Solar PV - Solar PV Survey - Solar PV Array
Solar PV installers should conduct detailed site assessments before carrying out any installation work. They should study the project drawings and co-ordinate their work with that of other trades to ensure that no obstacles will be placed in the way of the Solar PV installation
Location for a Solar PV Array
If the Solar PV array is to be mounted at ground level or on and existing flat roof then the opportunities to achieve an optimum orientation and optimum angle of tilt are much more likely. In the case of a proposed installation on the roof of a new building, there will be a certain amount of design flexibility.
Solar PV Array - Existing Pitched Roof
If a Solar PV system is planned for an existing building, the roof of the building is likely to be the most suitable place to install the Solar PV array.
In the case of a Solar PV array that is to be mounted on an existing pitched roof it is likely that the parameters are already set i.e. where the orientation of the house and the angle of tilt of the roof are already established.
Solar PV Arrays - Available Sunlight in the UK
The amount of available sunlight in the UK varies with the latitude of the site. The south of the country has more available light than the north. The total annual energy available varies from approximately 1,259 kWh per m² per year in the South-West of England to 850 kWp per m² per year in Scotland. The light energy varies during the year; more daylight is available in the summer and less in the winter when the visibility is poor. This is a result of the sun being considerably higher in the sky in mid summer than it is in mid winter.
Locating a Solar PV Array
It is likely that the first principles of locating the Solar PV array will initially be decided on rule of thumb basis. It is later that more accurate date can be collected to optimise the energy collected at any particular location.
Solar PV panels can be fitted on, or integral with, pitched roofs. Alternatively they can be fitted on to the flat roof of a building using using angled mountings. Another possibility is to mount the Solar PV panels on a wall. This can work well with longer, slimmer panels that can be mounted at an angle without protruding too far from the wall itself. Any of these options can work well as long as no part of the panel is shaded from the sun.
In addition to roofs, solar equipment may also be mounted on racks sitting on the ground or on the roofs of sheds, carports, or other outbuildings. All of the same rules apply for site evaluation.
Solar PV Arrays on the Ground
A Solar PV system can be installed on the ground with the Solar PV panels fitted to a frame, where it is more accessible. The benefits of a ground mounted Solar PV array are that the panels can be easily cleaned. It is also possible to change the angle of the frame of the Solar PV array at different times of the year.
Solar PV Trackers
Solar PV tracking devices are available that will move the Solar PV panel allowing it to track the sun across the sky during the day. Solar PV trackers can increase the amount of usable sunlight by about 15 to 20 per cent in winter and up to 55 per cent in summer. At present commercial Solar PV trackers are expensive so unless space is at an absolute premium it would probably be be better to install a larger Solar PV array.
Ideally, Solar PV arrays should be installed in a shade free location. The best way to avoid a reduction in output power is to avoid shading whenever possible
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