Friday, September 29, 2006

Get Some Sun

Hello My Friends,

I wanted to talk today about solar thermal hot water systems.

Solar water heating systems use heat from the sun to work alongside your conventional water heater. The technology is well developed with a large choice of equipment to suit many applications.


Can provide almost all of your hot water during the summer months and about 50% year round
reduces your impact on the environment - the average domestic system reduces carbon dioxide emissions by around 400kg per year, depending on the fuel replaced.

Different types of system:

What best suits your needs depends on a range of factors, including the area of south facing roof, the existing water heating system (e.g. some combination boilers aren't suitable) and your budget.
A competent professional installer should assess your situation and discuss with you the best configuration to meet your needs. A solar thermal hot water system will reduce water heating costs more dramatically in a home that has an electrically heated water system like an immersion heater.

Solar water heating and your home:

Solar water heating can be used in the home or for larger applications, such as swimming pools. For domestic hot water there are three main components: solar panels, a heat transfer system, and a hot water cylinder. Solar panels - or collectors - are fitted to your roof. They collect heat from the sun's radiation. The heat transfer system uses the collected heat to heat water. A hot water cylinder stores the hot water that is heated during the day and supplies it for use later.

Is my property suitable?

Preferably you will need 2-4m2 of southeast to southwest facing roof receiving direct sunlight for the main part of the day. You'll also need space to locate an additional water cylinder if required. Most systems use a dual coil cylinder and some systems may also have an overflow cylinder unit too.

Cost and maintenance

The typical installation cost for a domestic flat plate collector system is £2,000 - £3,000. Evacuated tube systems will cost £3,500 - £4,500.

Some systems use a drain back process utilising gravity to run the water circulating in the collector to drain back into the cylinder when the external temperature falls below a set level or when the daylight reduces (ie night time). The only element of this kind of system that may need maintenance is a simple pump - no other working parts should need attention.

Other systems include an anti freeze agent like glycol that surrounds the tubes in the collector and this may need checking on a regular basis as part of a maintenance regime.

You can also fit or build the system yourself. It may be cheaper but will take longer and you'll need a certain level of skill. However, DIY jobs are not eligible for grant funding.

Solar hot water systems generally come with a 5 to 10-year warranty and require very little maintenance. A yearly check by the householder and a more detailed check by a professional installer every 3-5 years should be sufficient (consult your system supplier for exact maintenance requirements).

Interested in introducing a renewable energy technology into your home? The low carbon buildings programme will provide grants towards installing this technology.

I will be posting more information shortly about ground source heat pumps and biomass heating systems. As always I hope you find the information useful and if you have any questions or comments please dont hesitate to give me your feedback on the comments section of the blog.

Take care - come back soon

From Your Friend The Energy Angel


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