What do we mean by photovoltaics? The word itself helps to explain how photovoltaic (PV) or solar electric technologies work. First used in about 1890, the word has two parts: photo, a stem derived from the Greek phos, which means light, and volt, a measurement unit named for Alessandro Volta (1745-1827), a pioneer in the study of electricity. So, photovoltaics could literally be translated as light-electricity. And that's just what photovoltaic materials and devices do; they convert light energy to electricity, as Edmond Becquerel and others discovered in the 18th Century.
When certain semiconducting materials, such as certain kinds of silicon, are exposed to sunlight, they release small amounts of electricity. This process is known as the photoelectric effect. The photoelectric effect refers to the emission, or ejection, of electrons from the surface of a metal in response to light. It is the basic physical process in which a solar electric or photovoltaic (PV) cell converts sunlight to electricity.
Sunlight is made up of photons, or particles of solar energy. Photons contain various amounts of energy, corresponding to the different wavelengths of the solar spectrum. When photons strike a PV cell, they may be reflected or absorbed, or they may pass right through. Only the absorbed photons generate electricity. When this happens, the energy of the photon is transferred to an electron in an atom of the PV cell (which is actually a semiconductor).
With its newfound energy, the electron escapes from its normal position in an atom of the semiconductor material and becomes part of the current in an electrical circuit. By leaving its position, the electron causes a hole to form. Special electrical properties of the PV cell—a built-in electric field—provide the voltage needed to drive the current through an external load (such as a light bulb).
A PV system is made up of different components. These include PV modules (groups of PV cells), which are commonly called PV panels; one or more batteries; a charge regulator or controller for a stand-alone system; an inverter for a utility-grid-connected system and when alternating current (ac) rather than direct current (dc) is required; wiring; and mounting hardware or a framework.
the photovoltaic panel will convert light into electric DC power , the batteries are needed to store the electrical energy , the controller should protect your batteries from being over charged ,and the Inverter is used to change DC power into AC power .the mounting hardware is needed to fix the panels at the right angle and on the sun line direction .
Solar or photovoltaic panels can give a DC energy (Direct Current ) at low voltage from 12 V to 30V , so an inverter is necessary to convert DC energy to AC energy and lift the voltage to 220 V . the Batteries can be removed if we have a continuous sun light and you don’t need to use electricity after sun set .
it depends on your applicants but as a ruff estimation you would need as follow;
Energy Lamps : 35 W
Air fan : 50 W
Air Conditioner : 1300 W (12000 BTU)
Refrigerator : 300 W
Water Pump : 400 W
42 Inch TV : 250 W
Computer : 350 W
So you can count how many of the above items you have and add their wattage .
the wattage will determine the size of inverter you need , then you have to select the battery bank according to the time needed (how many hours with no mains power ), and solar panels according to the way you want to use them .
the solar power is usually selected to back up the charging , so it should be around 50% of your wattage ,but if you need it to back up mains failure it should be 100% of the wattage needed, but if you need to use it as mains it should be twice the wattage used .
A PV system that is designed, installed, and maintained well will operate for more than 20 years. The basic PV module (interconnected, enclosed panel of PV cells) has no moving parts and can last more than 30 years. The best way to ensure and extend the life and effectiveness of your PV system is by having it installed and maintained properly. Experience has shown that most problems occur because of poor or sloppy system installation.
There are four main types of solar energy technologies:
A photovoltaic (PV) system needs unobstructed access to the sun's rays for most or all of the day. Shading on the system can significantly reduce energy output. Climate is not really a concern, because PV systems are relatively unaffected by severe weather. In fact, some PV modules actually work better in colder weather. Most PV modules are angled to catch the sun's rays, so any snow that collects on them usually melts quickly. There is enough sunlight to make solar energy systems useful and effective nearly everywhere.
: People decide to buy solar energy systems for a variety of reasons. For example, some individuals buy solar products to preserve the Earth's finite fossil-fuel resources and to reduce air pollution. Others would rather spend their money on an energy-producing improvement to their property than send their money to a utility. Some people like the security of reducing the amount of electricity they buy from their utility, because it makes them less vulnerable to future increases in the price of electricity.
If it's designed correctly, a solar system might be able to provide power during a utility power outage, thereby adding power reliability to your home. Finally, some individuals live in areas where the cost of extending power lines to their home is more expensive than buying a solar energy system.
You could install a photovoltaic (PV) or solar electric system yourself. But to avoid complications or injury, you will probably want to hire a reputable professional contractor with experience in installing solar systems. PV systems have few moving parts, so they require little maintenance. The components are designed to meet strict dependability and durability standards so they can stand up to the elements. However, they are fairly sophisticated electric systems, so installation usually requires the knowledge and experience of a licensed electrical equipment contractor.