We considered the steady flow of Buongiorno’s model over a permeable exponentially stretching channel. The mathematical model was constructed with the assumptions on curved channels. After applying the boundary layer approximation on the Navier–Stocks equation, we produced nonlinear partial differential equations. These equations were converted into a system of non-dimensional ordinary differential equations through an appropriate similarity transformation. The dimensionless forms of the coupled ordinary differential equations were elucidated numerically through boundary value problem fourth order method. This method gains fast convergence as compared to other method such as the shooting method and the Numerical Solution of Differential Equations Mathematica method. The influence of the governing parameters which are involved in ordinary differential equations are highlighted through graphs while $R{e}_s^{1/2}{C}_f$ , $R{e}_s^{1/2}{N}_{u_s}$ , and $R{e}_s^{-1/2}S{h}_s$ are highlighted through the tables. Our interest of study was to analyze the heat transfer rate of nanofluids. Surprisingly, for momentum boundary layer thickness, thermal boundary layer thickness and solutal boundary layer thickness became larger when $\lambda >0$ , as compared to the case when $\lambda <0$ .

Solar energy is considered the greatest source of renewable energy. In this paper, a case study was performed for a single-axis solar tracking model to analyze the performance of the solar panels in an office building under varying ambient temperatures and solar radiation over the course of one year (2018). This case study was performed in an office building at the College of Engineering at Shaqra University, Dawadmi, Saudi Arabia. The office building was supplied with electricity for a full year by the designed solar energy system. The study was conducted across the four seasons of the studied year to analyze the performance of a group of solar panels with the total capacity of a 4 kW DC system. The solar radiation, temperature, output DC power, and consumed AC power of the system were measured using wireless sensor networks (for temperature and irradiance measurement) and a signal acquisition system for each hour throughout the whole day. A single-axis solar tracker was designed for each panel (16 solar panels were used) using two light-dependent resistors (LDR) as detecting light sensors, one servo motor, an Arduino Uno, and a 250 W solar panel installed with an array tilt angle of 21°. Finally, an artificial neural network (ANN) was utilized to estimate energy consumption, according to the dataset of AC load power consumption for each month and the measurement values of the temperature and irradiance. The relative error between the measured and estimated energy was calculated in order to assess the accuracy of the proposed ANN model and update the weights of the training network. The maximum absolute relative error of the proposed system did not exceed 2 × 10⁻⁴. After assessment of the proposed model, the ANN results showed that the average energy in the region of the case study from a 4 kW DC solar system for one year, considering environmental impact, was around 8431 kWh/year.

Photovoltaic (PV) systems are a very popular energy conversion system for electric energy supply due to their ease of connection and fast rate of conversion. However, a disadvantage of these systems is their low efficiency. Many techniques have been proposed to enhance the efficiency of PV systems. In this article, numerical and experimental studies were performed to test the effect of pyramidal transparent covers made of Perspex on the incident radiation reaching PV panels. The energy of light depends on the electric field, and the electric field depends on the permittivity. As the relative permittivity of Perspex is higher than the relative permittivity of air, the energy of the panel with the pyramidal Perspex cover is higher than the energy of the panel without pyramids. In addition, the total irradiance reaching the base of the pyramids was investigated in order to show the effect of the incidence angle on the computed irradiance. A 3D model was constructed and tested with different pyramidal cover dimensions and incidence angles. The tested dimensions were height to base length ratios of 1.5, 1.0, and 0.5. It was found that pyramidal covers with a height to base length ratio of 1.0 achieved the best performance of the three sizes. The simulation model was applied in order to study the solar radiation model for the solar panel with and without pyramids. Two parameters were studied in order to show the effect of the pyramidal covers on solar panel irradiance; these parameters used three different sizes of pyramids to study the effect of changing the incidence angle of the radiation source. The model was constructed in ANSYS-ICEM, then the mesh was exported to FLUENT 14.5. Moreover, the incident radiation on the panel for all tested incidence angles was found to be higher than for the panels without covers. In addition, the existence of the pyramidal cover was found to enhance the homogeneity of the distribution incident of rays on the PV panels. In the case of pyramids with R = 1, enhancement became clear at an incidence angle ranging from 69° to 90°, and the percentage increase in the energy fraction reached 0.2%.