R. Velicu1*, G. Moldovean1, V. Popa1

1 Centre of Product Design for Sustainable Development, Transilvania University of Bra§ov, Romania

* Corresponding Author, rvelicu@unitbv. ro

Abstract

As a meaning for efficiency improvement of conversion of solar radiation to other types of energy, solar tracking systems are used. The paper presents the results of the embodiment design process of the main rotational axes of an experimental solar tracking system. The tracking system is azimuthal, with two rotational axis: a vertical fixed axis and a horizontal mobile axis. The system is one of ten different tracking systems for PV individual panels implemented, this year, in the campus of the Transilvania University of Bra§ov, Romania. It has been developed in order to research the optimization of the mechanical system of trackers as a meaning of improving the costs and energy efficiency of the system. There have been considered the loading cases depending on the functional positions of the tracking system (positions corresponding to minimum and maximum rotational angles), considering different distributions of wind pressure. Final constructive solutions, elements of preliminary design and conclusions on loads and loading cases involved in optimal embodiment design are presented.

Keywords: tracker, design,

1. Introduction

In order to improve the energy efficiency of fixed PV or thermal collectors (panels), two possibilities are available [1]. The first option is to use materials with better solar absorbent properties and the second is to orientate the panels towards the sun, method which is called “Tracking”. As the first possibility is quite expensive and new materials take more time to be developed, the second option can be reliable and costs less. An optimal design is mainly improving a tracking system by diminishing the costs of building and exploitation.

In order to perform a comparison between different solutions of tracking system, in the frame of a Project developed at Transilvania University of Bra§ov, a platform with 10 different tracking systems was developed.

This paper is referring to an azimuthal tracking system [2]

(fig. 1). It has two rotational axes: a vertical fixed axis (setting the у orientation angle) and a horizontal mobile axis (setting the a orientation angle). The system is using linear actuators in order to perform both two movements.

A proper design must consider the loading cases depending on the functional positions of the tracking system (positions corresponding to minimum, medium and maximum rotational angles on the two main axes) and also the loads caused by own masses, wind, snow etc. (given by the specific of the region). This paper is presenting a methodology of determining the loads involved in preliminary strength calculus of the elements of the tracking system and also some conclusions on the loading cases and their involvement in the specific loading of elements. Some elements of detailed design of the system are also presented.