Open-loop altitude-azimuth concentrated solar tracking system for solar-thermal applications

An open-looped altitude-azimuth concentrated solar-tracking system without additional power was developed in this study. This system adopted the Fresnel lens module to concentrate sunlight on a Stirling engine's heating head while conducting measurements for the temperature profile of the heating head. We also installed solar panels on both sides of the solar tracking system to supply power to the driving motors and reduce the torque needed for mechanism operation. The results show that the energy obtained from the solar panels and stored in the power storage module was greater than the energy needed for driving the tracking system. Therefore, we propose a possible way of combing the photovoltaic and photothermal devices on our concentration tracking system to obtain more energy from sun. Moreover, the gust intensity and cloud amount influenced the efficiency of the concentrated solar-tracking system. The cloud amount affected the amount of solar energy to the heating head, and the gust intensity influenced the thermal radiation on the heating head. In this experiment, we also installed insulative material surrounding the heating head to reduce the loss of thermal energy. Under a cloudless environment, the temperature of the heating head reached approximately 900 °C. This mechanism can be extensively applied to solar-thermal applications.