UNSW School of Photovoltaic & Renewable Energy Engineering
Dielectric solar concentrators for building integration of hybrid photovoltaic-thermal systems
Alberto Riverola - University of Lleida

Alberto Riverola, at UNSW SPREE, 14 August 2018

Alberto Riverola (42Min)

University of Lleida

Alberto Riverola speaks at UNSW SPREE


Building-integrated photovoltaic-thermal (PVT) systems provide on-site cogeneration of electricity and heat with overall efficiencies around 70% and lower space utilisation compared to a separate thermal collector and PV module. Low-concentrating systems improve the cost effectiveness by using standard cells, single axis-tracking and reduced cell areas. Also, direct-immersion of solar cells in dielectric fluids brings additional benefits such as a reduction of Fresnel losses and a better temperature control. We have proposed, built, optimised and tested a low-concentration photovoltaic-thermal system (CPVT) for building fa├žade integration where the cells are directly immersed in a dielectric liquid (deionised water or isopropyl alcohol). The spectral distribution of the incident solar irradiance to which solar cells are exposed under real working conditions has been modelled. An in-depth analysis of candidate dielectric fluids has been performed. The absorptivity/emissivity of standard silicon solar cells has been modelled from the ultraviolet to the mid-infrared and validated by an experimental measurement. Then, a full ray-tracing algorithm was developed to optimise the concentrator optical design and the optimum collector was fabricated and analysed by a CFD simulation to thermally characterise it. The system performance has been studied in locations with mild winters achieving satisfactory solar fractions for domestic hot water, electrical and space heating / cooling demands.

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Brief Bio

Since 2015, Alberto has been a PhD student supervised by Prof. Dr. Daniel Chemisana in the Applied Physics Section of the Environmental Science Department at the University of Lleida. His work addresses building-integrated PVT systems through modelling and experimental approaches.