Long term performance analysis of low concentrating photovoltaic (LCPV) systems for building retrofit

Abstract

Low concentrating photovoltaic (LCPV) systems offer viable solution for generating higher energy output per unit cell area compared to a typical flat PV panel, making them potential candidates for building retrofit. However, the best LCPV geometry for a given location is yet to be identified. The current study investigates the technical, economic and environmental feasibility of three geometrically equivalent LCPV designs installed at a building within Brunel University London (UK). The studied LCPV systems comprised of Asymmetric Compound Parabolic Concentrating (ACPC), Compound Parabolic Concentrating (CPC) and V-Trough optical concentrators with the post-truncation geometric concentration ratios of 1.53, 1.46, 1.40 respectively. The performances of the prototypes have been monitored every 15 min over 10 months and analyzed on hourly, daily, and monthly basis. Performance parameters such as reference yield, array yield, performance ratio, electrical conversion efficiency and the generated energy output per unit area have been derived and presented. Payback periods have been estimated in two separate scenarios. Measurements have showed that the ACPC integrated LCPV achieved the highest annual optical efficiency generating the highest amount of electrical energy per unit cell area of 246.2 kWh/m2 compared to CPC-LCPV, V-Trough-LCPV and conventional flat modules which produced 224.6 kWh/m2, 196.1 kWh/m2 and 185.4 kWh/m2 respectively. One particular conclusion of the study is that the ACPC based LCPVs perform better in locations where diffuse component of solar radiation is predominant as in the case of the UK. Consequently, ACPC based LCPV modules are recommended for the building retrofit in such locations.