Investigation of a nanofluid‐based photovoltaic thermal system usingsingle‐wallcarbon nanotubes: An experimental study

The temperature of photovoltaic cell is reduced by heat transfer fluids (HTF) in cooling channels, which are attached to the back of the photovoltaic module in a hybrid thermal photovoltaic system (PV/T). Recently, nanofluids have been implemented as HTF's in PV/T systems. Various types of nanofluids have been synthesized, prepared, and tested, however, not a specific type in particular. In this paper, experiments were carried out using Single-walled carbon nanotubes (SWCNTs) nanofluids. The proposed nanofluid consisted of a primary fluid that is water with a volume ratio of 75.0% and glycol Ethylene with a volume ratio of 25% and a surfactant, Cetyltrimethylammonium Bromide(CTAB), in an amount of 0.5 mL. Single-walled carbon nanotubes (SWCNTs) were added in four weight ratios of 0.1%, 0.5%, 1.0%, and 2.0%. The samples were examined and compared based on their thermophysical properties, and from these properties, a volume fraction of 0.5% SWCNT was chosen to form the nanofluid. In this study, the performance characteristics of the PV/T were investigated. The results of the study showed that the proposed nanofluid caused an increase in the electrical power generated by 11.7% while the electrical efficiency of PV/T was increased up to 25.2% compared to the PV system. It is found that the cell temperature reduced by 18% on average for a whole day operation. The studied PV/T system produced an impressive overall efficiency of 71% compared to the PV system, which generated no more than 11%. SWCNTs have shown superior results in improving the performance of the studied PV/T system compared to other types of nanofluids used in PV/T systems in the literature.