Glossary of Solar Terms
The process of converting sunlight into electricity is called "photovoltaics" or "pv" for short. When we speak of "solar pv" we mean solar technology that produces electricity. Current technology utlizes solar "cells" composed of silicon to generate DC (direct current) electricity when sunlight falls upon them.
Thermal - SDHW
The process of converting sunlight into heat is termed "Solar Thermal" or "SDHW". SDHW stands for "Solar Domestic Hot Water", because hot water is the most common end produce of Solar Thermal. This is typically accomplished by trapping the heat with a dark colored surface, transferring the heat to a conducting liquid (e.g. glycol), and transfering the heat from this liquid to water through a coil.
DC electricity is "Direct Current", meaning that there is a constant flow of electrons through a wire when the DC electricity is used. This is the same type of electricity as produced by batteries, and used inside of electronic devices like TVs and computers. DC electricity is produced by solar cells.
AC electricity is "Alternating Current", meaning that the flow of electrons alternates from one direction to the other in a cycle. In the USA electricity cycles at 60 times per second. AC electricity is what is provided by the utility company, and supplies our homes and businesses. Household outlets, and most household appliances and light fixtures use AC electricity.
The smallest unit of hardware that can generate electricity from sunlight is the Solar Cell. It is single piece of silicon that can produce DC electricity. It typically has either two wires or two tabs where wires can be connected to harvest electricity. Solar cells are not usually dealt with individually in a solar installation. Each one produces very little electriciy, but when many of them are combined into a module they are powerful. Some solar toys, calculators, or flashlights have just one or a few solar cells.
Solar Module / Solar Panel
The primary unit of a Solar PV installation is a "module" or "panel". Module is the more modern term, but both are universally understood. The module is a large, somewhat heavy frame which contains a sheet of solar cells arranged in a grid and interconnected, which is covered with a durable glass surface. The module acts like a large solar cell.
The inverter converts the DC electricity produced by solar cells and modules into the AC electricity that your home or business can use to power appliances or to feed into the grid. There are several different types of inverters, and many different manufacturers. This is a key component of your solar system.