Grades 9-12: Off-Grid Demo and automatic Dual-Axis Tracking Solar Dish with Stirling Engine:
Solar energy capture, measurements, and storage:
One of the environmental challenges for Canada, and indeed for the rest of the world, is the excessive consumption of fossil fuels that has resulted in global issues such as air pollution, changes in precipitation patterns, and increases in atmospheric temperatures. It is now generally accepted that the consumption of fossil fuels to generate energy must be replaced using renewable energy technologies like solar and wind generation. To achieve this replacement, there is an urgent need to educate the public in these fields and to create a renewable energy culture in our society.
Students must become aware of the negative consequences of using fossil-fuel-based technologies. To this objective, GREENBMG dual-axis solar tracker aims to educate students about renewable energies like solar.
Outcome: First, students will more likely re-orientate their activities towards the use of renewable energies as they become adults and thus consume less fossil fuel. Second, they may transfer this knowledge to their families and encourage them to reduce fossil fuel consumption and switch to more renewable energy technologies.
GREENBMG Automatic Dual-Axis Solar Tracker provides practical and hands-on experience in the field of solar energy and its use can transform students’ theoretical knowledge into practical and applied experience. With the help of this simple apparatus, by performing simple experiments, they will engage more closely with, and achieve a deeper understanding of, the use of renewables. It allows students to participate directly in solar experiments and thereby develop a better understanding of solar energy fundamentals. For example, through interaction with this apparatus, students will gain an understanding of changes in solar energy intensity throughout the day and the year. Understanding the dynamic nature of renewable energies like solar will help students later to efficiently harvest these energies and manage their production and consumption.
The dual-axis tracker, according to figure 1, is composed of a control panel, a chamber that contains the hardware components and supports the mechanical structure, a base, a vertical movement screw jack, and a horizontal rotational top panel. A concave mirror can be installed on the apparatus to focus the sunlight and heat the air, which operates a Stirling engine at the focal point. Alternatively, a PV panel can be installed on the apparatus to generate solar electricity at high efficiency when compared to a panel without sun tracking. The apparatus works in two modes: Remote, and automatic. It tracks the sun, or any light source located outdoors or indoors. The dual-axis tracker can hold panels or dishes up to 80 cm in diameter and 8 kg in weight. It can be used during cold Canadian winter days as an indoor training tool by installing it inside classrooms beside a window.
The following experiments are performed by two students of grades 9 to 12 with supervision:
Experiment No. 1: Dual Axis Solar Tracker experiment
Objectives: To learn about fundamentals in solar tracking, the movement of the sun in the sky relative to the time of day, the change of azimuth and elevation angles, and the change of solar intensity with date, time, and location
Experiment No. 2: Solar Stirling Engine experiment
Objectives: To learn about the harvesting of solar thermal energy, the principles of concave mirrors, the Stirling engine, and different forms of energy (thermal, mechanical, and electrical). To learn about the effects of collector surface area on the collector power
Experiment No. 3: Boiling Water and Heating Copper Slab using Off-Centre Dish
Objectives: Measurement of collector thermal power and efficiency of solar energy collection.
Experiment No. 4: Use of Solar PV panel with sun-tracker
Objectives: To learn the fundamentals of a solar photovoltaic panel, to measure DC current and voltage, to become familiar with closed circuit and open circuit measurements, to observe the dynamic nature of changes in panel output with time and location, and the effect of clouds on the PV panels’ output.
Experiment No. 6: Parametric study of the output of PV panels
Objectives: Familiarize students with elevation angles, azimuth angles, and the dependency of solar panel output to those parameters. Students will also learn about the dynamic nature of the sun by observing the change of angles/degrees of the sun every few minutes. Experiment No. 7: Off-grid experiment (panel connected with charge controller, battery, and consumer)
Experiment No. 7: Off-grid experiment (panel connected with charge controller, battery, and consumer)
Objectives: Measurement and monitoring of electrical energy parameters and the energy loss across various equipment: panel, charge controller, inverter, consumer, generator, flywheel
Solar thermal technology and solar PV technology are two main types of capturing and using the sun’s energy. When we use the heat or concentrated heat of the sun, the technology is called solar thermal. While when we use photo-voltaic cells to generate direct current electricity, the technology is called solar PV.
Setup Includes:
GREENBMG's off-grid demonstration setup shows the fundamentals of solar PV and solar thermal energy in the same setup. It is composed of:
A PV panel charge controller
12 V battery
Inverter
Automatic sun tracker that operates a Stirling engine.
How It Works
Sunlight first is received by the panel and a DC current of 12-17 volts is generated The current is sent to a charge controller. The charge controller charges a 12-V battery and it prevents the battery from overcharging. An inverter changes the DC current from the battery to 110V AC electricity. The tracker motors use this electricity to track the sun. The sun rays are concentrated by an off-center dish. The Stirling engine changes the concentrated heat into mechanical work and rotates a flywheel. The flywheel rotates a generator to generate electricity.