Parametric Investigation of Concentrating PV/T System With Spectral Filtering Utilizing a 2-D Model

Hybrid photovoltaic/thermal (PV/T) systems are continually being investigated, in particular the use of such systems in concentrating collectors as part of the ARPA-E FOCUS program. While many combined thermal and electrical models exist, most are limited to 0-D energy balance approaches or 1-D approaches where temperature variations through insulation, glazing and substrates are considered. Here, we develop a 2-D model for a concentrating PV/T system where the model accounts for temperature variations along the length of the collector. The proposed configuration consists of a GaAs cell laminated to an aluminum extrusion. The working fluid, a transparent high temperature heat transfer fluid with suspended nanoparticles, flows through the extrusion where it actively cools the PV cell before passing in front of the cell acting as an optical filter. The model includes PV cell efficiency, temperature, and bandgap dependence, a detail often neglected in prior works. This paper focuses on PV efficiency along the length of the system and outlet fluid temperature for both counter and parallel flow arrangements. Of particular interest here is the wavelength used in the design of the fluid filter and how changing the design impacts the exergetic efficiency and percent of exergy created as heat.