A Solar Photovoltaic (PV) system, mounted on the roof or integrated into the façade of a building, is an electrical installation that converts Solar energy into electricity.
This can be used to meet the building’s own energy consumption requirements or, in certain situations, feed back the excess power into the utility grid network.

The capacity of the Solar modules can vary; and is dependent on the amount of electricity the building requires, the funding available for the project, and the grid operator’s willingness to accept excess capacity.

Core system components include PV Solar modules, their accompanying mounting structure and an inverter.

The layout and configuration of systems can differ, depending on the electric load type and the energy supply requirements. The performance of a PV Solar system is influenced by the amount of Solar energy available at a specific location and by the effectiveness of the system to convert Solar energy to electrical energy.

Key Issues to Consider in PV Solar System Design

  • Global Horizontal Irradiation: The quantity and quality of the Solar energy resource differs depending on the location of the desired site.
  • Module efficiency: Solar module efficiency (its effectiveness in converting Solar energy into electrical energy) continues to improve through advances in research and development. However, module performance typically deteriorates over time, depending on the module type and local conditions. PV Solar module performance decreases as ambient temperatures increase.
  • Energy loss during operation: There are losses associated with the individual components of the system, as the energy is converted from Solar to electrical energy. These losses are inherent in all PV Solar systems, but can be reduced through appropriate design considerations such module layout & spacing in addition to inverter sizing. Operations and Maintenance protocols (O&M) are also important in order to avoid increasing losses over time through activities such as module cleaning and inverter maintenance.
  • Shading losses: Inter-row shading and the surrounding landscape influences how much exposure the system has to the sun. Neighboring buildings, trees or natural features can shade part or whole of a system, affecting overall energy generation.

courtesy of the National Renewable Energy Laboratory (NREL)

Types of PV Solar Panel Modules & Thin Film
Poly-crystalline, Mono-crystalline and Thin Film modules are different types of PV Solar modules. Each of these modules have different properties, which influence the suitability of their application. Poly-crystalline modules are widely used with many proven manufacturers around the world. They are typically less expensive to produce than Mono-crystalline modules, but are not as efficient. Because of the way they are manufactured, Mono-crystalline modules on the other hand have a higher efficiency than most other types of modules, but are more expensive as a result. Finally, Thin Film modules are made with a variety of different substrates (typically CIGS, CdTe and a-Si).

Mounting Solutions

Different roofs require different mounting solutions. While PV Solar systems add relatively a bit of load on a roof, it is still important to ensure that the overall system is in line with structural allowances, and that it does not compromise the building’s weather-proofing. The module mounting system selected is dependent on the roof type and the structural characteristics of the building. For building structures with a profiled roof sheeting, the mounting system can often be clipped on, without any drilling required. For ballast systems or low-pitch, low ballast aerodynamic structures can be used similar to flat roof installations, which also require no drilling. For tiled roofs, bespoke mounting clips can be used that attach to the supporting structure under the tiles, while maintaining the integrity of the weatherproofing of the roof assembly.