Green Side Out - The green lifestyle

Photo by Gili Soffer

Maybe you have seen the little bluish or black panels on rooftops and wondered, how does a solar panel work? It is a fairly simple system, with complex parts. Briefly, the solar panels are set to capture as much natural sunlight as possible. They may be permanently installed, or movable. Some are relatively fragile and breakable, while others are thin and flexible, and portable. They can be seen on rooftops, on cars, on boats, as well as in large “farm” configurations. Small solar panels are used on electronics like calculators. All need to be directed towards sunlight to receive sun energy to convert to electrical current.

How does a solar panel work? The important material is inside a small solar cell. Usually it is crystalline silicon, or a combination of silicon with another material, or stacked layers of alloy materials. The silicon is cut into tiny disks. They are less than a centimeter in thickness, and are then polished and repaired from any cutting damage. Once polished, metal conductors, typically thin silver wires, are spread across each disk and they are laid out in a grid design on top of the panel. After being covered with a thin layer of glass, there is a substrate added to the bottom of the panel with a thermally conducive cement to help prevent overheating. These solar panels are then mounted slightly above a surface facing the sun, in order to allow cooling breezes to run under the panels.

With an amorphous silicon solar panel, silicon and other alloys are stacked to absorb larger parts of the solar spectrum, making the panel more efficient than if constructed with just silicon material. Light that makes it past the silicon materials is bounced around and reabsorbed for more intensity instead of being lost. This type of solar panel is thinner, more flexible and less breakable than the crystalline panels. New stacked material solar cells are proving to be less expensive and more productive than those using just expensive silicon materials.

The solar panel, called a photovoltaic module, is like a sandwich, with individual solar cells honeycombed in the middle. The top may be glass, the bottom may be aluminum. A silver or metal wire grid connects the cells across the top of the cells. The solar cells use their silicon or alloy materials to convert sunlight into electrical current, which is then collected and stored in a DC battery and used from the battery, or converted to AC current via an inverter that boosts the voltage up to AC current. Solar silicon cells produce about .5 Volts each. Smaller panels are usually 12V. Solar panels are used in multiples, called an array, for increased power output. Solar power is clean, environmentally safe, and renewable.

Reduced cost is important to help spread the use of the solar panel. Using a thinner, light weight solar panel that offer increased efficiency is one way to reduce the costs and recovery time from cost of installation and purchase of the panels over time. Solar panel power is seen as an eco-friendly alternative to fossil fuels such as oil.