Design and testing of a modular photovoltaic and insulation solution for flat roofs

Abstract

The study presented in this dissertation sought to design, develop, and test a combined modular photovoltaic and insulation solution for flat roofs, which was based on a conceptual design referred to as MedSolar. MedSolar sought to present a building integrated photovoltaic which is specifically designed for the requirements of Malta, and other countries with similar climatic conditions, adding value in terms of increased energy generation, minimised aesthetics and improved ease of installation This study optimised the initial conceptual design, and further altered the optimised design into a prototype, resulting in nine variants with most of them tested. The design incorporated features such as insulation, reflectors placed within the space between two sets of custom designed photovoltaic (PV) modules, wiring embedded within the design, and modularity features. An experimental campaign studied the energy generated from set ups with the following configurations: Flat PVs, PVs with a tilt angle of 30° with and without reflectors, and PVs with a tilt angle of 15° with and without reflectors. The experiment also studied the impact of the design itself had on the performance of the full-scale prototype. Data from different seasons were collected, and overall, the configuration with reflectors having PVs tilted at 30° yielded the best results. The same configuration was found to produce exceptional results during the summer month, with the reflector aiding in an increase of 15% in energy generation when compared to its counterpart without reflector whilst at the same time shielding the MedSolar tile from direct solar irradiance. Reflectors used for the configuration with PVs tilted at 15° were also found to be very effective, but not effective during the summer months. In addition, reflectors were found to be effective on days with significant cloudiness, leading to the conclusion that reflectors were effective in reflecting diffused irradiance onto the surface of the opposing custom PV module. In addition, reflectors from adjacent PV modules were found to be positively impacting electricity generation. Finally, this study contributed towards the research in the field of insulation incorporated within building integrated photovoltaics (BIPVs), which during the Literature Review was found to be very limited. Testing of the effectiveness of insulation during the summer months found that insulation incorporated within the proposed tiles was very effective, resulting in a significant reduction in the U-Value when compared to the original U-Value of the roof section that was studied.