In the summer of 2009, the department decided to install solar panels on the roof above the electronics labs. The main purpose of this project was to provide a learning platform for students to see electricity and electronics concepts in action in a renewable energy system. By studying this system, students will be able to see that there is nothing magical or too complex about renewable energy systems. In fact, the operation of the system can be analyzed using basic electrical concepts such as Kirchoff’s Voltage and Current Laws as well as Ohm’s Law.
The system we ordered and installed consisted of:
- two 130 Watt Kyocera solar panels
- A DC-DC converter with Maximum Power Point Tracking
- an inverter
- Sealed, deep-cycle, lead acid battery
- Network based monitoring equipment to measure and record charging and discharging cycles and usage
Photovoltaic System Before Unpacking
Almost directly above the cardboard box containing the solar panel is a conduit that goes straight to the roof of the building. The conduit was designed for cabling to go between the roof and the lab and so was perfect for connecting the solar panels to the rest of the electronics. This picture shows the conduit on the roof and the solar panels were placed right beside the conduit:
I chose what must have been the hottest day of the year to go up on the asphalt roof to install these panels, but other than that the installation went smoothly. There’s a collection of photos of the installation at the bottom of this article, but, here is one picture showing how the panels fit together and are “installed” on the roof:
The panels were stacked horizontally on an aluminum mounting bracket and then the mounting bracket was attached to a pallet which sat on some foam insulation on the roof. Several bricks (many more than is shown here) were used to hold the pallet down because the panels create a fairly large wind load.
Here are the mounted panels:
and you can see that the aluminum mounting brackets are adjustable to set the panels to the best angle for capturing the sun’s rays:
Once the panels were installed, the next step was to connect them to the electrical system that would convert the PV panel output to a constant 12 volts for connecting to the inverter and for recharging the battery. The other important piece of this system was the electronic monitoring which would monitor the current and power output of the panels, the charging and discharging rate of the batteries as well as the current and power to the inverter. Stay tuned for details.