PacB Group // The Various Types of Solar Power Installations

Articles

The Various Types of Solar Power Installations

The sun’s rays have the power to catalyse the reaction between carbon dioxide and water, producing the glucose required for plant nutrition. During this process, which is known as photosynthesis, carbon dioxide is drawn from the atmosphere and replaced by a by-product of this reaction – the oxygen essential for animal respiration. The radiant output of the sun also has other valuable properties, and findings made in the early 19^th-century have since been exploited to create various solar installations that benefit humans in other ways.

The two main properties of the sun are its ability to radiate heat and light. The benefit of the former was known, perhaps, as early as 212 BC, when Archimedes is said to have used a so-called “burning glass” to focus the sun’s heat in order to incinerate the Roman fleet at the siege of Syracuse. Whether or not the tale is true remains unknown, but what child has not used a magnifying glass to ignite a piece of paper or a leaf? Huge solar installations of this type are already being used to produce steam to drive electrical generators. On a more modest scale, the Olympic torch is still lit in this manner today.

This application of concentrated solar power (CSP) is clearly not suitable for domestic use, and seems likely to remain the domain of commercial power companies. There are, however, two alternative ways in which to leverage the suns’ energy that are rather more practical for residential purposes. Domestic solar installations can take one of two main forms. They may be either thermal of photovoltaic (PV).

In a thermal system, the heat of the sun is harnessed in order to heat water for use in the home. However, this is not achieved with lenses or concave mirrors as in CSP systems, but with a structure that combines a roof-mounted flat-plate collector and a storage tank. The collector consists of a rectangular box containing small tubes through which water is circulated. In thermal solar installations, the tubes are attached to a black plate, which absorbs heat from the sun’s rays that reach it via a transparent cover. As the heat builds up, the hot water is pumped along the tubes to the storage tank from which it can then be drawn as required. This type of hot water system can meet the needs of an average household while consuming only a fraction of the power needed by conventional gas or electric water heaters.

That said, in thermal systems, other electrical equipment must still be powered by mains electricity. By contrast, photovoltaic solar installations actually generate electricity directly, which can then be stored and used for a variety of additional purposes when necessary. Just how much of a home’s power requirements this type of system will be able to support will be determined by its surface area, as this determines its total output capacity. Depending upon local municipality policy, it may even be possible to channel and excess power back to the national grid in exchange for payment or tariff concessions.

In this case, the rooftop structure consists of one or more panels, each of which contains several rows of photovoltaic cells connected in series. In PV solar installations, each cell contains two layers of specially treated semiconducting material. The upper layer has an excess of electrons, which are displaced by the incoming photons in sunlight. The liberated electrons then travel along a wire to an electron-deficient lower layer, resulting in a small flow of direct current in the opposite direction. By connecting multiple cells and panels, the current is increased proportionately.

PV solar installations must be undertaken by professionals and require the mandatory addition of an inverter needed to convert direct to alternating current, as well as connection to the domestic distribution board, whilst storage batteries are optional. Let PacB Group propel your home into the solar age.