Factsheet - Solar Energy

Promoting Renewable Energy in Nottinghamshire & Derbyshire SOLAR WATER HEATING There has long been a misconception that the UK is not sunny enough to realistically use solar power. However, even in the UK, with its uncertain weather patterns, solar water heating can provide about 50% of a household's hot water requirements. Solar energy is one of the most affordable and accessible forms of renewable energy for both the domestic and commercial market. Systems can be installed on homes, community centres, village halls, industrial units and especially swimming pools.

What are the savings? Installing solar water heaters on domestic properties can save 1.2 -1.5 tonnes of carbon dioxide per house annually

important to remember that the cost decreases as more people get involved. Communities can publicise local examples of solar water heating systems in local newsletters, church circulars or on parish notice boards. Contact your local Council Energy Advice Centre to see if there are any special offers available. It is worth saying that for many people the primary reason for installing a solar hot water system is not finance. Many install this equipment because they want to do their bit for the environment, using a relatively simple and reliable technology.

What does it look like?

Annual hot water bills should be halved, and between April and October up to 80% of the domestic hot water required should be provided. Modern systems can provide hot water heated to a temperature of 70°C in the summer and 40°C in winter. Realistically, annual savings of between £50 - £150 should be expected. It is important to note that the extent of the savings depends on both current hot water use and current fuel used for heating water within the house. For instance if you use a lot of hot water (such as a swimming pool) and heat it with onpeak electricity you could save considerably more money. If you only use a little and heat it with gas your savings will be lower. Thermomax evacuated tube collector

What does it cost? For a standard three or four bedroomed home a solar water heating system can cost from £1,000 (DIY) to around £3,000 for an installed system. This includes the collectors, a new dual coil hot water cylinder, a controller, expansion vessel, pipework and fittings. Note: VAT on DIY systems has been recently reduced to only 5%. On a larger scale, community groups can encourage people to use solar water heating systems. It is

The size of the installation depends on the water use of the property. The panels will be situated on a south facing roof and the typical size of a flat plate collector system for a family of up to four persons is 2.5-4m2. An evacuated tube collector system will cover two thirds of the area of the corresponding flat plate collector system. However, these are only general guidelines.

AES flat plate collector

How does it work Solar water heating systems are straightforward and reliable. They operate throughout daylight hours, even if the sky is overcast and there is no direct sunlight. There is minimal maintenance and they have a proven life span of at least 20 years.

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4. Controller

The sun's heat is collected by solar collectors normally mounted on an approximately south facing roof. A sensor detects when the collector is warmer than water in the hot water cylinder and then turns on a pump. Fluid (usually a mixture of water and antifreeze) is pumped around the closed circuit and it is heated up by the collectors. The hot fluid then passes through a heat exchanger coil in the hot water storage cylinder and so heats up the hot water. The fluid will at no time come into direct contact with the hot water to be used in the building. Hot water is then drawn from the storage tank in the normal way for washing and cooking. The backup of a conventional boiler or electric immersion heater is still needed for those times when the demand is greater than the amount of stored hot water, but this will be minimised by correctly sizing the solar system. Solar water heating systems will only provide enough heat for hot water, they can not normally be used to supplement your space heating.

plate has a dark coloured layer on its top surface. This can vary from a simple covering of black paint to a more sophisticated selective surface coating, which is designed to absorb solar radiation, whilst reducing heat lost from the plate. The plates have fine channels set into them to allow the fluid to flow through, heating up as it passes through the plate. The collector is embedded in foam insulation and cased in a box which has a glass or clear plastic on the front to reduce heat loss even further. Evacuated tubes - The collector consists of an absorber plate similar to those used in flat plates, except it is much narrower and contains a heat pipe running up the centre. The heat pipe is a tube which contains a liquid with a very low boiling point (e.g. alcohol), which evaporates quickly when it is hot. The resulting gas transfers the heat to a copper condenser at the top of the heat pipe. This heats up fluid flowing past, which in turn heats up the hot water as with a flat plate.

There are two main types of collector - flat plate or evacuated tubes. Flat Plate – The most common type of system used across the world. As the name suggests these collectors are constructed from a flat plate of steel, aluminium or copper, called the absorber plate. Although these materials are good at absorbing solar radiation they are also good at loosing heat, think of the radiators in your house. To enhance the systems efficiency the

The absorber plate runs down the centre of a glass tube which has been evacuated (i.e. all the air has been removed thus making a vacuum) just like a thermos flask. Evacuated tubes therefore lose less heat than flat plate collectors. To form a solar collector several tubes are connected together

and even put you in touch with local people doing the same thing, this way you can help each other.

Getting started However, before handing over your hard earned cash there are several questions you should consider before contacting a supplier.

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How efficient is my property? Although solar water heating provides free, nonpolluting energy it should only be considered after you have carried out simple energy saving measures such as loft and cavity wall insulation. Where can I get impartial advice from? With over 42,000 systems installed in the UK it is very likely that there may be an example locally. It is worth contacting people who have had systems installed and finding out about the user's experiences. As a first point of contact talk to you local Council Energy Efficiency Advice Centre, they will also be able to let you know about any special offers. Further contacts are provided on the back page. What type of system should I buy? Both flat plate and evacuated tube systems will operate perfectly well in the UK. Evacuated tubes should provide more heat in the winter time, but flat plate systems are cheaper to buy.

