A novel ultralight dish system based on a three-extensible-rod solar tracker

Abstract

The use of dish systems is among the most potential methods for solar power collection. However, the popularization of the application of traditional dish systems has been impeded because they are heavy, structurally complex, and costly. Accordingly, a novel ultralight dish system is proposed; it consists of a cable mesh reflector, an ultralight thermoelectric conversion device, and a three-extensible-rod (TER) solar tracker. Compared with previous reflectors consisting of rigid solid panels, the reflector of the proposed dish system (PDS) adopts an ultralight rigid–flexible combined structure based on a space cable mesh reflector antenna. The lightweight thermoelectric conversion device of the PDS is reasonably considered. Thereafter, a TER solar tracker (specifically, 3-RPS) is mainly selected and designed for the PDS. Through an inverse kinematic analysis of the tracker, a sun-tracking control strategy of height variation is employed to reduce the number of sections in each extensible rod from three to two and to decrease total energy consumption. Meanwhile, a compound joint consisting of hook and rotary joints is substituted for the spherical joint of the solar tracker to overcome its inadequate rotational range and facilitate fabrication. By setting the PDS to an extreme orientation and subjecting it to wind and gravitational loads, its structural parameters are further determined through analysis and optimization. Although the surface density of the PDS is only approximately 1 kg/m2, the system performs satisfactorily even when subjected to loads. The dynamic model of the PDS is established by the Newton–Euler formulation. The power requirement of the PDS is determined through the dynamic analysis; it is found that during winter solstice, its maximum power is only 0.024 W, and the daily energy consumption is only 210.05 J. Finally, sun-tracking experiments on the TER solar tracker are performed to verify the theoretical and simulation analysis results; the sun-tracking accuracy is estimated to be within ±0.7°, which satisfies the PDS requirement although the machining precision of its components is not high.