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How do solar water heating systems work? Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to warm water which is stored in a hot water cylinder.
There are two types of solar water heating panels, they are evacuated tubes and flat plate collectors
(like in the picture above).
Flat plates collectors can be fixed on the roof tiles or integrated into the roof.
A boiler or immersion heater can be used as a back up to heat the water further to reach the temperature set by the cylinders thermostat when the solar water heating system does not reach that temperature. (The cylinder thermostat should be set at 60 degrees centigrade.)
Larger solar panels can also provide energy to heat your home as well - though usually only in the summer months when home heating is unnecessary.
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The benefits of solar water heating Hot water throughout the year: the system works all year round, though you'll need to heat the water further with a boiler or immersion heater during the winter months.
Cut your bills: sunlight is free, so once you've paid for the initial installation your hot water costs will be reduced.
Cut your carbon footprint: solar hot water is a green, renewable heating system and can reduce your carbon dioxide emissions
Is a solar water heating system suitable for my home? To tell if solar water heating is right for you, there are a few key questions to consider:
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Do you have a sunny place to put solar panels? You'll need around 5 square metres of roof space which faces east to west through south and receives direct sunlight for the main part of the day. Alternatively, if you do not have a south facing roof and if you have space, you could install two panels, one facing east and one facing west - but this will make installation more costly. The panels don't always have to be mounted on a roof, they can be fixed to a frame on flat roofs.
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Do you have space for a larger, or an extra, hot water cylinder? If a dedicated solar cylinder is not already installed then you will need to replace the existing cylinder, or add a dedicated cylinder with a solar heating coil.
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Is your current boiler compatible with solar water heating? Most conventional boiler and hot water cylinder systems are compatible with solar water heating. If your boiler is a combination boiler (combi) and you don't currently have a hot water tank then a solar hot water system may not be compatible.
Heat your home with energy absorbed from the ground.
Ground source heat pumps use pipes buried in the garden to extract heat from the ground. This is usually used to heat radiators or underfloor heating systems and hot water.
Beneath the surface, the ground stays at a fairly constant temperature, so a ground source heat pump can be used throughout the year - even in the middle of winter.
A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe - called a ground loop - which is buried in the garden. Heat from the ground is absorbed into this fluid and is pumped through a heat
exchanger in the heat pump.
Low grade heat passes through the heat pump compressor and is concentrated into a higher temperature useful heat capable of heating water for the heating and hot water circuits of the house. Ground loop fluid, now cooler, passes back into the ground where it absorbs further energy from the ground in a continuous process while heating is required.
The length of the ground loop depends on the size of your home and the amount of heat you need - longer loops can draw more heat from the ground, but need more space to be buried in.
Normally the loop is laid flat, or coiled in trenches about two metres deep, but if there is not enough space in your garden you can install a vertical loop down into the ground to a depth of up to 100 metres for a typical domestic home.
Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, air, or water is constantly being renewed naturally.
Unlike gas or oil boilers, heat pumps deliver heat at lower temperatures over much longer periods. This means that during the winter they may need to be left on 24/7 to heat your home efficiently. It also means that radiators should never feel as hot to the touch as they would do when using a gas or oil boiler.
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