Fractional Order PV/T Model Design and Estimation using the Fractional Observer Topics: Energy Efficiency and Green Manufacturing; Engineering Applications; Intelligent Fault Detection, Diagnosis and Prognostics; Performance Evaluation and Optimization; System Modeling; Systems Modeling and Simulation; Systems Modeling and Simulation In Proceedings of the 18th International Conference on Informatics in Control, Automation and Robotics ICINCO - Volume 1, 649-655, 2021