Solar panels are used to collect solar radiation from the sun and actively convert that energy to electricity.
Solar panels are comprised of several individual solar cells. These solar cells function similarly to large semiconductors and utilize a large-area p-n junction diode. When the solar cells are exposed to sunlight, the p-n junction diodes convert the energy from sunlight into usable electrical energy. The energy generated from photons striking the surface of the solar panel allows electrons to be knocked out of their orbits and released, and electric fields in the solar cells pull these free electrons in a directional current, from which metal contacts in the solar cell can generate electricity. The more solar cells in a solar panel and the higher the quality of the solar cells, the more total electrical output the solar panel can produce. The conversion of sunlight to usable electrical energy has been dubbed the Photovoltaic Effect.
The photovoltaic effect arises from the properties of the p-n junction diode, as such there are no moving parts in a solar panel.
Solar Insolation is a measure of how much solar radiation a given solar panel or surface recieves. The greater the insolation, the more solar energy can be converted to electricity by the solar panel.
Other factors that affect the output of solar panels are weather conditions, shade caused by obstructions to direct sunlight, and the angle and position at which the solar panel is installed. Solar panels function the best when placed in direct sunlight, away from obstructions that might cast shade, and in areas with high regional solar insolation ratings.
Solar panel efficiency can be optimized by using dynamic mounts that follow the position of the sun in the sky and rotate the solar panel to get the maximum amount of direct exposure during the day as possible. For more information on solar panel efficiency through the use of mounts, see our section on solar panel mounts and accessories.
Solar panels are leading the way in renewable energy and they are at the forefront of the government’s campaign to cut down on rising carbon emissions. The rise in the number of people installing systems at their home or business in the UK is largely due to the numerous benefits that they provide; the main benefit being their ability to save owners money on heating bills which can amount to hundreds of pounds each year. The function of solar panels is important in their ability to provide energy to the home.
There are two different types of solar panel that can be purchased, these are solar photovoltaic (PV) and solar water (thermal) heating. Both have different functions and work in individual ways to produce renewable energy.
Solar photovoltaic panels
The function of solar panels of the photovoltaic kind is to generate electricity to power appliances in the home or business. This is done by utilising the free energy from the sun. Solar PV panels are made up of a number of individual cells, each cell is made up of two layers of semiconducting material such as silicon which are create and electric field upon contact with sunlight. The electrons are then transferred into electricity which can be used around the home or place of work. The use of solar PV panels can provide up to 100% of electricity needs depending on the amount of usage; a general system will provide around 40% of electricity which will amount to savings of around £200 per year on energy bills and a reduction of carbon emissions by up to one tonne.
There four main types of Solar PV panel, each has the same function but differs in efficiency and cost, types include:
Hybrid
Amorphous silicon
Polycrystalline
Monocrystalline
Hybrid and monocrystalline solar panels are the most effective in terms of how much of the suns energy is harnessed and turned into electricity; however, they are also a lot more expensive when compared to polycrystalline and amorphous silicon.
Solar thermal panels
The function of solar panels for heating water is different to that of solar photovoltaic panels. Solar thermal systems are the most widely used in the UK and they are also the cheaper of the two types of panel to install. There are two variations of solar thermal, flat plate or evacuated tubes, both provide the same end result but work in a different way.
The function of solar panels when purchased as flat plates work in a similar way to a radiator with a glass covered insulated absorber. Flat plate systems are cheaper to install than evacuated systems but are also less effective. Evacuated tube systems work by allowing water to pass through tubes backed by an absorber plate, this system can heat the water to much higher levels.
The function of the solar panels that heat water can lead to helpful savings in water bills with an average saving of £70-£90 on heating bills.