Photovoltaic’ is a marriage of two words: ‘photo’, meaning light, and ‘voltaic’, meaning electricity. Photovoltaic technology, the term used to describe the hardware that converts solar energy into usable power, generates electricity from light.
At the heart of photovoltaic (PV) technology is a semi-conductor material which can be adapted to release electrons, the negatively charged particles that form the basis of electricity. The most common semi-conductor material used in photovoltaic cells is silicon, an element most commonly found in sand. There is no limitation to its availability as a raw material; silicon is the second most abundant material in the earth’s mass.
All PV cells have two layers of semi conductors, one positively charged and one negatively charged. When light shines on the semi-conductor, the electric field across the junction between these two layers causes electricity to flow. The greater the intensity of the light, the greater the flow of electricity. The electrical circuit is created by many solar cells connected in series within special PV modules. The consequent physical reaction in the solar cells generates direct current, which can be converted to alternating current, depending on requirements. As the PV modules that perform this function have no moving parts, the system requires only minimal maintenance, and are silent in operation. Best of all, they generate electricity without generating any of the harmful emissions currently threatening our environment and climate.
The sun delivers 219,000 billion kilowatt hours of energy every year to the earth – more than 2,500 times more than the total world population currently requires.
A photovoltaic system therefore does not need bright sunlight in order to operate. It can also generate electricity on cloudy days. Due to the reflection of sunlight, days with slight cloud can even result in higher energy yields than days with a completely cloudless sky.
Solar PV panels
Solar PV panels will operate at maximum efficiency if they are orientated towards the south. The most efficient tilt angle can be calculated by subtracting 20° from the geographic latitude. Therefore, for an installation in London (latitude of 51°) the optimum tilt is (51 minus 20) 31° from the horizontal.A solar PV panel installation causes minimum disruption to the home and systems can be retrofitted. A typical silicon cell is quite small, approx 100mm x 100mm square. Solar cells produce electricity at low voltage but when more power is required a number of cells can be connected together to create photovoltaic modules, or solar PV panels.
Solar PV panels that are connected together in series are often referred to as an ‘array’. A grouping of solar PV panels can be fitted in different configurations depending on the local conditions e.g. to follow the shape of a roof or to avoid a roof light. Solar PV panels usually have a backing sheet that is opaque but the backing can be transparent, allowing some light through and creating a dappled effect.Proven Design
Solar Essence offers Electric PV systems in a number of standard sizes, with solar panels from major manufacturers, and may be mounted to many different type of roof surfaces and vertical facades. We provide services and solutions to all sectors of the construction industry including, specifies, developers and contractors.
An off grid system means that it is not connected to the national power grid, this may be because there is no electrical power supply to the property. In this case the power must be stored in heavy and expensive batteries.
There is also no opportunity to benefit from the Governments new feed in tariffs. Unless off grid is your only option we do not recommend these solar PV systems.