Approaches to increase the efficiencies of solar energy conversions

This thesis discusses a number of approaches which increase the efficiency of photovoltaic (PV) cells. PV cells generate electricity they become inefficient at high temperatures. Contemporary heat dissipation approaches are reviewed to maintain PV cells at their optimal temperature. Exploiting this excess heat through a novel technology termed solar photovoltaic-thermal (PVT) system which enables both electricity and heat to be generated from a single system is the focus of the research presented in this thesis. In order to maintain an optimal PV cell temperature a number of phase change materials (PCMs) have been used in the PVT panel assembly which absorb heat whilst charging and release heat whilst discharging. A number of PCMs were tested within the PVT panels such as RT27, OM35, OM46 and OM56. PVT simulation showed that electrical output can be increased by 9% coupled with an average water temperature rise of 20°e. Four types of PVTs have been developed by modifying the standard thermal collector and standard PV panel which constitute the PVT collector and PVT panel respectively. It was observed that modification of the standard thermal collectors for PVT purpose is not feasible due to brittleness of the PV cell and the ambient high temperature in the collector. However, modification of the PV panel is feasible with the integration of a heat carrying fluid at the rear of the panel. A significant part of the research is an innovative design where a polycarbonate {PC} channel type PVT panel was developed. It was observed that the PC is a good PV base with the channels suitable for both water and PCM heat transfer. It was concluded this offered the best solution. The feasibility of a PV panel using PC and other polymers was tested for optical properties, electrical insulation, physical insulation, physical protection and climatic impact. The PV panel fabrication, testing and installation were undertaken in India. It was demonstrated that the polymer PV panels are cost effective and feasible to be fabricated locally even in a rural undeveloped environment.EThOS - Electronic Theses Online ServiceGBUnited Kingdo