Solar PV Cells Explained
Also, photovoltaic (PV) cells convert the sun’s energy into electricity without creating any pollution whatsoever.
In this article we’ll introduce solar panels and discuss how these devices work.
What are photovoltaic systems? In simplest terms, solar PV cells are devices that convert light directly into electricity. In almost all cases, the light source is the sun, so we often refer to these devices as “solar cells.” The meaning of the word comes from the word “photo,” meaning light, and “voltaic,” which refers to electricity.
PV systems are installed by people who already use “grid power” (power for the utility company) but who want more freedom, lower bills, less impact on the environment, or some combination of all three.
In certain self contained systems, such as emergency call boxes, a small solar system is an easily justified expense. The same goes for many home systems, as a homeowner can recoup an investment quickly. This is more so the case with less expensive home made solar energy systems.
How do solar PV cells work? Electricity is created by the PV cells silently and without and pollution. The cells are made of at least two layers of semiconductor material, with one layer having a positive charge, and the other a negative charge. When sunlight hits the cell, some of the photons from the light are absorbed by the atoms in the semiconductor.
This frees up electrons in the cell’s negative layer and allows them to flow through an external circuit and back to the positive layer. This flow of electrons is what produces an electric current.
Single solar PV cells do not produce a substantial amount of electricity, so dozens of them are grouped together and placed in a weather proof package called a module. Users can employ two different methods of wiring multiple modules together to produce more electricity.
When two modules are wired together in a series, the current will remain the same while the voltage is doubled. It’s the opposite when modules are wired in parallel: the current doubles while the voltage stays the same. Combinations of modules wired in both series and parallel are used in a PV array to achieve the exact voltage and current needed, no matter how large or small the need is.
It’s interesting to note that this phenomenon was first discovered in the 18th century. Photovoltaic cells were first fully developed at Bell Labs in 1950, initially intended for space applications. Since that time, solar power (much like every other technology on earth) has benefited from the advance of technology. This means greater efficiency, more power, and less cost.