الفهرس 
Chapter (1) IntroductionOnly 14 pages are availabe for public view
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Abstract
Single-junction photovoltaic (PV) cells are considered the most straightforward method to harness solar energy. However, PV cells’ efficiencies are limited and require large installation areas to make up for their low electrical efficiency. Recently, research focus has shifted towards multi-junction concentrator photovoltaic (CPV) cells for their high efficiencies. CPV cells uses lenses to focus a higher portion of the incident solar irradiance into a smaller area, and thus reduces the required installation areas for CPV systems. Then again, due to the high intensity of the solar irradiance, CPV cells operate at higher temperature levels and require cooling systems, further adding to the cost of the CPV system. The work in this thesis is mainly aimed at utilizing a portion of the wasted heat from back of CPV cells to directly generate electricity without exceeding safe operating temperature. This is achieved by conducting an outdoor experimental investigation of a hybrid CPV/thermoelectric generator (TEG) system’s performance under a concentration ratio (CR) of 50. The experimental investigation is performed under actual atmospheric conditions, providing a reliable performance assessment of the hybrid systems. In order to perform such task, a dual-axis elliptic solar tracker is designed, fabricated, and experimentally tested. The tracker uses equations to track an elliptical path around the sun, and adjusts the altitude and solar azimuth angles accordingly. The solar tracker’s performance is measured independent of CPV cell, using two different techniques mentioned in literature. The first was a manual technique used to determine the area where the tracking error is most likely to occur. While the second was an automatic error calculation method that uses a series of light-dependent resistors. Results indicate that the maximum error in the altitude and solar azimuth angles equals 0.5°. In addition, the measured errors are independent of dust and cloudy weather. Several configurations were experimentally investigated including CPV combined with heat sink (HS), TEG-HS, CPV-TEG-HS, and CPV-TEG-micro-channel heat pipe (MCHP)-HS. The CPV cell and TEG areas were 1 cm2 and 16 cm2, respectively. At a total solar irradiance of 990 W/m2, the CPV-MCHP-TEG-HS output power was about 1.14 W, showing a significant enhancement when compared to alternate systems. The output power for CPV-HS, and CPV-TEG hybrid system were approximately 1.1 W, and 1.05 W, respectively. In addition, the electrical efficiency of CPV system and CPV-TEG hybrid system were 28%, and 24.5%, respectively. However, the electrical efficiency of hybrid CPV-MCHP-TEG was 31.2%. An additional theoretical investigation was carried out using ANSYS software to test the hybrid CPV-TEG system’s performance under a CR of 900 as given in appendix. C. The CPV system was validated with previous theoretical work in literature. Further, its performance under different configurations of heat spreader was also investigated in appendix. A. The TEG model was also validated against results obtained from manufacturer’s datasheet in appendix. B. The theoretical investigation of both CPV system and CPV-TEG hybrid system shows that the hybrid integration of the TEG with the CPV cell in the CPV-TEG hybrid system under higher CRs leads to an increase in the CPV cell’s operating temperature where the maximum electrical efficiency of the CPV system and CPV-TEG hybrid system reached 38.3%, and 30.6%, respectively. Organization of the thesis: This thesis is comprised of five chapters and five appendices as follows: Chapter (1) Introduction: This chapter shows the importance of solar energy as a renewable energy source, while listing different types of solar trackers and hybrid PV systems. Chapter (2) Literature Review: This chapter gives a thorough literature review of PV technology, different configurations of solar trackers as well as different PV-TEG hybrid configurations for both single and multi-junction solar cells. Chapter (3) Experimental Work: This chapter contains a full description of the components used in the solar tracker and CPV-TEG hybrid system. Chapter (4) Results and Discussion: This chapter contains a detailed analysis of the measured results obtained in the investigation. In addition, a comparison between performance of hybrid configurations is also presented. Chapter (5) Conclusion: Conclusions based on comparison are drawn. Appendix (A) CPV Theoretical Analysis : This appendix, Provides a theoretical investigation of performance of the CPV cell under higher CRs. Appendix (B) TEG Theoretical Analysis: This appendix, Provides a validation between the theoretical model of TEG and the TEG’s data sheet results. Appendix (C) CPV-TEG Hybrid System Theoretical Analysis: This appendix, provides a theoretical investigation of the performance of the CPV-TEG hybrid system under higher CRs. Appendix (D) Uncertainty Analysis: This appendix, contains the uncertainty analysis calculations for experimental results. Appendix (E) Tracker Equations’ Data Sample: This appendix, contains the data collected from solar tracker for a specific day. ”