Passive solar tracker using a bimetallic strip activator with an integrated night return mechanism

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.