Abstract
This thesis investigates different approaches for enhancing the performance of photovoltaic solar panels and optimising energy generation using photovoltaic thermal techniques that provide electrical and thermal energy from the same device. A comprehensive literature review for the last two decades showed that photovoltaic thermal systems are promising in terms of efficiency, area utilisation and economics but still need more development to be ready for the energy market.An active photovoltaic thermal system with Multi Walls Carbon Nano Tubes (MWNCT) Nanofluid as a working medium was first investigated under outdoor test conditions. It proved that the overall system efficiency could be as high as 61%, including thermal and electrical energies. A numerical model was also created using ANSYS Fluent. It was validated against outdoor and indoor test conditions and showed that it could simulate the thermal performance with an accuracy of +/- 1ᵒ C compared to the experimental data. An improved exergy model that can be used for lower solar radiation levels was introduced, and an average exergetic efficiency of 16.6 % was achieved using 0.075% MWCNT Nanofluid.
A novel passive cooling system called a water evaporative-based cooling system was introduced in this research using saturated activated alumina tablets and hydrogels attached to the back surface of the solar panels. The PV cooling system was tested under indoor test conditions, showing that it could achieve a temperature reduction of approximately (9-13) ͦ C, compared with the uncooled PV system. The system was also tested using saline water as a saturation/evaporation agent with the activated alumina tablets and showed viability up to salinity of 35 Particles Per Thousands (PPT). A novel photovoltaic thermal system was also introduced by recovering the heat stored within the activated alumina tablets. When using a 10 cm depth of activated alumina, the photovoltaic thermal efficiency of the proposed system was calculated as 53.6% at 1000 W/m2.
CuO and Al₂O₃ Nanofluids were also used as hydrogel saturation agents and proved to perform better than water alone. They could achieve a temperature reduction as high as 17 ᵒC compared with the uncooled panel. An economic analysis was done using the Break-Even Analysis method. Results indicated that hydrogels saturated with 0.25% CuO could have a pay back period of 12 years.
| Date of Award | 27 Sept 2022 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Mike Tierney (Supervisor) & Hind Saidani-Scott (Supervisor) |