Solar thermal systems use heat from the sun to warm up domestic water. This is connected to a conventional boiler or immersion heater to make the water warmer or when solar heat is not available for use. This is known as the water heating system and the technology is well developed to offer a large choice of equipment to suit many applications. This system is commonly used domestically, but there are solar thermal systems on the market to cater for any size of building. Ideally they will need to be mounted on a south facing surface, which receives direct sunlight for most of the day.
There are many uses for such a system in domestic households as water is taken from the cold mains-pressure water to be heated and supplied around the house. Additionally, it can be used to heat swimming pools. These are most frequently in use in the summer when the sun’s radiation is at its strongest so heating a swimming pool is an ideal solar heating application.
How it works
Solar Thermals heat water from the sun by collecting its heat. Solar panels or collectors are fitted onto the roof, which trap the heat. In a heat transfer system, the heat accumulated is used to warm the water, which is then stored in hot water cylinders for use.
There are two main types of solar water heating collectors:
- Flat plate systems
- Evacuated tube systems
The flat plate systems can be attached to or integrated into the roof. It is made up of an absorber plate which has a transparent cover to collect heat from the sun.
The evacuated tube system contains a row of glass tubes, each containing an absorber plate absorber plate feeding into a manifold which transports the heated fluid.
If the water does not reach the required temperature, a boiler or immersion heater can be used as a back up to reach the temperatures set by a cylindrical thermostat.
The system needs to be connected to a twin coil cylinder so that one coil can receive heat from the solar thermal panel, whilst the second receives heat from the boiler or immersion heater.
Benefits
- Solar thermals have no carbon emissions as it is green and is a renewable energy. A typical home reduces carbon dioxide emissions by around 325kg per year and about £65 a year of your hot water bills, when installed in a gas heated home.
- There is a wide range of installation options so can be applied to a wide range of roofs.
- Grants are also available to cut costs.
- Sunlight is free so after initial costs bills would be greatly reduced.
- They can easily be integrated with other heating systems to meet the additional hot water requirements during winter.
- The 360° cylindrical design of evacuated tube solar collectors are able to capture light at many more angles and even work at full efficiency when the sun is lower in the sky.
- Minimal maintenance is required and there are no moving parts.
- It is easy-to-install and maintain.
Installation and where it can be used
The system is relatively easy to install and there are a number of installation options available including surface-mounted options for pitch or flat roofs, A-frames, in-roof and complete roof installation, canopy or façade construction.
In cases of insufficient sunlight the hot water cylinders are available so this system can be used in most cases. Space should be allowed for these cylinders when planning your project and mainly the South-East to South-West facing roof space is required.