When we think about capturing the energy in daylight, we immediately think of the heat and power provided by the sun – then we look up and see the all too familiar cloudy skies above the UK. Surprisingly, even on the cloudiest days we receive energy from indirect sunlight (diffuse solar radiation).
In fact, we get so much diffuse solar radiation from our cloudy skies in the UK that we receive around 60% of the solar radiation found at the equator! By harnessing the energy available in daylight, properties in the UK can easily meet their needs for hot water.
Modern lifestyles need a flexible supply of hot water. Although daylight can provide all of your hot water, you cannot turn it on when you want to. Our solar system is designed to compliment your original hot water system to create the flexibility you need.
The average household needs the equivalent of 3000-kilowatt hours (kWh) of energy per year to provide all of its hot water. The map shows that energy in daylight can provide at least 900 kWh per square metre of roof per year.
Vacuum tube technology
With a typical active solar heating system layout, an electronic controller constantly compares the temperature of the solar collectors with the temperature of the water in the cylinder. Whenever the collectors are hotter than the cylinder, the controller activates the systems' circulating pump. A mixture of antifreeze and water is then circulated through the collectors and the cylinders' heat exchanger - thus heating the cylinder in just the same way as a central heating boiler.
Installation is straightforward and usually involves changing the existing cylinder to a new twin coil version, and connecting the solar tubes fitted on the roof tiles.
There is little disturbance to the household as most of the work is on the roof and in the airing cupboard and is usually completed in 2 days.
A solar system can work in conjunction with virtually all other types of heating systems and requires very little maintenance - just a check-over every 3-4 years (many of the first systems are now 20 years old and still going strong). In some instances, a customer may have a relatively new single coiled cylinder installed in their property, cylinders are not cheap bits of kit (some pressurised ones are £1000+!). Therefore rather than throw away the existing cylinder we can fit a solar syphon.
For most homes, we recommend the Thermomax tube system. This world leading UK-made system uses vacuum tube technology to give total insulation against cold winds and temperatures. It works solely on daylight (rather than clear sunlight) - allowing it to work in cloudy conditions, and providing good year-round performance. A 20-tube system, covering an area of 2m squared, is suitable for a 3-bedroom house. This should supply 90% of hot water from April to November and pre-heat water throughout the winter months.
For more information on Thermomax tube systems click here >
A government grant of £400 per system is available for Solar Hot Water systems - see our information pages for grant details.
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