Solar Heating Systems

Solar heating systems have been popular overseas for many years now, and the technology is very well developed. In the early days, it did require a hotter climate to be effective, but technological advances have now reduced the reliance on temperature, daylight is sufficient to have an effect these days.

Now the technology is suitable for our climate, it is becoming increasingly attractive to install a system which will make a contribution to reducing your own Carbon emissions (by the equivalent of over half a ton a year compared to a system using fossil fuels), while at the same time making a considerable saving on your fuel costs as explained below.

The sun is by far the most abundant source of energy available on earth. Energy arriving at the earth's surface by way of solar radiation over a period of 40 minutes, is the equivalent of the power used by the entire population of the earth in one year.

The sun is the ultimate source of nearly all our energy supplies. The difference between renewable and non-renewable sources is a matter of time-scale and geological opportunity.

Fossil fuels (non-renewable) are reservoirs of stored solar energy laid down over millions of years and modified by great geological upheaval.

Solar energy is its direct conversion into electricity by photovoltaic solar cells and into heat when absorbed by a dark object.

Solar technology broadly falls into three categories:

• Photovoltaic: The direct conversion of solar radiation into electricity.
• Passive solar technology: Absorption of solar energy directly into a building to reduce the energy required for space heating. This includes conservatories, and south facing atria to collect the energy and circulate the hot air mostly without fans.

• Active solar heating: This always involves a discreet solar collector mounted in such a way as to gather the radiation. Mostly the heat will be used for domestic hot water or swimming pool heating.

It is active solar heating, also called solar domestic hot water systems, that tend to be the most effective place for a typical home-owner to begin tackling ever increasing energy costs, and the associated emissions from fossil-fuel consumption.

A solar powered domestic hot water system will require your property to have a south-east to south-westerly facing roof onto which typically, two collectors or absorber tubes are mounted. The roof can be pitched or flat, and most types of fixture can be accommodated. You don't normally need planning permission for the collector or absorber tubes, provided they do not protrude more than 150mm (6") proud/above the roof line, which in most installations they do not. That said, one should always check with your local authority just to be sure.

Try not to allow yourself to become too embroiled in which type of technology you should have installed at your home, the difference in performance between for example collector plates and tubes is not significant. The solar manufacturing industry has developed predominantly in Germany and Switzerland, the quality of most solar equipment is very high.

A new hot water cylinder will be installed in the airing cupboard, which is about 300mm (12") taller than a standard one, so you will lose one of the shelves in your airing cupboard.

A separate pump and controller is installed either in the airing cupboard or loft space depending upon space constraints and your personal preferences. The pump and controller consume the same amount of electricity as a 40W light bulb, no more.

The installation would normally take 3 days to complete, all works and equipment installed by a solar installer registered with the Governments Clearskies initiative, are guaranteed for 2 years. The Clearskies initiative can be found via the Energy Saving Trust website; www.est.org.uk .

A typical installation will deliver usable energy from early spring to mid-autumn. The modern collectors only need daylight to operate not full sunshine, a popular mis-conception. The system will save you a significant amount of energy, the exact amount depends a little on the technology you employ, and a lot on who you ask!

At Entropic we try to be honest and realistic about the savings. A reasonable, and proven saving assumption is 66% of the total annual hot water costs you currently pay for using fossil-fuels.

A solar system uses Glycol, which deteriorates over a period of time, at Entropic we recommend a service every three years to replenish the Glycol and re-pressure the system.

As well as the Energy Saving Trust, further information can be found at the Solar Trade Association; www.solartradeassociation.org.uk and HSE Books at; www.hsebooks.co.uk .

You can receive a Government grant towards your solar installation, but you must secure the grant before you instruct any installer to commence work on your behalf. The application form for a grant is on the low carbon buildings website, which is part of the Energy Saving Trust, the site is; www.lowcarbonbuildings.org.uk .

Please call us if you would like a free quotation on 01296 715485.