Tipos de sistemas de montaje

Marco del módulo con orificios de montaje.
Izquierda - Un sistema de riel y abrazadera.
Derecha - Un módulo FV con los orificios de montaje adecuados marcados.

módulos FV deben estar conectados a algún tipo de estructura por razones pragmáticas como prevenir daños por viento y pérdidas por robo, pero también para asegurar que el inclinación y azimut es correcto para maximizar la producción de energía. Un módulo FV típico viene con un marco de aluminio con el fin de proteger el resto del módulo y proporcionar un medio para asegurarlo. Un módulo FV debe asegurarse y apoyarse correctamente. Los fabricantes de módulos proporcionan orificios en el marco para el montaje con pernos, que sirven para identificar dónde es apropiado anclar el módulo. Hay dos formas principales de montar un módulo FV en una estructura:

1. A través de los tornillos que se encuentran en la parte posterior del marco del módulo.
2. Utilizando abrazaderas que fijan el módulo a un riel.

En cualquier caso, un módulo debe apoyarse y asegurarse en las áreas donde están los orificios de los pernos en el marco, de lo contrario, podría dañarse debido al clima. Es importante que el módulo esté bien apretado independientemente del sistema que se utilice para asegurarlo, pero no hasta el punto de distorsionar el marco. El fabricante tendrá especificaciones sobre qué tan apretado es apropiado en la hoja de especificaciones de un módulo, pero para apretar correctamente un perno a estas especificaciones es necesaria una llave dinamométrica ajustable. En muchas partes del mundo, las llaves dinamométricas ajustables pueden tener un costo prohibitivo o poco común, por lo tanto, un instalador puede confiar en la experiencia previa en el uso de una llave dinamométrica o simplemente en su buen juicio. Cualquiera de los estilos de montaje (usando los orificios o abrazaderas) se puede utilizar con una variedad de sistemas de montaje diferentes que tienen diferentes ventajas y desventajas que normalmente hacen que un tipo sea el más apropiado para una aplicación determinada.

The performance of PV modules is greatly affected by high temperatures. Therefore, properly installing modules to permit ventilation can have a great impact upon system performance. A PV module should not, for example, be placed directly onto a metal roof surface as there will be no ventilation at the back of the module and performance will suffer. In many locations PV modules may experience temperature swings of more than 60°C throughout the year, which means that space also has to be left for modules to expand and contract, otherwise the glass or cells inside of a module could be compressed and damaged. There are no set rules about how much space to allow around modules or between modules, but there are some guidelines:

• A module should be at least 1cm from a roof surface for optimal performance. Less distance will have a significant impact on performance and more distance will not greatly increase performance.
• The space between modules in an array will typically be determined by the mounting system that is used. At least 10mm between modules is recommended to permit expansion, contraction and adequate ventilation.

Roof mount

A roof mounted PV system using rails and clamps.

PV modules are mounted on the roof of a home or building. This is the most typical approach around the world. The PV modules sit on rails that are anchored into A system of this type the structure that underlies the roof (purlins, timbers, etc). Clamps are used to hold the modules to rails.

Advantages

• Low cost as the roof structure already exists.
• Many roofs have lots of open space that can be used for a sizable PV system.
• No custom fabrication required.
• Limited amount of material required. Easy to transport to the jobsite.
• Simple installation. No concrete.
• Does not occupy space around the home that could be used for another purpose.
• Out of the reach of children, domesticated animals, and thieves.

Disadvantages

• Requires the creation of holes in the roof which can lead to leaks.
• Makes roof repairs or replacement difficult.
• Existing roof structure may not be appropriate to work on or support a PV system. It needs to be evaluated.
• The tilt and azimuth of the roof is typically used and is often not optimal. This can reduce system performance.
• Roof surfaces can generate significant amounts of heat that can reduce PV module production.
• Module tilt cannot be adjusted seasonally like with a pole mount.

Pole mount

A pole mounted PV system.

PV modules are mounted onto a racking structure that sits atop one or two poles that are anchored into concrete. Pole mount systems are common for small-scale off-grid PV systems as they can be installed nearly anywhere and allow the design to be optimized for the site.

Advantages

• Relatively low cost for small systems.
• Can be installed in nearly any location.
• Installation does not depend on the strength or quality of a roof.
• Angle and orientation of the PV modules can be chosen.
• Can easily be built to permit the tilt of the modules to be adjusted seasonally.
• Keeps modules cooler than a roof mounted system.

Disadvantages

• Pole mount will occupy otherwise usable space near the home.
• Installation is more involved. Requires concrete.
• Custom design and fabrication of the pole mount for the project is required.
• Transport of the pole and mounting structure can be difficult.
• Other mounting system designs are often more appropriate for larger systems.

Ground mount

A ground mounted PV system.

PV modules are mounted onto a racking structure that sits atop four or more poles that are anchored into concrete. Ground mount systems share many of the same advantages of pole mount systems but work better for larger off-grid systems.

Advantages

• Can be installed in nearly any location with any size system.
• May be fabricated on site with the right design and materials.
• Installation does not depend on the strength or quality of a roof.
• Angle and orientation of the PV modules can be chosen.
• Keeps modules cooler than a roof mounted system.

Disadvantages

• Involved installation involving many different holes with concrete.
• Requires the transportation of a significant quantity of materials and racking.
• Ground mount will occupy otherwise usable space near the home.
• Custom design of the ground mount system will be required.
• Not as easy to build to incorporate adjustable tilt like as with a pole mount.

Ballast mount

A ballast mounted PV system.

PV modules are mounted onto a racking structure that sits atop the ground or a flat roof surface that relies upon the weight of heavy concrete blocks to secure it rather than any type of concrete or anchors to the roof structure. Ballast mount systems are not as common with off-grid PV systems as other mounting systems, but they have a lot of advantages if the location is appropriate.

Advantages

• Simple installation. No concrete or roof penetrations required.
• Does not occupy space around the home that could be used for another purpose.
• Relatively low cost if the location is appropriate.
• Installation does not depend on the strength or quality of a roof.
• Orientation and tilt (to some degree) of the modules can be chosen.

Disadvantages

• Site specific. Only typically appropriate for roofs with a low angle (flat) or fenced-in/secure areas.
• Theft can be relatively easy.
• Requires a an appropriate ballast racking structure that either must be bought or custom fabricated beforehand.
• Roof structure must be able to support the additional weight of the concrete blocks.
• Requires a significant number of concrete blocks to be purchased or fabricated on-site.