Solar PV System Design Considerations

Solar Photovoltaic (PV) solutions have defined performance characteristics and these are determined by several factors, including overall design of the Solar PV system, its installation and ongoing maintenance. There are many potential areas that require professional attention, from the selection of the right PV panels and their size, to the solar inverters, DC isolators and electrical cables. Maintenance can also be an issue to ensure that the system is cleaned, inspected and electrically tested.

The key factor about solar power system design is to choose the right system for the job, taking into account the property owner’s needs and what they want it to do (reduce energy bills, provide back-up power) and environmental issues. It is crucial to ensure the installation site (whether a roof, wall or other permanent structure) is capable of handling the desired system size without reinforcement. Materials that are sunlight and weather resistant should be specified for all outdoor equipment. The impact of shading on the effectiveness of the solar array should be taken into account at the design stage so as to be minimised. Even a tiny bit of shading from a vent pipe could detrimentally affect system performance.

In the UK, it is unlikely planning permission will be required for solar PV installations but your local authority planning office should be consulted. Your system should also comply with building and electrical regulations. Electrical losses should also be considered at the design stage. Every electrical system will suffer from loss to some degree. It can be minimised at the planning stages if the system is designed correctly.

The system’s battery (if there is one) should be properly housed and managed. If the intention is to connect to a utility supply to take advantage of the FITs (Feed-in Tariff) scheme, your installer should contact your utility company on your behalf and obtain all the necessary permissions, technical data and information. A good installation company should assist in all these areas. The basic steps to follow at installation are:

• Improve the roof structure as necessary.
• Properly seal roof penetrations using roofing-industry-approved sealing methods.
• Solar PV equipment should be installed in accordance with the manufacturers instructions, using the correct procedures as outlined.
• It is extremely important that all system parts are properly grounded to reduce the threat of shock hazards and surges.
• The system should be properly tested once installed to ensure proper and correct working and operation.
• Ensure the design and installation meets with local utility connection requirements.

Solar power PV renewable power systems do not require much in the way of maintenance, however, a full inspection annually is desirable to ensure the system continues to operate at peak performance. Solar panels themselves will last a long time, but other equipment contained within the system may not and will need replacing at some point, such as the inverter and batteries, for example. A good indication as to whether equipment renewals may be required is a check on system performance. On a sunny day in March and September each year, review the output of the system at around midday. Compare it with the previous year’s reading. A rapid decline may indicate a system problem. It is a good idea to clean the PV array once a year (but only when it is cool) if there is a noticeable build up of dust or deposits. Inspect the system to ensure wiring has not degraded and all connections are sound.