There are seven steps involved in designing a successful captive solar PV installation
- Scoping of the project
- Calculating the amount of solar energy available
- Surveying the site
- Calculating the amount of energy needed
- Sizing the solar system
- Component selection and costing
- Detailed design
As with any project, you need to know what you want to achieve. This basically involves detailing what you want from the captive PV installation, once installed. Do you want it to completely provide your day time electricity usage? Or do you want it to support a part of your usage? To start with, the scope of the project can be simple and later as we progress we can flesh it out to suit the requirements.
Step 2 is calculating the amount of solar energy available. Solar insolation is the amount of electromagnetic energy (solar radiation) incident on the surface of the earth. Basically that means how much sunlight is shining down on the area under consideration. By knowing the insolation levels of a particular region one can determine the number of PV modules that are required. An area with poor insolation levels will need a larger number of PV modules than an area with high insolation levels. Once the region’s insolation level is known, one can more accurately calculate collector size and energy output.
Surveying the site follows next. A site survey basically consists of a brief interview with the developer to get a feel for their electricity needs and a physical inspection of the proposed array site to see if it is suitable for solar. When a qualified photovoltaic design professional visits a potential solar site, he or she has many things to watch out for.
The next big task for any photovoltaic system designer is to determine the system load. This load estimate is one of the key factors in the design and cost of the stand-alone PV system. This is followed by sizing the system, component selection and costing, and detailed design.
The final and integral part of any completed installation is the periodic checks that are recommended for any stand-alone PV system so that little problems can be found and corrected before they affect system operation. The system should be checked soon after installation when it is presumably operating well.