Use of Silicone Oil and Coconut Oil as Liquid Spectrum Filters for BSPVT: With Emphasis on Degradation of Liquids by Sunlight

The solar photovoltaic thermal system (PVT) facilitates conversion of incoming solar radiations into heat and electricity simultaneously. The beam split photovoltaic thermal system (BSPVT) is one of the PVT systems. In this system, the incoming solar beam is splitted and used separately for PV and thermal system. The feasibility of water, silicone oil, and coconut oil as spectrum filter for C–Si solar photovoltaic system is reported in the literature recently. However, the changes in the optical behavior of the liquids due to extended exposure to sunlight (aging effect) had not been considered in most of the previous studies. The current study includes the methodology for the selection of liquids for BSPVT systems, estimation of external quantum efficiency (EQE) of a solar cell using liquids, and the aging effect on the liquid spectrum filters. The spectral response of the solar cell is analyzed using BENTHAM, (PVE 300) for 300–1100 nm. In this study, it has been observed that the aging of silicone oil reduces the electrical performance of the solar cell. On the other hand, the aged coconut oil improves the electrical performance of the solar cell as compared to the fresh coconut oil spectrum filter.