How Does Solar Energy Work?

Solar energy is harvested by solar panels. Solar panels are technically any kind of panel that uses solar energy to produce energy.You have probably seen them on houses in your neighborhood on roofs or on road side signs. The big rectangle or sometimes square shape that is angled to the sun is the solar panel. There are basically two methods used for solar energy conversion. Both convert the sunshine into useable energy. The two methods are;

1. Solar thermal
2. Photovoltaic (PV)

Solar thermal

The solar thermal method captures the rays of sunshine and generates heat. This heat is transferred into water and used for space heating or making hot water for your plumbing fixtures. In a more commercial use, hot water is generated and used for air conditioning. I know that sounds a bit funny, but it is a proven system which we will discuss later.

A solar thermal panel circulates water through the panel where it is heated. The water is then returned to a system that uses the hot water. The panel is positioned to get as much sunshine as possible through the course of the day. The water is piped to the panel and circulates within the panel in tubing where it is heated. The amount of heat collected by the water depends on the type of thermal panel you install. If your thermal panel is used during the summer only, water is the only thing circulated to collect the heat. If your thermal panel is used during the summer and winter (which could possible freeze the water), an anti-freeze is used instead of water. You can recognize a solar thermal panel immediately by seeing the piping that connects to the panel.

Solar Thermal Summary

Sunshine hits the solar panel causing the water or anti-freeze solution to be heated. Piping carries the heated water back to a system which then uses the heated water.

Photovoltaic

First, lets define this term so you can use it easier. The "photo" part refers to the rays of sunshine you are harvesting. The "voltaic" part means the sunshine is converted to electricity. So a photovoltaic panel harvests the sunshine and converts it directly into electricity. You can recognize a solar photovoltaic panel immediately by seeing the wiring that connects to the panel. If you look closer at a photovoltaic panel you will see that it is made up of smaller "cells and modules" that are wired together to produce the electricity. It takes many cellsand modules to make up a photovoltaic panel. Each cell produces a small amount of electricity, but when the cells are combined into modules, this small amount of electricity is added together to produce the panel's output power.

Solar cells are generally made from very pure silicon. The silicon molecules get "excited" when the sunshine hits them resulting in the release of electrons. These electrons flow through the panel's wiring and the end result is electricity. Now this definition is somewhat simplified but you get the idea, sunshine on a solar cell produces electricity. The electricity produced is DC (direct current) and is normally sent to batteries where the electricity is stored for use at a later time, normally at nights when the solar panel is not producing energy.

Since most electrical devices us AC (alternating current) instead of DC, the last step of the process is converting the DC electricity into AC electricity. This is done by using a device called an inverter. An inverter takes the electricity stored in the batteries and converts it to a more useable form such as 120 volts AC. This is the same electricity normally used in homes and buildings.

Photovoltaic Summary

Sunshine hits the solar cell producing a small amount of electricity. The cells are wired together to produce a photovoltaic panel which adds the power of all the cells. The electricity from the panel is wired to batteries and stored. When electricity is discharged from the batteries, it is converted into a more usable voltage by the inverter.