A spectral-splitting PV-thermal volumetric solar receiver

Abstract

Spectral beam splitting of sunlight can improve the efficiency of solar receivers. Hybrid photovoltaic-thermal receivers designed for the concurrent generation of high grade heat and electricity can benefit considerably from this approach. In this paper, we introduce a novel method for filtering sunlight for high temperature hybrid solar receivers employed in linear solar concentrators. In this method, semiconductor doped glass is combined with propylene glycol to act simultaneously as the heat transfer fluid and a band pass filter for the optimal wavelength band, 700-1100 nm, required by silicon (Si) solar cells. Ray tracing and experimental analysis of the proposed design has shown that this filtering method directs 29% of the incoming concentrated solar spectrum to the silicon cells in the receiver with the remainder absorbed as heat. This means that 77% of the light in the optimal spectral band is effectively collected by the solar cells. The cell efficiency under this band can reach 26% in theory. The results demonstrate the potential for a simpler spectral filtering mechanism that is suitable for concentrating hybrid solar receivers.