Wednesday, November 12, 2014
What Do Solar Panels Do? How Do They Work?
What is PV solar power? You have heard the term, but you are unsure as to its meaning. You are vaguely aware that solar power has something to do with making energy from sunlight. But what is PV solar power? Is it different from other kinds of solar power?
PV solar power is different from other types. Of the two main categories of solar power, active and passive, PV solar power is active. Let's look at it.
Active solar power relies on solar panels. You may picture them as flat, rectangular boxes on rooftops.
There are two main types of solar panel. From a distance, both look like rectangular boxes. Both convert sunlight into energy, but in two different ways. The terms for the two solar panel types are solar thermal collector and photovoltaic module.
1. Solar thermal collector: This solar panel takes in solar energy from the sun and uses it to heat air or water.
2. Photovoltaic module: This second type of solar panel collects solar energy and converts it to usable electricity.
Meet the PV
To answer the question, what is PV solar power, we must know what the PV is. The short answer is that PV refers to a photovoltaic module. "P" is for photo and "V" for voltaic.
The Merriam-Webster Online Dictionary defines "photovoltaic" this way.
"of, relating to, or utilizing the generation of a voltage when radiant energy falls on the boundary between dissimilar substances."
In simpler terms, "photo" refers to sunlight and "voltaic" refers to electrical energy. PV panels convert sunlight into electrical energy. Sunlight flows into the solar panel. Electrical energy flows out of the solar panel.
A PV solar panel is made up of many photovoltaic (light to volts) cells. These cells are electrically connected, and then covered with glass. The glass provides electrical insulation. It is also good protection from weather and other damaging forces.
When minimal energy is needed, such as that necessary to power a small appliance, a single PV solar panel is sufficient. When more power is needed, an "array" of solar panels is created by connecting panels to one another. If the power will not be supplied to the power grid, the solar panel(s) is connected to a charge controller, and battery. If it is intended for on-grid use, the solar panel array will be connected to an electrical inverter.
What Is PV Solar Power?
PV solar power is solar energy in the form of sunlight, which has been collected by a photovoltaic module, and converted into usable electricity.
Conventional silicon solar panels convert about 14 to 17 percent of sunlight into usable electricity. That isn't much. Late in 2006, however, a new solar cell was introduced. Solar panels that utilize the new cell can convert into electricity 22 percent of the sunlight they collect. Theoretically, the maximum that the cells of a solar panel can convert is said to be around 26 to 27 percent of incoming sunlight.
How does it work? Let's look at a very simple explanation.
Each photovoltaic cell in a PV solar panel is a semiconductor. When sunlight hits those cells, a certain part of the sunlight is absorbed by those silicon cells. The cells take in that part of the sunlight's energy. The cells then transfer the absorbed sunlight's energy to the electrons in the silicon. The electrons begin to flow, and this creates an electrical current. Metal contacts built into the top and bottom of the PV cells draw off that current and it is sent to the grid or battery. It is now usable electricity. The power grid sends it on its way, if you have used an on-grid connection. If you are using a battery, it is stored in the battery awaiting your need.
PV solar power is being used increasingly with great success, and while it is true that cloud cover can affect it, the cloudy country of Germany leads the world in successful use of solar panels.