Solar thermal energy systems absorb the sun’s light and transfer it to hot water which can be used for washing or cleaning. The main part of the system is the solar collector.
Solar collectors are essentially black metal plates, which are heated by the sun’s energy. The metal then transfers the heat to liquid (usually come sort of anti-freeze) which is used to move the heat to a usable place, by being circulated to the domestic hot water cylinder. There is usually a sheet of glass placed above the metal plates to reduce loss of heat to the air.
The standard procedure for operating a solar thermal energy system, is to add another heat exchanger to the hot water cylinder (it probably already has one for the boiler) or change the cylinder for a system which already has multiple heat exchangers. The control system for solar panels monitors the temperature at the panel, and provided the temperature is sufficiently high, circulates the transfer fluid to bring the heat down to the cylinder.
So how well does it work?
The objective of Solar Thermal systems is to generate hot water. This does not mean heating, but hot water. In a domestic house the heating demand is mainly in the winter, when solar panels do not work that well. There is a hot water demand all year round however. So once you realise that that is what they are trying to achieve, they are great. Most people suggest they provide all the house’s hot water demands in summer, and over half in winter. Some are even more impressed with them, but it is fair to say that the reduction is in the region of 75%.
Furthermore Solar panels generally replace electrical energy, which as we saw before, is the most expensive and dirtiest type of energy.
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