Enhancing the Performance of Photovoltaic Thermal Solar Collectors using Twisted Absorber Tubes and Nanofluids with Optimal Design Parameters

Abstract

A Photovoltaic Thermal Solar Collector (PVT) is a technology that combines the benefits of photovoltaic panels (PV) and solar thermal collectors. This study introduces a novel approach by incorporating twisted absorber tubes and nanofluids as working fluids into the PVT system. This innovative design aims to enhance the efficiency of the PV modules while simultaneously generating hot water. Computational Fluid Dynamics (CFD) simulations were used to determine the optimal header tube diameter and the number of absorber riser tubes. Increasing the number of riser tubes from 7 to 11 resulted in a decrease in the PV panel temperature from 73.41°C to 65.5°C, with a minimal further decrease observed at 13 tubes (64.6°C). The optimal values determined were a header tube diameter of 51mm and 11 absorber riser tubes. The implementation of twisted tubes resulted in significant improvements in the photovoltaic, thermal, and combined photovoltaic-thermal efficiencies. Specifically, the combined photovoltaic-thermal efficiency increased from 61.2% to 84.6% at a mass-flow rate of 0.04kg/s and a solar irradiance level of 800W/m2. Furthermore, by employing nanofluids, we observed even more significant gains in the combined photovoltaic-thermal efficiency, which further increased from 84.6% to 88.2%. These findings provide valuable insights into the design of high-performance fluid-based PVT systems and, furthermore, highlight the exceptional potential of twisted tubes combined with nanofluids for enhancing overall system performance. The integration of these innovative elements showcases a significant advancement in PVT technology, offering promising opportunities for sustainable energy generation.