Towards a standard approach for annual energy production of concentrator-based building-integrated photovoltaics

Abstract

A form of building-integrated photovoltaics, luminescent solar concentrators are devices used to enhance solar cell output per unit area through red-shifted, concentrated internal reflection of sunlight. Luminescent solar concentrators have shown promise, but they have yet to achieve commercial success. At present, it is prohibitively difficult for architects and solar engineers to assess their annual energy production and subsequently conceptualize their economic potential. To bridge this gap, this paper provides an approach for annual performance evaluation of luminescent solar concentrators that parallels conventional processes used internationally for existing photovoltaic projects and solar development proposals. The approach starts by following conventional processes to evaluate the plane-of-array irradiance. Then, two metrics are introduced to evaluate the effective irradiance incident on solar cells within an LSC: 1) LSC optical efficiency is employed to determine the proportion of light reaching solar cells relative to the exposed surface; 2) LSC spectral mismatch factor is defined to represent the impact of spectral differences due to absorption and luminescent emission within an LSC. These metrics have never been employed in such a context before. With their addition, the process to produce LSC energy estimates becomes analogous to the conventional process to produce estimates for solar panels. The proposed approach is first validated against the commercial software, PVsyst. Then, case studies in Albany, NY and Phoenix, AZ are conducted to present energy estimates (at the maximum power point) for solar panels, and both planar and wedge-shaped luminescent solar concentrators when mounted vertically on a southern facing surface.