) in a clear day, month of January Hourly variation of average solar cell temperature and electrical efficiency of PV module for partially covered N-PVT-CPC collector connected in series for [case (i) (a)] and [case (i) (b)] (molten salt and water Hourly as variation a fluid, respectively). of thermal exergy of all proposed cases (i-iv) of PVT systems in a clear day, January Hourly variation of electrical gain of [case (i) (a)] and [case (ii)] in a clear day, January. Hourly variation of overall thermal energy gain of all proposed PVT systems [cases (i-iv)] in a clear day, January Hourly variation of overall exergy of all proposed PVT systems [cases (i-iv)] in a clear day, January Monthly variation of overall thermal energy gain of all proposed PVT systems [cases (i-iv)] in a year. Monthly variation of overall exergy of all proposed PVT systems [cases (i-iv)] for a clear day condition, in a year. Proposed System: one arrangement of N-PVT-CPC water collectors connected in series. [Case (i)]. Series connected N-Convectional compound parabolic concentrator (CPC) collector. [Case (ii)]. Hourly variation of mass flow rate of N-PVT-CPC collector [case (i)] for two different fluid: water and ethylene glycol Hourly variation of average solar cell temperature to electrical efficiency of PV module of N-PVT-CPC collector [case (i)] for two fluids: water and ethylene glycol xv

21 Figure 5.5: Figure 5.6: Figure 5.7: Figure 5.8: Figure 5.9 (a): Figure 5.9 (b): Figure 5.9 (c): Hourly variation of mass flow rate of N-PVT-CPC collector [case (i)] for different constant collection temperature for a clear day condition in January, New Delhi. Hourly variation of mass flow rate at constant collection temperature (150 0 C) for N-PVT-CPC collector [case (i)] and N- CPC collector [case (ii)] with fluid: ethylene glycol.. Hourly variation of overall thermal energy gain at constant collection temperature (150 0 C) for N-PVT-CPC collector [case (i)] N- CPC collector [case (ii)] with fluid: ethylene glycol. Hourly variation of overall exergy at constant collection temperature for N-PVT-CPC collector [case (i)] N- CPC collector [case (ii)] with fluid: ethylene glycol. Monthly variation of electrical gain for N-PVT-CPC collector [case (i)] and N-CPC [case (ii)] with fluid: ethylene glycol at constant collection temperature mode. Monthly variation of overall thermal energy gain for N-PVT-CPC collector [case (i)] and N-CPC [case (ii)] with fluid: ethylene glycol at constant collection temperature. Monthly variation of overall exergy for N-PVT-CPC collector [case (i)] and N-CPC [case (ii)] with fluid: ethylene glycol at constant collection temperature mode Figure 6.1: Series connected partially covered N-PVT-CPC collector 108 Figure 6.2: Flow chart (Methodology) for analysis of N-PVT-CPC collector 111 Figure 6.3: Hourly variation of average solar cell temperature and electrical efficiency of PV module at the end of N th collector of PVT-CPC collector. 112 xvi

22 Figure 6.4: Figure 6.5: Figure 6.6: Figure 6.7: Figure 6.8: Figure 6.9: Figure 6.10: Hourly variation of outlet fluid temperature at the end of N th collector of PVT-CPC collector for a day of clear day condition, New Delhi, India Hourly variation of electrical gain of proposed system for all cases (i-iv) including both fluids: molten salt and water Hourly variation of overall thermal energy for all cases (i-iv) including both fluids: molten salt and water. Hourly variation of overall exergy system for all cases (i-iv) including both fluids: molten salt and water, clear day condition, New Delhi, India. Monthly variation of electrical gain of proposed systems [case (i-iv)] considering all weather conditions with both fluids in a year Monthly variation of overall thermal energy of proposed systems [case (i-iv)] considering all weather conditions with both fluids in a year Monthly variation of overall exergy of proposed systems [case (i-iv)] considering all weather conditions with both fluids in a year Figure 6.11 (a): Figure 6.11 (b): Variation of different cases to CO2 mitigation per annum of proposed system on the basis of overall thermal energy and exergy gain. Variation of different cases to cost to CO2 mitigation (carbon credits) per annum of present system on the basis of overall thermal energy and exergy gain xvii

23 List of tables Table No. Table Caption Page No. Table 2.1: Design parameters of N-PVT-CPC collector system, used in 26 analytical computation. Table 3.1 Least count of measuring instruments used in experimental study 46 Table 3.2: Table 4.1: Table 5.1: Table 5.2: Values of design parameters of fully covered PVT-CPC collector [cases (i-ii)]. Values of design parameters of N-PVT-CPC collector and other proposed systems Mass flow rate of the ethylene glycol to the corresponding constant collection temperature (Tcc) at N th collector of PVT-CPC [case (i)] Mass flow rate of the ethylene glycol to the corresponding constant collection temperature (Tcc) at N th collector of CPC system [case (ii)] Table 5.3 (a): CO2 mitigation of partially covered N-PVT-CPC collector [case (i)] and N-N-CPC collector [case (ii)] on the basis of annual energy and exergy gain Table 5.3 (b): Carbon credits of partially covered N-PVT-CPC collector [case (i)] and N-N-CPC collector [case (ii)] on the basis of energy and exergy gain for n=30 year Table 6.1: Annual CO2 mitigation and carbon credits of all proposed cases (i-iv). 118 xviii

24 Nomenclature A area (m 2 ) A a total aperture area (m 2 ) ( A a A am A ac ) A am aperture area over PV module (m 2 ) A ac aperture area over glazed portion (m 2 ) A r total receiver area (m 2 ) ( A r A rm A rc ) A rm receiver area covered by PV module (m 2 ) A rc receiver area covered by glass (m 2 ) B B o breadth of receiver (m) breadth of aperture area (glass) (m) C f Dx F ' specific heat of fluid (J/kgK) elemental length (m) flat plate collector efficiency factor F R flow rate factor, dimensionless H heat transfer coefficient, ( W/ m 2 K ) L rm length of receiver covered by PV module (m) L rc length of receiver covered by glass (m) L r PF 1 PF 2 PF c total length of the aperture area (m) first penalty factor due to glass cover second penalty factor due to absorber/receiver plate penalty factor due to glass cover for the portion covered by glazing I t total radiation, ( W/m 2 ) xix

25 I b beam radiation, ( W/m 2 ) I d diffuse radiation, ( W/m 2 ) m f mass flow rate of water in (kg/sec) U t,ca overall heat transfer coefficient from solar cell to ambient through glass cover U t,cp overall heat transfer coefficient from solar cell to plate (W/m 2 K) U t,pa total (top and bottom) overall heat transfer coefficient from plate to ambient (W/m 2 K) U L1 overall heat transfer coefficient from blackened surface to ambient ( W/m 2 K ) o efficiency at standard test condition ( I t =1000 W/m, T o =25 0 C) o temperature coefficient of efficiency (K -1 ) Abbreviations CCPC conventional compound parabolic concentrator CPC compound parabolic concentrator PVT-CPC photovoltaic thermal compound parabolic concentrator CPT PVT parabolic trough photovoltaic thermal Greek Letters c i ( ) eff absorptivity packing factor reflectivity transmittivity instantaneous thermal efficiency product of effective absorptivity and transmittivity xx

26 Subscript a c eff fi fo g m p ambient solar cell effective inlet fluid outlet fluid glass module plate xxi