• Energy Research

Abstract An automatic solar tracking system is an approach for optimizing the generation of solar power and modifying the angles and direction of a solar panel by considering changes in the position and path of the sun. The performance status of an automatic solar tracking system depends on various factors, including its design, location, and maintenance or repairs. The solar energy from the sun that the Earth intercepts is approximately 1.8 × 1011 MW, which is thousands of times greater than the intensity at which the Earth now uses all other commercially available energy sources combined. Currently, research into automatic solar trackers is on the rise, as solar energy is abundant in nature, but its use in a highly efficient way is still lacking. This paper provides a detailed literature review and highlights some key advancements and challenges associated with state-of-the-art automatic solar tracking systems. The performance of the dual-axis photovoltaic tracking system outperforms that of the stationary systems by more than 27% based on the overall system efficiency. Under diverse weather conditions, the efficiency of the scheduled-based solar tracking systems was enhanced by 4.2% compared with that of the light-dependent resistor-based solar trackers.

The rapid increase in the penetration of photovoltaic (PV) power plants results in an increased risk of grid failure, primarily due to the intermittent nature of the plant. To overcome this problem, the flexible power point tracking (FPPT) algorithm has been proposed in the literature over the maximum power point tracking (MPPT) algorithm. These algorithms regulate the PV power to a certain value instead of continuously monitoring the maximum power point (MPP). The proposed work carries out a detailed comparative study of various constant power generation (CPG) control strategies. The control strategies are categorized in terms of current-, voltage-, and power-based tracking capabilities. The comparative analysis of various reported CPG/FPPT techniques was carried out. This analysis was based on some key performance indices, such as the type of control strategy, irradiance pattern, variation in G, region of operation, speed of tracking, steady-state power oscillations, drift severity scenario, partial shading scenario, implementation complexity, stability, fast dynamic response, robustness, reactive power, cost, and tracking efficiency. Among existing FPPT algorithms, model-based control has a superior performance in terms of tracking speed and low steady-state power oscillations, with a maximum tracking efficiency of 98.57%.

In the present paper, a relation is developed to study the velocity of sound in liquid metals as a function of pressure at different temperatures. The relation obtained is applied in the cases of liquid Na, K, Rb, Cs and Hg. The calculated and experimental results in each liquid are found to be in very good agreement throughout range of pressure and temperature studied. Furthermore, several thermodynamic parameters are also calculated.