Solar power is relatively new source of renewable energy and when considering the usefulness of a solar energy implementation in the domestic environment, one can divide solar energy into three major areas, which are – passive, photovoltaic (pv) and solar water heating.
Passive solar energy is heat that is derived naturally from the sun. This is a consideration in the architecture of many buildings so that less conventional heating is required.
Solar Photovoltaics (PV) harnesses the sun's heat to create electricity that will run various appliances in the home. A major misconception about this type of solar power is that direct sunlight is required - this is not the case as only daylight is required and direct sunlight is not required.
Solar water heating systems work in conjunction with your standard water heater in order to capture the sun's energy and convert it into hot water.
These are explained in greater depth below.
A selection of architectural features that can be used in a solar energy efficient
- South facing windows with insulated glazing that has high ultraviolet transmittance.
- The use of thermal masses. Basically this means any mass such as walls or the roof that can absorb and hold the sun's heat. Materials with high specific heat like stone, concrete, or water work most effectively.
- The position of awnings is an important factor as they can be used to create shade in the summer months, but positioned so that they can capture sunlight in winter.
- Shutters can be used effectively to trap solar heat into a home so that less conventional heating is required.
- Passive warm air solar panels could be incorporated into the building, which would encompass black surfaces fixed behind a glass pane so that when air passes over the sun heats it and it will flow into the building. This method can also be used for pre-heating water.
- Solar chimneys can be implemented to produce a cooling effect.
Photovoltaic 'solar panels' are banks of photovoltaic cells (otherwise known as "solar cells") and these convert solar radiation into electricity direct from daylight. The cells themselves are multi-layered (usually composed of silicon) so that when the sun shines on the cells an electricity field is created across the layers, which will in turn create the electricity. The more the cells are exposed to sunlight, the more energy is captured, which is turn creates more electricity. It is a common misconception that these are only of use in hot areas that experience regular bright sunlight - daylight is sufficient.
Solar PV is a form of renewable energy that does not produce any climate changing gases. A typical home solar PV installation would be approximately 1.5kWp (kilowatts, peak output under ideal conditions) and could produce roughly a third of the average family's annual supply of electricity (based on gas being used as the main source of heating throughout the house).
A 1.5kWp system would cover approximately 10-15m2 of the roof area and we would advise that an accredited installer should always carry out the installation.
The cost for an average home system would be around £6,000 per kWp, with the average home system requiring approximately 1.5 kWp.
Before undertaking an installation it is advisable to consult with your local authority as some councils require planning permission, particularly on listed buildings or conservation areas.
Solar Water Heating
Solar water heating is a fairly well established technology in the UK and works in conjunction with your existing water heater.
This effective technology can create the vast majority of a family's domestic hot water and also larger scale requirements such as heating swimming pools during the summer months and up to 50% during the remainder of the year.
A solar water heating installation consists of three main facets
- Solar panels fitted to the roof
- A hot water cylinder to store the hot water
- A simple plumbing arrangement designed to pump the water around the system
In order for the implementation to be successful it is important to allow space for an additional water cylinder and have approximately 3m2 of southeast to southwest roof space that has minimal amounts of shade during the day.
A typical installation can cost anywhere between £2,000 and £4,500. It is possible to design and fit a system yourself, but this would require a certain amount of DIY skill and it would negatively affect the chances of receiving a grant.
Note: kWp = kilowatts peak - the output of solar panels is stated in terms of their maximum output under ideal conditions.
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