Hybrid PV/T (Photovoltaic/thermal) systems are a robust alternative to the limitations of PV panels and thermal collectors in energy production. Improving their performance is therefore necessary. This article presents a new configuration of hybrid photovoltaic and thermal (PV/T) air/water-CuO/MgO/TiO₂ collector which is optimized by seeking a better combination of design parameters which maximize the exergy performance. An energy and exergy analysis of the system is carried out and a multi-objective optimization with the genetic algorithm is developed using Matlab. These to determine the values of these nine (9) design parameters such as collector tilt angle, collector area, center to center distance between tubes, inside and outside diameter of tubes and thicknesses of the cells, of the glass layer, of the insulation, of the absorber. The other parameters are taken constant and a set of optimal solutions are sought for 1000 generations. The comparison of the different numerical results from this article with the design parameters from previous work shows good agreement. It is observed that the total exergy efficiency is maximum between the values of 23.41–36.6% and the majority of the design parameters studied in general are minimum. The discussions deduced that the minimization of the components of the bi-fluid PV/T hybrid collector could reduce the losses inside the latter by favoring the cooling as well as the displacement of the heat at the back of the PV cell. This work shows that the mixture of water and ternary nanoparticles with a flow rate of 0.00575 kg/s cooled more than air at 0.008 kg/s, but the system performed better when the two fluids operated simultaneously at 0.0035 kg/s. Due to the requirement of optimal efficiency and minimum costs, the hybridization of nanoparticles presents better thermo-economic performances.

This paper aims to highlight the use of different heat transfer fluid (HTF) configurations based on vegetable oils in Parabolic Trough Solar Concentrator (PTSC). Rapeseed and jatropha oils as innovative heat transfer materials combined with SiO₂ and Al₂O₃ to obtain six (6) HTF configurations are used in a 1-dimensional PTSC model. The thermophysical properties of the nanofluids are determined from correlations derived from the literature, using Gauss-Seidel method from a numerical code developed in Matlab software. Model validation is obtained. Thermal sensitivity analysis shows that the use of rapeseed increases the thermal efficiency of the PTSC by around 4.21 % compared with jatropha. The use of nanofluids reduces thermal losses within the system due to thermal gradients. For a fixed irradiance and each 1 %-4 % increase in volume fraction, thermal efficiency increases by around 1.96 % when Al₂O₃/rapeseed is used and by 0.47 % when SiO₂/rapeseed is used compared with rapeseed. Similarly, thermal efficiency increases by around 1.98 % when Al₂O₃/jatropha is used and decreases by around 0.20 % when SiO₂/jatropha is used compared with jatropha. However, the positive effects of nanoparticles on thermal conductivity alone are not always sufficient to improve thermal efficiency, and thermal effects on heat capacity should also be considered.

This manuscript deals with a quasi-steady regime thermal analysis of a solar parabolic trough collector in the climatic conditions of the city of N'Djamena located in a Sahelian region of the Chad Republic. The objective is to develop the solar electricity potential of N'Djamena and contribute to the development of renewable energies in the country. A one-dimensional numerical model was developed in a quasi-steady regime to simulate and analyze the thermal behavior of the system. The energy balance equations governing the thermal behavior of the collector are solved by the implicit finite difference method, while considering the variation of the solar radiation over time. Initially, the model was validated by experimental data existing in the literature. Excellent agreement is observed when comparing the numerical results to experimental data. The effect of various parameters, including the type of heat transfer fluids, wind speed, and mass flow rate of fluid, on the thermal performance of the parabolic trough solar collector in quasi-steady regime operation was observed. It is shown that the variation of wind speed has a very slight effect on the thermal performance of the collector. Four fluids (therminol 66, therminolV-P1, untreated water, and treated water) were simulated between 11:00 and 15:00 local time. Through the simulation of four fluids, it was shown that the energy efficiency of the collector when using oil is much better than with water.