A Solar Club member with their Filsol flat plate collector

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Where would I put the collector? The ideal place is on a pitched roof facing somewhere between South East and South West. Flat roofs are also suitable although the panel will obviously stick up at about 45°. If you do not have a suitable roof the collector could be mounted in a frame on the side of the house or in the garden, but remember the further away from your hot water cylinder the less efficient your system will be due to heat loss from the pipework. What about my existing heating system? You will still need to use your existing heating system to provide hot water when demand is high or the sun weak and of course to provide heat for your radiators. Usually this can be solved by using a hot water cylinder with either two heat exchangers (one for the solar system and one for the heating system) or by fitting an electric immersion heater. Combi boiler or any other system where there is no hot water cylinder are generally not suitable. Could I do it myself? For the individual, there are DIY solar water heating kits on the market. Although it only requires fairly basic plumbing skills, remember you will also be working on the roof and will probably need assistance to get the collectors into place. The best thing to do is join a Solar club. This is a scheme run by Environ an environmental charity based in Leicester. They will teach you all the skills needed, provide systems at a discount price

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Do I need planning permission? It must be remembered that planning permission may be needed. Generally, water heating systems fall in to the permitted development category. However, in some instances a formal planning application may be needed, for example on listed buildings or properties within a conservation area. Is there any danger from Legionnaires’Disease? Some people have expressed the worry that solar heating systems may give rise to a risk from Legionnaires’ Disease. This is a form of pneumonia caused by bacteria commonly found in the water systems of large buildings. Water contaminated by the bacteria only presents a risk when it is dispersed into the air in the form of an aerosol, such as a spray of very fine droplets and whilst it is unlikely, this could occur in showers, whirlpool baths etc. The most effective way to control the bacteria is through water temperature. Legionellae will grow in water between temperatures of 20-45°C, but is killed by temperatures above this, a temperature of 60°C. will ensure they are all destroyed. All solar systems are designed with the backup of a conventional boiler or immersion heater. These can be used to top up your hot water cylinder to 60°C on those days the solar system doesn’t achieve this. Remember this advice is just as important for conventional heating systems.

Remember four simple facts H Shop around - don’t just take the first quote you are given. H Check references - ask to speak to someone who has had a system fitted by the supplier. H Check how you pay - don’t pay for everything up front. H Spread the word - when the system has been installed to your satisfaction.

Renewable Energy Most of the energy we use in our homes and cars comes from “fossil fuels” notably oil, coal and gas. When we burn fossil fuels, large amounts of carbon dioxide (CO2) are released into the atmosphere, wrapping around the planet like the glass of a huge greenhouse. The greenhouse effect traps the sun's heat causing the plant to warm up. Global warming is the change to the world's climate which is leading to flooding, famine and water shortages. It is estimated that in years to come millions of people will lose their land and homes and virtually everyone on the planet will be affected. In addition, burning fossil fuels causes other environmental problems, such as acid rain, reduced air quality and the extraction and transport of oil, gas and coal brings further blight. Fossil fuels will also eventually run out. whereas energy from the sun, wind and waves will continue and are comparatively benign to the environment.

For further information contact H Solar Trade Association Ltd, The National Energy Centre, Davy Avenue, Knowlhill, Milton Keynes, MK5 8NG. Tel: 01908 442 290 Web: www.solartradeassociation.org.uk H ETSU, New and renewable energy enquiry bureau, Harwell, Oxfordshire, OX11 0RA. Tel: 01235 432 450 Web: http://www2.dti.gov.uk/renewable/index.html H Environ, Parkfield, Western Park, Hinckley Road, Leicester, LE3 6HX Tel: 0116 222 0222 Web www.environ.org.uk

The Local Authorities Energy Partnership represents all district, borough, unitary and county councils within Nottinghamshire & Derbyshire. The Partnership promotes the sustainable use of energy to residents, businesses and within our own operations. Further advice can be obtained from your local Energy Efficiency Advice Centre Amber Valley BC Ashfield DC Bassetlaw DC Broxtowe BC Chesterfield BC Derby City Derbyshire Dales DC District of Bolsover Erewash BC Gedling BC High Peak BC Mansfield DC Newark & Sherwood DC North East Derbyshire DC Nottingham City Rushcliffe BC South Derbyshire DC

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Or Contact the Nottinghamshire & Derbyshire Energy Efficiency Advice Centre for free impartial advice.

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H Centre for Alternative Technology, Machynlleth, Powys, SY20 9AZ Tel: 01654 705950 Web www.cat.org.uk

Thanks to The Northern Energy Initiative/Renew North for their assistance with the text of this document Published on behalf of the Local Authorities Energy Partnership in August 2001 By Derbyshire County Council, Chatsworth Hall, Matlock, Derbyshire DE4 3FW. Whilst every effort has been made to ensure that the information contained within this leaflet is accurate, Derbyshire County Council and the Local Authorities Energy Partnership do not endorse any particular manufacturer or supplier and take no responsibility for any errors or omissions.