The term solar power is used to describe methods of harnessing energy from the sun. As environmental concerns, such as greenhouse gases and the depletion of fossil fuels increase, renewable–energy resources, such as solar power are becoming ever more popular around the world.
Even in the UK we receive vast amounts of solar energy, up to 60% of the amount received on the Equator. This radiation is similar to the output of 1,000 power stations.
Using the Sun’s energy reduces our consumption of conventional fuel and helps to reduce the emission of harmful greenhouse gases.
The effectiveness and efficiency of solar energy in the UK is far greater than most people imagine. In the summer, when items such as black tarmac and car bodies are often too hot to touch we become aware of the Sun’s heat. However, even in the spring and autumn and on clear winter days we receive very useful amounts of solar energy. By tilting a surface to an angle the amount of solar radiation falling on it will be greater than that falling on a flat surface in this country.
Fortunately, the average tilt of a UK house roof is about the optimum for receiving solar energy in the UK. The average property requires approximately 3,000 kWh per year for domestic water heating.
How Solar Heating Works
Solar panels act like a mini power station on your roof. They collect sunlight which is absorbed by the panel’s specially engineered surface and convert it into heat. This heats up a heat transfer fluid in a heat transfer pipe to a temperature higher than the water temperature in the hot water cylinder. When a temperature greater than that in the hot water cylinder is achieved, a digital controller activates a pump which pumps the heat transfer fluid through the heat transfer pipework in the hot water cylinder heating up the water. When there is sufficient hot water in the hot water cylinder the pump stops. If the temperature in the hot water cylinder drops, or water is drawn off the pump starts again bringing the water temperature back up to the desired level.
Ordinary solar panel systems can provide up to 70% of your yearly hot water needs but during the winter, when days are short, they will make a smaller contribution to your hot water than during the summer, when they could provide you with up to 93% of your hot water needs. Now, with the development of thermodynamic solar systems, performance figures can be greatly improved – please click on the ‘Free Energy’ button to read more.
