Analysis and CFD Modeling of Thermal Collectors with a Tracker System

Abstract

Thermal solar systems are currently one of the most suitable ways to convert solar radiation into usable energy. To ensure maximum energy gain, it is necessary to correctly adjust the direction of the collectors in the southern direction. The deviation from the south is energy acceptable, but there are losses that reduce the overall efficiency of the system. A suitable tool for increasing the efficiency of solar thermal collectors is the usage of tracker systems which track the position of the Sun along the ecliptic orbit. The system is directed south towards the equator. It is important to know the effectiveness of the system in terms of assessment. For the monitored period of the equinox, the increase of the solar thermal gain of the system with rotation of the collectors represents 16.23%. One of the methods is to use simulation tools to simulate different conditions of solar energy flow. A model in the Ansys software was developed for solar thermal flat collectors. The model is based on setting the material parameters of the collector construction, the properties of the absorber in terms of absorption as well as the materials and its geometry, the properties of the heat transfer medium, and the setting of the volume flows. At the same time, it is possible to define the change in the energy flow of the incident radiation. The model is a useful tool for evaluating collectors used by different tracking systems. The model was experimentally verified on a tracker system and compared with experimental data with good agreement. For sunny days, the model shows an accuracy rate of 98.7% in the condition without rotation, and 99.1% in the condition with rotation of the collector. After including the 5% degree of uncertainty for the condition of the rotated collectors, the accuracy of the model is 94.2% and for the condition without rotation 93.8%.