Passive solar tracker using a bimetallic strip activator with an integrated night return mechanism
Mintesinot Alemayehu, Bimrew Tamrat Admasu
Abstract
Passive solar trackers face challenges in returning PV panels to the east position before sunrise. Specifically, bimetallic strip deflection-based trackers are unreliable due to ambient temperature changes at night, resulting in inconsistency across different locations and times. This study addresses this issue by designing a passive solar tracker with a bimetallic strip deflector independent of nighttime temperature differences. Field tests were conducted comparing a fixed system to the proposed tracker. Performance parameters included power output, power density, and energy collection. The proposed tracker achieved a daily average power output of 70-120 W, while the fixed system ranged from 10 to 120 W. The proposed system exhibited steady changes in power output, providing an additional 47 W per unit area compared to the fixed system. This optimization maximized power output within a given area, resulting in a cost savings of $71.75 per unit area. The proposed system also demonstrated 24.86% higher energy collection efficiency relative to the fixed system and 96.4% accuracy compared to an ideal tracking system. It is a cost-effective alternative to fixed-panel PV and easy to install and operate. Additionally, it can be used in conjunction with active tracking systems, offering comparable efficiency at a lower operational cost. The designed system presents a reliable solution by being independent of nighttime temperature fluctuations, making it more stable relative to other passive solar trackers.