Solar-wind tree based on 2-axis tracking

Scientists in india have created a wind-solar system in a tree shape, which combines wind turbines and a PV system with two-axis trackers. The team constructed a hardware-in-the-loop prototype that can generate up to 444.5 Wh per day.

A research team led by scientists from India's Dayananda Sagar College of Engineering has developed a tree-type of PV-wind power system for off-grid applications.

“A hybrid tree is a synthetic construction that looks a lot like a real tree, with solar panels or wind turbines installed on its branches. It will enable the delivery of electricity to lighting loads, cell phones, household devices, laptops, and electric vehicles, making it a suitable source of energy for green cities or smart cities,” said the researchers. “To maximize energy output, PV panels should be oriented perpendicular to the sun's rays. This research includes an automated two-axis intelligent solar tracking system that automatically positions PV panels to achieve optimum energy output from any part of the world.”

Dubbed wind-solar hybrid tree (WSHT), the system includes a pole that holds a wind turbine (WT) on top, with different branches carrying two-axis solar trackers.

Initially, the WSHT was simulated in MATLAB/Simulink, using one fixed PV panel, one PV panel on a two-axis solar tracking system, and one wind turbine system. Both PV panels had a rated capacity of 100 W, while the WT had a rated capacity of 500 W. A microcontroller system is used to control the orientation of the two-axis tracker using a mathematical model. It uses inputs such as GPS data and data from a gyro-orientation sensor and a digital compass.

Using the typical WT variables, the scientists also modeled the WT unit at various wind speeds (m/s).

Following the simulation, the team has built a semi-physical model, which uses two real 100 W PV panels, one of them fixed and the other one on a two-axis tracker, and a simulated 500 W WT, which used data from a NASA database.

The WSHT was placed in India's Bangalore region and measured for four days between 6:00 and 18:00. The days were January 5, May 5, September 5, and December 5 of 2024. The system always used the WT, while the PV source changed. It used either the two-axis or the fixed PV at tilt angles of 18°, 15°, or 10°.

The prototype underwent extensive testing and the tracking system was found to require minimal operating energy.

“The suggested WSHT may generate up to 444.5 Wh/day with a two-axis tracking system and 409.5 Wh/day with solar panels installed at a fixed angle,” the researchers stressed. “The highest output from the solar component was determined to be 144 Wh/day with a two-axis tracking system and 109 Wh/day with solar panels at a fixed angle. Wind turbines generate 300.5 Wh/day.”

The system could be used to power lighting loads, cell phones, household devices, laptops, and electric vehicles.

It was presented in the study “Intelligent Two-Axis Solar Tracker for Hybrid Renewable Energy Tree System,” published in Franklin Open. Researchers from India's Dayananda Sagar College of Engineering, Sri Venkateshwara College of Engineering, Jain (Deemed-to-be University), and Nitte Meenakshi Institute of Technology participated in the research.