What are Solar Panels
Solar panels collect heat energy from the sun. We call this heat solar thermal energy. A simple example of a solar panel is a closed box with a top made of a transparent material such as glass or plastic.
The sun shines through the glass and heats up the inside of the box. This is the same type of heating that happens to the inside of a car when it sits in the sun. In some cases the inside of the box is painted black so that it absorbs more heat. The heat that is collected inside the box can then be used for several purposes. The most common uses for solar panels is to heat air or water.
A system that uses solar thermal energy to heat air is not complex. A transparent top is attached to a box. The box has an inlet pipe for cool air. The cool air can be pushed into the box using a fan. The cool air moves through the inlet pipe into the box. Inside the box the air is warmed by the heat energy from the sun rays. As more cool air is pushed into the box the warm air is forced out the other end of the box through the outlet pipe. The warm air can now be used to heat something like your home. Some very large systems use a solar panel on the roof of a house to heat a whole room. The warm air in that room is then blown through vents to heat the whole house.
Solar panels that are designed to heat water work almost the same way as ones designed to heat air. In a simple example there is a pipe that runs through the inside of the box.
The sun rays heat the air inside the box. The heat in the air is transferred to the pipes then the heat in the pipes is transferred to the water. As cool water is pumped into the inlet pipe the warm water is forced out of the outlet pipe. We can now use this warm water for something like a bath or shower.
These pictures are only a simple representation of the basic concepts. In practice, solar water and air heaters can be more complex.
The terms "Solar Panel" and "Photovoltaic Panel" describe two different devices. We use the terms as follows:
A Solar Panel collects and utilizes heat energy from the sun.
A Photovoltaic Panel transforms light energy into electrical energy.