Designing complete grid-connected systems

Naps grid-connected solar electric systems are designed to provide well-matched solar array and inverter combinations, plus a suitable mounting method. When solar electric systems are installed in buildings, the visual appearance of the solar system is of great importance. The variety of our flexible mounting systems, together with our expertise, should enable you to take visual appearance into account, also.

Selection of the most suitable mounting method depends on the exact location of the array (roof, wall, sunshade, glazed area, etc) and selection of the most suitable module type largely depends on the space available.

Matching an inverter to a certain array size is not simply a matter of matching voltage and current rating. The solar array characteristics have to be matched to the various over- and under- current/voltage/power protection mechanisms of the inverter as well as to the main operating conditions. The inverter should not be harmed by the worst case conditions of the highest possible array open circuit voltage. We take all these factors into consideration when working out the most suitable inverter for a particular solar array. The optimum ratio of array peak Watts to inverter rated Watts is normally greater than 1. This does not mean that the inverter will be overloaded to any great extent.

Our 'packaged' grid-connected systems, such as the NSR range of solar roof systems for domestic houses, are standardised systems in which the array and a single inverter are well-matched in characteristics. They are modular in that larger systems can be built up by using two or more standard systems (not necessarily of the same type).

Systems for larger buildings are in general designed on a customised basis, although it is also possible to use standardised 'building blocks' if these will fit into the available space. In a custom-designed larger system, the array is normally designed to give the best possible coverage of the available area, and then it is split into electrical subsections to match a suitable inverter type. In doing this, attention is paid to the likely patterns of shadows that will be encountered (which can determine the optimum way that the modules are wired together). Configuring a larger system into separate electrical blocks, each with its own inverter, increases system reliability and also reduces the losses in total output owing to shadowing.

Our experts are at your disposal to advise you on the most appropriate standardised or customised system. Our complete specification will include all the mounting hardware and electrical hardware needed, along with any data logging or display equipment.

We will be happy to assist in designing a system that best fits the requirements of your project. Please e-mail us.