Plastic photovoltaic roof tiles

Donkin, Richard Philip (2009-12)

Thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Renewable and Sustainable Energy at the Stellenbosch University.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009.

Thesis

ENGLISH ABSTRACT: This project investigated the feasibility of incorporating photovoltaic cells into plastic roof tiles using injection moulding. Such tiles have the potential to provide robust and distributed electricity contained within the building envelope. Current-voltage curves of amorphous silicon modules were measured under illumination using the PVPM 2540C power measuring instrument, both before and after moulding. The efficiency after moulding was reduced by 53% to 88%, with modules that were heated for longer being degraded more. Thus the duration of exposure to high temperatures affected the extent of performance reduction during moulding. This suggested that faster moulding at a lower temperature or faster cooling could solve the problem. Economic feasibility was examined by calculating the levellised cost of electricity provided by the tiles. A large-scale development in the Western Cape was simulated using a typical meteorological year of weather data and using the anisotropic diffuse irradiance model of Perez et al. (1988). Avoided costs due to replaced roofing, avoided costs due to electricity distribution infrastructure, and Clean Development Mechanism credits were accounted for. The cost of energy calculated was R11/kWh in 2010 rands, which did not compete with the price of conventional grid-based electricity at R1.8/kWh. The importance of the cost of balance-of-system components, such as the inverter, and not only of the photovoltaic modules, was highlighted for future cost reductions. Several clear guidelines for manufacturing photovoltaic roof tiles were discovered. The most important of these was that many bypass diodes make the system more robust.

AFRIKAANSE OPSOMMING: Hierdie projek het die haalbaarheid van die integrasie van fotovoltaïse selle in plastiek dakteëls deur spuitvorming ondersoek. Sulke dakteëls het die vermoë om robuuste en verspreide elektrisiteit te lewer, sonder om die gebou se vorm te verander. Stroom-spanning kurwes van struktuurlose silikon eenhede is onder verligting gemeet met die PVPM 2540C kragmeet instrument, voor en na spuitvorming. Die doeltreffendheid na spuitvorming is met 53% tot 88% verminder, met groter vermindering in die eenhede wat langer warm was. Dus het die duur van blootstelling aan hoë temperature die mate van vermindering van doeltreffendheid beïnvloed. Dit het suggereer dat óf vinniger spuitvorming by laer temperature óf vinniger verkoeling die probleem kan oplos. Ekonomiese haalbaarheid is ondersoek deur die koste van die elektrisiteit wat deur die dakteëls gelewer is te bereken. ’n Groot behuisingsontwikkeling in die Wes-Kaap is gesimuleer deur ’n tipiese weerkundige jaar van weerdata en die anisotroop model vir verspreide ligstraling van Perez et al. (1988) te gebruik. Vermyde kostes van vervangde dakteëls, vermyde kostes van elektrisiteit distribusie infrastruktuur en krediete van die Meganisme vir Skoonontwikkeling is in ag geneem. Die elektrisiteitskoste was R11/kWh in 2010 se randwaarde, wat nie mededingend met die R1.8/kWh koste van gewone netwerk elektrisiteit was nie. Die belang van die kostes van die res van die installasieonderdele, soos die wisselrigter, en nie net die fotovoltaïse eenhede nie, is beklemtoon vir kostevermindering in die toekoms. Verskeie duidelike riglyne vir die vervaardiging van fotovoltaïse dakteëls is voorgestel. Die belangrikste van hierdie was dat meer omloopdiodes die installasie meer robuust maak.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/4397