solar energy
There are two main types of solar panels: water heating (Solar Thermal) and electricity generating (Photovoltaics). Both of these systems rely on energy from the sun.
SOLAR THERMAL - Heating Hot Water
The Concept:-
Thermal energy is absorbed by a specially coated heat absorbent collector panel, which in turn transfers the sun's heat energy to a water system where it contributes to heating the domestic hot water. Such a system does not require direct sunlight to absorb solar energy. A thermal heating system may be connected to a water heating system (from hot water cylinders to swimming pools) reducing bills and reliance on fossil fuels. There are different types of solar thermal systems such as flat plated panels or vacuum tubes, which have different advantages in different situations.
Even in a climate such as Scotland's Solar Thermal systems can provide about 60% of annual hot water, ranging from nearly 100% during the summer to nearer 25% through the middle of winter.
SOLAR PHOTOVOLTAICS - Generating Electricity (PV)
The Concept:-
Solar cells absorb sunlight and convert it directly into electricity, which may be used to power a home's electrical systems. Solar cells do not necessarily require direct, bright sunlight to work. The cells are thin rectangular wafers, typically made of silicon. The electricity produced is direct current (DC -the same electricity that comes from a battery) and usually at 12Volts. This may be used as it is, stored in batteries for later use or converted using an inverter to alternating current (AC), which is typically used for household appliances at 230 volts, and may even be fed back into the mains.
Copyright Glendevon Energy Company Limited 2009