Retractable roof module with photovoltaic panel as small solar power plant

Abstract

The use of building-integrated photovoltaic (PV) systems in the form of retractable roofs is an alternative option to existing installations without tracking systems (NT) or horizontal single-axis tracking systems (HSAT). This paper presents a retractable roofing module intended for the installation of PV panels. The main objective of this study is to identify modern solutions for these systems in terms of geometry and kinematics, which would allow the displacement of the roof slopes to follow the trajectory of the Sun during the day. This study is based on the parametric modelling and virtual prototyping of engineering objects. A moveable roof module is obtained, which, in addition to its function of shading and protection from rainfall, serves as a small movable solar power plant. The structure of the roof module is based on the construction of a mechanism comprising three revolute kinematic pairs and one prismatic kinematic pair, whose movement is strictly defined. The roof comprised three moving slopes of the same length. One of the slopes is designed for the installation of a PV panel; it moves according to the Sun to obtain maximum energy gains. For an adopted PV panel length of 1.0a, the maximum roof covering space is 2.69a. An analysis of the natural lighting for the panel following the Sun was performed, and the angle of inclination with respect to the horizontal plane was determined. The inclination of the panel ranges from +80º to –75º. In the case analysed, the HSAT delivers approximately 16% more energy than the NT system. The adaptation of retractable roofs with PV panels enables the optimal use of space around buildings, which are occupied by fixed or moveable installations with PV panels.