Patent Application
20120211252
The various embodiments relate generally to photovoltaic solar panels and more particularly to efficiently grounding solar panel arrays.
In general, photovoltaic panel frames are anodized to help protect the frames from exposure to the elements. Mounting rails are used to attach photovoltaic panel frames to racking systems. The tops of the mounting rails are generally made of flat, smooth aluminum. The surfaces of the mounting rails are generally anodized, although mill finishes are used on some manufacturer's products. The anodized coating on a solar panel frame helps to minimize the corrosion due to weather. However, the anodized coating also presents a barrier that reduces the effectiveness of the grounding connection.
Under the National Electric Code (NEC), all photovoltaic panel frames are required to be grounded to the racking systems. Grounding may be accomplished by either grounding each individual panel, or by making a contact point of exposed metal between the panels and the rails to create a safe electrical ground. The present technology on the market to create such an exposed metal contact point is the use of grounding clips.
A grounding clip consists of a piece of metal with sharp extruded burrs on both sides. The extruded burrs pierce the anodized coating on panels and rails when tightened by nuts and bolts at the points where the panels are secured to the rails. An example Industry standard product using this technology is the grounding clip produced by WEEB® brand, although other manufacturers in photovoltaic equipment produce various other grounding clips that serve the same purpose. Such grounding clips are separate components from photovoltaic panels and rails.
The various embodiments illustrated herein provide devices and methods for grounding photovoltaic solar and building integrated photovoltaic panel (BIPV) power systems without the use of additional parts. The various embodiments provide a solar panel racking system with an integrated grounding bar rail. The integrated grounding bar rail of the various embodiments enables grounding of photovoltaic solar and BIPV panels to the racking system. Further, an integrated grounding bar rail according to the various embodiments may be adaptable to use with all framed solar panel brands and sizes and major solar racking system products, for example, BIPV systems, pole-mounted photovoltaic systems, etc. The integrated grounding bar rail may incorporate “screw bosses” on the top and face of the rail to accommodate not only slide-in bolts, but also self-tapping screws. Furthermore, the integrated grounding bar technology may also be adapted for use on the underside of solar panel frames to achieve proper grounding to the rails.
The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary aspects of the invention. Together with the general description given above and the detailed description given below, the drawings serve to explain features of the invention.
The various embodiments will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. References made to particular examples and implementations are for illustrative purposes and are not intended to limit the scope of the invention or the claims.
The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations.
The term “photovoltaic panel” as used herein means a solar panel that can be used to convert light into energy.
The term “ballast mounted system” as used herein means a photovoltaic panel racking system in which a mounting rack is held on top of a surface (e.g., a roof) by weights, as opposed to secured by fastening to a structure itself (i.e., penetrating a roof). Ballast mounted systems may be positioned on other surfaces, for example, on the ground. Concrete blocks are commonly used as ballasts in such a system. Alternatively, ballasts may be made of materials including, but not limited to, sand, water, metal, etc.
The various embodiments illustrated herein relate to a passive device designed to be used specifically during photovoltaic solar panel and BIPV installation. Mounting rails are used to attach the solar panels to a racking system, and are configured with integrated grounding bars comprising sharp, triangle-shaped extruded bars and/or cone shaped prongs, or other forms of sharp serrations running the entire length of the top surface of the rail. These contact the bottom of the anodized aluminum frame of a solar panel. When pressure is applied during mounting process, the grounding bar perforates the anodized coating of solar panel frames, thereby grounding the solar panels to the racking system.
The term “photovoltaic system” as used herein means a system with one or more photovoltaic panels, mechanical and electrical connections, and mountings, which generates and supplies electricity in commercial and residential applications.
The various embodiments provide a mounting rail for a photovoltaic system with one or more integrated grounding bars. When photovoltaic panels are installed onto mounting rails, the integrated grounding bar on the rails may perforate the anodized coating of the panel frames. Mounting clamps, standard with installation of any photovoltaic panel racking system, may be used to tighten the connection between the panel frames and the mounting rails and create a safe ground. Once the panels are grounded to the rails by these metal-to-metal contacts, a continuous ground wire may be run to each rail, connecting to the ends of the rails. In a preferred embodiment, the mounting rail may be configured to span long distances between mounting brackets, thereby minimizing the number of mounting brackets and reducing the number of roof penetrations necessary.
Further, the various embodiments employ ballast pans to hold ballast blocks to anchor a row of photovoltaic panels to a surface. Advantageously, a ballast pan may also function as a grounding conductor to an adjacent row of photovoltaic panels in a preferred embodiment. Thus, the ballast pans serve a dual function of anchoring the photovoltaic system and facilitating electrical grounding, and therefore safety of the system.
In an alternative embodiment, grounding bars 14a, 14b may be configured as cone-shaped grounding prongs, or serrations running the entire length of the top surface of the rail. As will be understood by one of ordinary skill in the art, grounding bars may take on other shapes, provided that when the rail contacts the bottom of the anodized aluminum frame and pressure applied during mounting, the grounding rail is sufficiently sharp to perforate the anodized coating of the frame, thereby grounding the panel.
In an alternative embodiment photovoltaic racking system, one or more grounding bars may be integrated in the frames of the photovoltaic panels.
The various embodiment integrated grounding bar rails and frames require no special tools for installation. The various embodiments eliminate the problems associated with grounding clips that can move around during installation and not properly ground the panels to the rails. Further, the various embodiments may be used for installation of solar panels regardless of the type of mounting configuration. This includes roof mounted systems, for example, both penetrating and non-penetrating or ballasted, ground mounted systems, pole mounted systems, canopies and carports, etc. The various embodiments and associated grounding bars illustrated herein are universally adaptable to all brands and sizes of solar panels.
The embodiments described above may be implemented on any of a variety of roof types, including, but not limited to, cross-gabled, hipped, mansard, flat, or shed roofs. Further, the various embodiments may be implemented on other flat surfaces, including, but not limited to, a field in a photovoltaic farm, a parking lot, etc. The foregoing method descriptions and process diagram are provided merely as illustrative examples and are not intended to require or imply that the processes of the various embodiments must be performed in the order presented. Skilled artisans may implement the described functionality in varying ways for each particular roofing system, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. Words such as “thereafter,” “then,” “next,” etc. are not intended to limit the order of the processes; these words are simply used to guide the reader through the description of the methods. Further, any reference to claim elements in the singular, for example, using the articles “a,” “an” or “the” is not to be construed as limiting the element to the singular.
The foregoing description of the various embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, and instead the claims should be accorded the widest scope consistent with the principles and novel features disclosed herein. Further, the Abstract that appears in this application is simply a summary of the various embodiments, and is not meant to limit the claims.
| Number | Date | Country | |
|---|---|---|---|
| 61443798 | Feb 2011 | US | |
| 61567835 | Dec 2011 | US |
