Deciding between concentrated and non-concentrated photovoltaic systems via direct comparison of experiment with opto-thermal computation

摘要

Concentrated photovoltaic system provides higher efficiency at the expense of complexity and cost. A direct comparison in performance is made between concentrated and non-concentrated PV units. It is observed that a concentrated system outperforms, not for all, but only for a range of insolation. The range depends majorly on the relative difference between the conversion efficiencies of the PV materials. Inhouse experiments are performed to evaluate the performance metrics. A GaAs based concentrating PV module is characterized showing nominal efficiency and temperature coefficient to be 24.0% and -0.045%/degrees C, respectively. A Fresnel lens based tracked concentrator system is designed, fabricated and characterized under different DNI, ambient temperatures and operating cell temperatures (maintained by constant temperature coolant flow). An opto-thermal model, validated against the aforementioned experiments, is employed to make systematic comparison under different insolations. As for example, a CPV system (with CR = 90) with 40%-efficient cells outperforms an NCPV system with 25%-efficient cells only above DNI similar to 630 W/m(2). Exact value of the critical DNI depends on other operating conditions and effective conversion efficiencies. Here, the presumption of better performance of CPV system under all conditions is proven incorrect and a general methodology is provided for such an important design decision. (C) 2021 Elsevier Ltd. All rights reserved.