5.Tracking solar collection technologies for solar heating and cooling systems
C. Chang
Key Laboratory of Solar Thermal Energy and Photovoltaic System, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
5.1.Definition of solar tracking technology
5.2.Classification and features
5.3.Control system
5.4.Practical examples
The solar tracking device (also called a solar tracker) is a key component to improve the performance of solar collectors. A solar tracker can keep the collector aperture perpendicular to the incident light to maximize the solar radiation. It must be reliable and able to follow the sun with a certain degree of accuracy, return the collector to its original position at the end of the day or during the night, and track during periods of intermittent cloud cover. In addition, a solar tracker can turn the collector out of focus to protect it from hazardous environmental and working conditions, such as wind gusts, overheating, and failure of the system. A solar tracker is usually composed of three parts: the structure, the transmission device, and the control system. According to the operation mode, solar trackers can be divided into two categories: manual tracking and automatic tracking. Automatic tracking is divided into time tracking and servo tracking. According to the number of degrees of freedom of the drive device, the solar tracker can be divided into single-axis tracking and dual-axis tracking. According to the control mode of the control system, the solar tracker can be divided into photoelectric sensor tracking and sun position tracking. According to the control information feedback, the solar tracker can be divided into closed-loop, open-loop, and hybrid control.
