In concentrating photovoltaic systems (CPV) the incident solar radiation is multiplied by a factor equal to the concentration ratio. The electricity production per cell area is increasing almost linear with the concentration ratio. Concentration on PV cells surface, directly results in a proportional temperature increase, deteriorating the performance of the cells. To cope with this effect, in some configurations the cells are cooled and the removing heat is then used for other purposes, like for domestic hot water production, resulting in a CPV/Thermal (CPV/T) configuration. On the other hand, Organic Rankine Cycle (ORC) is one the most efficient technologies to convert heat to power. The proposed innovative concept deals with the conversion of that CPV/T heat to additional electricity through the Supercritical ORC (SCORC) process. SCORC is selected because enjoys better efficiencies at low temperatures in comparison to Subcritical ORC. This integrated CPV/T-SCORC system minimizes the temperature effect on the PV cells performance and improves the annual energy productivity (in kWh/kWp). In comparison to a flat PV system a performance improvement between 15-40% is anticipated, depending on the season, along with a more efficient heat transfer from the CPV/T system to the Rankine process (i.e. lower pinch point), due to the supercritical cycle. The aim of the proposed project is to extensively study this integrated process and to develop, construct and test a hybrid CPV/T- SCORC system of 14 kWp, where CPV/T heat is effectively recovered by the SCORC process for electricity generation. A significant reduction of specific electricity cost is anticipated, reaching 0.12 €/kWh by the end of the project and around 0.10 €/kWh by 2016, making the current technology competitive in the PV market and increasing significantly the competitiveness and business cycle of the involved SMEs.
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