Solar heating refers to the renewable energy system that collects energy from the sun in the form of heat rather than using the sun’s energy to produce electricity, as is the case with solar photovoltaics. Solar heating systems can be used to provide space heating and water heating to be used in residential, commercial, or industrial facilities.
In the case of solar water heating (SWH) systems, heated water is used in showers, kitchen and bathroom faucets, swimming pools, washing machines, Jacuzzis, and other appliances that require warm water. Solar space heating techniques circulate the heated liquid in a radiant heat system through piping in the walls or floors to allow the heat to naturally warm indoor spaces.
Today, there are also solar heaters that passively warm air instead of a liquid, which are commonly used in the UK and other European countries. By warming external air and then circulating it indoors, these systems provide a unique method of space heating using renewable energy.
These are two solar thermal techniques that are commonly used: