Photovoltaic mounting system
Photovoltaic mounting systems are used to fix solar panels on surfaces like roofs, empty plots etc. These mounting systems enable retrofitting of solar panels on roofs or as part of the structure of the building.
The solar array of a PV system can be mounted on rooftops, generally with a few inches gap and parallel to the surface of the roof. If the rooftop is horizontal, the array is mounted with each panel aligned at an angle. If the panels are planned to be mounted before the construction of the roof, the roof can be designed accordingly by installing support brackets for the panels before the materials for the roof are installed. The installation of the solar panels can be undertaken by the crew responsible for installing the roof. If the roof is already constructed, it is most probably designed so that it is capable of bearing only the weight of the roof. For installing solar panels in such roofs, the roof structure must be strengthened before-hand with particular consideration to weather sealing or the roof can be converted to composition shingles wherever the panels are planned to be installed. By converting to composition shingles, the weight of the removed roof materials can compensate the additional weight of the panels structure. The general practice for installation of roof mounted solar panels include having a support bracket per hundred watts of panels.
Ground mounted PV systems are usually large, utility-scale photovoltaic power stations. The PV array consist of solar modules held in place by racks or frames that are attached to ground based mounting supports.
Ground based mounting supports include:
- Pole mounts, which are driven directly into the ground or embedded in concrete.
- Foundation mounts, such as concrete slabs or poured footings
- Ballasted footing mounts, such as concrete or steel bases that use weight to secure the solar module system in position and do not require ground penetration. This type of mounting system is well suited for sites where excavation is not possible such as capped landfills and simplifies decommissioning or relocation of solar module systems.
Mounting as a shade structure
Solar panels can also be mounted as shade structures where the solar panels can provide shade instead of patio covers. The cost of such shading systems are generally different from standard patio covers, especially in cases where the entire shade required is provided by the panels. The support structure for the shading systems can be normal systems as the weight of a standard PV array is between 3 and 5 pounds/ft2. If the panels are mounted at an angle steeper than normal patio covers, the support structures may require additional strengthening. Other issues that are considered include:
- Simplified array access for maintenance.
- Module wiring may be concealed to maintain the aesthetics of the shading structure.
- Growing vines around the structure must be avoided as they may come in contact with the wiring.
Building-integrated photovoltaics (BIPV) are photovoltaic materials that are used to replace conventional building materials in parts of the building envelope such as the roof, skylights, or facades. They are increasingly being incorporated into the construction of new buildings as a principal or ancillary source of electrical power, although existing buildings may be retrofitted with BIPV modules as well. The advantage of integrated photovoltaics over more common non-integrated systems is that the initial cost can be offset by reducing the amount spent on building materials and labor that would normally be used to construct the part of the building that the BIPV modules replace.
Roof-Jack mounting system
In the mid-1980s Ascension Technology's principals, then working at the Massachusetts Institute of Technology, developed the Roof-Jack mounting system for attaching PV arrays to pitched and shingled residential roofs. The motivation of that effort was to simplify and reduce the cost of residential PV array balance-of-systems.
Orientation and Inclination
Solar cell performs the best when its surface is perpendicular to sun's ray which changes constantly in the course of the day and month. It is a common practice to tilt a fixed PV module (without solar tracker) equal to the latitude of array's location to maximize the annual energy yield of module. The orientation of module in northern hemisphere is recommended to be directed at south and if located in southern hemisphere at north direction. For example, rooftop PV module at the tropics provides highest annual energy yield when inclination of panel surface is close to horizontal direction. The results of an investigation at the tropics showed that orientation of low-slope rooftop PV has negligible impact on annual energy yield but in case of PV external sunshade, east façade and panel slope of 30–40° are the most suitable location and inclination.
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- Solar tracker
- Rooftop photovoltaic power station
- Stand-alone photovoltaic power system
- Grid-connected photovoltaic power system